blend_gui.c

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/*
    This file is part of darktable,
    Copyright (C) 2012 johannes hanika.
    Copyright (C) 2012 Richard Wonka.
    Copyright (C) 2012-2014, 2016-2019 Tobias Ellinghaus.
    Copyright (C) 2012-2015, 2017, 2019 Ulrich Pegelow.
    Copyright (C) 2013, 2016, 2022 Aldric Renaudin.
    Copyright (C) 2013 Dennis Gnad.
    Copyright (C) 2013 parafin.
    Copyright (C) 2013, 2018-2022 Pascal Obry.
    Copyright (C) 2013-2016 Roman Lebedev.
    Copyright (C) 2013 Thomas Pryds.
    Copyright (C) 2017-2018, 2020 Heiko Bauke.
    Copyright (C) 2017, 2019, 2021 luzpaz.
    Copyright (C) 2018-2019 Edgardo Hoszowski.
    Copyright (C) 2018 rawfiner.
    Copyright (C) 2019, 2022-2023, 2025-2026 Aurélien PIERRE.
    Copyright (C) 2019-2022 Diederik Ter Rahe.
    Copyright (C) 2019 Florian Wernert.
    Copyright (C) 2019 mepi0011.
    Copyright (C) 2020-2022 Chris Elston.
    Copyright (C) 2020-2021 Harold le Clément de Saint-Marcq.
    Copyright (C) 2020-2021 Marco.
    Copyright (C) 2020-2021 Ralf Brown.
    Copyright (C) 2021 Hanno Schwalm.
    Copyright (C) 2021 Hubert Kowalski.
    Copyright (C) 2021 Marco Carrarini.
    Copyright (C) 2021 Mark-64.
    Copyright (C) 2021-2022 Nicolas Auffray.
    Copyright (C) 2022 Martin Bařinka.
    Copyright (C) 2022 Philipp Lutz.
    Copyright (C) 2023 Alynx Zhou.
    Copyright (C) 2023 Luca Zulberti.
    Copyright (C) 2025-2026 Guillaume Stutin.
    
    darktable is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.
    
    darktable is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
    
    You should have received a copy of the GNU General Public License
    along with darktable.  If not, see <http://www.gnu.org/licenses/>.
*/
#include "system/macros.h"
#include "system/mem_alloc.h"
#include "system/simd.h"
#include "control/signal.h"
#include "common/usermanual_url.h"
#include "develop/blend.h"
#include "develop/blend_gui.h"
#include "widgets/bauhaus.h"
#include "widgets/accelerators.h"
#include "gui/bauhaus_conf.h"
#include "system/dtpthread.h"
#include "math/math.h"
#include "develop/iop_profile.h"
#include "common/conf.h"
#include "control/control.h"
#include "develop/develop.h"
#include "develop/imageop.h"
#include "develop/imageop_gui.h"
#include "develop/masks.h"
#include "develop/masks_group.h"   // dt_masks_group_set_member_operation()
#include "develop/masks_gui.h"
#include "widgets/button.h"
#include "widgets/gradientslider.h"
 
#include "gui/actions/menu.h"
#include "gui/application.h"
#include "libs/colorpicker.h"
 
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include "widgets/collapsible_section.h"
#include "widgets/container.h"
#include "widgets/label.h"
#include "widgets/notebook.h"
#include "widgets/popup.h"
#include "widgets/scroll_wrap.h"
#include "widgets/widget_style.h"
#include "widgets/togglebutton.h"
 
#define NEUTRAL_GRAY 0.5
#define BLEND_MASKMODE_CONF_KEY "plugins/darkroom/blending/mask_mode_tab"
 
/* The seven blend name tables are DEFINED in blend.c now: backend consumers
 * (develop/supervisor.c) read them, so they cannot live in a GUI-only file. */
const dt_iop_gui_blendif_colorstop_t _gradient_L[]
    = { { 0.0f,   { 0, 0, 0, 1.0 } },
        { 0.125f, { NEUTRAL_GRAY / 8, NEUTRAL_GRAY / 8, NEUTRAL_GRAY / 8, 1.0 } },
        { 0.25f,  { NEUTRAL_GRAY / 4, NEUTRAL_GRAY / 4, NEUTRAL_GRAY / 4, 1.0 } },
        { 0.5f,   { NEUTRAL_GRAY / 2, NEUTRAL_GRAY / 2, NEUTRAL_GRAY / 2, 1.0 } },
        { 1.0f,   { NEUTRAL_GRAY, NEUTRAL_GRAY, NEUTRAL_GRAY, 1.0 } } };
 
// The values for "a" are generated in the following way:
//   Lab (with L=[90 to 68], b=0, and a=[-56 to 56] -> sRGB (D65 linear) -> normalize with MAX(R,G,B) = 0.75
const dt_iop_gui_blendif_colorstop_t _gradient_a[] = {
    { 0.000f, { 0.0112790f, 0.7500000f, 0.5609999f, 1.0f } },
    { 0.250f, { 0.2888855f, 0.7500000f, 0.6318934f, 1.0f } },
    { 0.375f, { 0.4872486f, 0.7500000f, 0.6825501f, 1.0f } },
    { 0.500f, { 0.7500000f, 0.7499399f, 0.7496052f, 1.0f } },
    { 0.625f, { 0.7500000f, 0.5054633f, 0.5676756f, 1.0f } },
    { 0.750f, { 0.7500000f, 0.3423850f, 0.4463195f, 1.0f } },
    { 1.000f, { 0.7500000f, 0.1399815f, 0.2956989f, 1.0f } },
};
 
// The values for "b" are generated in the following way:
//   Lab (with L=[58 to 62], a=0, and b=[-65 to 65] -> sRGB (D65 linear) -> normalize with MAX(R,G,B) = 0.75
const dt_iop_gui_blendif_colorstop_t _gradient_b[] = {
    { 0.000f, { 0.0162050f, 0.1968228f, 0.7500000f, 1.0f } },
    { 0.250f, { 0.2027354f, 0.3168822f, 0.7500000f, 1.0f } },
    { 0.375f, { 0.3645722f, 0.4210476f, 0.7500000f, 1.0f } },
    { 0.500f, { 0.6167146f, 0.5833379f, 0.7500000f, 1.0f } },
    { 0.625f, { 0.7500000f, 0.6172369f, 0.5412091f, 1.0f } },
    { 0.750f, { 0.7500000f, 0.5590797f, 0.3071980f, 1.0f } },
    { 1.000f, { 0.7500000f, 0.4963975f, 0.0549797f, 1.0f } },
};
 
const dt_iop_gui_blendif_colorstop_t _gradient_gray[]
    = { { 0.0f,   { 0, 0, 0, 1.0 } },
        { 0.125f, { NEUTRAL_GRAY / 8, NEUTRAL_GRAY / 8, NEUTRAL_GRAY / 8, 1.0 } },
        { 0.25f,  { NEUTRAL_GRAY / 4, NEUTRAL_GRAY / 4, NEUTRAL_GRAY / 4, 1.0 } },
        { 0.5f,   { NEUTRAL_GRAY / 2, NEUTRAL_GRAY / 2, NEUTRAL_GRAY / 2, 1.0 } },
        { 1.0f,   { NEUTRAL_GRAY, NEUTRAL_GRAY, NEUTRAL_GRAY, 1.0 } } };
 
const dt_iop_gui_blendif_colorstop_t _gradient_red[] = {
    { 0.000f, { 0.0000000f, 0.0000000f, 0.0000000f, 1.0f } },
    { 0.125f, { 0.0937500f, 0.0000000f, 0.0000000f, 1.0f } },
    { 0.250f, { 0.1875000f, 0.0000000f, 0.0000000f, 1.0f } },
    { 0.500f, { 0.3750000f, 0.0000000f, 0.0000000f, 1.0f } },
    { 1.000f, { 0.7500000f, 0.0000000f, 0.0000000f, 1.0f } }
};
 
const dt_iop_gui_blendif_colorstop_t _gradient_green[] = {
    { 0.000f, { 0.0000000f, 0.0000000f, 0.0000000f, 1.0f } },
    { 0.125f, { 0.0000000f, 0.0937500f, 0.0000000f, 1.0f } },
    { 0.250f, { 0.0000000f, 0.1875000f, 0.0000000f, 1.0f } },
    { 0.500f, { 0.0000000f, 0.3750000f, 0.0000000f, 1.0f } },
    { 1.000f, { 0.0000000f, 0.7500000f, 0.0000000f, 1.0f } }
};
 
const dt_iop_gui_blendif_colorstop_t _gradient_blue[] = {
    { 0.000f, { 0.0000000f, 0.0000000f, 0.0000000f, 1.0f } },
    { 0.125f, { 0.0000000f, 0.0000000f, 0.0937500f, 1.0f } },
    { 0.250f, { 0.0000000f, 0.0000000f, 0.1875000f, 1.0f } },
    { 0.500f, { 0.0000000f, 0.0000000f, 0.3750000f, 1.0f } },
    { 1.000f, { 0.0000000f, 0.0000000f, 0.7500000f, 1.0f } }
};
 
// The chroma values are displayed in a gradient from {0.5,0.5,0.5} to {0.5,0.0,0.5} (pink)
const dt_iop_gui_blendif_colorstop_t _gradient_chroma[] = {
    { 0.000f, { 0.5000000f, 0.5000000f, 0.5000000f, 1.0f } },
    { 0.125f, { 0.5000000f, 0.4375000f, 0.5000000f, 1.0f } },
    { 0.250f, { 0.5000000f, 0.3750000f, 0.5000000f, 1.0f } },
    { 0.500f, { 0.5000000f, 0.2500000f, 0.5000000f, 1.0f } },
    { 1.000f, { 0.5000000f, 0.0000000f, 0.5000000f, 1.0f } }
};
 
// The hue values for LCh are generated in the following way:
//   LCh (with L=65 and C=37) -> sRGB (D65 linear) -> normalize with MAX(R,G,B) = 0.75
// Please keep in sync with the display in the gamma module
const dt_iop_gui_blendif_colorstop_t _gradient_LCh_hue[] = {
    { 0.000f, { 0.7500000f, 0.2200405f, 0.4480174f, 1.0f } },
    { 0.104f, { 0.7500000f, 0.2475123f, 0.2488547f, 1.0f } },
    { 0.200f, { 0.7500000f, 0.3921083f, 0.2017670f, 1.0f } },
    { 0.295f, { 0.7500000f, 0.7440329f, 0.3011876f, 1.0f } },
    { 0.377f, { 0.3813996f, 0.7500000f, 0.3799668f, 1.0f } },
    { 0.503f, { 0.0747526f, 0.7500000f, 0.7489037f, 1.0f } },
    { 0.650f, { 0.0282981f, 0.3736209f, 0.7500000f, 1.0f } },
    { 0.803f, { 0.2583821f, 0.2591069f, 0.7500000f, 1.0f } },
    { 0.928f, { 0.7500000f, 0.2788102f, 0.7492077f, 1.0f } },
    { 1.000f, { 0.7500000f, 0.2200405f, 0.4480174f, 1.0f } },
};
 
// The hue values for HSL are generated in the following way:
//   HSL (with S=0.5 and L=0.5) -> any RGB(linear) -> (normalize with MAX(R,G,B) = 0.75)
// Please keep in sync with the display in the gamma module
const dt_iop_gui_blendif_colorstop_t _gradient_HSL_hue[] = {
    { 0.000f, { 0.7500000f, 0.2500000f, 0.2500000f, 1.0f } },
    { 0.167f, { 0.7500000f, 0.7500000f, 0.2500000f, 1.0f } },
    { 0.333f, { 0.2500000f, 0.7500000f, 0.2500000f, 1.0f } },
    { 0.500f, { 0.2500000f, 0.7500000f, 0.7500000f, 1.0f } },
    { 0.667f, { 0.2500000f, 0.2500000f, 0.7500000f, 1.0f } },
    { 0.833f, { 0.7500000f, 0.2500000f, 0.7500000f, 1.0f } },
    { 1.000f, { 0.7500000f, 0.2500000f, 0.2500000f, 1.0f } },
};
 
// The hue values for JzCzhz are generated in the following way:
//   JzCzhz (with Jz=0.011 and Cz=0.01) -> sRGB(D65 linear) -> normalize with MAX(R,G,B) = 0.75
// Please keep in sync with the display in the gamma module
const dt_iop_gui_blendif_colorstop_t _gradient_JzCzhz_hue[] = {
    { 0.000f, { 0.7500000f, 0.1946971f, 0.3697612f, 1.0f } },
    { 0.082f, { 0.7500000f, 0.2278141f, 0.2291548f, 1.0f } },
    { 0.150f, { 0.7500000f, 0.3132381f, 0.1653960f, 1.0f } },
    { 0.275f, { 0.7483232f, 0.7500000f, 0.1939316f, 1.0f } },
    { 0.378f, { 0.2642865f, 0.7500000f, 0.2642768f, 1.0f } },
    { 0.570f, { 0.0233180f, 0.7493543f, 0.7500000f, 1.0f } },
    { 0.650f, { 0.1119025f, 0.5116763f, 0.7500000f, 1.0f } },
    { 0.762f, { 0.3331225f, 0.3337235f, 0.7500000f, 1.0f } },
    { 0.883f, { 0.7464700f, 0.2754816f, 0.7500000f, 1.0f } },
    { 1.000f, { 0.7500000f, 0.1946971f, 0.3697612f, 1.0f } },
};
 
enum _channel_indexes
{
  CHANNEL_INDEX_L = 0,
  CHANNEL_INDEX_a = 1,
  CHANNEL_INDEX_b = 2,
  CHANNEL_INDEX_C = 3,
  CHANNEL_INDEX_h = 4,
  CHANNEL_INDEX_g = 0,
  CHANNEL_INDEX_R = 1,
  CHANNEL_INDEX_G = 2,
  CHANNEL_INDEX_B = 3,
  CHANNEL_INDEX_H = 4,
  CHANNEL_INDEX_S = 5,
  CHANNEL_INDEX_l = 6,
  CHANNEL_INDEX_Jz = 4,
  CHANNEL_INDEX_Cz = 5,
  CHANNEL_INDEX_hz = 6,
};
 
static void _blendop_blendif_update_tab(dt_iop_module_t *module, const int tab);
static void _blendop_blendif_sync_channel_display_buttons(dt_iop_module_t *module);
 
static inline dt_iop_colorspace_type_t _blendif_colorpicker_cst(dt_iop_gui_blend_data_t *data)
{
  dt_iop_colorspace_type_t cst = dt_iop_color_picker_get_active_cst(data->module);
  if(cst == IOP_CS_NONE)
  {
    switch(data->channel_tabs_csp)
    {
      case DEVELOP_BLEND_CS_LAB:
        cst = IOP_CS_LAB;
        break;
      case DEVELOP_BLEND_CS_RGB_DISPLAY:
      case DEVELOP_BLEND_CS_RGB_SCENE:
        cst = IOP_CS_RGB;
        break;
      case DEVELOP_BLEND_CS_RAW:
      case DEVELOP_BLEND_CS_NONE:
        cst = IOP_CS_NONE;
        break;
    }
  }
  return cst;
}
 
static gboolean _blendif_blend_parameter_enabled(dt_develop_blend_colorspace_t csp, dt_develop_blend_mode_t mode)
{
  if(csp == DEVELOP_BLEND_CS_RGB_SCENE)
  {
    switch(mode & ~DEVELOP_BLEND_REVERSE)
    {
      case DEVELOP_BLEND_ADD:
      case DEVELOP_BLEND_MULTIPLY:
      case DEVELOP_BLEND_SUBTRACT:
      case DEVELOP_BLEND_SUBTRACT_INVERSE:
      case DEVELOP_BLEND_DIVIDE:
      case DEVELOP_BLEND_DIVIDE_INVERSE:
      case DEVELOP_BLEND_RGB_R:
      case DEVELOP_BLEND_RGB_G:
      case DEVELOP_BLEND_RGB_B:
        return TRUE;
      default:
        return FALSE;
    }
  }
  return FALSE;
}
 
static inline float _get_boost_factor(const dt_iop_gui_blend_data_t *data, const int channel, const int in_out)
{
  return exp2f(data->module->blend_params->blendif_boost_factors[data->channel[channel].param_channels[in_out]]);
}
 
static void _blendif_scale(dt_iop_gui_blend_data_t *data, dt_iop_colorspace_type_t cst, const float *in,
                           float *out, const dt_iop_order_iccprofile_info_t *work_profile, int in_out)
{
  out[0] = out[1] = out[2] = out[3] = out[4] = out[5] = out[6] = out[7] = -1.0f;
 
  switch(cst)
  {
    case IOP_CS_LAB:
      out[CHANNEL_INDEX_L] = (in[0] / _get_boost_factor(data, 0, in_out)) / 100.0f;
      out[CHANNEL_INDEX_a] = ((in[1] / _get_boost_factor(data, 1, in_out)) + 128.0f) / 256.0f;
      out[CHANNEL_INDEX_b] = ((in[2] / _get_boost_factor(data, 2, in_out)) + 128.0f) / 256.0f;
      break;
    case IOP_CS_RGB:
    case IOP_CS_RGB_DISPLAY:
      if(IS_NULL_PTR(work_profile))
        out[CHANNEL_INDEX_g] = 0.3f * in[0] + 0.59f * in[1] + 0.11f * in[2];
      else
        out[CHANNEL_INDEX_g] = dt_ioppr_get_rgb_matrix_luminance(in, work_profile->matrix_in,
                                                                 work_profile->lut_in,
                                                                 work_profile->unbounded_coeffs_in,
                                                                 work_profile->lutsize,
                                                                 work_profile->nonlinearlut);
      out[CHANNEL_INDEX_g] = out[CHANNEL_INDEX_g] / _get_boost_factor(data, 0, in_out);
      out[CHANNEL_INDEX_R] = in[0] / _get_boost_factor(data, 1, in_out);
      out[CHANNEL_INDEX_G] = in[1] / _get_boost_factor(data, 2, in_out);
      out[CHANNEL_INDEX_B] = in[2] / _get_boost_factor(data, 3, in_out);
      break;
    case IOP_CS_LCH:
      out[CHANNEL_INDEX_C] = (in[1] / _get_boost_factor(data, 3, in_out)) / (128.0f * sqrtf(2.0f));
      out[CHANNEL_INDEX_h] = in[2] / _get_boost_factor(data, 4, in_out);
      break;
    case IOP_CS_HSL:
      out[CHANNEL_INDEX_H] = in[0] / _get_boost_factor(data, 4, in_out);
      out[CHANNEL_INDEX_S] = in[1] / _get_boost_factor(data, 5, in_out);
      out[CHANNEL_INDEX_l] = in[2] / _get_boost_factor(data, 6, in_out);
      break;
    case IOP_CS_JZCZHZ:
      out[CHANNEL_INDEX_Jz] = in[0] / _get_boost_factor(data, 4, in_out);
      out[CHANNEL_INDEX_Cz] = in[1] / _get_boost_factor(data, 5, in_out);
      out[CHANNEL_INDEX_hz] = in[2] / _get_boost_factor(data, 6, in_out);
      break;
    default:
      break;
  }
}
 
static void _blendif_cook(dt_iop_colorspace_type_t cst, const float *in, float *out,
                          const dt_iop_order_iccprofile_info_t *const work_profile)
{
  out[0] = out[1] = out[2] = out[3] = out[4] = out[5] = out[6] = out[7] = -1.0f;
 
  switch(cst)
  {
    case IOP_CS_LAB:
      out[CHANNEL_INDEX_L] = in[0];
      out[CHANNEL_INDEX_a] = in[1];
      out[CHANNEL_INDEX_b] = in[2];
      break;
    case IOP_CS_RGB:
    case IOP_CS_RGB_DISPLAY:
      if(IS_NULL_PTR(work_profile))
        out[CHANNEL_INDEX_g] = (0.3f * in[0] + 0.59f * in[1] + 0.11f * in[2]) * 100.0f;
      else
        out[CHANNEL_INDEX_g] = dt_ioppr_get_rgb_matrix_luminance(in, work_profile->matrix_in,
                                                                 work_profile->lut_in,
                                                                 work_profile->unbounded_coeffs_in,
                                                                 work_profile->lutsize,
                                                                 work_profile->nonlinearlut) * 100.0f;
      out[CHANNEL_INDEX_R] = in[0] * 100.0f;
      out[CHANNEL_INDEX_G] = in[1] * 100.0f;
      out[CHANNEL_INDEX_B] = in[2] * 100.0f;
      break;
    case IOP_CS_LCH:
      out[CHANNEL_INDEX_C] = in[1] / (128.0f * sqrtf(2.0f)) * 100.0f;
      out[CHANNEL_INDEX_h] = in[2] * 360.0f;
      break;
    case IOP_CS_HSL:
      out[CHANNEL_INDEX_H] = in[0] * 360.0f;
      out[CHANNEL_INDEX_S] = in[1] * 100.0f;
      out[CHANNEL_INDEX_l] = in[2] * 100.0f;
      break;
    case IOP_CS_JZCZHZ:
      out[CHANNEL_INDEX_Jz] = in[0] * 100.0f;
      out[CHANNEL_INDEX_Cz] = in[1] * 100.0f;
      out[CHANNEL_INDEX_hz] = in[2] * 360.0f;
      break;
    default:
      break;
  }
}
 
static inline int _blendif_print_digits_default(float value)
{
  int digits;
  if(value < 0.0001f) digits = 0;
  else if(value < 0.01f) digits = 2;
  else if(value < 0.999f) digits = 1;
  else digits = 0;
 
  return digits;
}
 
static inline int _blendif_print_digits_ab(float value)
{
  int digits;
  if(fabsf(value) < 10.0f) digits = 1;
  else digits = 0;
 
  return digits;
}
 
static void _blendif_scale_print_ab(float value, float boost_factor, char *string, int n)
{
  const float scaled = (value * 256.0f - 128.0f) * boost_factor;
  snprintf(string, n, "%-5.*f", _blendif_print_digits_ab(scaled), scaled);
}
 
static void _blendif_scale_print_hue(float value, float boost_factor, char *string, int n)
{
  snprintf(string, n, "%-5.0f", value * 360.0f);
}
 
static void _blendif_scale_print_default(float value, float boost_factor, char *string, int n)
{
  const float scaled = value * boost_factor;
  snprintf(string, n, "%-5.*f", _blendif_print_digits_default(scaled), scaled * 100.0f);
}
 
static gboolean _blendif_are_output_channels_used(const dt_develop_blend_params_t *const blend,
                                                  const dt_develop_blend_colorspace_t cst)
{
  const gboolean mask_inclusive = blend->mask_combine & DEVELOP_COMBINE_INCL;
  const uint32_t mask = cst == DEVELOP_BLEND_CS_LAB
    ? DEVELOP_BLENDIF_Lab_MASK & DEVELOP_BLENDIF_OUTPUT_MASK
    : DEVELOP_BLENDIF_RGB_MASK & DEVELOP_BLENDIF_OUTPUT_MASK;
  const uint32_t active_channels = blend->blendif & mask;
  const uint32_t inverted_channels = (blend->blendif >> 16) ^ (mask_inclusive ? mask : 0);
  const uint32_t cancel_channels = inverted_channels & ~blend->blendif & mask;
  return active_channels || cancel_channels;
}
 
static gboolean _blendif_clean_output_channels(dt_iop_module_t *module)
{
  const dt_iop_gui_blend_data_t *const bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd) || !bd->blendif_support || !bd->blendif_inited) return FALSE;
 
  gboolean changed = FALSE;
  if(!bd->output_channels_shown)
  {
    const uint32_t mask = bd->csp == DEVELOP_BLEND_CS_LAB
      ? DEVELOP_BLENDIF_Lab_MASK & DEVELOP_BLENDIF_OUTPUT_MASK
      : DEVELOP_BLENDIF_RGB_MASK & DEVELOP_BLENDIF_OUTPUT_MASK;
 
    dt_develop_blend_params_t *const d = module->blend_params;
 
    // clear the output channels and invert them when needed
    const uint32_t old_blendif = d->blendif;
    const uint32_t need_inversion = d->mask_combine & DEVELOP_COMBINE_INCL ? (mask << 16) : 0;
 
    d->blendif = (d->blendif & ~(mask | (mask << 16))) | need_inversion;
 
    changed = (d->blendif != old_blendif);
 
    for (size_t ch = 0; ch < DEVELOP_BLENDIF_SIZE; ch++)
    {
      if ((DEVELOP_BLENDIF_OUTPUT_MASK & (1 << ch))
          && (   d->blendif_parameters[ch * 4 + 0] != 0.0f
              || d->blendif_parameters[ch * 4 + 1] != 0.0f
              || d->blendif_parameters[ch * 4 + 2] != 1.0f
              || d->blendif_parameters[ch * 4 + 3] != 1.0f))
      {
        changed = TRUE;
        d->blendif_parameters[ch * 4 + 0] = 0.0f;
        d->blendif_parameters[ch * 4 + 1] = 0.0f;
        d->blendif_parameters[ch * 4 + 2] = 1.0f;
        d->blendif_parameters[ch * 4 + 3] = 1.0f;
      }
    }
  }
  return changed;
}
 
static void _blendop_masks_mode_callback(const unsigned int mask_mode, dt_iop_gui_blend_data_t *data)
{
  data->module->blend_params->mask_mode = mask_mode;
 
  dt_iop_set_mask_mode(data->module, mask_mode);
 
  if(data->blending_box)
    dt_iop_gui_update_blending(data->module);
}
 
static void _blendop_blend_mode_callback(GtkWidget *combo, dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_develop_blend_params_t *bp = data->module->blend_params;
  dt_develop_blend_mode_t new_blend_mode = GPOINTER_TO_INT(dt_bauhaus_combobox_get_data(combo));
  if(new_blend_mode != (bp->blend_mode & DEVELOP_BLEND_MODE_MASK))
  {
    bp->blend_mode = new_blend_mode | (bp->blend_mode & DEVELOP_BLEND_REVERSE);
    if(_blendif_blend_parameter_enabled(data->blend_modes_csp, bp->blend_mode))
    {
      gtk_widget_set_visible(data->blend_mode_parameter_slider, TRUE);
    }
    else
    {
      bp->blend_parameter = 0.0f;
      dt_bauhaus_slider_set(data->blend_mode_parameter_slider, bp->blend_parameter);
      gtk_widget_set_visible(data->blend_mode_parameter_slider, FALSE);
    }
    dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
    dt_iop_gui_update_header(data->module);
  }
}
 
static void _blendop_compositing_changed(GtkWidget *combobox, dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_develop_blend_params_t *bp = data->module->blend_params;
  const int val = GPOINTER_TO_INT(dt_bauhaus_combobox_get_data(combobox));
  if(val == 0)
    bp->blend_mode &= ~DEVELOP_BLEND_REVERSE;
  else
    bp->blend_mode |= DEVELOP_BLEND_REVERSE;
 
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
  dt_control_queue_redraw_widget(GTK_WIDGET(combobox));
}
 
static void _blendop_masks_combine_callback(GtkWidget *combo, dt_iop_gui_blend_data_t *data)
{
  dt_develop_blend_params_t *const d = data->module->blend_params;
 
  const unsigned combine = GPOINTER_TO_UINT(dt_bauhaus_combobox_get_data(data->masks_combine_combo));
  d->mask_combine &= ~(DEVELOP_COMBINE_INV | DEVELOP_COMBINE_INCL);
  d->mask_combine |= combine;
 
  // inverts the parametric mask channels that are not used
  if(data->blendif_support && data->blendif_inited)
  {
    const uint32_t mask = data->csp == DEVELOP_BLEND_CS_LAB ? DEVELOP_BLENDIF_Lab_MASK : DEVELOP_BLENDIF_RGB_MASK;
    const uint32_t unused_channels = mask & ~d->blendif;
    d->blendif &= ~(unused_channels << 16);
    if(d->mask_combine & DEVELOP_COMBINE_INCL)
    {
      d->blendif |= unused_channels << 16;
    }
    _blendop_blendif_update_tab(data->module, data->tab);
  }
 
  _blendif_clean_output_channels(data->module);
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
}
 
static void _blendop_masks_invert_toggled(GtkToggleButton *togglebutton, dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed()) return;
  const gboolean active = gtk_toggle_button_get_active(togglebutton);
  if(active)
    data->module->blend_params->mask_combine |= DEVELOP_COMBINE_INV;
  else
    data->module->blend_params->mask_combine &= ~DEVELOP_COMBINE_INV;
  _blendif_clean_output_channels(data->module);
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
}
 
static void _blendop_blendif_sliders_callback(GtkDarktableGradientSlider *slider, dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_develop_blend_params_t *bp = data->module->blend_params;
 
  const dt_iop_gui_blendif_channel_t *channel = &data->channel[data->tab];
 
  const int in_out = (slider == data->filter[1].slider) ? 1 : 0;
  dt_develop_blendif_channels_t ch = channel->param_channels[in_out];
  GtkLabel **label = data->filter[in_out].label;
 
  if(!gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker))
     && !gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker_set_values)))
  {
    dt_iop_color_picker_reset(data->module, FALSE);
  }
 
  float *parameters = &(bp->blendif_parameters[4 * ch]);
 
  dt_pthread_mutex_lock(&data->lock);
  for(int k = 0; k < 4; k++) parameters[k] = dtgtk_gradient_slider_multivalue_get_value(slider, k);
  dt_pthread_mutex_unlock(&data->lock);
 
  const float boost_factor = _get_boost_factor(data, data->tab, in_out);
  for(int k = 0; k < 4; k++)
  {
    char text[256];
    (channel->scale_print)(parameters[k], boost_factor, text, sizeof(text));
    gtk_label_set_text(label[k], text);
  }
 
  if(parameters[1] == 0.0f && parameters[2] == 1.0f)
    bp->blendif &= ~(1 << ch);
  else
    bp->blendif |= (1 << ch);
 
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
}
 
static void _blendop_blendif_sliders_reset_callback(GtkDarktableGradientSlider *slider,
                                                    dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_develop_blend_params_t *bp = data->module->blend_params;
 
  const dt_iop_gui_blendif_channel_t *channel = &data->channel[data->tab];
 
  const int in_out = (slider == data->filter[1].slider) ? 1 : 0;
  dt_develop_blendif_channels_t ch = channel->param_channels[in_out];
 
  // invert the parametric mask if needed
  if(bp->mask_combine & DEVELOP_COMBINE_INCL)
    bp->blendif |= (1 << (16 + ch));
  else
    bp->blendif &= ~(1 << (16 + ch));
 
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
  _blendop_blendif_update_tab(data->module, data->tab);
}
 
static void _blendop_blendif_polarity_callback(GtkToggleButton *togglebutton, dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed()) return;
 
  int active = gtk_toggle_button_get_active(togglebutton);
 
  dt_develop_blend_params_t *bp = data->module->blend_params;
 
  const dt_iop_gui_blendif_channel_t *channel = &data->channel[data->tab];
 
  const int in_out = (GTK_WIDGET(togglebutton) == data->filter[1].polarity) ? 1 : 0;
  dt_develop_blendif_channels_t ch = channel->param_channels[in_out];
  GtkDarktableGradientSlider *slider = data->filter[in_out].slider;
 
  if(!active)
    bp->blendif |= (1 << (ch + 16));
  else
    bp->blendif &= ~(1 << (ch + 16));
 
  dtgtk_gradient_slider_multivalue_set_marker(
      slider, active ? GRADIENT_SLIDER_MARKER_LOWER_OPEN_BIG : GRADIENT_SLIDER_MARKER_UPPER_OPEN_BIG, 0);
  dtgtk_gradient_slider_multivalue_set_marker(
      slider, active ? GRADIENT_SLIDER_MARKER_UPPER_FILLED_BIG : GRADIENT_SLIDER_MARKER_LOWER_FILLED_BIG, 1);
  dtgtk_gradient_slider_multivalue_set_marker(
      slider, active ? GRADIENT_SLIDER_MARKER_UPPER_FILLED_BIG : GRADIENT_SLIDER_MARKER_LOWER_FILLED_BIG, 2);
  dtgtk_gradient_slider_multivalue_set_marker(
      slider, active ? GRADIENT_SLIDER_MARKER_LOWER_OPEN_BIG : GRADIENT_SLIDER_MARKER_UPPER_OPEN_BIG, 3);
 
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
  dt_control_queue_redraw_widget(GTK_WIDGET(togglebutton));
}
 
static float log10_scale_callback(GtkWidget *self, float inval, int dir)
{
  float outval;
  const float tiny = 1.0e-4f;
  switch(dir)
  {
    case GRADIENT_SLIDER_SET:
      outval = (log10(CLAMP(inval, 0.0001f, 1.0f)) + 4.0f) / 4.0f;
      break;
    case GRADIENT_SLIDER_GET:
      outval = CLAMP(exp(M_LN10 * (4.0f * inval - 4.0f)), 0.0f, 1.0f);
      if(outval <= tiny) outval = 0.0f;
      if(outval >= 1.0f - tiny) outval = 1.0f;
      break;
    default:
      outval = inval;
  }
  return outval;
}
 
 
static float magnifier_scale_callback(GtkWidget *self, float inval, int dir)
{
  float outval;
  const float range = 6.0f;
  const float invrange = 1.0f/range;
  const float scale = tanh(range * 0.5f);
  const float invscale = 1.0f/scale;
  const float eps = 1.0e-6f;
  const float tiny = 1.0e-4f;
  switch(dir)
  {
    case GRADIENT_SLIDER_SET:
      outval = (invscale * tanh(range * (CLAMP(inval, 0.0f, 1.0f) - 0.5f)) + 1.0f) * 0.5f;
      if(outval <= tiny) outval = 0.0f;
      if(outval >= 1.0f - tiny) outval = 1.0f;
      break;
    case GRADIENT_SLIDER_GET:
      outval = invrange * atanh((2.0f * CLAMP(inval, eps, 1.0f - eps) - 1.0f) * scale) + 0.5f;
      if(outval <= tiny) outval = 0.0f;
      if(outval >= 1.0f - tiny) outval = 1.0f;
      break;
    default:
      outval = inval;
  }
  return outval;
}
 
static int _blendop_blendif_disp_alternative_worker(GtkWidget *widget, dt_iop_module_t *module, int mode,
                                                    float (*scale_callback)(GtkWidget*, float, int), const char *label)
{
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
  GtkDarktableGradientSlider *slider = (GtkDarktableGradientSlider *)widget;
 
  int in_out = (slider == data->filter[1].slider) ? 1 : 0;
 
  dtgtk_gradient_slider_multivalue_set_scale_callback(slider, (mode == 1) ? scale_callback : NULL);
  gchar *text = g_strdup_printf("%s%s",
                                (in_out == 0) ? _("input") : _("output"),
                                (mode == 1) ? label : "");
  gtk_label_set_text(data->filter[in_out].head, text);
  dt_free(text);
 
  return (mode == 1) ? 1 : 0;
}
 
 
static int _blendop_blendif_disp_alternative_mag(GtkWidget *widget, dt_iop_module_t *module, int mode)
{
  return _blendop_blendif_disp_alternative_worker(widget, module, mode, magnifier_scale_callback, _(" (zoom)"));
}
 
static int _blendop_blendif_disp_alternative_log(GtkWidget *widget, dt_iop_module_t *module, int mode)
{
  return _blendop_blendif_disp_alternative_worker(widget, module, mode, log10_scale_callback, _(" (log)"));
}
 
static void _blendop_blendif_disp_alternative_reset(GtkWidget *widget, dt_iop_module_t *module)
{
  (void) _blendop_blendif_disp_alternative_worker(widget, module, 0, NULL, "");
}
 
static void _blendop_blendif_log_scale_toggled(GtkToggleButton *button, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_iop_gui_blend_data_t *data = !IS_NULL_PTR(module) ? module->gui->blend_data : NULL;
  if(IS_NULL_PTR(data) || IS_NULL_PTR(data->channel)) return;
 
  const int in_out = GTK_WIDGET(button) == data->filter[1].log_scale ? 1 : 0;
  const dt_iop_gui_blendif_channel_t *channel = &data->channel[data->tab];
  if(IS_NULL_PTR(channel->altdisplay)) return;
 
  const gboolean active = gtk_toggle_button_get_active(button);
  gtk_button_set_label(GTK_BUTTON(button), active ? _("Linear scale") : _("Log scale"));
 
  const int requested_mode = active ? 1 : 0;
  data->altmode[data->tab][in_out]
      = channel->altdisplay(GTK_WIDGET(data->filter[in_out].slider), module, requested_mode);
}
 
 
static dt_iop_colorspace_type_t _blendop_blendif_get_picker_colorspace(dt_iop_gui_blend_data_t *bd)
{
  dt_iop_colorspace_type_t picker_cst = IOP_CS_NONE;
 
  if(bd->channel_tabs_csp == DEVELOP_BLEND_CS_RGB_DISPLAY)
  {
    if(bd->tab < 4)
      picker_cst = IOP_CS_RGB;
    else
      picker_cst = IOP_CS_HSL;
  }
  else if(bd->channel_tabs_csp == DEVELOP_BLEND_CS_RGB_SCENE)
  {
    if(bd->tab < 4)
      picker_cst = IOP_CS_RGB;
    else
      picker_cst = IOP_CS_JZCZHZ;
  }
  else if(bd->channel_tabs_csp == DEVELOP_BLEND_CS_LAB)
  {
    if(bd->tab < 3)
      picker_cst = IOP_CS_LAB;
    else
      picker_cst = IOP_CS_LCH;
  }
 
  return picker_cst;
}
 
static inline int _blendif_print_digits_picker(float value)
{
  int digits;
  if(value < 10.0f) digits = 2;
  else digits = 1;
 
  return digits;
}
 
static void _update_gradient_slider_pickers(GtkWidget *callback_dummy, dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
  if(callback_dummy == data->colorpicker_set_values
     && !gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker_set_values)))
  {
    data->picker_set_values_box_valid = FALSE;
    data->picker_set_values_manual_boost_lock = FALSE;
  }
 
  dt_iop_color_picker_set_cst(module, _blendop_blendif_get_picker_colorspace(data));
 
  float *raw_mean, *raw_min, *raw_max;
 
  dt_gui_freeze_begin();
 
  for(int in_out = 1; in_out >= 0; in_out--)
  {
    if(in_out)
    {
      raw_mean = module->picked_output_color;
      raw_min = module->picked_output_color_min;
      raw_max = module->picked_output_color_max;
    }
    else
    {
      raw_mean = module->picked_color;
      raw_min = module->picked_color_min;
      raw_max = module->picked_color_max;
    }
 
    if((gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker)) ||
        gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker_set_values))) &&
       (raw_min[0] != INFINITY))
    {
      float picker_mean[8], picker_min[8], picker_max[8];
      float cooked[8];
 
      const dt_develop_blend_colorspace_t blend_csp = data->channel_tabs_csp;
      const dt_iop_colorspace_type_t cst = _blendif_colorpicker_cst(data);
      const dt_iop_order_iccprofile_info_t *work_profile = (blend_csp == DEVELOP_BLEND_CS_RGB_SCENE)
          ? dt_ioppr_get_pipe_current_profile_info(module, module->dev->pipe)
          : dt_ioppr_get_iop_work_profile_info(module, module->dev->iop);
 
      _blendif_scale(data, cst, raw_mean, picker_mean, work_profile, in_out);
      _blendif_scale(data, cst, raw_min, picker_min, work_profile, in_out);
      _blendif_scale(data, cst, raw_max, picker_max, work_profile, in_out);
      _blendif_cook(cst, raw_mean, cooked, work_profile);
 
      gchar *text = g_strdup_printf("(%.*f)", _blendif_print_digits_picker(cooked[data->tab]), cooked[data->tab]);
 
      dtgtk_gradient_slider_multivalue_set_picker_meanminmax(
          data->filter[in_out].slider,
          CLAMP(picker_mean[data->tab], 0.0f, 1.0f),
          CLAMP(picker_min[data->tab], 0.0f, 1.0f),
          CLAMP(picker_max[data->tab], 0.0f, 1.0f));
      gtk_label_set_text(data->filter[in_out].picker_label, text);
 
      dt_free(text);
    }
    else
    {
      dtgtk_gradient_slider_multivalue_set_picker(data->filter[in_out].slider, NAN);
      gtk_label_set_text(data->filter[in_out].picker_label, "");
    }
  }
 
  dt_gui_freeze_end();
}
 
 
static void _blendop_blendif_update_tab(dt_iop_module_t *module, const int tab)
{
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
  dt_develop_blend_params_t *bp = module->blend_params;
  dt_develop_blend_params_t *dp = module->default_blendop_params;
  const float epsilon = 1e-6f;
 
  dt_gui_freeze_begin();
 
  const dt_iop_gui_blendif_channel_t *channel = &data->channel[tab];
 
  for(int in_out = 1; in_out >= 0; in_out--)
  {
    const dt_develop_blendif_channels_t ch = channel->param_channels[in_out];
    dt_iop_gui_blendif_filter_t *sl = &data->filter[in_out];
 
    float *parameters = &(bp->blendif_parameters[4 * ch]);
    float *defaults = &(dp->blendif_parameters[4 * ch]);
 
    const int polarity = !(bp->blendif & (1 << (ch + 16)));
 
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(sl->polarity), polarity);
 
    dtgtk_gradient_slider_multivalue_set_marker(
        sl->slider,
        polarity ? GRADIENT_SLIDER_MARKER_LOWER_OPEN_BIG : GRADIENT_SLIDER_MARKER_UPPER_OPEN_BIG, 0);
    dtgtk_gradient_slider_multivalue_set_marker(
        sl->slider,
        polarity ? GRADIENT_SLIDER_MARKER_UPPER_FILLED_BIG : GRADIENT_SLIDER_MARKER_LOWER_FILLED_BIG, 1);
    dtgtk_gradient_slider_multivalue_set_marker(
        sl->slider,
        polarity ? GRADIENT_SLIDER_MARKER_UPPER_FILLED_BIG : GRADIENT_SLIDER_MARKER_LOWER_FILLED_BIG, 2);
    dtgtk_gradient_slider_multivalue_set_marker(
        sl->slider,
        polarity ? GRADIENT_SLIDER_MARKER_LOWER_OPEN_BIG : GRADIENT_SLIDER_MARKER_UPPER_OPEN_BIG, 3);
 
    dt_pthread_mutex_lock(&data->lock);
    for(int k = 0; k < 4; k++)
    {
      dtgtk_gradient_slider_multivalue_set_value(sl->slider, parameters[k], k);
      dtgtk_gradient_slider_multivalue_set_resetvalue(sl->slider, defaults[k], k);
    }
    dt_pthread_mutex_unlock(&data->lock);
 
    const float boost_factor = _get_boost_factor(data, tab, in_out);
    for(int k = 0; k < 4; k++)
    {
      char text[256];
      channel->scale_print(parameters[k], boost_factor, text, sizeof(text));
      gtk_label_set_text(sl->label[k], text);
    }
 
    dtgtk_gradient_slider_multivalue_clear_stops(sl->slider);
 
    for(int k = 0; k < channel->numberstops; k++)
    {
      dtgtk_gradient_slider_multivalue_set_stop(sl->slider, channel->colorstops[k].stoppoint,
                                                channel->colorstops[k].color);
    }
 
    dtgtk_gradient_slider_multivalue_set_increment(sl->slider, channel->increment);
 
    if(channel->altdisplay)
    {
      data->altmode[tab][in_out] = channel->altdisplay(GTK_WIDGET(sl->slider), module, data->altmode[tab][in_out]);
      gtk_widget_set_sensitive(sl->log_scale, TRUE);
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(sl->log_scale), data->altmode[tab][in_out] == 1);
      gtk_button_set_label(GTK_BUTTON(sl->log_scale),
                           data->altmode[tab][in_out] == 1 ? _("Linear scale") : _("Log scale"));
    }
    else
    {
      _blendop_blendif_disp_alternative_reset(GTK_WIDGET(sl->slider), module);
      data->altmode[tab][in_out] = 0;
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(sl->log_scale), FALSE);
      gtk_button_set_label(GTK_BUTTON(sl->log_scale), _("Log scale"));
      gtk_widget_set_sensitive(sl->log_scale, FALSE);
    }
  }
 
  _update_gradient_slider_pickers(NULL, module);
 
  const gboolean boost_factor_enabled = channel->boost_factor_enabled;
  float boost_factor = 0.0f;
  if(boost_factor_enabled)
  {
    boost_factor = bp->blendif_boost_factors[channel->param_channels[0]] - channel->boost_factor_offset;
  }
  gtk_widget_set_sensitive(GTK_WIDGET(data->channel_boost_factor_slider), boost_factor_enabled);
  dt_bauhaus_slider_set(GTK_WIDGET(data->channel_boost_factor_slider), boost_factor);
 
  for(int page_num = 0; !IS_NULL_PTR(data->channel[page_num].label); page_num++)
  {
    gboolean modified = FALSE;
    const dt_iop_gui_blendif_channel_t *page_channel = &data->channel[page_num];
 
    for(int in_out = 0; in_out < 2 && !modified; in_out++)
    {
      const dt_develop_blendif_channels_t ch = page_channel->param_channels[in_out];
 
      const float *params = &bp->blendif_parameters[4 * ch];
      const float *defaults = &dp->blendif_parameters[4 * ch];
      for(int k = 0; k < 4; k++)
      {
        if(fabsf(params[k] - defaults[k]) > epsilon)
        {
          modified = TRUE;
          break;
        }
      }
    }
 
    GtkWidget *page = gtk_notebook_get_nth_page(data->channel_tabs, page_num);
    GtkWidget *label = GTK_IS_WIDGET(page) ? gtk_notebook_get_tab_label(data->channel_tabs, page) : NULL;
    if(GTK_IS_LABEL(label))
    {
      gchar *tab_title = modified
                             ? g_markup_printf_escaped("<b>%s</b>", _(page_channel->label))
                             : g_markup_printf_escaped("%s", _(page_channel->label));
      gtk_label_set_markup(GTK_LABEL(label), tab_title);
      dt_free(tab_title);
    }
  }
 
  if(module->request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_CHANNEL)
  {
    const gboolean output
        = (module->request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_OUTPUT) != 0;
    dt_dev_pixelpipe_display_mask_t new_request_mask_display
        = module->request_mask_display & ~DT_DEV_PIXELPIPE_DISPLAY_ANY;
    new_request_mask_display |= channel->display_channel;
    if(output) new_request_mask_display |= DT_DEV_PIXELPIPE_DISPLAY_OUTPUT;
 
    if(new_request_mask_display != module->request_mask_display)
    {
      module->request_mask_display = new_request_mask_display;
      dt_iop_set_cache_bypass(module, TRUE);
      dt_dev_pixelpipe_update_history_main(module->dev);
    }
  }
 
  _blendop_blendif_sync_channel_display_buttons(module);
  dt_gui_freeze_end();
}
 
 
static void _blendop_blendif_tab_switch(GtkNotebook *notebook, GtkWidget *page, guint page_num,
                                        dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed() || IS_NULL_PTR(data) || !data->blendif_inited) return;
  const int cst_old = _blendop_blendif_get_picker_colorspace(data);
  dt_iop_color_picker_reset(data->module, FALSE);
 
  data->tab = page_num;
 
  if(cst_old != _blendop_blendif_get_picker_colorspace(data)
     && (gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker))
         || gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker_set_values))))
  {
    dt_iop_color_picker_set_cst(data->module, _blendop_blendif_get_picker_colorspace(data));
    dt_dev_pixelpipe_update_history_all(data->module->dev);
  }
 
  _blendop_blendif_update_tab(data->module, data->tab);
}
 
static void _blendop_blending_notebook_switch(GtkNotebook *notebook, GtkWidget *page, guint page_num,
                                              dt_iop_gui_blend_data_t *data)
{
  (void)notebook;
  (void)page;
  if(IS_NULL_PTR(data)) return;
 
  dt_conf_set_int(BLEND_MASKMODE_CONF_KEY, (int)page_num);
}
 
static void _blendop_blendif_boost_factor_callback(GtkWidget *slider, dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed() || IS_NULL_PTR(data) || !data->blendif_inited) return;
  dt_develop_blend_params_t *bp = data->module->blend_params;
  const int tab = data->tab;
 
  const float value = dt_bauhaus_slider_get(slider);
  for(int in_out = 1; in_out >= 0; in_out--)
  {
    const int ch = data->channel[tab].param_channels[in_out];
    float off = 0.0f;
    if(data->csp == DEVELOP_BLEND_CS_LAB && (ch == DEVELOP_BLENDIF_A_in || ch == DEVELOP_BLENDIF_A_out
        || ch == DEVELOP_BLENDIF_B_in || ch == DEVELOP_BLENDIF_B_out))
    {
      off = 0.5f;
    }
    const float new_value = value + data->channel[tab].boost_factor_offset;
    const float old_value = bp->blendif_boost_factors[ch];
    const float factor = exp2f(old_value) / exp2f(new_value);
    float *parameters = &(bp->blendif_parameters[4 * ch]);
    if(parameters[0] > 0.0f) parameters[0] = clamp_range_f((parameters[0] - off) * factor + off, 0.0f, 1.0f);
    if(parameters[1] > 0.0f) parameters[1] = clamp_range_f((parameters[1] - off) * factor + off, 0.0f, 1.0f);
    if(parameters[2] < 1.0f) parameters[2] = clamp_range_f((parameters[2] - off) * factor + off, 0.0f, 1.0f);
    if(parameters[3] < 1.0f) parameters[3] = clamp_range_f((parameters[3] - off) * factor + off, 0.0f, 1.0f);
    if(parameters[1] == 0.0f && parameters[2] == 1.0f)
      bp->blendif &= ~(1 << ch);
    bp->blendif_boost_factors[ch] = new_value;
  }
 
  if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(data->colorpicker_set_values)))
  {
    data->picker_set_values_manual_boost_lock = TRUE;
  }
 
  _blendop_blendif_update_tab(data->module, tab);
 
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
}
 
static void _blendop_blendif_details_callback(GtkWidget *slider, dt_iop_gui_blend_data_t *data)
{
  if(dt_gui_widgets_suppressed() || IS_NULL_PTR(data) || !data->blendif_inited) return;
  dt_develop_blend_params_t *bp = data->module->blend_params;
  const float oldval = bp->details;
  bp->details = dt_bauhaus_slider_get(slider);
  dt_dev_add_history_item(data->module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
 
  if((oldval == 0.0f) && (bp->details != 0.0f))
  {
    dt_dev_pixelpipe_update_history_all(data->module->dev);
  }
}
 
static gboolean _blendop_blendif_showmask_clicked(GtkToggleButton *button, GdkEventButton *event, dt_iop_module_t *module)
{
  // FIXME : there are more than 3 functions getting clever about how to setup module->request_mask_display depending on user input.
  // These should all use an uniform setter function.
  //
  // The lack of setter implies we don't guaranty that only 1 module can request mask display at a time.
  // The consequence is pipeline needs to check if module->request_mask_display AND module == dev->gui_module,
  // but the global pipe->mask_display is set from *_blend_process() at runtime, so it's a pipe property
  // that changes over the pipe lifecycle.
  //
  // This is a self-feeding loop of madness because it ties the pipeline to GUI states
  // (but not all pipes are connected to a GUI, so you need to cover all cases all the time and don't forget to test everything),
  // and because the pipeline is executed recursively from the end, but pipe->mask_display is set in the middle,
  // when it reaches the process() method of the module capturing mask preview, so you don't have this info when
  // planning for pipeline execution.
  // And you need to plan for mask preview ahead in pipe because mask preview needs to work
  // without using the pixelpipe cache, at least between the module requiring mask preview and gamma.c, which will actually render
  // the preview at the far end of the pipe.
  // So the not-so-clever workaround inherited from darktable was to flush all cache lines when requesting mask preview,
  // which flushed lines that could be reused later and were only temporarily not needed.
  if(dt_gui_widgets_suppressed()) return TRUE;
 
  if(event->button == 1)
  {
    const int has_mask_display = module->request_mask_display & (DT_DEV_PIXELPIPE_DISPLAY_MASK | DT_DEV_PIXELPIPE_DISPLAY_CHANNEL);
 
    module->request_mask_display
        &= ~(DT_DEV_PIXELPIPE_DISPLAY_MASK | DT_DEV_PIXELPIPE_DISPLAY_CHANNEL
             | DT_DEV_PIXELPIPE_DISPLAY_ANY | DT_DEV_PIXELPIPE_DISPLAY_STICKY);
 
    if(dt_modifier_is(event->state, DT_PRIMARY_MASK | GDK_SHIFT_MASK))
      module->request_mask_display |= (DT_DEV_PIXELPIPE_DISPLAY_MASK | DT_DEV_PIXELPIPE_DISPLAY_CHANNEL);
    else if(dt_modifier_is(event->state, GDK_SHIFT_MASK))
      module->request_mask_display |= DT_DEV_PIXELPIPE_DISPLAY_CHANNEL;
    else if(dt_modifier_is(event->state, DT_PRIMARY_MASK))
      module->request_mask_display |= DT_DEV_PIXELPIPE_DISPLAY_MASK;
    else
      module->request_mask_display |= (has_mask_display ? 0 : DT_DEV_PIXELPIPE_DISPLAY_MASK);
 
    gtk_toggle_button_set_active(button,
                                 module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
 
    module->enabled = TRUE;
    if(module->gui->off) gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(module->gui->off), TRUE);
 
    dt_gui_freeze_begin();
    // (re)set the header mask indicator too
    if(module->gui->mask_indicator)
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(module->gui->mask_indicator),
                                   module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
    dt_gui_freeze_end();
 
    dt_iop_set_cache_bypass(module, module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
    _blendop_blendif_sync_channel_display_buttons(module);
    dt_iop_request_focus(module);
 
    // We don't want to re-read the history here
    dt_dev_pixelpipe_update_zoom_main(module->dev);
  }
 
  return TRUE;
}
 
static void _blendop_masks_mode_changed(GtkToggleButton *togglebutton, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return;
 
  const unsigned int bit = GPOINTER_TO_UINT(g_object_get_data(G_OBJECT(togglebutton), "mask-bit"));
  if(!bit) return;
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
 
  uint32_t mask_mode = module->blend_params->mask_mode;
  const gboolean active = gtk_toggle_button_get_active(togglebutton);
  const gboolean is_disable_toggle = bit == DEVELOP_MASK_RASTER
                                     || bit == DEVELOP_MASK_SHAPE
                                     || bit == DEVELOP_MASK_PARAMETRIC;
  const gboolean enable_bit = is_disable_toggle ? !active : active;
 
  switch(bit)
  {
    case DEVELOP_MASK_ENABLED:
      if(enable_bit)
        mask_mode |= DEVELOP_MASK_ENABLED;
      else
        mask_mode &= ~DEVELOP_MASK_ENABLED;
      break;
 
    case DEVELOP_MASK_RASTER:
      if(enable_bit)
        mask_mode |= DEVELOP_MASK_ENABLED | DEVELOP_MASK_RASTER;
      else
        mask_mode &= ~DEVELOP_MASK_RASTER;
      break;
 
    case DEVELOP_MASK_SHAPE:
      if(enable_bit)
        mask_mode |= DEVELOP_MASK_ENABLED | DEVELOP_MASK_SHAPE;
      else
        mask_mode &= ~DEVELOP_MASK_SHAPE;
      break;
 
    case DEVELOP_MASK_PARAMETRIC:
      if(enable_bit)
        mask_mode |= DEVELOP_MASK_ENABLED | DEVELOP_MASK_PARAMETRIC;
      else
        mask_mode &= ~DEVELOP_MASK_PARAMETRIC;
      break;
 
    default:
      break;
  }
 
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
  _blendop_masks_mode_callback(mask_mode, data);
  dt_iop_add_remove_mask_indicator(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_DEVELOP_MASKS_GUI_CHANGED);
  dt_dev_add_history_item(module->dev, data->module, TRUE, TRUE);
  dt_iop_gui_update_header(data->module);
}
 
static gboolean _blendop_blendif_reset(GtkButton *button, GdkEventButton *event, dt_iop_module_t *module)
{
  module->blend_params->blendif = module->default_blendop_params->blendif;
  memcpy(module->blend_params->blendif_parameters, module->default_blendop_params->blendif_parameters,
         4 * DEVELOP_BLENDIF_SIZE * sizeof(float));
  module->blend_params->details = module->default_blendop_params->details;
 
  dt_iop_color_picker_reset(module, FALSE);
  dt_iop_gui_update_blendif(module);
  dt_dev_add_history_item(module->dev, module, TRUE, TRUE);
  dt_iop_gui_update_header(module);
 
  return TRUE;
}
 
static gboolean _blendop_blendif_invert(GtkButton *button, GdkEventButton *event, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return TRUE;
 
  const dt_iop_gui_blend_data_t *data = module->gui->blend_data;
 
  unsigned int toggle_mask = 0;
 
  switch(data->channel_tabs_csp)
  {
    case DEVELOP_BLEND_CS_LAB:
      toggle_mask = DEVELOP_BLENDIF_Lab_MASK << 16;
      break;
    case DEVELOP_BLEND_CS_RGB_DISPLAY:
    case DEVELOP_BLEND_CS_RGB_SCENE:
      toggle_mask = DEVELOP_BLENDIF_RGB_MASK << 16;
      break;
    case DEVELOP_BLEND_CS_RAW:
    case DEVELOP_BLEND_CS_NONE:
      toggle_mask = 0;
      break;
  }
 
  module->blend_params->blendif ^= toggle_mask;
  module->blend_params->mask_combine ^= DEVELOP_COMBINE_MASKS_POS;
  module->blend_params->mask_combine ^= DEVELOP_COMBINE_INCL;
  dt_iop_gui_update_blending(module);
  dt_dev_add_history_item(module->dev, module, TRUE, TRUE);
  dt_iop_gui_update_header(module);
 
  return TRUE;
}
 
static gboolean _blendop_masks_shape_can_start(GtkWidget *button, dt_iop_module_t *module,
                                               dt_masks_type_t type, gpointer user_data)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)user_data;
  if(IS_NULL_PTR(module) || IS_NULL_PTR(bd)) return FALSE;
 
  // we want to be sure that the iop has focus
  dt_iop_request_focus(module);
  dt_iop_color_picker_reset(module, FALSE);
  bd->masks_shown = DT_MASKS_EDIT_FULL;
  if(GTK_IS_TOGGLE_BUTTON(bd->masks_edit))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->masks_edit), FALSE);
  return TRUE;
}
 
static gboolean _blendop_masks_show_and_edit(GtkWidget *widget, GdkEventButton *event, dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return FALSE;
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)self->gui->blend_data;
 
  if(event->button == 1)
  {
    dt_gui_freeze_begin();
 
    dt_iop_request_focus(self);
    dt_iop_color_picker_reset(self, FALSE);
 
    dt_masks_form_t *grp = dt_masks_get_from_id(self->dev, self->blend_params->mask_id);
    if(grp && (grp->type & DT_MASKS_GROUP) && grp->points)
    {
      const gboolean control_button_pressed = dt_modifier_is(event->state, DT_PRIMARY_MASK);
 
      switch(bd->masks_shown)
      {
        case DT_MASKS_EDIT_FULL:
          bd->masks_shown = control_button_pressed ? DT_MASKS_EDIT_RESTRICTED : DT_MASKS_EDIT_OFF;
          break;
 
        case DT_MASKS_EDIT_RESTRICTED:
          bd->masks_shown = !control_button_pressed ? DT_MASKS_EDIT_FULL : DT_MASKS_EDIT_OFF;
          break;
 
        default:
        case DT_MASKS_EDIT_OFF:
          bd->masks_shown = control_button_pressed ? DT_MASKS_EDIT_RESTRICTED : DT_MASKS_EDIT_FULL;
      }
    }
    else
    {
      bd->masks_shown = DT_MASKS_EDIT_OFF;
      /* remove hinter messages */
      dt_control_hinter_message(dt_control_get_global(), "");
    }
 
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->masks_edit), bd->masks_shown != DT_MASKS_EDIT_OFF);
    dt_masks_set_edit_mode(self, bd->masks_shown);
 
    // Deactivate every masks shape toolbar because edit mode replaces creation mode.
    dt_masks_shape_buttons_deactivate_all(NULL);
 
    dt_gui_freeze_end();
 
    return TRUE;
  }
 
  return FALSE;
}
 
static gboolean _blendop_masks_polarity_callback(GtkToggleButton *togglebutton, GdkEventButton *event, dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return TRUE;
 
  const int active = !gtk_toggle_button_get_active(togglebutton);
  gtk_toggle_button_set_active(togglebutton, active);
 
  dt_develop_blend_params_t *bp = (dt_develop_blend_params_t *)self->blend_params;
 
  if(active)
    bp->mask_combine |= DEVELOP_COMBINE_MASKS_POS;
  else
    bp->mask_combine &= ~DEVELOP_COMBINE_MASKS_POS;
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
  dt_iop_gui_update_header(self);
  dt_control_queue_redraw_widget(GTK_WIDGET(togglebutton));
 
  return TRUE;
}
 
typedef enum _blendop_masks_all_cols_t
{
  BLENDOP_MASKS_ALL_COL_ACTIVE = 0,
  BLENDOP_MASKS_ALL_COL_NAME,
  BLENDOP_MASKS_ALL_COL_FORMID,
  BLENDOP_MASKS_ALL_COL_SENSITIVE,
  BLENDOP_MASKS_ALL_COL_MARKUP,
  BLENDOP_MASKS_ALL_COL_STATUS_MARKUP,
  BLENDOP_MASKS_ALL_COL_COUNT
} _blendop_masks_all_cols_t;
 
typedef enum _blendop_masks_group_cols_t
{
  BLENDOP_MASKS_GROUP_COL_OP_ICON = 0,
  BLENDOP_MASKS_GROUP_COL_INV_ICON,
  BLENDOP_MASKS_GROUP_COL_NAME,
  BLENDOP_MASKS_GROUP_COL_FORMID,
  BLENDOP_MASKS_GROUP_COL_PARENTID,
  BLENDOP_MASKS_GROUP_COL_STATE,
  BLENDOP_MASKS_GROUP_COL_INDEX,
  BLENDOP_MASKS_GROUP_COL_COUNT
} _blendop_masks_group_cols_t;
 
static dt_masks_form_t *_blendop_masks_group_from_module(dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return NULL;
  if(IS_NULL_PTR(module->blend_params)) return NULL;
  return dt_masks_get_from_id(module->dev, module->blend_params->mask_id);
}
 
static void _blendop_masks_check_id(dt_develop_t *dev, dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(mask_form)) return;
 
  int new_form_id = 100;
  for(GList *form_node = dev->forms; form_node;)
  {
    const dt_masks_form_t *existing_form = (dt_masks_form_t *)form_node->data;
    if(existing_form->formid == mask_form->formid)
    {
      mask_form->formid = new_form_id++;
      form_node = dev->forms;
    }
    else
    {
      form_node = g_list_next(form_node);
    }
  }
}
 
static dt_masks_form_t *_blendop_masks_group_create(dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return NULL;
 
  dt_masks_form_t *group_form = dt_masks_create(DT_MASKS_GROUP);
  if(IS_NULL_PTR(group_form)) return NULL;
 
  _blendop_masks_check_id(module->dev, group_form);
  dt_masks_append_form(module->dev, group_form);
  module->blend_params->mask_id = group_form->formid;
 
  // Named by id, once the group is in dev->forms and its id is settled: the masks module owns the
  // naming convention and the copy-on-write, and nothing here writes into the form. The touch may
  // replace the group with a clone, so the live one is resolved again rather than returned from
  // the pointer created above.
  dt_masks_group_set_name_from_module(module->dev, module->blend_params->mask_id, module);
  group_form = dt_masks_get_from_id(module->dev, module->blend_params->mask_id);
 
  return group_form;
}
 
static void _blendop_masks_init_icons(dt_iop_gui_blend_data_t *bd)
{
  if(IS_NULL_PTR(bd)) return;
 
  // Only initialize icons if they haven't been created yet
  if(bd->masks_ic_inverse && bd->masks_ic_union && bd->masks_ic_intersection
     && bd->masks_ic_difference && bd->masks_ic_exclusion)
    return;
 
  const int icon_size = DT_PIXEL_APPLY_DPI(13);
  if(IS_NULL_PTR(bd->masks_ic_inverse))
    bd->masks_ic_inverse = dt_draw_get_pixbuf_from_cairo(dtgtk_cairo_paint_masks_inverse, icon_size, icon_size);
  if(IS_NULL_PTR(bd->masks_ic_union))
    bd->masks_ic_union = dt_draw_get_pixbuf_from_cairo(dtgtk_cairo_paint_masks_union, icon_size * 2, icon_size);
  if(IS_NULL_PTR(bd->masks_ic_intersection))
    bd->masks_ic_intersection = dt_draw_get_pixbuf_from_cairo(dtgtk_cairo_paint_masks_intersection, icon_size * 2, icon_size);
  if(IS_NULL_PTR(bd->masks_ic_difference))
    bd->masks_ic_difference = dt_draw_get_pixbuf_from_cairo(dtgtk_cairo_paint_masks_difference, icon_size * 2, icon_size);
  if(IS_NULL_PTR(bd->masks_ic_exclusion))
    bd->masks_ic_exclusion = dt_draw_get_pixbuf_from_cairo(dtgtk_cairo_paint_masks_exclusion, icon_size * 2, icon_size);
}
 
static const GdkPixbuf *_blendop_masks_get_op_icon(const dt_iop_gui_blend_data_t *bd, const int state,
                                                   const int index)
{
  if(IS_NULL_PTR(bd) || index == 0) return NULL;
 
  if(state & DT_MASKS_STATE_UNION) return bd->masks_ic_union;
  if(state & DT_MASKS_STATE_INTERSECTION) return bd->masks_ic_intersection;
  if(state & DT_MASKS_STATE_DIFFERENCE) return bd->masks_ic_difference;
  if(state & DT_MASKS_STATE_EXCLUSION) return bd->masks_ic_exclusion;
  return NULL;
}
 
static const GdkPixbuf *_blendop_masks_get_inverse_icon(const dt_iop_gui_blend_data_t *bd, const int state)
{
  return (bd && (state & DT_MASKS_STATE_INVERSE)) ? bd->masks_ic_inverse : NULL;
}
 
static int _blendop_masks_group_tree_append(const dt_iop_gui_blend_data_t *bd, GtkTreeStore *tree_store,
                                            GtkTreeIter *parent_iter, const dt_masks_form_t *parent_group);
 
// Check if this is a parent mask reusing a single parent mask (and no shapes).
// Such a wrapper is redundant and should be hidden: the child mask should be used directly instead.
static gboolean _blendop_masks_is_single_group_wrapper(dt_develop_t *dev, const dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(mask_form)) return FALSE;
  if(!(mask_form->type & DT_MASKS_GROUP)) return FALSE;
  if(IS_NULL_PTR(mask_form->points)) return FALSE;
  
  // Check if there is exactly one item
  if(g_list_length(mask_form->points) != 1) return FALSE;
  
  // Get the single child
  const dt_masks_form_group_t *group_entry = (const dt_masks_form_group_t *)mask_form->points->data;
  if(IS_NULL_PTR(group_entry)) return FALSE;
  
  const dt_masks_form_t *child_form = dt_masks_get_from_id((dt_develop_t *)dev, group_entry->formid);
  if(IS_NULL_PTR(child_form)) return FALSE;
  
  // Check if the single child is a group
  return (child_form->type & DT_MASKS_GROUP) ? TRUE : FALSE;
}
 
static gboolean _blendop_masks_is_group_with_shapes(const dt_develop_t *dev, const dt_masks_form_t *mask_form)
{
  if(IS_NULL_PTR(mask_form)) return FALSE;
  if(!(mask_form->type & DT_MASKS_GROUP)) return FALSE;
  if(IS_NULL_PTR(mask_form->points)) return FALSE;
 
  for(const GList *group_node = mask_form->points; group_node; group_node = g_list_next(group_node))
  {
    const dt_masks_form_group_t *group_entry = (const dt_masks_form_group_t *)group_node->data;
    if(IS_NULL_PTR(group_entry)) continue;
 
    const dt_masks_form_t *child_form = dt_masks_get_from_id((dt_develop_t *)dev, group_entry->formid);
    if(IS_NULL_PTR(child_form)) continue;
    if(!(child_form->type & DT_MASKS_GROUP)) return TRUE;
    if(_blendop_masks_is_group_with_shapes(dev, child_form)) return TRUE;
  }
 
  return FALSE;
}
 
static int _blendop_masks_group_tree_append_entry(const dt_iop_gui_blend_data_t *bd, GtkTreeStore *tree_store,
                                                  GtkTreeIter *parent_iter,
                                                  const dt_masks_form_group_t *group_entry,
                                                  const dt_masks_form_t *mask_form, const int index)
{
  if(IS_NULL_PTR(bd) || IS_NULL_PTR(tree_store) || IS_NULL_PTR(group_entry) || IS_NULL_PTR(mask_form)) return 0;
 
  GtkTreeIter iter;
 
  // Append the opacity to the displayed name, same as the masks library treeview.
  char display_name[256] = "";
  if(group_entry->opacity != 1.0f)
    g_snprintf(display_name, sizeof(display_name), "%s %d%%", mask_form->name,
               (int)(group_entry->opacity * 100));
  else
    g_strlcpy(display_name, mask_form->name, sizeof(display_name));
 
  gtk_tree_store_append(tree_store, &iter, parent_iter);
  gtk_tree_store_set(tree_store, &iter, BLENDOP_MASKS_GROUP_COL_OP_ICON,
                     _blendop_masks_get_op_icon(bd, group_entry->state, index),
                     BLENDOP_MASKS_GROUP_COL_INV_ICON,
                     _blendop_masks_get_inverse_icon(bd, group_entry->state),
                     BLENDOP_MASKS_GROUP_COL_NAME, display_name,
                     BLENDOP_MASKS_GROUP_COL_FORMID, group_entry->formid,
                     BLENDOP_MASKS_GROUP_COL_PARENTID, group_entry->parentid,
                     BLENDOP_MASKS_GROUP_COL_STATE, group_entry->state,
                     BLENDOP_MASKS_GROUP_COL_INDEX, index, -1);
 
  int row_count = 1;
  if(mask_form->type & DT_MASKS_GROUP)
    row_count += _blendop_masks_group_tree_append(bd, tree_store, &iter, mask_form);
 
  return row_count;
}
 
static int _blendop_masks_group_tree_append(const dt_iop_gui_blend_data_t *bd, GtkTreeStore *tree_store,
                                            GtkTreeIter *parent_iter, const dt_masks_form_t *parent_group)
{
  if(IS_NULL_PTR(bd)) return 0;
  if(IS_NULL_PTR(tree_store)) return 0;
  if(IS_NULL_PTR(parent_group)) return 0;
  if(!(parent_group->type & DT_MASKS_GROUP)) return 0;
 
  int row_count = 0;
 
  /* One pass, in the group's own membership order. This used to run twice -- the members that
   * are groups holding shapes, then everything else -- which put every sub-group at the top of
   * the mask whatever its rank inside it. The rank is what the combine operators are read
   * against, so the list has to show it. */
  int index = 0;
  for(const GList *group_node = parent_group->points; group_node; group_node = g_list_next(group_node))
  {
    const dt_masks_form_group_t *group_entry = (const dt_masks_form_group_t *)group_node->data;
    const dt_masks_form_t *mask_form = group_entry
                                           ? dt_masks_get_from_id(bd->module->dev, group_entry->formid)
                                           : NULL;
    if(mask_form)
      row_count += _blendop_masks_group_tree_append_entry(bd, tree_store, parent_iter, group_entry, mask_form,
                                                          index);
    index++;
  }
 
  return row_count;
}
 
static gboolean _blendop_masks_find_iter_by_formid(GtkTreeModel *model, GtkTreeIter *iter,
                                                    const int formid_col, const int formid)
{
  if(IS_NULL_PTR(model) || IS_NULL_PTR(iter)) return FALSE;
 
  gboolean valid = gtk_tree_model_get_iter_first(model, iter);
  while(valid)
  {
    int current_formid = -1;
    gtk_tree_model_get(model, iter, formid_col, &current_formid, -1);
    if(current_formid == formid) return TRUE;
    valid = gtk_tree_model_iter_next(model, iter);
  }
 
  return FALSE;
}
 
static void _blendop_masks_all_selection_changed(GtkTreeSelection *selection, dt_iop_module_t *module);
static gboolean _blendop_masks_all_button_pressed(GtkWidget *treeview, GdkEventButton *event,
                                                  dt_iop_module_t *module);
static void _blendop_masks_group_selection_changed(GtkTreeSelection *selection, dt_iop_module_t *module);
static gboolean _blendop_masks_group_button_pressed(GtkWidget *treeview, GdkEventButton *event,
                                                    dt_iop_module_t *module);
static void _blendop_masks_group_name_activate(GtkEntry *entry, dt_iop_module_t *module);
static gboolean _blendop_masks_group_name_focus_out(GtkWidget *widget, GdkEventFocus *event,
                                                    dt_iop_module_t *module);
 
static void _blendop_masks_refresh_lists(dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd)) return;
  if(!GTK_IS_TREE_VIEW(bd->masks_treeview)) return;
  if(!GTK_IS_TREE_VIEW(bd->masks_group_treeview)) return;
 
  GtkTreeModel *all_model = gtk_tree_view_get_model(GTK_TREE_VIEW(bd->masks_treeview));
  GtkTreeModel *group_model = gtk_tree_view_get_model(GTK_TREE_VIEW(bd->masks_group_treeview));
  if(!GTK_IS_LIST_STORE(all_model)) return;
  if(!GTK_IS_TREE_STORE(group_model)) return;
 
  // Block signals during model updates to prevent callbacks from accessing inconsistent state
  GtkTreeSelection *all_selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(bd->masks_treeview));
  GtkTreeSelection *group_selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(bd->masks_group_treeview));
  g_signal_handlers_block_by_func(all_selection, G_CALLBACK(_blendop_masks_all_selection_changed), module);
  g_signal_handlers_block_by_func(group_selection, G_CALLBACK(_blendop_masks_group_selection_changed), module);
  g_signal_handlers_block_by_func(bd->masks_treeview, G_CALLBACK(_blendop_masks_all_button_pressed), module);
  g_signal_handlers_block_by_func(bd->masks_group_treeview, G_CALLBACK(_blendop_masks_group_button_pressed), module);
 
  gtk_list_store_clear(GTK_LIST_STORE(all_model));
  gtk_tree_store_clear(GTK_TREE_STORE(group_model));
 
  dt_masks_form_t *group_form = _blendop_masks_group_from_module(module);
 
  /* The available shapes keep the groups at the top, ahead of the loose shapes: this list is a
   * catalogue to pick from rather than a rendering order, and a group is the coarser thing to
   * pick. The mask's own tree, above, is the one that must show rank. */
 
  // First pass: groups containing shapes first.
  for(const GList *form_node = module->dev->forms; form_node; form_node = g_list_next(form_node))
  {
    dt_masks_form_t *mask_form = (dt_masks_form_t *)form_node->data;
    if(IS_NULL_PTR(mask_form)) continue;
    if(mask_form->type & (DT_MASKS_CLONE | DT_MASKS_NON_CLONE)) continue;
    if(!IS_NULL_PTR(group_form) && mask_form->formid == group_form->formid) continue;
    if(!_blendop_masks_is_group_with_shapes(module->dev, mask_form)) continue;
    // Skip groups containing only a single group
    if(_blendop_masks_is_single_group_wrapper(module->dev, mask_form)) continue;
 
    const gboolean active = dt_masks_form_group_find_entry(group_form, mask_form->formid, NULL) != NULL;
    GtkTreeIter iter;
    gtk_list_store_append(GTK_LIST_STORE(all_model), &iter);
    gchar *display_markup = g_markup_printf_escaped("%s", mask_form->name);
    gtk_list_store_set(GTK_LIST_STORE(all_model), &iter, BLENDOP_MASKS_ALL_COL_ACTIVE, active,
                       BLENDOP_MASKS_ALL_COL_NAME, mask_form->name, BLENDOP_MASKS_ALL_COL_FORMID, mask_form->formid,
                       BLENDOP_MASKS_ALL_COL_SENSITIVE, TRUE,
               BLENDOP_MASKS_ALL_COL_MARKUP, display_markup,
               BLENDOP_MASKS_ALL_COL_STATUS_MARKUP, "",
                       -1);
    g_free(display_markup);
  }
 
  // Second pass: then all non-group (and empty-group) entries.
  for(const GList *form_node = module->dev->forms; form_node; form_node = g_list_next(form_node))
  {
    dt_masks_form_t *mask_form = (dt_masks_form_t *)form_node->data;
    if(IS_NULL_PTR(mask_form)) continue;
    if(mask_form->type & (DT_MASKS_CLONE | DT_MASKS_NON_CLONE)) continue;
    if(!IS_NULL_PTR(group_form) && mask_form->formid == group_form->formid) continue;
    if(_blendop_masks_is_group_with_shapes(module->dev, mask_form)) continue;
 
    const gboolean active = dt_masks_form_group_find_entry(group_form, mask_form->formid, NULL) != NULL;
    gboolean sensitive = TRUE;
    const gchar *locked_group_name = NULL;
    
    // Check if this shape belongs to an active group
    for(const GList *parent_node = module->dev->forms; parent_node; parent_node = g_list_next(parent_node))
    {
      dt_masks_form_t *parent_form = (dt_masks_form_t *)parent_node->data;
      if(IS_NULL_PTR(parent_form) || !_blendop_masks_is_group_with_shapes(module->dev, parent_form)) continue;
      
      const gboolean parent_active = dt_masks_form_group_find_entry(group_form, parent_form->formid, NULL) != NULL;
      if(parent_active && dt_masks_form_group_find_entry(parent_form, mask_form->formid, NULL))
      {
        sensitive = FALSE;
        locked_group_name = parent_form->name;
        break;
      }
    }
 
    const gboolean display_active = active || !sensitive;
    gchar *display_markup = NULL;
    gchar *status_markup = NULL;
    display_markup = g_markup_printf_escaped("%s", mask_form->name);
 
    if(!sensitive && !IS_NULL_PTR(locked_group_name) && *locked_group_name)
    {
      gchar *already_in = g_strdup_printf(_("Already in '%s'"), locked_group_name);
      status_markup = g_markup_printf_escaped("<i>%s</i>", already_in);
      g_free(already_in);
    }
    else
      status_markup = g_strdup("");
 
    GtkTreeIter iter;
    gtk_list_store_append(GTK_LIST_STORE(all_model), &iter);
    gtk_list_store_set(GTK_LIST_STORE(all_model), &iter, BLENDOP_MASKS_ALL_COL_ACTIVE, display_active,
                       BLENDOP_MASKS_ALL_COL_NAME, mask_form->name, BLENDOP_MASKS_ALL_COL_FORMID, mask_form->formid,
                       BLENDOP_MASKS_ALL_COL_SENSITIVE, sensitive, BLENDOP_MASKS_ALL_COL_MARKUP, display_markup,
                       BLENDOP_MASKS_ALL_COL_STATUS_MARKUP, status_markup,
                       -1);
    g_free(display_markup);
    g_free(status_markup);
  }
 
  if(!IS_NULL_PTR(group_form) && (group_form->type & DT_MASKS_GROUP))
  {
    if(GTK_IS_ENTRY(bd->group_shapes_label))
      gtk_entry_set_text(GTK_ENTRY(bd->group_shapes_label), group_form->name);
    _blendop_masks_group_tree_append(bd, GTK_TREE_STORE(group_model), NULL, group_form);
  }
 
  // Unblock signals after model updates are complete
  g_signal_handlers_unblock_by_func(all_selection, G_CALLBACK(_blendop_masks_all_selection_changed), module);
  g_signal_handlers_unblock_by_func(group_selection, G_CALLBACK(_blendop_masks_group_selection_changed), module);
  g_signal_handlers_unblock_by_func(bd->masks_treeview, G_CALLBACK(_blendop_masks_all_button_pressed), module);
  g_signal_handlers_unblock_by_func(bd->masks_group_treeview, G_CALLBACK(_blendop_masks_group_button_pressed), module);
}
 
static void _blendop_masks_apply_and_commit(dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(module->dev)) return;
 
  dt_iop_gui_blend_masks_update(module);
  dt_dev_add_history_item(module->dev, module, TRUE, TRUE);
  dt_iop_gui_update_header(module);
  dt_control_queue_redraw_center();
}
 
gboolean dt_iop_gui_blend_set_drawn_mask_group(dt_iop_module_t *module, const int group_id)
{
  if(!dt_iop_module_supports_drawn_mask(module)) return FALSE;
 
  const dt_masks_form_t *group = dt_masks_get_from_id(module->dev, group_id);
  if(IS_NULL_PTR(group) || !(group->type & DT_MASKS_GROUP)) return FALSE;
 
  const uint32_t drawn = DEVELOP_MASK_ENABLED | DEVELOP_MASK_SHAPE;
  const gboolean changed = (module->blend_params->mask_id != group_id)
                           || ((module->blend_params->mask_mode & drawn) != drawn);
  if(!changed) return FALSE;
 
  module->blend_params->mask_id = group_id;
  module->blend_params->mask_mode |= drawn;
 
  // Reads blend_params->mask_mode back rather than taking it as an argument, so it has to come
  // after the write above.
  dt_iop_set_mask_mode(module, module->blend_params->mask_mode);
 
  /* A module the user has never expanded has no blend GUI to refresh, and one whose blending
   * body was never built has a dt_iop_gui_blend_data_t but no widgets in it -- which is exactly
   * what blending_box records, the same gate _blendop_masks_mode_callback() applies. */
  if(!IS_NULL_PTR(module->gui) && !IS_NULL_PTR(module->gui->blend_data))
  {
    const dt_iop_gui_blend_data_t *bd = (const dt_iop_gui_blend_data_t *)module->gui->blend_data;
    if(bd->blending_box) dt_iop_gui_update_blending(module);
    dt_iop_gui_blend_masks_update(module);
  }
 
  dt_iop_add_remove_mask_indicator(module);
  dt_iop_gui_update_header(module);
 
  return TRUE;
}
 
static void _blendop_masks_group_name_commit(dt_iop_module_t *module, const gchar *new_text)
{
  if(IS_NULL_PTR(module)) return;
  dt_masks_form_t *group_form = _blendop_masks_group_from_module(module);
  if(IS_NULL_PTR(group_form)) return;
 
  gchar *mask_default_name = dt_masks_group_name_for_module(module);
  gchar *text = (new_text && *new_text) ? g_strdup(new_text) : g_strdup(mask_default_name);
  g_free(mask_default_name);
 
  g_strlcpy(group_form->name, text, sizeof(group_form->name));
  _blendop_masks_apply_and_commit(module);
  g_free(text);
 
  _blendop_masks_refresh_lists(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, group_form->formid, 0,
                                DT_MASKS_EVENT_CHANGE);
}
 
static void _blendop_masks_group_name_activate(GtkEntry *entry, dt_iop_module_t *module)
{
  if(!GTK_IS_ENTRY(entry)) return;
  _blendop_masks_group_name_commit(module, gtk_entry_get_text(entry));
}
 
static gboolean _blendop_masks_group_name_focus_out(GtkWidget *widget, GdkEventFocus *event,
                                                    dt_iop_module_t *module)
{
  (void)event;
  if(GTK_IS_ENTRY(widget))
    _blendop_masks_group_name_commit(module, gtk_entry_get_text(GTK_ENTRY(widget)));
  return FALSE;
}
 
static void _blendop_masks_all_name_edited(GtkCellRendererText *cell, gchar *path_string,
                                           gchar *new_text, dt_iop_module_t *module)
{
  (void)cell;
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
 
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(bd->masks_treeview));
  if(!GTK_IS_TREE_MODEL(model)) return;
 
  GtkTreeIter iter;
  if(!gtk_tree_model_get_iter_from_string(model, &iter, path_string)) return;
 
  int formid = -1;
  gtk_tree_model_get(model, &iter, BLENDOP_MASKS_ALL_COL_FORMID, &formid, -1);
  dt_masks_form_t *mask_form = dt_masks_get_from_id(module->dev, formid);
  if(IS_NULL_PTR(mask_form)) return;
 
  const gchar *text = (new_text && *new_text) ? new_text : " ";
  g_strlcpy(mask_form->name, text, sizeof(mask_form->name));
 
  dt_dev_add_history_item(module->dev, NULL, FALSE, TRUE);
  _blendop_masks_refresh_lists(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, mask_form->formid, 0,
                                DT_MASKS_EVENT_CHANGE);
}
 
static void _blendop_masks_all_selection_changed(GtkTreeSelection *selection, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return;
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(selection)) return;
 
  GtkTreeModel *model = NULL;
  GtkTreeIter iter;
  if(!gtk_tree_selection_get_selected(selection, &model, &iter)) return;
  if(!GTK_IS_TREE_MODEL(model)) return;
 
  int formid = -1;
  gtk_tree_model_get(model, &iter, BLENDOP_MASKS_ALL_COL_FORMID, &formid, -1);
  if(formid <= 0) return;
  dt_masks_form_t *mask_form = dt_masks_get_from_id(module->dev, formid);
  if(IS_NULL_PTR(mask_form)) return;
 
  // Keep the global shape manager in sync without firing its selection handler.
  // That handler rebuilds the visible mask GUI and can be re-entered while this
  // blend list selection is still being processed.
  dt_dev_masks_selection_change(module->dev, NULL, formid, FALSE);
  dt_masks_change_form_gui(module->dev, mask_form);
  if(module->dev && module->dev->form_gui)
  {
    module->dev->form_gui->group_selected = 0;
    module->dev->form_gui->form_selected = TRUE;
  }
  dt_masks_center_view_on_form(module->dev, mask_form);
}
 
static void _blendop_masks_all_toggled(GtkCellRendererToggle *cell, gchar *path_string, dt_iop_module_t *module)
{
  (void)cell;
  if(dt_gui_widgets_suppressed()) return;
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
 
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(bd->masks_treeview));
  if(!GTK_IS_TREE_MODEL(model)) return;
 
  GtkTreeIter iter;
  if(!gtk_tree_model_get_iter_from_string(model, &iter, path_string)) return;
 
  gboolean active = FALSE;
  gboolean sensitive = TRUE;
  int formid = -1;
  gtk_tree_model_get(model, &iter, BLENDOP_MASKS_ALL_COL_ACTIVE, &active,
                     BLENDOP_MASKS_ALL_COL_FORMID, &formid,
                     BLENDOP_MASKS_ALL_COL_SENSITIVE, &sensitive, -1);
 
  if(!sensitive) return;
 
  dt_masks_form_t *mask_form = dt_masks_get_from_id(module->dev, formid);
  if(IS_NULL_PTR(mask_form)) return;
 
  dt_masks_form_t *group_form = _blendop_masks_group_from_module(module);
  const int parentid_before = group_form ? group_form->formid : 0;
 
  if(active)
  {
    if(!IS_NULL_PTR(group_form))
      dt_masks_form_delete(module->dev, module, group_form, mask_form);
  }
  else
  {
    if(IS_NULL_PTR(group_form))
      group_form = _blendop_masks_group_create(module);
    if(IS_NULL_PTR(group_form)) return;
 
    if(!dt_masks_form_group_find_entry(group_form, mask_form->formid, NULL))
    {
      group_form = dt_masks_cow_touch(module->dev, group_form);
      dt_masks_group_add_form(module->dev, group_form, mask_form);
      dt_masks_set_edit_mode(module, DT_MASKS_EDIT_FULL);
    }
  }
 
  // If this is a group with shapes, update sensitive state of child shapes
  if(_blendop_masks_is_group_with_shapes(module->dev, mask_form))
  {
    const gboolean new_active = !active;  // Toggle state
    GtkTreeIter search_iter;
    gboolean valid = gtk_tree_model_get_iter_first(model, &search_iter);
    
    while(valid)
    {
      int child_formid = -1;
      gtk_tree_model_get(model, &search_iter, BLENDOP_MASKS_ALL_COL_FORMID, &child_formid, -1);
      
      // Check if this child belongs to the toggled group
      if(dt_masks_form_group_find_entry(mask_form, child_formid, NULL))
      {
        // Lock (gray out) if group is being activated, unlock if deactivated
        gtk_list_store_set(GTK_LIST_STORE(model), &search_iter, 
                          BLENDOP_MASKS_ALL_COL_SENSITIVE, !new_active, -1);
      }
      
      valid = gtk_tree_model_iter_next(model, &search_iter);
    }
  }
 
  _blendop_masks_apply_and_commit(module);
 
  const int parentid_after = group_form ? group_form->formid : parentid_before;
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, formid,
                                active ? parentid_before : parentid_after,
                                active ? DT_MASKS_EVENT_REMOVE : DT_MASKS_EVENT_ADD);
}
 
// Permanently delete a shape from the "all shapes" list: the row's trash icon is the only
// entry point, gated by dt_masks_gui_confirm_permanent_delete().
static void _blendop_masks_all_delete(dt_iop_module_t *module, const int formid)
{
  if(IS_NULL_PTR(module)) return;
 
  dt_masks_form_t *mask_form = dt_masks_get_from_id(module->dev, formid);
  if(IS_NULL_PTR(mask_form)) return;
 
  if(!dt_masks_gui_confirm_permanent_delete(mask_form->name)) return;
 
  dt_masks_change_form_gui(module->dev, NULL);
  dt_masks_form_delete(module->dev, module, NULL, mask_form);
  _blendop_masks_apply_and_commit(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, formid, 0, DT_MASKS_EVENT_DELETE);
}
 
static void _blendop_masks_all_duplicate_callback(GtkWidget *menu_item, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return;
 
  const int formid = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-formid"));
  if(dt_masks_form_duplicate(module->dev, formid) <= 0) return;
 
  _blendop_masks_apply_and_commit(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, 0, 0, DT_MASKS_EVENT_RESET);
}
 
static void _blendop_masks_all_rename_callback(GtkWidget *menu_item, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
 
  const int formid = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-formid"));
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  GtkTreeView *view = GTK_TREE_VIEW(bd->masks_treeview);
  GtkTreeModel *model = gtk_tree_view_get_model(view);
  if(!GTK_IS_TREE_MODEL(model)) return;
 
  GtkTreeIter iter;
  if(!_blendop_masks_find_iter_by_formid(model, &iter, BLENDOP_MASKS_ALL_COL_FORMID, formid)) return;
 
  GtkTreePath *path = gtk_tree_model_get_path(model, &iter);
  GtkTreeViewColumn *column = gtk_tree_view_get_column(view, 1);
  GtkCellRenderer *renderer = g_object_get_data(G_OBJECT(view), "blendop-masks-name-renderer");
  if(path && column && renderer)
    gtk_tree_view_set_cursor_on_cell(view, path, column, renderer, TRUE);
  if(path) gtk_tree_path_free(path);
}
 
static gboolean _blendop_masks_all_handle_left_click(GtkWidget *treeview, GtkTreePath *path,
                                                        GtkTreeViewColumn *column, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return FALSE;
  if(IS_NULL_PTR(path) || IS_NULL_PTR(column)) return FALSE;
 
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd) || column != bd->all_shapes_col) return FALSE;
 
  GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(treeview));
  GtkTreeIter iter;
  if(!gtk_tree_model_get_iter(model, &iter, path)) return FALSE;
 
  gboolean sensitive = TRUE;
  int formid = -1;
  gtk_tree_model_get(model, &iter, BLENDOP_MASKS_ALL_COL_SENSITIVE, &sensitive,
                     BLENDOP_MASKS_ALL_COL_FORMID, &formid, -1);
 
  if(formid <= 0) return FALSE;
 
  if(!sensitive)
  {
    gtk_tree_path_free(path);
    return TRUE;
  }
 
  // Toggle the checkbox value.
  gchar *path_string = gtk_tree_path_to_string(path);
  _blendop_masks_all_toggled(NULL, path_string, module);
  dt_free(path_string);
  gtk_tree_path_free(path);
  return TRUE; // Block default selection behavior.
}
 
static gboolean _blendop_masks_all_button_pressed(GtkWidget *treeview, GdkEventButton *event,
                                                  dt_iop_module_t *module)
{
  if(IS_NULL_PTR(event) || event->type != GDK_BUTTON_PRESS) return FALSE;
 
  GtkTreePath *path = NULL;
  GtkTreeViewColumn *column = NULL;
  if(!gtk_tree_view_get_path_at_pos(GTK_TREE_VIEW(treeview), (gint)event->x, (gint)event->y, &path,
                                    &column, NULL, NULL))
    return FALSE;
 
  // Handle left click on the per-row delete icon column.
  if(event->button == GDK_BUTTON_PRIMARY && !IS_NULL_PTR(column))
  {
    dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
    if(!IS_NULL_PTR(bd) && column == bd->all_shapes_delete_col)
    {
      GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(treeview));
      GtkTreeIter iter;
      int formid = -1;
      if(gtk_tree_model_get_iter(model, &iter, path))
        gtk_tree_model_get(model, &iter, BLENDOP_MASKS_ALL_COL_FORMID, &formid, -1);
      gtk_tree_path_free(path);
      if(formid > 0) _blendop_masks_all_delete(module, formid);
      return TRUE;
    }
  }
 
  // Handle left click on checkbox column - toggle directly without requiring selection
  if(event->button == GDK_BUTTON_PRIMARY && !IS_NULL_PTR(column))
  {
    if(_blendop_masks_all_handle_left_click(treeview, path, column, module))
      return TRUE;
  }
 
  // Handle right click for context menu
  if(event->button != GDK_BUTTON_SECONDARY)
  {
    gtk_tree_path_free(path);
    return FALSE;
  }
 
  GtkTreeSelection *selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(treeview));
  gtk_tree_selection_unselect_all(selection);
  gtk_tree_selection_select_path(selection, path);
 
  GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(treeview));
  GtkTreeIter iter;
  int formid = -1;
  if(gtk_tree_model_get_iter(model, &iter, path))
    gtk_tree_model_get(model, &iter, BLENDOP_MASKS_ALL_COL_FORMID, &formid, -1);
  gtk_tree_path_free(path);
  if(formid <= 0) return TRUE;
 
  GtkWidget *menu = gtk_menu_new();
  GtkWidget *item = gtk_menu_item_new_with_label(_("Duplicate"));
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_signal_connect(item, "activate", G_CALLBACK(_blendop_masks_all_duplicate_callback), module);
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
 
  item = gtk_menu_item_new_with_label(_("Rename"));
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_signal_connect(item, "activate", G_CALLBACK(_blendop_masks_all_rename_callback), module);
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
 
  gtk_widget_show_all(menu);
  gtk_menu_popup_at_pointer(GTK_MENU(menu), (GdkEvent *)event);
  return TRUE;
}
 
static void _blendop_masks_group_operation_callback(GtkWidget *menu_item, gpointer user_data)
{
  dt_iop_module_t *module = (dt_iop_module_t *)user_data;
  if(IS_NULL_PTR(module)) return;
 
  const int formid = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-formid"));
  const int parentid = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-parentid"));
  const dt_masks_state_t state = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-state"));
 
  /* The touch-then-resolve dance this used to spell out by hand -- and which every other caller
   * of it got wrong -- now lives inside the module, where it cannot be omitted. UNCHANGED means
   * the row already had this operator, so there is nothing to commit. */
  if(dt_masks_group_set_member_operation(module->dev, parentid, formid, state, NULL) != DT_MASKS_OK)
    return;
 
  _blendop_masks_apply_and_commit(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, formid, parentid,
                                DT_MASKS_EVENT_UPDATE);
}
 
static void _blendop_masks_group_selection_changed(GtkTreeSelection *selection, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return;
  if(IS_NULL_PTR(module)) return;
  if(IS_NULL_PTR(selection)) return;
 
  GtkTreeModel *model = NULL;
  GtkTreeIter iter;
  if(!gtk_tree_selection_get_selected(selection, &model, &iter)) return;
  if(!GTK_IS_TREE_MODEL(model)) return;
 
  int formid = -1;
  gtk_tree_model_get(model, &iter, BLENDOP_MASKS_GROUP_COL_FORMID, &formid, -1);
  if(formid <= 0) return;
  dt_masks_form_t *mask_form = dt_masks_get_from_id(module->dev, formid);
  if(IS_NULL_PTR(mask_form)) return;
 
  // Switching edit mode rebuilds the visible module group. Do it only when the
  // current overlay does not already contain the selected row, because this
  // callback runs inside a GtkTreeSelection::changed emission.
  dt_masks_form_gui_t *gui = module->dev ? module->dev->form_gui : NULL;
  dt_masks_form_t *visible_form = module->dev ? dt_masks_get_visible_form(module->dev) : NULL;
  if(IS_NULL_PTR(gui) || gui->edit_mode != DT_MASKS_EDIT_FULL
     || dt_masks_group_index_from_formid(visible_form, formid) < 0)
  {
    // Rebuilding the visible group may update Gtk widgets. Hold the GUI reset
    // guard so selection callbacks emitted during that rebuild don't recurse.
    dt_gui_freeze_begin();
    dt_masks_set_edit_mode(module, DT_MASKS_EDIT_FULL);
    dt_gui_freeze_end();
  }
 
  // Keep lib/masks tree selection in sync without re-triggering its selection handler,
  // otherwise the visible overlay can be replaced by only the clicked shape.
  dt_dev_masks_selection_change(module->dev, module, formid, FALSE);
 
  // Mark the selected shape as active in the central mask GUI state.
  if(module->dev && module->dev->form_gui)
  {
    gui = module->dev->form_gui;
    visible_form = dt_masks_get_visible_form(module->dev);
    const int selected_index = dt_masks_group_index_from_formid(visible_form, formid);
    if(selected_index >= 0)
    {
      gui->group_selected = selected_index;
      gui->form_selected = TRUE;
      gui->border_selected = FALSE;
      gui->source_selected = FALSE;
      gui->node_selected = FALSE;
      gui->handle_selected = FALSE;
      gui->seg_selected = FALSE;
      gui->handle_border_selected = FALSE;
      gui->node_selected_idx = -1;
      gui->form_dragging = FALSE;
      gui->source_dragging = FALSE;
      gui->form_rotating = FALSE;
      gui->pivot_selected = FALSE;
    }
  }
  dt_masks_center_view_on_form(module->dev, mask_form);
}
 
static gboolean _blendop_masks_group_move_by_index(dt_develop_t *dev, dt_masks_form_t *group_form,
                                                   const int index, const gboolean move_up)
{
  if(IS_NULL_PTR(group_form)) return FALSE;
  if(!(group_form->type & DT_MASKS_GROUP)) return FALSE;
  if(index < 0) return FALSE;
 
  const guint length = g_list_length(group_form->points);
  if(length == 0 || (guint)index >= length) return FALSE;
  if(move_up && index == 0) return FALSE;
  if(!move_up && (guint)index >= length - 1) return FALSE;
 
  // Touch before resolving `entry`: cloning group_form also clones its points (fresh
  // dt_masks_form_group_t blocks), so an entry resolved from the pre-touch list would not
  // be a member of the (possibly cloned) list touched below.
  group_form = dt_masks_cow_touch(dev, group_form);
  dt_masks_form_group_t *entry = (dt_masks_form_group_t *)g_list_nth_data(group_form->points, index);
  if(IS_NULL_PTR(entry)) return FALSE;
 
  const int new_index = move_up ? index - 1 : index + 1;
  group_form->points = g_list_remove(group_form->points, entry);
  group_form->points = g_list_insert(group_form->points, entry, new_index);
  return TRUE;
}
 
static void _blendop_masks_group_move_callback(GtkWidget *menu_item, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return;
 
  const int parentid = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-parentid"));
  const int index = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-index"));
  const gboolean move_up = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-move-up"));
  dt_masks_form_t *group_form = dt_masks_get_from_id(module->dev, parentid);
  if(!_blendop_masks_group_move_by_index(module->dev, group_form, index, move_up)) return;
 
  dt_masks_change_form_gui(module->dev, NULL);
  _blendop_masks_apply_and_commit(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, 0, parentid, DT_MASKS_EVENT_UPDATE);
}
 
static void _blendop_masks_group_duplicate_callback(GtkWidget *menu_item, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module)) return;
 
  const int formid = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-formid"));
  const int parentid = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menu_item), "blend-parentid"));
 
  // dt_masks_form_duplicate_in_group also attaches the duplicate to the group right away,
  // inheriting the source entry's state/opacity -- same helper used by the shape manager's
  // own "Duplicate shape" action (libs/shape_manager.c).
  const int nid = dt_masks_form_duplicate_in_group(module->dev, parentid, formid);
  if(nid <= 0) return;
 
  _blendop_masks_apply_and_commit(module);
  _blendop_masks_refresh_lists(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, nid, parentid, DT_MASKS_EVENT_ADD);
}
 
static void _blendop_masks_edit_list_toggle(GtkToggleButton *togglebutton, dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  if(!GTK_IS_TOGGLE_BUTTON(togglebutton)) return;
 
  // The edit toggle swaps the visible list between:
  // - current module mask tree
  // - global all-shapes list
  const gboolean edit_mode = gtk_toggle_button_get_active(togglebutton);
 
  if(edit_mode)
    gtk_button_set_label(GTK_BUTTON(togglebutton), _("OK"));
  else
    gtk_button_set_label(GTK_BUTTON(togglebutton), _("Attach shapes"));
 
  if(GTK_IS_STACK(bd->lists_stack))
    gtk_stack_set_visible_child_name(GTK_STACK(bd->lists_stack), edit_mode ? "all" : "group");
 
  if(GTK_IS_ENTRY(bd->group_shapes_label))
    gtk_widget_set_sensitive(bd->group_shapes_label, !edit_mode);
}
 
static GtkWidget *_blendop_masks_create_shape_buttons(dt_iop_module_t *module, dt_iop_gui_blend_data_t *bd)
{
  if(IS_NULL_PTR(module) || IS_NULL_PTR(bd)) return NULL;
 
  const dt_masks_shape_buttons_config_t config = {
    .dev = module->dev,
    .owner_module = module,
    .creation_module = module,
    .buttons = bd->masks_shapes,
    .types = bd->masks_type,
    .action_section = "blend_shapes",
    .flags = DT_MASKS_SHAPE_BUTTONS_ALL,
    .register_flags = DT_MASKS_SHAPE_BUTTONS_POLYGON,
    .local = FALSE,
    .user_data = bd,
    .can_start = _blendop_masks_shape_can_start,
    .form_type = NULL,
    .started = NULL,
    .exited = NULL
  };
  GtkWidget *widget = dt_masks_shape_buttons_create(&config);
 
  return widget;
}
 
static GtkWidget *_blendop_masks_group_ctx_menu(dt_iop_gui_blend_data_t *bd, dt_iop_module_t *module,
                                                const int formid, const int parentid, const int state,
                                                const int index, const int list_length)
{
  if(IS_NULL_PTR(bd) || IS_NULL_PTR(module)) return NULL;
 
  // Initialize mask operation icons if needed
  _blendop_masks_init_icons(bd);
 
  GtkWidget *menu = gtk_menu_new();
  gtk_style_context_add_class(gtk_widget_get_style_context(menu), "dt-masks-context-menu");
 
  // Same shape-parameter sliders (size/fading/rotation/opacity) as the darkroom canvas's own
  // shape context menu (dt_masks_create_menu). The sliders name the row by identity and let the
  // write API copy-on-write per step, so this no longer has to touch the parent group up front --
  // which never worked anyway once a slider started committing history mid-drag.
  dt_masks_form_t *form = dt_masks_get_from_id(module->dev, formid);
 
  if(!IS_NULL_PTR(form))
  {
    dt_masks_gui_populate_interaction_sliders(menu, module->dev, form, parentid, module->dev->form_gui, module);
    gtk_menu_shell_append(GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
  }
 
  GtkWidget *op_item = gtk_menu_item_new_with_label(_("Operation"));
  GtkWidget *op_submenu = gtk_menu_new();
  gtk_menu_item_set_submenu(GTK_MENU_ITEM(op_item), op_submenu);
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), op_item);
 
  GtkWidget *item = ctx_gtk_check_menu_item_new_with_markup_and_pixbuf(_("Invert"), bd->masks_ic_inverse,
                                                                        op_submenu,
                                                                        _blendop_masks_group_operation_callback,
                                                                        module,
                                                                        (state & DT_MASKS_STATE_INVERSE) != 0, TRUE);
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_object_set_data(G_OBJECT(item), "blend-state", GINT_TO_POINTER(DT_MASKS_STATE_INVERSE));
 
  gtk_menu_shell_append(GTK_MENU_SHELL(op_submenu), gtk_separator_menu_item_new());
 
  item = ctx_gtk_check_menu_item_new_with_markup_and_pixbuf(_("Union"), bd->masks_ic_union, op_submenu,
                                                            _blendop_masks_group_operation_callback, module,
                                                            (state & DT_MASKS_STATE_UNION) != 0, FALSE);
  gtk_widget_set_sensitive(item, index > 0);
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_object_set_data(G_OBJECT(item), "blend-state", GINT_TO_POINTER(DT_MASKS_STATE_UNION));
 
  item = ctx_gtk_check_menu_item_new_with_markup_and_pixbuf(_("Intersection"), bd->masks_ic_intersection, op_submenu,
                                                            _blendop_masks_group_operation_callback, module,
                                                            (state & DT_MASKS_STATE_INTERSECTION) != 0, FALSE);
  gtk_widget_set_sensitive(item, index > 0);
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_object_set_data(G_OBJECT(item), "blend-state", GINT_TO_POINTER(DT_MASKS_STATE_INTERSECTION));
 
  item = ctx_gtk_check_menu_item_new_with_markup_and_pixbuf(_("Difference"), bd->masks_ic_difference, op_submenu,
                                                            _blendop_masks_group_operation_callback, module,
                                                            (state & DT_MASKS_STATE_DIFFERENCE) != 0, FALSE);
  gtk_widget_set_sensitive(item, index > 0);
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_object_set_data(G_OBJECT(item), "blend-state", GINT_TO_POINTER(DT_MASKS_STATE_DIFFERENCE));
 
  item = ctx_gtk_check_menu_item_new_with_markup_and_pixbuf(_("Exclusion"), bd->masks_ic_exclusion, op_submenu,
                                                            _blendop_masks_group_operation_callback, module,
                                                            (state & DT_MASKS_STATE_EXCLUSION) != 0, FALSE);
  gtk_widget_set_sensitive(item, index > 0);
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_object_set_data(G_OBJECT(item), "blend-state", GINT_TO_POINTER(DT_MASKS_STATE_EXCLUSION));
 
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
 
  item = gtk_menu_item_new_with_label(_("Move Up"));
  gtk_widget_set_sensitive(item, index > 0);
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_object_set_data(G_OBJECT(item), "blend-index", GINT_TO_POINTER(index));
  g_object_set_data(G_OBJECT(item), "blend-move-up", GINT_TO_POINTER(TRUE));
  g_signal_connect(item, "activate", G_CALLBACK(_blendop_masks_group_move_callback), module);
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
 
  item = gtk_menu_item_new_with_label(_("Move Down"));
  gtk_widget_set_sensitive(item, index >= 0 && index < list_length - 1);
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_object_set_data(G_OBJECT(item), "blend-index", GINT_TO_POINTER(index));
  g_object_set_data(G_OBJECT(item), "blend-move-up", GINT_TO_POINTER(FALSE));
  g_signal_connect(item, "activate", G_CALLBACK(_blendop_masks_group_move_callback), module);
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
 
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
 
  item = gtk_menu_item_new_with_label(_("Duplicate shape"));
  g_object_set_data(G_OBJECT(item), "blend-formid", GINT_TO_POINTER(formid));
  g_object_set_data(G_OBJECT(item), "blend-parentid", GINT_TO_POINTER(parentid));
  g_signal_connect(item, "activate", G_CALLBACK(_blendop_masks_group_duplicate_callback), module);
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), item);
 
  return menu;
}
 
// Detach the form from its parent group, but keep it in dev->forms for potential reuse.
static void _blendop_masks_group_unlink(dt_iop_module_t *module, const int formid, const int parentid)
{
  if(IS_NULL_PTR(module)) return;
  dt_masks_form_t *parent_group = dt_masks_get_from_id(module->dev, parentid);
  dt_masks_form_t *form = dt_masks_get_from_id(module->dev, formid);
  if(IS_NULL_PTR(parent_group) || !(parent_group->type & DT_MASKS_GROUP) || IS_NULL_PTR(form)) return;
 
  // Discard any visible overlay before mutating the group.
  dt_masks_change_form_gui(module->dev, NULL);
 
  // Passing the parent group only detaches the form from this group.
  dt_masks_form_delete(module->dev, module, parent_group, form);
 
  _blendop_masks_apply_and_commit(module);
  _blendop_masks_refresh_lists(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, formid, parentid,
                                DT_MASKS_EVENT_REMOVE);
}
 
// Detach the form from its parent group and remove it from dev->forms altogether.
static void _blendop_masks_group_delete(dt_iop_module_t *module, const int formid, const int parentid)
{
  if(IS_NULL_PTR(module)) return;
  dt_masks_form_t *form = dt_masks_get_from_id(module->dev, formid);
  if(IS_NULL_PTR(form)) return;
 
  if(!dt_masks_gui_confirm_permanent_delete(form->name)) return;
 
  // Discard any visible overlay before mutating the masks.
  dt_masks_change_form_gui(module->dev, NULL);
 
  // Passing no group permanently deletes the form from every module and dev->forms.
  dt_masks_form_delete(module->dev, module, NULL, form);
 
  _blendop_masks_apply_and_commit(module);
  _blendop_masks_refresh_lists(module);
  DT_DEBUG_CONTROL_SIGNAL_RAISE(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED, formid, parentid,
                                DT_MASKS_EVENT_REMOVE);
}
 
// Handle a left click on the per-row unlink / delete icon columns.
// Returns TRUE if the click was consumed (so row selection is not triggered).
static gboolean _blendop_masks_group_handle_action_click(GtkWidget *treeview, GtkTreePath *path,
                                                         GtkTreeViewColumn *column, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module) || IS_NULL_PTR(path) || IS_NULL_PTR(column)) return FALSE;
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd)) return FALSE;
  if(column != bd->group_unlink_col && column != bd->group_delete_col) return FALSE;
 
  GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(treeview));
  GtkTreeIter iter;
  if(!gtk_tree_model_get_iter(model, &iter, path)) return TRUE;
 
  int formid = -1;
  int parentid = -1;
  gtk_tree_model_get(model, &iter, BLENDOP_MASKS_GROUP_COL_FORMID, &formid,
                     BLENDOP_MASKS_GROUP_COL_PARENTID, &parentid, -1);
  if(formid <= 0 || parentid <= 0) return TRUE;
 
  if(column == bd->group_unlink_col)
    _blendop_masks_group_unlink(module, formid, parentid);
  else
    _blendop_masks_group_delete(module, formid, parentid);
 
  return TRUE;
}
 
static gboolean _blendop_masks_group_button_pressed(GtkWidget *treeview, GdkEventButton *event,
                                                    dt_iop_module_t *module)
{
  if(IS_NULL_PTR(event) || event->type != GDK_BUTTON_PRESS) return FALSE;
 
  GtkTreePath *path = NULL;
  GtkTreeViewColumn *column = NULL;
  if(!gtk_tree_view_get_path_at_pos(GTK_TREE_VIEW(treeview), (gint)event->x, (gint)event->y, &path,
                                    &column, NULL, NULL))
    return FALSE;
 
  // Left click on the unlink / delete icon columns triggers the row action.
  if(event->button == GDK_BUTTON_PRIMARY)
  {
    const gboolean consumed = _blendop_masks_group_handle_action_click(treeview, path, column, module);
    gtk_tree_path_free(path);
    return consumed;
  }
 
  if(event->button != GDK_BUTTON_SECONDARY)
  {
    gtk_tree_path_free(path);
    return FALSE;
  }
 
  GtkTreeSelection *selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(treeview));
  gtk_tree_selection_unselect_all(selection);
  gtk_tree_selection_select_path(selection, path);
 
  GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(treeview));
  GtkTreeIter iter;
  int formid = -1;
  int parentid = -1;
  int state = 0;
  int index = -1;
  if(gtk_tree_model_get_iter(model, &iter, path))
    gtk_tree_model_get(model, &iter, BLENDOP_MASKS_GROUP_COL_FORMID, &formid,
                       BLENDOP_MASKS_GROUP_COL_PARENTID, &parentid,
                       BLENDOP_MASKS_GROUP_COL_STATE, &state,
                       BLENDOP_MASKS_GROUP_COL_INDEX, &index, -1);
  gtk_tree_path_free(path);
 
  if(formid <= 0 || parentid <= 0) return TRUE;
 
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  dt_masks_form_t *parent_group = dt_masks_get_from_id(module->dev, parentid);
  const int list_length = (parent_group && (parent_group->type & DT_MASKS_GROUP))
                              ? g_list_length(parent_group->points)
                              : 0;
 
  GtkWidget *menu = _blendop_masks_group_ctx_menu(bd, module, formid, parentid, state, index, list_length);
  if(IS_NULL_PTR(menu)) return TRUE;
  gtk_widget_show_all(menu);
  gtk_menu_popup_at_pointer(GTK_MENU(menu), (GdkEvent *)event);
  return TRUE;
}
 
// Per-column tooltips for the unlink / delete action icons.
static gboolean _blendop_masks_group_query_tooltip(GtkWidget *treeview, gint x, gint y, gboolean keyboard_tip,
                                                   GtkTooltip *tooltip, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module) || keyboard_tip) return FALSE;
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd)) return FALSE;
 
  gint bx = 0, by = 0;
  gtk_tree_view_convert_widget_to_bin_window_coords(GTK_TREE_VIEW(treeview), x, y, &bx, &by);
 
  GtkTreePath *path = NULL;
  GtkTreeViewColumn *column = NULL;
  if(!gtk_tree_view_get_path_at_pos(GTK_TREE_VIEW(treeview), bx, by, &path, &column, NULL, NULL))
    return FALSE;
  gtk_tree_path_free(path);
 
  const char *text = NULL;
  if(column == bd->group_unlink_col)
    text = _("Detach this shape from the mask. The shape is kept and stays available for reuse.");
  else if(column == bd->group_delete_col)
    text = _("Permanently delete this shape. It is detached from the mask and removed from the list of available shapes.");
 
  if(IS_NULL_PTR(text)) return FALSE;
 
  gtk_tooltip_set_text(tooltip, text);
  return TRUE;
}
 
// Depth-first search for the row matching (formid, parentid) anywhere in the group tree.
static gboolean _blendop_masks_group_find_row(GtkTreeModel *model, GtkTreeIter *parent,
                                              const int formid, const int parentid, GtkTreeIter *out)
{
  GtkTreeIter iter;
  gboolean valid = gtk_tree_model_iter_children(model, &iter, parent);
  while(valid)
  {
    int fid = -1;
    int pid = -1;
    gtk_tree_model_get(model, &iter, BLENDOP_MASKS_GROUP_COL_FORMID, &fid,
                       BLENDOP_MASKS_GROUP_COL_PARENTID, &pid, -1);
    if(fid == formid && pid == parentid)
    {
      *out = iter;
      return TRUE;
    }
    if(gtk_tree_model_iter_has_child(model, &iter)
       && _blendop_masks_group_find_row(model, &iter, formid, parentid, out))
      return TRUE;
    valid = gtk_tree_model_iter_next(model, &iter);
  }
  return FALSE;
}
 
// Refresh a single row in place (name + opacity + operation/inverse icons), the same way
// the masks library treeview does, so live opacity changes don't rebuild and collapse the tree.
static void _blendop_masks_group_update_row(dt_iop_module_t *module, const int formid, const int parentid)
{
  if(IS_NULL_PTR(module) || IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(!GTK_IS_TREE_VIEW(bd->masks_group_treeview)) return;
  GtkTreeModel *model = gtk_tree_view_get_model(GTK_TREE_VIEW(bd->masks_group_treeview));
  if(!GTK_IS_TREE_STORE(model)) return;
 
  GtkTreeIter iter;
  if(!_blendop_masks_group_find_row(model, NULL, formid, parentid, &iter)) return;
 
  dt_masks_form_t *form = dt_masks_get_from_id(module->dev, formid);
  dt_masks_form_t *parent_group = dt_masks_get_from_id(module->dev, parentid);
  int index = -1;
  dt_masks_form_group_t *entry = dt_masks_form_group_find_entry(parent_group, formid, &index);
  if(IS_NULL_PTR(form) || IS_NULL_PTR(entry)) return;
 
  char display_name[256] = "";
  if(entry->opacity != 1.0f)
    g_snprintf(display_name, sizeof(display_name), "%s %d%%", form->name, (int)(entry->opacity * 100));
  else
    g_strlcpy(display_name, form->name, sizeof(display_name));
 
  gtk_tree_store_set(GTK_TREE_STORE(model), &iter, BLENDOP_MASKS_GROUP_COL_NAME, display_name,
                     BLENDOP_MASKS_GROUP_COL_OP_ICON, _blendop_masks_get_op_icon(bd, entry->state, index),
                     BLENDOP_MASKS_GROUP_COL_INV_ICON, _blendop_masks_get_inverse_icon(bd, entry->state),
                     BLENDOP_MASKS_GROUP_COL_STATE, entry->state, -1);
}
 
static void _blendop_masks_handler_callback(gpointer instance, const int formid, const int parentid,
                                            const dt_masks_event_t event, dt_iop_module_t *module)
{
  (void)instance;
  // A plain value update (e.g. opacity) only needs the affected row refreshed in place.
  // Structural changes rebuild the whole list.
  if(event == DT_MASKS_EVENT_UPDATE)
    _blendop_masks_group_update_row(module, formid, parentid);
  else
    _blendop_masks_refresh_lists(module);
}
 
gboolean blend_color_picker_apply(dt_iop_module_t *module, GtkWidget *picker, dt_dev_pixelpipe_t *pipe,
                                  dt_dev_pixelpipe_iop_t *piece)
{
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
 
  if(picker == data->colorpicker_set_values)
  {
    if(dt_gui_widgets_suppressed()) return TRUE;
 
    dt_gui_freeze_begin();
 
    dt_develop_blend_params_t *bp = module->blend_params;
 
    const int tab = data->tab;
    dt_aligned_pixel_t raw_min, raw_max;
    float picker_min[8] DT_ALIGNED_PIXEL, picker_max[8] DT_ALIGNED_PIXEL;
    dt_aligned_pixel_t picker_values;
 
    const int in_out = (dt_modifier_is(dt_key_modifier_state(), DT_PRIMARY_MASK) && data->output_channels_shown) ? 1 : 0;
 
    if(in_out)
    {
      for(size_t i = 0; i < 4; i++)
      {
        raw_min[i] = module->picked_output_color_min[i];
        raw_max[i] = module->picked_output_color_max[i];
      }
    }
    else
    {
      for(size_t i = 0; i < 4; i++)
      {
        raw_min[i] = module->picked_color_min[i];
        raw_max[i] = module->picked_color_max[i];
      }
    }
 
    const dt_iop_gui_blendif_channel_t *channel = &data->channel[data->tab];
    dt_develop_blendif_channels_t ch = channel->param_channels[in_out];
    dt_iop_gui_blendif_filter_t *sl = &data->filter[in_out];
 
    float *parameters = &(bp->blendif_parameters[4 * ch]);
 
    const dt_develop_blend_colorspace_t blend_csp = data->channel_tabs_csp;
    const dt_iop_colorspace_type_t cst = _blendif_colorpicker_cst(data);
    const dt_iop_order_iccprofile_info_t *work_profile = (blend_csp == DEVELOP_BLEND_CS_RGB_SCENE)
        ? dt_ioppr_get_pipe_current_profile_info(piece->module, pipe)
        : dt_ioppr_get_iop_work_profile_info(module, module->dev->iop);
 
    gboolean reverse_hues = FALSE;
    if(cst == IOP_CS_HSL && tab == CHANNEL_INDEX_H)
    {
      if((raw_max[3] - raw_min[3]) < (raw_max[0] - raw_min[0]) && raw_min[3] < 0.5f && raw_max[3] > 0.5f)
      {
        raw_max[0] = raw_max[3] < 0.5f ? raw_max[3] + 0.5f : raw_max[3] - 0.5f;
        raw_min[0] = raw_min[3] < 0.5f ? raw_min[3] + 0.5f : raw_min[3] - 0.5f;
        reverse_hues = TRUE;
      }
    }
    else if((cst == IOP_CS_LCH && tab == CHANNEL_INDEX_h) || (cst == IOP_CS_JZCZHZ && tab == CHANNEL_INDEX_hz))
    {
      if((raw_max[3] - raw_min[3]) < (raw_max[2] - raw_min[2]) && raw_min[3] < 0.5f && raw_max[3] > 0.5f)
      {
        raw_max[2] = raw_max[3] < 0.5f ? raw_max[3] + 0.5f : raw_max[3] - 0.5f;
        raw_min[2] = raw_min[3] < 0.5f ? raw_min[3] + 0.5f : raw_min[3] - 0.5f;
        reverse_hues = TRUE;
      }
    }
 
    _blendif_scale(data, cst, raw_max, picker_max, work_profile, in_out);
 
    gboolean picker_box_changed = FALSE;
    const dt_colorpicker_sample_t *const sample = module->dev->color_picker.primary_sample;
    if(!IS_NULL_PTR(sample) && sample->size == DT_LIB_COLORPICKER_SIZE_BOX)
    {
      if(!data->picker_set_values_box_valid)
      {
        picker_box_changed = TRUE;
      }
      else
      {
        const float epsilon = 1e-6f;
        for(int k = 0; k < 4; k++)
        {
          if(fabsf(sample->box[k] - data->picker_set_values_box[k]) > epsilon)
          {
            picker_box_changed = TRUE;
            break;
          }
        }
      }
 
      if(picker_box_changed)
      {
        for(int k = 0; k < 4; k++) data->picker_set_values_box[k] = sample->box[k];
        data->picker_set_values_box_valid = TRUE;
        data->picker_set_values_manual_boost_lock = FALSE;
      }
    }
    else
    {
      data->picker_set_values_box_valid = FALSE;
      data->picker_set_values_manual_boost_lock = FALSE;
    }
 
    if(channel->boost_factor_enabled && picker_box_changed
       && !data->picker_set_values_manual_boost_lock)
    {
      const float picker_margin = 0.02f;
      const float boost_step = 0.25f;
      const int max_boost_iters = 64;
      const float boost_min = channel->boost_factor_offset;
      const float boost_max = channel->boost_factor_offset + 18.0f;
      const float target_max = (picker_max[tab] > (1.0f - picker_margin)) ? 1.0f : (1.0f - picker_margin);
      float trial = bp->blendif_boost_factors[ch];
      gboolean within_bounds = picker_max[tab] <= target_max;
 
      if(!within_bounds)
      {
        for(int iter = 0; iter < max_boost_iters && trial < boost_max; iter++)
        {
          trial = fminf(trial + boost_step, boost_max);
          bp->blendif_boost_factors[ch] = trial;
          _blendif_scale(data, cst, raw_max, picker_max, work_profile, in_out);
          within_bounds = picker_max[tab] <= target_max;
          if(within_bounds) break;
        }
      }
 
      if(within_bounds)
      {
        for(int iter = 0; iter < max_boost_iters && trial > boost_min; iter++)
        {
          const float candidate = fmaxf(trial - boost_step, boost_min);
          bp->blendif_boost_factors[ch] = candidate;
          _blendif_scale(data, cst, raw_max, picker_max, work_profile, in_out);
          if(picker_max[tab] > target_max)
            break;
          trial = candidate;
        }
      }
 
      bp->blendif_boost_factors[ch] = trial;
      _blendif_scale(data, cst, raw_max, picker_max, work_profile, in_out);
    }
 
    _blendif_scale(data, cst, raw_min, picker_min, work_profile, in_out);
 
    const float feather = 0.01f;
 
    if(picker_min[tab] > picker_max[tab])
    {
      const float tmp = picker_min[tab];
      picker_min[tab] = picker_max[tab];
      picker_max[tab] = tmp;
    }
 
    picker_values[0] = CLAMP(picker_min[tab] - feather, 0.f, 1.f);
    picker_values[1] = CLAMP(picker_min[tab] + feather, 0.f, 1.f);
    picker_values[2] = CLAMP(picker_max[tab] - feather, 0.f, 1.f);
    picker_values[3] = CLAMP(picker_max[tab] + feather, 0.f, 1.f);
 
    if(picker_values[1] > picker_values[2])
    {
      picker_values[1] = CLAMP(picker_min[tab], 0.f, 1.f);
      picker_values[2] = CLAMP(picker_max[tab], 0.f, 1.f);
    }
 
    picker_values[0] = CLAMP(picker_values[0], 0.f, picker_values[1]);
    picker_values[3] = CLAMP(picker_values[3], picker_values[2], 1.f);
 
    dt_pthread_mutex_lock(&data->lock);
    for(int k = 0; k < 4; k++)
      dtgtk_gradient_slider_multivalue_set_value(sl->slider, picker_values[k], k);
    dt_pthread_mutex_unlock(&data->lock);
 
    // update picked values
    _update_gradient_slider_pickers(NULL, module);
 
    const float boost_factor = _get_boost_factor(data, data->tab, in_out);
    for(int k = 0; k < 4; k++)
    {
      char text[256];
      channel->scale_print(dtgtk_gradient_slider_multivalue_get_value(sl->slider, k), boost_factor,
                           text, sizeof(text));
      gtk_label_set_text(sl->label[k], text);
    }
 
    dt_gui_freeze_end();
 
    // save values to parameters
    dt_pthread_mutex_lock(&data->lock);
    for(int k = 0; k < 4; k++)
      parameters[k] = dtgtk_gradient_slider_multivalue_get_value(sl->slider, k);
    dt_pthread_mutex_unlock(&data->lock);
 
    // de-activate processing of this channel if maximum span is selected
    if(parameters[1] == 0.0f && parameters[2] == 1.0f)
      bp->blendif &= ~(1 << ch);
    else
      bp->blendif |= (1 << ch);
 
    // set the polarity of the channel to include the picked values
    if(reverse_hues == ((bp->mask_combine & DEVELOP_COMBINE_INV) == DEVELOP_COMBINE_INV))
      bp->blendif &= ~(1 << (16 + ch));
    else
      bp->blendif |= 1 << (16 + ch);
 
    dt_dev_add_history_item(module->dev, module, TRUE, TRUE);
 
    dt_iop_gui_update_header(module);
    _blendop_blendif_update_tab(module, tab);
 
    return TRUE;
  }
  else if(picker == data->colorpicker)
  {
    if(dt_gui_widgets_suppressed()) return TRUE;
 
    _update_gradient_slider_pickers(NULL, module);
 
    return TRUE;
  }
  else return FALSE; // needs to be handled by module
}
 
static gboolean _blendif_change_blend_colorspace(dt_iop_module_t *module, dt_develop_blend_colorspace_t cst)
{
  switch(cst)
  {
    case DEVELOP_BLEND_CS_RAW:
    case DEVELOP_BLEND_CS_LAB:
    case DEVELOP_BLEND_CS_RGB_DISPLAY:
    case DEVELOP_BLEND_CS_RGB_SCENE:
      break;
    default:
      cst = dt_develop_blend_default_module_blend_colorspace(module);
      break;
  }
  if(!dt_develop_blend_colorspace_is_compatible(module, cst)) return FALSE;
  if(cst != module->blend_params->blend_cst)
  {
    dt_develop_blend_init_blendif_parameters(module->blend_params, cst);
 
    // look for last history item for this module with the selected blending mode to copy parametric mask settings
    for(const GList *history = g_list_last(module->dev->history); history; history = g_list_previous(history))
    {
      const dt_dev_history_item_t *data = (dt_dev_history_item_t *)(history->data);
      if(data->module == module && data->blend_params->blend_cst == cst)
      {
        const dt_develop_blend_params_t *hp = data->blend_params;
        dt_develop_blend_params_t *np = module->blend_params;
 
        np->blend_mode = hp->blend_mode;
        np->blend_parameter = hp->blend_parameter;
        np->blendif = hp->blendif;
        memcpy(np->blendif_parameters, hp->blendif_parameters, sizeof(hp->blendif_parameters));
        memcpy(np->blendif_boost_factors, hp->blendif_boost_factors, sizeof(hp->blendif_boost_factors));
        break;
      }
    }
 
    dt_iop_gui_blend_data_t *bd = module->gui->blend_data;
    const int cst_old = _blendop_blendif_get_picker_colorspace(bd);
    dt_dev_add_history_item(module->dev, module, FALSE, TRUE);
    dt_iop_gui_update(module);
 
    if(cst_old != _blendop_blendif_get_picker_colorspace(bd) &&
       (gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(bd->colorpicker)) ||
        gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(bd->colorpicker_set_values))))
    {
      dt_iop_color_picker_set_cst(bd->module, _blendop_blendif_get_picker_colorspace(bd));
      dt_dev_pixelpipe_update_history_all(bd->module->dev);
    }
 
    return TRUE;
  }
  return FALSE;
}
 
static void _blendif_select_colorspace(GtkMenuItem *menuitem, dt_iop_module_t *module)
{
  dt_develop_blend_colorspace_t cst = GPOINTER_TO_INT(g_object_get_data(G_OBJECT(menuitem), "dt-blend-cst"));
  if(_blendif_change_blend_colorspace(module, cst))
  {
    gtk_widget_queue_draw(module->gui->widget);
  }
}
 
static void _blendif_show_output_channels(GtkMenuItem *menuitem, dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd) || !bd->blendif_support || !bd->blendif_inited) return;
  if(!bd->output_channels_shown)
  {
    bd->output_channels_shown = TRUE;
    dt_iop_gui_update(module);
  }
}
 
static void _blendif_hide_output_channels(GtkMenuItem *menuitem, dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd) || !bd->blendif_support || !bd->blendif_inited) return;
  if(bd->output_channels_shown)
  {
    bd->output_channels_shown = FALSE;
    if(_blendif_clean_output_channels(module))
    {
      dt_dev_add_history_item(module->dev, module, TRUE, TRUE);
    }
    dt_iop_gui_update(module);
  }
}
 
static void _blendif_append_colorspace_item(GtkMenu *menu, dt_iop_module_t *module, const char *label,
                                            const dt_develop_blend_colorspace_t cst)
{
  GtkWidget *mi = gtk_check_menu_item_new_with_label(label);
  const gboolean current = module->blend_params->blend_cst == cst;
  if(current)
  {
    gtk_check_menu_item_set_active(GTK_CHECK_MENU_ITEM(mi), TRUE);
    dt_gui_add_class(mi, "active_menu_item");
  }
  // the space an edit already uses stays readable as such, even where it would not be offered
  gtk_widget_set_sensitive(mi, current || dt_develop_blend_colorspace_is_compatible(module, cst));
  g_object_set_data_full(G_OBJECT(mi), "dt-blend-cst", GINT_TO_POINTER(cst), NULL);
  g_signal_connect(G_OBJECT(mi), "activate", G_CALLBACK(_blendif_select_colorspace), module);
  gtk_menu_shell_append(GTK_MENU_SHELL(menu), mi);
}
 
static void _blendif_options_callback(GtkButton *button, GdkEventButton *event, dt_iop_module_t *module)
{
  if(event->button != 1 && event->button != 2) return;
  const dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd) || !bd->blendif_support || !bd->blendif_inited) return;
 
  GtkWidget *mi;
  GtkMenu *menu = dt_gui_get_global()->presets_popup_menu;
  if(menu) gtk_widget_destroy(GTK_WIDGET(menu));
  dt_gui_get_global()->presets_popup_menu = GTK_MENU(gtk_menu_new());
  menu = dt_gui_get_global()->presets_popup_menu;
 
  // add a section to switch blending color spaces
  const dt_develop_blend_colorspace_t module_cst = dt_develop_blend_default_module_blend_colorspace(module);
  if(module_cst == DEVELOP_BLEND_CS_LAB || module_cst == DEVELOP_BLEND_CS_RGB_DISPLAY
      || module_cst == DEVELOP_BLEND_CS_RGB_SCENE)
  {
 
    mi = gtk_menu_item_new_with_label(_("reset to default blend colorspace"));
    g_object_set_data_full(G_OBJECT(mi), "dt-blend-cst", GINT_TO_POINTER(DEVELOP_BLEND_CS_NONE), NULL);
    g_signal_connect(G_OBJECT(mi), "activate", G_CALLBACK(_blendif_select_colorspace), module);
    gtk_menu_shell_append(GTK_MENU_SHELL(menu), mi);
 
    // every blending space is listed, the ones this module cannot blend in are greyed out
    _blendif_append_colorspace_item(menu, module, _("Lab"), DEVELOP_BLEND_CS_LAB);
    _blendif_append_colorspace_item(menu, module, _("RGB (display)"), DEVELOP_BLEND_CS_RGB_DISPLAY);
    _blendif_append_colorspace_item(menu, module, _("RGB (scene)"), DEVELOP_BLEND_CS_RGB_SCENE);
 
    gtk_menu_shell_append(GTK_MENU_SHELL(menu), gtk_separator_menu_item_new());
 
    if(bd->output_channels_shown)
    {
      mi = gtk_menu_item_new_with_label(_("reset and hide output channels"));
      g_signal_connect(G_OBJECT(mi), "activate", G_CALLBACK(_blendif_hide_output_channels), module);
      gtk_menu_shell_append(GTK_MENU_SHELL(menu), mi);
    }
    else
    {
      mi = gtk_menu_item_new_with_label(_("show output channels"));
      g_signal_connect(G_OBJECT(mi), "activate", G_CALLBACK(_blendif_show_output_channels), module);
      gtk_menu_shell_append(GTK_MENU_SHELL(menu), mi);
    }
  }
 
  dt_gui_menu_popup(dt_gui_get_global()->presets_popup_menu, GTK_WIDGET(button), GDK_GRAVITY_SOUTH_EAST, GDK_GRAVITY_NORTH_EAST);
 
  dtgtk_button_set_active(DTGTK_BUTTON(button), FALSE);
}
 
// activate channel/mask view
static void _blendop_blendif_channel_mask_view(GtkWidget *widget, dt_iop_module_t *module, dt_dev_pixelpipe_display_mask_t mode)
{
  // FIXME : there are more than 3 functions getting clever about how to setup module->request_mask_display depending on user input.
  // These should all use an uniform setter function.
  //
  // The lack of setter implies we don't guaranty that only 1 module can request mask display at a time.
  // The consequence is pipeline needs to check if module->request_mask_display AND module == dev->gui_module,
  // but the global pipe->mask_display is set from *_blend_process() at runtime, so it's a pipe property
  // that changes over the pipe lifecycle.
  //
  // This is a self-feeding loop of madness because it ties the pipeline to GUI states
  // (but not all pipes are connected to a GUI, so you need to cover all cases all the time and don't forget to test everything),
  // and because the pipeline is executed recursively from the end, but pipe->mask_display is set in the middle,
  // when it reaches the process() method of the module capturing mask preview, so you don't have this info when
  // planning for pipeline execution.
  // And you need to plan for mask preview ahead in pipe because mask preview needs to work
  // without using the pixelpipe cache, at least between the module requiring mask preview and gamma.c, which will actually render
  // the preview at the far end of the pipe.
  // So the not-so-clever workaround inherited from darktable was to flush all cache lines when requesting mask preview,
  // which flushed lines that could be reused later and were only temporarily not needed.
 
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
 
  dt_dev_pixelpipe_display_mask_t new_request_mask_display = module->request_mask_display | mode;
 
  // in case user requests channel display: get the cannel
  if(new_request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_CHANNEL)
  {
    dt_dev_pixelpipe_display_mask_t channel = data->channel[data->tab].display_channel;
 
    if(widget == GTK_WIDGET(data->filter[1].slider))
      channel |= DT_DEV_PIXELPIPE_DISPLAY_OUTPUT;
 
    new_request_mask_display &= ~DT_DEV_PIXELPIPE_DISPLAY_ANY;
    new_request_mask_display |= channel;
  }
 
  // only if something has changed: reprocess center view
  if(new_request_mask_display != module->request_mask_display)
  {
    module->request_mask_display = new_request_mask_display;
    dt_iop_set_cache_bypass(module, module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
    _blendop_blendif_sync_channel_display_buttons(module);
    dt_dev_pixelpipe_update_history_main(module->dev);
  }
}
 
// toggle channel/mask view
static void _blendop_blendif_channel_mask_view_toggle(GtkWidget *widget, dt_iop_module_t *module, dt_dev_pixelpipe_display_mask_t mode)
{
  // FIXME : there are more than 3 functions getting clever about how to setup module->request_mask_display depending on user input.
  // These should all use an uniform setter function.
  //
  // The lack of setter implies we don't guaranty that only 1 module can request mask display at a time.
  // The consequence is pipeline needs to check if module->request_mask_display AND module == dev->gui_module,
  // but the global pipe->mask_display is set from *_blend_process() at runtime, so it's a pipe property
  // that changes over the pipe lifecycle.
  //
  // This is a self-feeding loop of madness because it ties the pipeline to GUI states
  // (but not all pipes are connected to a GUI, so you need to cover all cases all the time and don't forget to test everything),
  // and because the pipeline is executed recursively from the end, but pipe->mask_display is set in the middle,
  // when it reaches the process() method of the module capturing mask preview, so you don't have this info when
  // planning for pipeline execution.
  // And you need to plan for mask preview ahead in pipe because mask preview needs to work
  // without using the pixelpipe cache, at least between the module requiring mask preview and gamma.c, which will actually render
  // the preview at the far end of the pipe.
  // So the not-so-clever workaround inherited from darktable was to flush all cache lines when requesting mask preview,
  // which flushed lines that could be reused later and were only temporarily not needed.
 
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
 
  dt_dev_pixelpipe_display_mask_t new_request_mask_display = module->request_mask_display & ~DT_DEV_PIXELPIPE_DISPLAY_STICKY;
 
  // toggle mode
  if(module->request_mask_display & mode)
    new_request_mask_display &= ~mode;
  else
    new_request_mask_display |= mode;
 
  dt_pthread_mutex_lock(&data->lock);
  if(new_request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_STICKY)
    data->save_for_leave |= DT_DEV_PIXELPIPE_DISPLAY_STICKY;
  else
    data->save_for_leave &= ~DT_DEV_PIXELPIPE_DISPLAY_STICKY;
  dt_pthread_mutex_unlock(&data->lock);
 
  new_request_mask_display &= ~DT_DEV_PIXELPIPE_DISPLAY_ANY;
 
  // in case user requests channel display: get the cannel
  if(new_request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_CHANNEL)
  {
    dt_dev_pixelpipe_display_mask_t channel = data->channel[data->tab].display_channel;
 
    if(widget == GTK_WIDGET(data->filter[1].slider))
      channel |= DT_DEV_PIXELPIPE_DISPLAY_OUTPUT;
 
    new_request_mask_display &= ~DT_DEV_PIXELPIPE_DISPLAY_ANY;
    new_request_mask_display |= channel;
  }
 
  if(new_request_mask_display != module->request_mask_display)
  {
    module->request_mask_display = new_request_mask_display;
    dt_iop_set_cache_bypass(module, module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
    _blendop_blendif_sync_channel_display_buttons(module);
    dt_dev_pixelpipe_update_history_main(module->dev);
  }
}
 
static void _blendop_blendif_sync_channel_display_buttons(dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *data = !IS_NULL_PTR(module) ? module->gui->blend_data : NULL;
  if(IS_NULL_PTR(data)) return;
 
  const gboolean channel_active
      = (module->request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_CHANNEL) != 0;
  const gboolean output_active
      = channel_active && (module->request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_OUTPUT) != 0;
 
  dt_gui_freeze_begin();
  if(GTK_IS_TOGGLE_BUTTON(data->filter[0].channel_display))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(data->filter[0].channel_display),
                                 channel_active && !output_active);
  if(GTK_IS_TOGGLE_BUTTON(data->filter[1].channel_display))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(data->filter[1].channel_display),
                                 output_active);
  dt_gui_freeze_end();
}
 
static void _blendop_blendif_channel_display_toggled(GtkToggleButton *button, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_iop_gui_blend_data_t *data = !IS_NULL_PTR(module) ? module->gui->blend_data : NULL;
  if(IS_NULL_PTR(data) || IS_NULL_PTR(data->channel)) return;
 
  const int in_out = GTK_WIDGET(button) == data->filter[1].channel_display ? 1 : 0;
  const gboolean active = gtk_toggle_button_get_active(button);
  GtkWidget *const other_button = data->filter[!in_out].channel_display;
 
  dt_gui_freeze_begin();
  if(active && GTK_IS_TOGGLE_BUTTON(other_button))
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(other_button), FALSE);
  dt_gui_freeze_end();
 
  dt_dev_pixelpipe_display_mask_t new_request_mask_display
      = module->request_mask_display
        & ~(DT_DEV_PIXELPIPE_DISPLAY_CHANNEL | DT_DEV_PIXELPIPE_DISPLAY_OUTPUT
            | DT_DEV_PIXELPIPE_DISPLAY_ANY | DT_DEV_PIXELPIPE_DISPLAY_STICKY);
 
  if(active)
  {
    new_request_mask_display |= DT_DEV_PIXELPIPE_DISPLAY_CHANNEL
                                | DT_DEV_PIXELPIPE_DISPLAY_STICKY
                                | data->channel[data->tab].display_channel;
    if(in_out) new_request_mask_display |= DT_DEV_PIXELPIPE_DISPLAY_OUTPUT;
  }
 
  dt_pthread_mutex_lock(&data->lock);
  if(active)
    data->save_for_leave |= DT_DEV_PIXELPIPE_DISPLAY_STICKY;
  else
    data->save_for_leave &= ~DT_DEV_PIXELPIPE_DISPLAY_STICKY;
  dt_pthread_mutex_unlock(&data->lock);
 
  if(new_request_mask_display == module->request_mask_display) return;
 
  module->request_mask_display = new_request_mask_display;
  dt_iop_set_cache_bypass(module, module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
 
  dt_iop_request_focus(module);
  dt_dev_pixelpipe_update_history_main(module->dev);
}
 
 
// magic mode: if mouse cursor enters a gradient slider with shift and/or control pressed we
// enter channel display and/or mask display mode
static gboolean _blendop_blendif_enter(GtkWidget *widget, GdkEventCrossing *event, dt_iop_module_t *module)
{
  // FIXME : there are more than 3 functions getting clever about how to setup module->request_mask_display depending on user input.
  // These should all use an uniform setter function.
  //
  // The lack of setter implies we don't guaranty that only 1 module can request mask display at a time.
  // The consequence is pipeline needs to check if module->request_mask_display AND module == dev->gui_module,
  // but the global pipe->mask_display is set from *_blend_process() at runtime, so it's a pipe property
  // that changes over the pipe lifecycle.
  //
  // This is a self-feeding loop of madness because it ties the pipeline to GUI states
  // (but not all pipes are connected to a GUI, so you need to cover all cases all the time and don't forget to test everything),
  // and because the pipeline is executed recursively from the end, but pipe->mask_display is set in the middle,
  // when it reaches the process() method of the module capturing mask preview, so you don't have this info when
  // planning for pipeline execution.
  // And you need to plan for mask preview ahead in pipe because mask preview needs to work
  // without using the pixelpipe cache, at least between the module requiring mask preview and gamma.c, which will actually render
  // the preview at the far end of the pipe.
  // So the not-so-clever workaround inherited from darktable was to flush all cache lines when requesting mask preview,
  // which flushed lines that could be reused later and were only temporarily not needed.
 
  if(dt_gui_widgets_suppressed()) return FALSE;
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
 
  dt_dev_pixelpipe_display_mask_t mode = 0;
 
  // depending on shift modifiers we activate channel and/or mask display
  if(dt_modifier_is(event->state, GDK_SHIFT_MASK | DT_PRIMARY_MASK))
  {
    mode = (DT_DEV_PIXELPIPE_DISPLAY_MASK | DT_DEV_PIXELPIPE_DISPLAY_CHANNEL);
  }
  else if(dt_modifier_is(event->state, GDK_SHIFT_MASK))
  {
    mode = DT_DEV_PIXELPIPE_DISPLAY_CHANNEL;
  }
  else if(dt_modifier_is(event->state, DT_PRIMARY_MASK))
  {
    mode = DT_DEV_PIXELPIPE_DISPLAY_MASK;
  }
 
  dt_pthread_mutex_lock(&data->lock);
  if(mode && data->timeout_handle)
  {
    // purge any remaining timeout handlers
    g_source_remove(data->timeout_handle);
    data->timeout_handle = 0;
  }
  else if(!data->timeout_handle && !(data->save_for_leave & DT_DEV_PIXELPIPE_DISPLAY_STICKY))
  {
    // save request_mask_display to restore later
    data->save_for_leave = module->request_mask_display & ~DT_DEV_PIXELPIPE_DISPLAY_STICKY;
  }
  dt_pthread_mutex_unlock(&data->lock);
 
  /* A plain hover only gives keyboard focus to the slider. Reapplying an
   * already-active CHANNEL request here would derive INPUT/OUTPUT again from
   * the hovered widget and switch the persistent channel toggle without a
   * click. Only modifier-assisted hover is allowed to change the preview. */
  if(mode != DT_DEV_PIXELPIPE_DISPLAY_NONE)
    _blendop_blendif_channel_mask_view(widget, module, mode);
 
  gtk_widget_grab_focus(widget);
  return FALSE;
}
 
 
// handler for delayed mask/channel display mode switch-off
static gboolean _blendop_blendif_leave_delayed(gpointer data)
{
  // FIXME : there are more than 3 functions getting clever about how to setup module->request_mask_display depending on user input.
  // These should all use an uniform setter function.
  //
  // The lack of setter implies we don't guaranty that only 1 module can request mask display at a time.
  // The consequence is pipeline needs to check if module->request_mask_display AND module == dev->gui_module,
  // but the global pipe->mask_display is set from *_blend_process() at runtime, so it's a pipe property
  // that changes over the pipe lifecycle.
  //
  // This is a self-feeding loop of madness because it ties the pipeline to GUI states
  // (but not all pipes are connected to a GUI, so you need to cover all cases all the time and don't forget to test everything),
  // and because the pipeline is executed recursively from the end, but pipe->mask_display is set in the middle,
  // when it reaches the process() method of the module capturing mask preview, so you don't have this info when
  // planning for pipeline execution.
  // And you need to plan for mask preview ahead in pipe because mask preview needs to work
  // without using the pixelpipe cache, at least between the module requiring mask preview and gamma.c, which will actually render
  // the preview at the far end of the pipe.
  // So the not-so-clever workaround inherited from darktable was to flush all cache lines when requesting mask preview,
  // which flushed lines that could be reused later and were only temporarily not needed.
 
  dt_iop_module_t *module = (dt_iop_module_t *)data;
  dt_iop_gui_blend_data_t *bd = module->gui->blend_data;
  int reprocess = 0;
 
  dt_pthread_mutex_lock(&bd->lock);
  // restore saved request_mask_display and reprocess image
  if(bd->timeout_handle && (module->request_mask_display != (bd->save_for_leave & ~DT_DEV_PIXELPIPE_DISPLAY_STICKY)))
  {
    module->request_mask_display = bd->save_for_leave & ~DT_DEV_PIXELPIPE_DISPLAY_STICKY;
    dt_iop_set_cache_bypass(module, module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
    reprocess = 1;
  }
  bd->timeout_handle = 0;
  dt_pthread_mutex_unlock(&bd->lock);
 
  if(reprocess)
  {
    _blendop_blendif_sync_channel_display_buttons(module);
    dt_dev_pixelpipe_update_history_main(module->dev);
  }
  // return FALSE and thereby terminate the handler
  return FALSE;
}
 
// de-activate magic mode when leaving the gradient slider
static gboolean _blendop_blendif_leave(GtkWidget *widget, GdkEventCrossing *event, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return FALSE;
  dt_iop_gui_blend_data_t *data = module->gui->blend_data;
 
  // do not immediately switch-off mask/channel display in case user leaves gradient only briefly.
  // instead we activate a handler function that gets triggered after some timeout
  dt_pthread_mutex_lock(&data->lock);
  if(!(module->request_mask_display & DT_DEV_PIXELPIPE_DISPLAY_STICKY) && !data->timeout_handle &&
    (module->request_mask_display != (data->save_for_leave & ~DT_DEV_PIXELPIPE_DISPLAY_STICKY)))
      data->timeout_handle = g_timeout_add(1000, _blendop_blendif_leave_delayed, module);
  dt_pthread_mutex_unlock(&data->lock);
 
  return FALSE;
}
 
 
static gboolean _blendop_blendif_key_press(GtkWidget *widget, GdkEventKey *event, dt_iop_module_t *module)
{
  if(dt_gui_widgets_suppressed()) return FALSE;
 
  gboolean handled = FALSE;
 
  switch(event->keyval)
  {
    case GDK_KEY_m:
    case GDK_KEY_M:
      _blendop_blendif_channel_mask_view_toggle(widget, module, DT_DEV_PIXELPIPE_DISPLAY_MASK);
      handled = TRUE;
  }
 
  if(handled)
    dt_iop_request_focus(module);
 
  return handled;
}
 
 
#define COLORSTOPS(gradient) sizeof(gradient) / sizeof(dt_iop_gui_blendif_colorstop_t), gradient
 
const dt_iop_gui_blendif_channel_t Lab_channels[]
    = { { N_("L"), N_("sliders for L channel"), 1.0f / 100.0f, COLORSTOPS(_gradient_L), TRUE, 0.0f,
          { DEVELOP_BLENDIF_L_in, DEVELOP_BLENDIF_L_out }, DT_DEV_PIXELPIPE_DISPLAY_L,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("lightness") },
        { N_("a"), N_("sliders for a channel"), 1.0f / 256.0f, COLORSTOPS(_gradient_a), TRUE, 0.0f,
          { DEVELOP_BLENDIF_A_in, DEVELOP_BLENDIF_A_out }, DT_DEV_PIXELPIPE_DISPLAY_a,
          _blendif_scale_print_ab, _blendop_blendif_disp_alternative_mag, N_("green/red") },
        { N_("b"), N_("sliders for b channel"), 1.0f / 256.0f, COLORSTOPS(_gradient_b), TRUE, 0.0f,
          { DEVELOP_BLENDIF_B_in, DEVELOP_BLENDIF_B_out }, DT_DEV_PIXELPIPE_DISPLAY_b,
          _blendif_scale_print_ab, _blendop_blendif_disp_alternative_mag, N_("blue/yellow") },
        { N_("C"), N_("sliders for chroma channel (of LCh)"), 1.0f / 100.0f, COLORSTOPS(_gradient_chroma),
          TRUE, 0.0f,
          { DEVELOP_BLENDIF_C_in, DEVELOP_BLENDIF_C_out }, DT_DEV_PIXELPIPE_DISPLAY_LCH_C,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("saturation") },
        { N_("h"), N_("sliders for hue channel (of LCh)"), 1.0f / 360.0f, COLORSTOPS(_gradient_LCh_hue),
          FALSE, 0.0f,
          { DEVELOP_BLENDIF_h_in, DEVELOP_BLENDIF_h_out }, DT_DEV_PIXELPIPE_DISPLAY_LCH_h,
          _blendif_scale_print_hue, NULL, N_("hue") },
        { NULL } };
 
const dt_iop_gui_blendif_channel_t rgb_channels[]
    = { { N_("g"), N_("sliders for gray value"), 1.0f / 255.0f, COLORSTOPS(_gradient_gray), TRUE, 0.0f,
          { DEVELOP_BLENDIF_GRAY_in, DEVELOP_BLENDIF_GRAY_out }, DT_DEV_PIXELPIPE_DISPLAY_GRAY,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("gray") },
        { N_("R"), N_("sliders for red channel"), 1.0f / 255.0f, COLORSTOPS(_gradient_red), TRUE, 0.0f,
          { DEVELOP_BLENDIF_RED_in, DEVELOP_BLENDIF_RED_out }, DT_DEV_PIXELPIPE_DISPLAY_R,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("red") },
        { N_("G"), N_("sliders for green channel"), 1.0f / 255.0f, COLORSTOPS(_gradient_green), TRUE, 0.0f,
          { DEVELOP_BLENDIF_GREEN_in, DEVELOP_BLENDIF_GREEN_out }, DT_DEV_PIXELPIPE_DISPLAY_G,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("green") },
        { N_("B"), N_("sliders for blue channel"), 1.0f / 255.0f, COLORSTOPS(_gradient_blue), TRUE, 0.0f,
          { DEVELOP_BLENDIF_BLUE_in, DEVELOP_BLENDIF_BLUE_out }, DT_DEV_PIXELPIPE_DISPLAY_B,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("blue") },
        { N_("H"), N_("sliders for hue channel (of HSL)"), 1.0f / 360.0f, COLORSTOPS(_gradient_HSL_hue),
          FALSE, 0.0f,
          { DEVELOP_BLENDIF_H_in, DEVELOP_BLENDIF_H_out }, DT_DEV_PIXELPIPE_DISPLAY_HSL_H,
          _blendif_scale_print_hue, NULL, N_("hue") },
        { N_("S"), N_("sliders for chroma channel (of HSL)"), 1.0f / 100.0f, COLORSTOPS(_gradient_chroma),
          FALSE, 0.0f,
          { DEVELOP_BLENDIF_S_in, DEVELOP_BLENDIF_S_out }, DT_DEV_PIXELPIPE_DISPLAY_HSL_S,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("chroma") },
        { N_("L"), N_("sliders for value channel (of HSL)"), 1.0f / 100.0f, COLORSTOPS(_gradient_gray),
          FALSE, 0.0f,
          { DEVELOP_BLENDIF_l_in, DEVELOP_BLENDIF_l_out }, DT_DEV_PIXELPIPE_DISPLAY_HSL_l,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("luminance") },
        { NULL } };
 
const dt_iop_gui_blendif_channel_t rgbj_channels[]
    = { { N_("g"), N_("sliders for gray value"), 1.0f / 255.0f, COLORSTOPS(_gradient_gray), TRUE, 0.0f,
          { DEVELOP_BLENDIF_GRAY_in, DEVELOP_BLENDIF_GRAY_out }, DT_DEV_PIXELPIPE_DISPLAY_GRAY,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("gray") },
        { N_("R"), N_("sliders for red channel"), 1.0f / 255.0f, COLORSTOPS(_gradient_red), TRUE, 0.0f,
          { DEVELOP_BLENDIF_RED_in, DEVELOP_BLENDIF_RED_out }, DT_DEV_PIXELPIPE_DISPLAY_R,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("red") },
        { N_("G"), N_("sliders for green channel"), 1.0f / 255.0f, COLORSTOPS(_gradient_green), TRUE, 0.0f,
          { DEVELOP_BLENDIF_GREEN_in, DEVELOP_BLENDIF_GREEN_out }, DT_DEV_PIXELPIPE_DISPLAY_G,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("green") },
        { N_("B"), N_("sliders for blue channel"), 1.0f / 255.0f, COLORSTOPS(_gradient_blue), TRUE, 0.0f,
          { DEVELOP_BLENDIF_BLUE_in, DEVELOP_BLENDIF_BLUE_out }, DT_DEV_PIXELPIPE_DISPLAY_B,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("blue") },
        { N_("Jz"), N_("sliders for value channel (of JzCzhz)"), 1.0f / 100.0f, COLORSTOPS(_gradient_gray),
          TRUE, -6.64385619f, // cf. _blend_init_blendif_boost_parameters
          { DEVELOP_BLENDIF_Jz_in, DEVELOP_BLENDIF_Jz_out }, DT_DEV_PIXELPIPE_DISPLAY_JzCzhz_Jz,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("luminance") },
        { N_("Cz"), N_("sliders for chroma channel (of JzCzhz)"), 1.0f / 100.0f, COLORSTOPS(_gradient_chroma),
          TRUE, -6.64385619f, // cf. _blend_init_blendif_boost_parameters
          { DEVELOP_BLENDIF_Cz_in, DEVELOP_BLENDIF_Cz_out }, DT_DEV_PIXELPIPE_DISPLAY_JzCzhz_Cz,
          _blendif_scale_print_default, _blendop_blendif_disp_alternative_log, N_("chroma") },
        { N_("hz"), N_("sliders for hue channel (of JzCzhz)"), 1.0f / 360.0f, COLORSTOPS(_gradient_JzCzhz_hue),
          FALSE, 0.0f,
          { DEVELOP_BLENDIF_hz_in, DEVELOP_BLENDIF_hz_out }, DT_DEV_PIXELPIPE_DISPLAY_JzCzhz_hz,
          _blendif_scale_print_hue, NULL, N_("hue") },
        { NULL } };
 
const char *slider_tooltip[] = { N_("adjustment based on input received by this module:\n* range defined by upper markers: "
                                    "blend fully\n* range defined by lower markers: do not blend at all\n* range between "
                                    "adjacent upper/lower markers: blend gradually"),
                                 N_("adjustment based on unblended output of this module:\n* range defined by upper "
                                    "markers: blend fully\n* range defined by lower markers: do not blend at all\n* range "
                                    "between adjacent upper/lower markers: blend gradually") };
 
void dt_iop_gui_update_blendif(dt_iop_module_t *module)
{
  // FIXME : there are more than 3 functions getting clever about how to setup module->request_mask_display depending on user input.
  // These should all use an uniform setter function.
  //
  // The lack of setter implies we don't guaranty that only 1 module can request mask display at a time.
  // The consequence is pipeline needs to check if module->request_mask_display AND module == dev->gui_module,
  // but the global pipe->mask_display is set from *_blend_process() at runtime, so it's a pipe property
  // that changes over the pipe lifecycle.
  //
  // This is a self-feeding loop of madness because it ties the pipeline to GUI states
  // (but not all pipes are connected to a GUI, so you need to cover all cases all the time and don't forget to test everything),
  // and because the pipeline is executed recursively from the end, but pipe->mask_display is set in the middle,
  // when it reaches the process() method of the module capturing mask preview, so you don't have this info when
  // planning for pipeline execution.
  // And you need to plan for mask preview ahead in pipe because mask preview needs to work
  // without using the pixelpipe cache, at least between the module requiring mask preview and gamma.c, which will actually render
  // the preview at the far end of the pipe.
  // So the not-so-clever workaround inherited from darktable was to flush all cache lines when requesting mask preview,
  // which flushed lines that could be reused later and were only temporarily not needed.
  dt_iop_gui_blend_data_t *bd = module->gui->blend_data;
 
  if(IS_NULL_PTR(bd) || !bd->blendif_support || !bd->blendif_inited) return;
 
  dt_gui_freeze_begin();
 
  dt_pthread_mutex_lock(&bd->lock);
  if(bd->timeout_handle)
  {
    g_source_remove(bd->timeout_handle);
    bd->timeout_handle = 0;
    if(module->request_mask_display != (bd->save_for_leave & ~DT_DEV_PIXELPIPE_DISPLAY_STICKY))
    {
      module->request_mask_display = bd->save_for_leave & ~DT_DEV_PIXELPIPE_DISPLAY_STICKY;
      dt_iop_set_cache_bypass(module, module->request_mask_display != DT_DEV_PIXELPIPE_DISPLAY_NONE);
      dt_dev_pixelpipe_update_history_all(module->dev);
    }
  }
  dt_pthread_mutex_unlock(&bd->lock);
 
  /* update output channel mask visibility */
  gtk_widget_set_visible(GTK_WIDGET(bd->filter[1].box), bd->output_channels_shown);
 
  /* update tabs */
  if(bd->channel_tabs_csp != bd->csp)
  {
    bd->channel = NULL;
 
    switch(bd->csp)
    {
      case DEVELOP_BLEND_CS_LAB:
        bd->channel = Lab_channels;
        break;
      case DEVELOP_BLEND_CS_RGB_DISPLAY:
        bd->channel = rgb_channels;
        break;
      case DEVELOP_BLEND_CS_RGB_SCENE:
        bd->channel = rgbj_channels;
        break;
      default:
        assert(FALSE); // blendif not supported for RAW, which is already caught upstream; we should not get
                       // here
    }
 
    dt_iop_color_picker_reset(module, TRUE);
 
    /* remove tabs before adding others */
    dt_gui_container_destroy_children(GTK_CONTAINER(bd->channel_tabs));
 
    bd->channel_tabs_csp = bd->csp;
 
    int index = 0;
    for(const dt_iop_gui_blendif_channel_t *ch = bd->channel; !IS_NULL_PTR(ch->label); ch++, index++)
    {
      dt_ui_notebook_page(bd->channel_tabs, ch->label, _(ch->tooltip));
      gtk_widget_show_all(GTK_WIDGET(gtk_notebook_get_nth_page(bd->channel_tabs, index)));
    }
 
    bd->tab = 0;
    gtk_notebook_set_current_page(GTK_NOTEBOOK(bd->channel_tabs), bd->tab);
  }
 
  _blendop_blendif_update_tab(module, bd->tab);
  dt_iop_add_remove_mask_indicator(module);
 
  dt_gui_freeze_end();
}
 
 
void dt_iop_gui_init_blendif(GtkBox *blendw, dt_iop_module_t *module, GtkWidget *blendif_header)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  bd->blendif_box = blendw;
 
  /* create and add blendif support if module supports it */
  if(bd->blendif_support)
  {
    dt_iop_togglebutton_new_no_register(module, "blend`tools", N_("reset blend mask settings"), NULL,
                                        G_CALLBACK(_blendop_blendif_reset), FALSE, 0, 0,
                                        dtgtk_cairo_paint_reset, blendif_header);
 
    GtkWidget *header = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
    gtk_widget_set_name(header, "blendif-pickers");
 
    bd->tab = 0;
    bd->channel_tabs_csp = DEVELOP_BLEND_CS_NONE;
    bd->channel_tabs = GTK_NOTEBOOK(gtk_notebook_new());
    gtk_notebook_set_scrollable(bd->channel_tabs, TRUE);
    gtk_box_pack_start(GTK_BOX(bd->blendif_box), GTK_WIDGET(bd->channel_tabs), FALSE, FALSE, 0);
    gtk_notebook_set_action_widget(GTK_NOTEBOOK(bd->channel_tabs), header, GTK_PACK_END);
    dt_gui_add_class(GTK_WIDGET(bd->channel_tabs), "empty");
 
    bd->colorpicker = dt_color_picker_new(module, DT_COLOR_PICKER_POINT_AREA, header);
    gtk_widget_set_tooltip_text(bd->colorpicker, _("pick GUI color from image\nctrl+click or right-click to select an area"));
 
    bd->colorpicker_set_values = dt_color_picker_new(module, DT_COLOR_PICKER_AREA, header);
    dtgtk_togglebutton_set_paint(DTGTK_TOGGLEBUTTON(bd->colorpicker_set_values),
                                 dtgtk_cairo_paint_colorpicker, CPF_ALTER, NULL);
 
    gtk_widget_set_tooltip_text(bd->colorpicker_set_values, _("set the range based on an area from the image\n"
                                                              "drag to use the input image\n"
                                                              "ctrl+drag to use the output image"));
 
    dt_iop_togglebutton_new_no_register(module, "blend`tools", N_("invert all channel's polarities"), NULL,
                                                         G_CALLBACK(_blendop_blendif_invert), FALSE, 0, 0,
                                                         dtgtk_cairo_paint_invert, header);
    
    gtk_widget_show_all(header);
 
    for(int in_out = 1; in_out >= 0; in_out--)
    {
      dt_iop_gui_blendif_filter_t *sl = &bd->filter[in_out];
 
      GtkWidget *slider_box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
 
      sl->slider = DTGTK_GRADIENT_SLIDER_MULTIVALUE(dtgtk_gradient_slider_multivalue_new_with_name(4,
                                                   in_out ? "blend-upper" : "blend-lower"));
      gtk_box_pack_start(GTK_BOX(slider_box), GTK_WIDGET(sl->slider), TRUE, TRUE, 0);
 
      sl->polarity = dtgtk_togglebutton_new(dtgtk_cairo_paint_invert, 0, NULL);
      dt_gui_add_class(sl->polarity, "dt_ignore_fg_state");
 
      gtk_widget_set_tooltip_text(sl->polarity, _("toggle polarity. best seen by enabling 'display mask'"));
      gtk_box_pack_end(GTK_BOX(slider_box), GTK_WIDGET(sl->polarity), FALSE, FALSE, 0);
 
      GtkWidget *label_box = gtk_grid_new();
      gtk_grid_set_column_homogeneous(GTK_GRID(label_box), TRUE);
 
      sl->head = GTK_LABEL(dt_ui_label_new(in_out ? _("output") : _("input")));
      gtk_grid_attach(GTK_GRID(label_box), GTK_WIDGET(sl->head), 0, 0, 1, 1);
 
      GtkWidget *overlay = gtk_overlay_new();
      gtk_grid_attach(GTK_GRID(label_box), overlay, 1, 0, 3, 1);
 
      sl->picker_label = GTK_LABEL(gtk_label_new(""));
      gtk_widget_set_name(GTK_WIDGET(sl->picker_label), "blend-data");
      gtk_label_set_xalign(sl->picker_label, .0);
      gtk_label_set_yalign(sl->picker_label, 1.0);
      gtk_container_add(GTK_CONTAINER(overlay), GTK_WIDGET(sl->picker_label));
 
      for(int k = 0; k < 4; k++)
      {
        sl->label[k] = GTK_LABEL(gtk_label_new(NULL));
        gtk_widget_set_name(GTK_WIDGET(sl->label[k]), "blend-data");
        gtk_label_set_xalign(sl->label[k], .35 + k * .65/3);
        gtk_label_set_yalign(sl->label[k], k % 2);
        gtk_overlay_add_overlay(GTK_OVERLAY(overlay), GTK_WIDGET(sl->label[k]));
      }
 
      gtk_widget_set_tooltip_text(GTK_WIDGET(sl->slider),
                                  _("double-click to reset.\npress 'm' to toggle mask view."));
      gtk_widget_set_tooltip_text(GTK_WIDGET(sl->head), _(slider_tooltip[in_out]));
 
      g_signal_connect(G_OBJECT(sl->slider), "value-changed", G_CALLBACK(_blendop_blendif_sliders_callback), bd);
      g_signal_connect(G_OBJECT(sl->slider), "value-reset", G_CALLBACK(_blendop_blendif_sliders_reset_callback), bd);
      g_signal_connect(G_OBJECT(sl->slider), "leave-notify-event", G_CALLBACK(_blendop_blendif_leave), module);
      g_signal_connect(G_OBJECT(sl->slider), "enter-notify-event", G_CALLBACK(_blendop_blendif_enter), module);
      g_signal_connect(G_OBJECT(sl->slider), "key-press-event", G_CALLBACK(_blendop_blendif_key_press), module);
      g_signal_connect(G_OBJECT(sl->polarity), "toggled", G_CALLBACK(_blendop_blendif_polarity_callback), bd);
 
      // The label is semantically "part of" the slider, even though it's a different widget,
      // so the parent box has no internal spacing between children to keep them grouped.
      sl->box = GTK_BOX(gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING));
      GtkWidget *channel_box = gtk_box_new(GTK_ORIENTATION_VERTICAL, 0);
      {
        gtk_box_pack_start(GTK_BOX(channel_box), GTK_WIDGET(label_box), FALSE, FALSE, 0);
        gtk_box_pack_start(GTK_BOX(channel_box), GTK_WIDGET(slider_box), FALSE, FALSE, 0);
      }
      gtk_box_pack_start(GTK_BOX(sl->box), channel_box, FALSE, FALSE, 0);
 
      GtkWidget *display_controls = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
      {
        sl->log_scale = gtk_toggle_button_new_with_label(_("Log scale"));
        gtk_widget_set_tooltip_text(sl->log_scale,
                      _("toggle the alternative logarithmic or magnified scale for this channel"));
        g_signal_connect(G_OBJECT(sl->log_scale), "toggled",
                        G_CALLBACK(_blendop_blendif_log_scale_toggled), module);
        gtk_box_pack_start(GTK_BOX(display_controls), sl->log_scale, FALSE, FALSE, 0);
 
        sl->channel_display = dtgtk_togglebutton_new(dtgtk_cairo_paint_eye_toggle, 0, NULL);
        gtk_widget_set_tooltip_text(
            sl->channel_display,
            in_out ? _("display the current channel from the unblended module output")
                  : _("display the current channel from the module input"));
        g_signal_connect(G_OBJECT(sl->channel_display), "toggled",
                        G_CALLBACK(_blendop_blendif_channel_display_toggled), module);
        gtk_box_pack_start(GTK_BOX(display_controls), sl->channel_display, FALSE, FALSE, 0);
      }
      gtk_box_pack_start(GTK_BOX(sl->box), display_controls, FALSE, FALSE, 0);
      gtk_box_pack_start(GTK_BOX(bd->blendif_box), GTK_WIDGET(sl->box), FALSE, FALSE, 0);
 
    }
 
    bd->channel_boost_factor_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), 0.0f, 18.0f, 0, 0.0f, 3);
    dt_bauhaus_disable_module_list(bd->channel_boost_factor_slider);
    dt_bauhaus_set_use_default_callback(bd->channel_boost_factor_slider);
    dt_bauhaus_slider_set_format(bd->channel_boost_factor_slider, _(" EV"));
    dt_bauhaus_widget_set_label(bd->channel_boost_factor_slider, N_("boost factor"));
    dt_bauhaus_slider_set_soft_range(bd->channel_boost_factor_slider, 0.0, 3.0);
    gtk_widget_set_tooltip_text(bd->channel_boost_factor_slider, _("adjust the boost factor of the channel mask"));
    gtk_widget_set_sensitive(bd->channel_boost_factor_slider, FALSE);
 
    g_signal_connect(G_OBJECT(bd->channel_boost_factor_slider), "value-changed",
                     G_CALLBACK(_blendop_blendif_boost_factor_callback), bd);
 
    gtk_box_pack_start(GTK_BOX(bd->blendif_box), GTK_WIDGET(bd->channel_boost_factor_slider), FALSE, FALSE, 0);
 
    g_signal_connect(G_OBJECT(bd->channel_tabs), "switch_page", G_CALLBACK(_blendop_blendif_tab_switch), bd);
    g_signal_connect(G_OBJECT(bd->colorpicker), "toggled", G_CALLBACK(_update_gradient_slider_pickers), module);
    g_signal_connect(G_OBJECT(bd->colorpicker_set_values), "toggled", G_CALLBACK(_update_gradient_slider_pickers), module);
 
    bd->blendif_inited = 1;
  }
  else
  {
    gchar *module_name = dt_history_item_get_name(module);
    gchar *markup = g_markup_printf_escaped(
      _("<i>Parametric masking is disabled because the <b>%s</b> module does not provide compatible color channels.</i>"),
      module_name);
    GtkWidget *label = gtk_label_new(NULL);
    gtk_label_set_markup(GTK_LABEL(label), markup);
    gtk_label_set_xalign(GTK_LABEL(label), 0.0f);
    gtk_label_set_line_wrap(GTK_LABEL(label), TRUE);
    gtk_box_pack_start(GTK_BOX(bd->blendif_box), label, FALSE, FALSE, 0);
    dt_free(markup);
    dt_free(module_name);
  }
}
 
void dt_iop_gui_init_contours(GtkBox *blendw, dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  gtk_box_pack_start(blendw, bd->details_slider, FALSE, FALSE, 0);
  gtk_box_pack_start(blendw, bd->blur_radius_slider, FALSE, FALSE, 0);
  gtk_box_pack_start(blendw, bd->masks_feathering_guide_combo, FALSE, FALSE, 0);
  gtk_box_pack_start(blendw, bd->feathering_radius_slider, FALSE, FALSE, 0);
  gtk_box_pack_start(blendw, bd->brightness_slider, FALSE, FALSE, 0);
  gtk_box_pack_start(blendw, bd->contrast_slider, FALSE, FALSE, 0);
}
 
void dt_iop_gui_blend_masks_update(dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = module->gui ? (dt_iop_gui_blend_data_t *)module->gui->blend_data : NULL;
  dt_develop_blend_params_t *bp = module->blend_params;
 
  if(IS_NULL_PTR(bd) || !bd->masks_support || !bd->masks_inited) return;
 
  dt_gui_freeze_begin();
 
  /* update masks state */
  dt_masks_form_gui_t *form_gui = module->dev->form_gui;
  dt_masks_form_t *visible_form = dt_masks_get_visible_form(module->dev);
  const gboolean module_creation = !IS_NULL_PTR(form_gui) && form_gui->creation
                                  && form_gui->creation_module == module;
  const dt_masks_type_t creation_type = module_creation && !IS_NULL_PTR(visible_form)
                                        ? visible_form->type
                                        : (module_creation ? form_gui->creation_type : DT_MASKS_NONE);
  dt_masks_form_t *grp = dt_masks_get_from_id(module->dev, module->blend_params->mask_id);
  const gboolean has_group_shapes = grp && (grp->type & DT_MASKS_GROUP) && grp->points;
  if(GTK_IS_WIDGET(bd->masks_combo))
  {
    dt_bauhaus_combobox_clear(bd->masks_combo);
    if(has_group_shapes)
    {
      char txt[512];
      const guint n = g_list_length(grp->points);
      snprintf(txt, sizeof(txt), ngettext("%d shape used", "%d shapes used", n), n);
      dt_bauhaus_combobox_add(bd->masks_combo, txt);
    }
    else
    {
      dt_bauhaus_combobox_add(bd->masks_combo, _("no mask used"));
    }
    dt_bauhaus_combobox_set(bd->masks_combo, 0);
    gtk_widget_queue_draw(bd->masks_combo);
  }
 
  if(!has_group_shapes)
  {
    bd->masks_shown = DT_MASKS_EDIT_OFF;
    // reset the gui
    dt_masks_set_edit_mode(module, DT_MASKS_EDIT_OFF);
  }
 
  if(bd->masks_support)
  {
    if(GTK_IS_TOGGLE_BUTTON(bd->masks_edit))
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->masks_edit),
                                   !module_creation && bd->masks_shown != DT_MASKS_EDIT_OFF);
 
    if(GTK_IS_TOGGLE_BUTTON(bd->masks_polarity))
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->masks_polarity),
                                   bp->mask_combine & DEVELOP_COMBINE_MASKS_POS);
  }
 
  // update buttons status
  for(int n = 0; n < DEVELOP_MASKS_NB_SHAPES; n++)
  {
    if(!GTK_IS_TOGGLE_BUTTON(bd->masks_shapes[n])) continue;
 
    if(module_creation && (creation_type & bd->masks_type[n]))
    {
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->masks_shapes[n]), TRUE);
    }
    else
    {
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->masks_shapes[n]), FALSE);
    }
  }
 
  _blendop_masks_refresh_lists(module);
  dt_iop_add_remove_mask_indicator(module);
 
  dt_gui_freeze_end();
}
 
/* Mouse-wheel mapping grid.
 *
 * One radio group per row: a wheel/modifier combination edits exactly one mask property, or
 * nothing at all. The mapping lives in conf and is read back by the shapes through
 * dt_masks_scroll_get_interaction() (masks_gui.h); this grid only displays and writes it, and
 * holds no state of its own. Hence the re-read on "map": every module's blending panel shows
 * the same application-wide mapping and any of them can change it, so the grid that becomes
 * visible must show what is stored, not what it was built with.
 */
#define BLENDOP_SCROLL_DATA_ROW "blendop-scroll-row"
#define BLENDOP_SCROLL_DATA_INTERACTION "blendop-scroll-interaction"
 
/* Property columns, in display order. DT_MASKS_INTERACTION_UNDEF ("nothing") is a column like
 * the others -- it is how a row is unmapped -- and comes last, after what it opts out of. */
static const dt_masks_interaction_t _blendop_scroll_columns[]
    = { DT_MASKS_INTERACTION_SIZE, DT_MASKS_INTERACTION_FADING, DT_MASKS_INTERACTION_OPACITY,
        DT_MASKS_INTERACTION_ROTATION, DT_MASKS_INTERACTION_UNDEF };
 
static void _blendop_masks_scroll_toggled(GtkToggleButton *button, gpointer user_data)
{
  // A radio group emits "toggled" twice per change, once for each side. Only the winner writes.
  if(!gtk_toggle_button_get_active(button)) return;
 
  const dt_masks_scroll_modifier_t modifier
      = (dt_masks_scroll_modifier_t)GPOINTER_TO_INT(g_object_get_data(G_OBJECT(button), BLENDOP_SCROLL_DATA_ROW));
  const dt_masks_interaction_t interaction
      = (dt_masks_interaction_t)GPOINTER_TO_INT(g_object_get_data(G_OBJECT(button), BLENDOP_SCROLL_DATA_INTERACTION));
 
  dt_masks_scroll_mapping_set(modifier, interaction);
}
 
static void _blendop_masks_scroll_sync(GtkWidget *grid, gpointer user_data)
{
  GList *children = gtk_container_get_children(GTK_CONTAINER(grid));
  for(GList *child = children; child; child = g_list_next(child))
  {
    GtkWidget *cell = GTK_WIDGET(child->data);
    if(!GTK_IS_RADIO_BUTTON(cell)) continue;
 
    const dt_masks_scroll_modifier_t modifier
        = (dt_masks_scroll_modifier_t)GPOINTER_TO_INT(g_object_get_data(G_OBJECT(cell), BLENDOP_SCROLL_DATA_ROW));
    const dt_masks_interaction_t interaction
        = (dt_masks_interaction_t)GPOINTER_TO_INT(g_object_get_data(G_OBJECT(cell), BLENDOP_SCROLL_DATA_INTERACTION));
    const gboolean active = (dt_masks_scroll_mapping_get(modifier) == interaction);
    if(gtk_toggle_button_get_active(GTK_TOGGLE_BUTTON(cell)) == active) continue;
 
    // Writing conf back from a display refresh would turn a stale panel into the authority.
    g_signal_handlers_block_by_func(cell, G_CALLBACK(_blendop_masks_scroll_toggled), NULL);
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(cell), active);
    g_signal_handlers_unblock_by_func(cell, G_CALLBACK(_blendop_masks_scroll_toggled), NULL);
  }
  g_list_free(children);
}
 
static GtkWidget *_blendop_masks_create_scroll_grid(void)
{
  GtkWidget *grid = gtk_grid_new();
  gtk_grid_set_row_spacing(GTK_GRID(grid), DT_GUI_BOX_SPACING);
  gtk_grid_set_column_spacing(GTK_GRID(grid), DT_GUI_BOX_SPACING);
  /* Natural width, not filled: handed more width than it needs, GtkGrid spreads the surplus
   * over its columns, which pushes the cells apart and re-centres every rotated title over a
   * cell wider than itself. What keeps the columns tight is this plus the spanning titles
   * below -- not the column spacing, which is free to stay at the panel's usual gutter
   * (measured: 24px columns either way, only the gutters change). */
  gtk_widget_set_halign(grid, GTK_ALIGN_START);
 
  for(size_t column = 0; column < G_N_ELEMENTS(_blendop_scroll_columns); column++)
  {
    const dt_masks_interaction_t interaction = _blendop_scroll_columns[column];
    const char *alias = dt_masks_interaction_alias_name(interaction);
    // Second word on its own line: rotated 90 degrees the lines stack sideways, so the column
    // stays as tall as the longest single word instead of as tall as both of them.
    gchar *title = alias ? g_strdup_printf("%s/%s", _(dt_masks_interaction_name(interaction)), _(alias))
                         : g_strdup(_(dt_masks_interaction_name(interaction)));
    GtkWidget *header = gtk_label_new(title);
    dt_free(title);
    gtk_label_set_angle(GTK_LABEL(header), 90.0 * 0.5);
    gtk_label_set_justify(GTK_LABEL(header), GTK_JUSTIFY_LEFT);
    // Anchor the rotated title to the bottom left of its cell, where the column it names
    // starts, instead of letting it float in the middle of whatever width the cell ends up with.
    gtk_label_set_xalign(GTK_LABEL(header), 0.0f);
    gtk_label_set_yalign(GTK_LABEL(header), 1.0f);
    gtk_widget_set_halign(header, GTK_ALIGN_START);
    gtk_widget_set_valign(header, GTK_ALIGN_END);
    /* Spanning, not one cell: a label rotated 45 degrees requests the width of its slanted
     * bounding box (measured: 102px for "Fading/Curvature" against 24px for a radio), and a
     * single-cell title makes its whole column that wide. Letting each title span the columns
     * to its right -- the direction it leans into, whose header space is free -- constrains the
     * sum instead of one column, and every column falls back to the width of its radio. */
    gtk_grid_attach(GTK_GRID(grid), header, (int)column + 1, 0,
                    (int)(G_N_ELEMENTS(_blendop_scroll_columns) - column) + 1, 1);
  }
 
  /* The rightmost title has no column to lean into, so it would widen its own the same way.
   * This trailing column exists only to absorb that overhang; it expands so the grid hands it
   * whatever width the titles need, rather than spreading it over the real columns. */
  GtkWidget *overhang = gtk_label_new("");
  gtk_widget_set_hexpand(overhang, TRUE);
  gtk_grid_attach(GTK_GRID(grid), overhang, (int)G_N_ELEMENTS(_blendop_scroll_columns) + 1, 0, 1, 1);
 
  for(int row = 0; row < DT_MASKS_SCROLL_MODIFIER_LAST; row++)
  {
    const dt_masks_scroll_modifier_t modifier = (dt_masks_scroll_modifier_t)row;
    GtkWidget *row_label = gtk_label_new(_(dt_masks_scroll_modifier_name(modifier)));
    gtk_label_set_xalign(GTK_LABEL(row_label), 0.0f);
    gtk_grid_attach(GTK_GRID(grid), row_label, 0, row + 1, 1, 1);
 
    GtkWidget *group = NULL;
    for(size_t column = 0; column < G_N_ELEMENTS(_blendop_scroll_columns); column++)
    {
      const dt_masks_interaction_t interaction = _blendop_scroll_columns[column];
      GtkWidget *cell = gtk_radio_button_new_from_widget(GTK_RADIO_BUTTON(group));
      if(IS_NULL_PTR(group)) group = cell;
 
      g_object_set_data(G_OBJECT(cell), BLENDOP_SCROLL_DATA_ROW, GINT_TO_POINTER(modifier));
      g_object_set_data(G_OBJECT(cell), BLENDOP_SCROLL_DATA_INTERACTION, GINT_TO_POINTER(interaction));
 
      const char *alias = dt_masks_interaction_alias_name(interaction);
      gchar *tooltip;
      if(interaction == DT_MASKS_INTERACTION_UNDEF)
        tooltip = g_strdup_printf(_("%s does nothing"), _(dt_masks_scroll_modifier_name(modifier)));
      else if(alias)
        tooltip = g_strdup_printf(_("%s edits the %s of the hovered shape, or its %s on a gradient"),
                                  _(dt_masks_scroll_modifier_name(modifier)),
                                  _(dt_masks_interaction_name(interaction)), _(alias));
      else
        tooltip = g_strdup_printf(_("%s edits the %s of the hovered shape"),
                                  _(dt_masks_scroll_modifier_name(modifier)),
                                  _(dt_masks_interaction_name(interaction)));
      gtk_widget_set_tooltip_text(cell, tooltip);
      dt_free(tooltip);
 
      // State first, handler after: building the group already emits "toggled" for every cell
      // it deactivates, and those must not be mistaken for the user picking something.
      gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(cell),
                                   dt_masks_scroll_mapping_get(modifier) == interaction);
      g_signal_connect(cell, "toggled", G_CALLBACK(_blendop_masks_scroll_toggled), NULL);
 
      gtk_grid_attach(GTK_GRID(grid), cell, (int)column + 1, row + 1, 1, 1);
    }
  }
 
  g_signal_connect(grid, "map", G_CALLBACK(_blendop_masks_scroll_sync), NULL);
 
  return grid;
}
 
void dt_iop_gui_init_masks(GtkBox *blendw, dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  bd->masks_box = blendw;
 
  /* create and add masks support if module supports it */
  if(bd->masks_support)
  {
    bd->masks_combo_ids = NULL;
    bd->masks_shown = DT_MASKS_EDIT_OFF;
 
    bd->lists_box = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
 
    GtkCellRenderer *renderer = NULL;
    GtkTreeSelection *selection = NULL;
 
    GtkWidget *group_shapes_header = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
    bd->group_shapes_label = gtk_entry_new();
    gchar *group_placeholder = dt_masks_group_name_for_module(module);
    gtk_entry_set_placeholder_text(GTK_ENTRY(bd->group_shapes_label), group_placeholder);
    g_free(group_placeholder);
    gtk_widget_set_tooltip_text(bd->group_shapes_label, _("Edit current module's group name"));
    gtk_widget_set_halign(bd->group_shapes_label, GTK_ALIGN_FILL);
    gtk_widget_set_hexpand(bd->group_shapes_label, TRUE);
    g_signal_connect(bd->group_shapes_label, "activate", G_CALLBACK(_blendop_masks_group_name_activate), module);
    g_signal_connect(bd->group_shapes_label, "focus-out-event",
             G_CALLBACK(_blendop_masks_group_name_focus_out), module);
    gtk_box_pack_start(GTK_BOX(group_shapes_header), bd->group_shapes_label, TRUE, TRUE, 0);
 
    // buttons for mask polarity and edit mode
    bd->masks_polarity = dt_iop_togglebutton_new_no_register(module, "blend`tools", N_("toggle polarity of drawn mask"), NULL,
                                                             G_CALLBACK(_blendop_masks_polarity_callback),
                                                             FALSE, 0, 0, dtgtk_cairo_paint_invert, group_shapes_header);
    dtgtk_togglebutton_set_paint(DTGTK_TOGGLEBUTTON(bd->masks_polarity), dtgtk_cairo_paint_invert, 0, NULL);
    dt_gui_add_class(bd->masks_polarity, "dt_ignore_fg_state");
 
    bd->masks_edit = dt_iop_togglebutton_new_no_register(module, "blend`tools", N_("show and edit mask elements"),
                                                         N_("show and edit in restricted mode"),
                                                         G_CALLBACK(_blendop_masks_show_and_edit),
                                                         FALSE, 0, 0, dtgtk_cairo_paint_masks_edit, group_shapes_header);
 
    gtk_box_pack_start(GTK_BOX(bd->lists_box), group_shapes_header, FALSE, FALSE, 0);
 
    // Current mask list
    bd->masks_group_treeview = gtk_tree_view_new();
    bd->group_shapes_store = gtk_tree_store_new(BLENDOP_MASKS_GROUP_COL_COUNT, GDK_TYPE_PIXBUF,
                                                          GDK_TYPE_PIXBUF, G_TYPE_STRING, G_TYPE_INT,
                                                          G_TYPE_INT, G_TYPE_INT, G_TYPE_INT);
    gtk_tree_view_set_model(GTK_TREE_VIEW(bd->masks_group_treeview), GTK_TREE_MODEL(bd->group_shapes_store));
 
    // Initialize mask operation icons for treeview display
    _blendop_masks_init_icons(bd);
 
    bd->group_shapes_col = gtk_tree_view_column_new();
    gtk_tree_view_append_column(GTK_TREE_VIEW(bd->masks_group_treeview), bd->group_shapes_col);
 
    renderer = gtk_cell_renderer_pixbuf_new();
    gtk_tree_view_column_pack_start(bd->group_shapes_col, renderer, FALSE);
    gtk_tree_view_column_add_attribute(bd->group_shapes_col, renderer, "pixbuf", BLENDOP_MASKS_GROUP_COL_OP_ICON);
 
    renderer = gtk_cell_renderer_pixbuf_new();
    gtk_tree_view_column_pack_start(bd->group_shapes_col, renderer, FALSE);
    gtk_tree_view_column_add_attribute(bd->group_shapes_col, renderer, "pixbuf", BLENDOP_MASKS_GROUP_COL_INV_ICON);
 
    renderer = gtk_cell_renderer_text_new();
    gtk_tree_view_column_pack_start(bd->group_shapes_col, renderer, TRUE);
    gtk_tree_view_column_add_attribute(bd->group_shapes_col, renderer, "text", BLENDOP_MASKS_GROUP_COL_NAME);
 
    // Per-row action icons: unlink (detach from this mask) and delete (remove altogether).
    // Clicks are handled in _blendop_masks_group_button_pressed by matching the column.
    bd->group_unlink_col = gtk_tree_view_column_new();
    renderer = gtk_cell_renderer_pixbuf_new();
    g_object_set(renderer, "icon-name", "list-remove-symbolic", "stock-size", GTK_ICON_SIZE_MENU, NULL);
    gtk_tree_view_column_pack_start(bd->group_unlink_col, renderer, FALSE);
    gtk_tree_view_column_set_sizing(bd->group_unlink_col, GTK_TREE_VIEW_COLUMN_FIXED);
    gtk_tree_view_column_set_fixed_width(bd->group_unlink_col, DT_PIXEL_APPLY_DPI(24));
    gtk_tree_view_append_column(GTK_TREE_VIEW(bd->masks_group_treeview), bd->group_unlink_col);
 
    bd->group_delete_col = gtk_tree_view_column_new();
    renderer = gtk_cell_renderer_pixbuf_new();
    g_object_set(renderer, "icon-name", "user-trash-symbolic", "stock-size", GTK_ICON_SIZE_MENU, NULL);
    gtk_tree_view_column_pack_start(bd->group_delete_col, renderer, FALSE);
    gtk_tree_view_column_set_sizing(bd->group_delete_col, GTK_TREE_VIEW_COLUMN_FIXED);
    gtk_tree_view_column_set_fixed_width(bd->group_delete_col, DT_PIXEL_APPLY_DPI(24));
    gtk_tree_view_append_column(GTK_TREE_VIEW(bd->masks_group_treeview), bd->group_delete_col);
 
    // Keep the name column expanding so the action icons stay flush right.
    gtk_tree_view_column_set_expand(bd->group_shapes_col, TRUE);
 
    selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(bd->masks_group_treeview));
    gtk_tree_selection_set_mode(selection, GTK_SELECTION_SINGLE);
    g_signal_connect(selection, "changed", G_CALLBACK(_blendop_masks_group_selection_changed), module);
    gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(bd->masks_group_treeview), FALSE);
    gtk_tree_view_set_show_expanders(GTK_TREE_VIEW(bd->masks_group_treeview), TRUE);
    g_signal_connect(bd->masks_group_treeview, "button-press-event",
                     G_CALLBACK(_blendop_masks_group_button_pressed), module);
 
    gtk_widget_set_has_tooltip(bd->masks_group_treeview, TRUE);
    g_signal_connect(bd->masks_group_treeview, "query-tooltip",
                     G_CALLBACK(_blendop_masks_group_query_tooltip), module);
 
    bd->group_shapes_sw = dt_ui_scroll_wrap(bd->masks_group_treeview, 90,
                                            "plugins/darkroom/masks/group_list_height", DT_UI_RESIZE_DYNAMIC);
    gtk_widget_set_vexpand(bd->group_shapes_sw, TRUE);
 
    // Creating shapes buttons (circle, ellipse ....)
    bd->all_shapes_buttons = _blendop_masks_create_shape_buttons(module, bd);
    if(!GTK_IS_WIDGET(bd->all_shapes_buttons)) return;
 
    // Wire shapes toggle button
    bd->wire_shape_toggle = gtk_toggle_button_new_with_label(_("Attach shapes"));
    gtk_widget_set_tooltip_text(bd->wire_shape_toggle, _("Show all shapes and groups to choose which ones to connect to or disconnect from the mask."));
 
    GtkWidget *bottom_bar = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
    gtk_box_pack_start(GTK_BOX(bottom_bar), bd->wire_shape_toggle, FALSE, FALSE, 0);
    gtk_box_pack_end(GTK_BOX(bottom_bar), bd->all_shapes_buttons, FALSE, FALSE, 0);
    gtk_box_pack_end(GTK_BOX(bd->lists_box), bottom_bar, FALSE, FALSE, 0);
 
 
    // All shapes list
    bd->masks_treeview = gtk_tree_view_new();
    bd->all_shapes_store = gtk_list_store_new(BLENDOP_MASKS_ALL_COL_COUNT, G_TYPE_BOOLEAN,
                                              G_TYPE_STRING, G_TYPE_INT, G_TYPE_BOOLEAN,
                                              G_TYPE_STRING, G_TYPE_STRING);
    gtk_tree_view_set_model(GTK_TREE_VIEW(bd->masks_treeview), GTK_TREE_MODEL(bd->all_shapes_store));
 
    bd->all_shapes_col = gtk_tree_view_column_new();
    gtk_tree_view_append_column(GTK_TREE_VIEW(bd->masks_treeview), bd->all_shapes_col);
 
    renderer = gtk_cell_renderer_toggle_new();
    g_object_set(renderer, "activatable", TRUE, NULL);
    g_signal_connect(renderer, "toggled", G_CALLBACK(_blendop_masks_all_toggled), module);
    gtk_tree_view_column_pack_start(bd->all_shapes_col, renderer, FALSE);
    gtk_tree_view_column_add_attribute(bd->all_shapes_col, renderer, "active", BLENDOP_MASKS_ALL_COL_ACTIVE);
    gtk_tree_view_column_add_attribute(bd->all_shapes_col, renderer, "sensitive", BLENDOP_MASKS_ALL_COL_SENSITIVE);
 
    GtkTreeViewColumn *all_shapes_name_col = gtk_tree_view_column_new();
    gtk_tree_view_append_column(GTK_TREE_VIEW(bd->masks_treeview), all_shapes_name_col);
 
    renderer = gtk_cell_renderer_text_new();
    g_object_set(renderer, "editable", TRUE, NULL);
    g_signal_connect(renderer, "edited", G_CALLBACK(_blendop_masks_all_name_edited), module);
    gtk_tree_view_column_pack_start(all_shapes_name_col, renderer, TRUE);
    gtk_tree_view_column_add_attribute(all_shapes_name_col, renderer, "markup", BLENDOP_MASKS_ALL_COL_MARKUP);
    gtk_tree_view_column_add_attribute(all_shapes_name_col, renderer, "sensitive", BLENDOP_MASKS_ALL_COL_SENSITIVE);
    g_object_set_data(G_OBJECT(bd->masks_treeview), "blendop-masks-name-renderer", renderer);
 
    GtkTreeViewColumn *all_shapes_status_col = gtk_tree_view_column_new();
    gtk_tree_view_append_column(GTK_TREE_VIEW(bd->masks_treeview), all_shapes_status_col);
 
    renderer = gtk_cell_renderer_text_new();
    g_object_set(renderer, "xalign", 1.0f, NULL);
    gtk_tree_view_column_pack_end(all_shapes_status_col, renderer, TRUE);
    gtk_tree_view_column_add_attribute(all_shapes_status_col, renderer, "markup",
                       BLENDOP_MASKS_ALL_COL_STATUS_MARKUP);
    gtk_tree_view_column_add_attribute(all_shapes_status_col, renderer, "sensitive",
                       BLENDOP_MASKS_ALL_COL_SENSITIVE);
 
    // Per-row delete icon, mirroring group_delete_col above. Clicks are handled in
    // _blendop_masks_all_button_pressed by matching the column.
    bd->all_shapes_delete_col = gtk_tree_view_column_new();
    renderer = gtk_cell_renderer_pixbuf_new();
    g_object_set(renderer, "icon-name", "user-trash-symbolic", "stock-size", GTK_ICON_SIZE_MENU, NULL);
    gtk_tree_view_column_pack_start(bd->all_shapes_delete_col, renderer, FALSE);
    gtk_tree_view_column_set_sizing(bd->all_shapes_delete_col, GTK_TREE_VIEW_COLUMN_FIXED);
    gtk_tree_view_column_set_fixed_width(bd->all_shapes_delete_col, DT_PIXEL_APPLY_DPI(24));
    gtk_tree_view_append_column(GTK_TREE_VIEW(bd->masks_treeview), bd->all_shapes_delete_col);
 
    // Keep the name column expanding so the status text and trash icon stay flush right,
    // same as group_shapes_col above.
    gtk_tree_view_column_set_expand(all_shapes_name_col, TRUE);
 
    selection = gtk_tree_view_get_selection(GTK_TREE_VIEW(bd->masks_treeview));
    gtk_tree_selection_set_mode(selection, GTK_SELECTION_SINGLE);
    g_signal_connect(selection, "changed", G_CALLBACK(_blendop_masks_all_selection_changed), module);
    gtk_tree_view_set_headers_visible(GTK_TREE_VIEW(bd->masks_treeview), FALSE);
    g_signal_connect(bd->masks_treeview, "button-press-event",
                     G_CALLBACK(_blendop_masks_all_button_pressed), module);
 
    bd->all_shapes_sw = dt_ui_scroll_wrap(bd->masks_treeview, 90,
                                          "plugins/darkroom/masks/all_list_height", DT_UI_RESIZE_DYNAMIC);
    gtk_widget_set_vexpand(bd->all_shapes_sw, TRUE);
 
    // The two lists share the same slot; Edit selects which one is visible.
    bd->lists_stack = gtk_stack_new();
    gtk_stack_set_transition_type(GTK_STACK(bd->lists_stack), GTK_STACK_TRANSITION_TYPE_NONE);
    gtk_stack_set_homogeneous(GTK_STACK(bd->lists_stack), FALSE);
    gtk_stack_add_named(GTK_STACK(bd->lists_stack), bd->group_shapes_sw, "group");
    gtk_stack_add_named(GTK_STACK(bd->lists_stack), bd->all_shapes_sw, "all");
    gtk_box_pack_start(GTK_BOX(bd->lists_box), bd->lists_stack, TRUE, TRUE, 0);
 
    // Default state:
    // - current-module tree is visible
    // - all-shapes tree is hidden
    // The toggle callback flips these two scrolled windows.
    g_signal_connect(bd->wire_shape_toggle, "toggled", G_CALLBACK(_blendop_masks_edit_list_toggle), module);
 
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->wire_shape_toggle), FALSE);
    _blendop_masks_edit_list_toggle(GTK_TOGGLE_BUTTON(bd->wire_shape_toggle), module);
 
    gtk_box_pack_start(GTK_BOX(bd->masks_box), bd->lists_box, TRUE, TRUE, 0);
 
    dt_gui_new_collapsible_section
      (&bd->masks_cs,
      "plugins/darkroom/masks/wacom",
      _("Brush options"),
      GTK_BOX(bd->masks_box), GTK_PACK_END);
 
    GtkWidget *brush_smoothing = dt_bauhaus_combobox_from_conf(dt_bauhaus_get_global(), DT_GUI_MODULE(NULL), "brush_smoothing");
    gtk_box_pack_start(GTK_BOX(bd->masks_cs.container), brush_smoothing, TRUE, TRUE, 0);
 
    GtkWidget *pressure_mapping = dt_bauhaus_combobox_from_conf(dt_bauhaus_get_global(), DT_GUI_MODULE(NULL), "pressure_sensitivity");
    gtk_box_pack_start(GTK_BOX(bd->masks_cs.container), pressure_mapping, TRUE, TRUE, 0);
 
    dt_gui_new_collapsible_section
      (&bd->scroll_cs,
      "plugins/darkroom/masks/scroll_mapping",
      _("Mouse wheel"),
      GTK_BOX(bd->masks_box), GTK_PACK_END);
    gtk_widget_set_tooltip_text(bd->scroll_cs.expander,
                                _("Choose which property of the hovered shape each mouse wheel "
                                  "combination edits. Shared by every mask of every module."));
    // Natural size, not filled: the grid must not be handed width it would spread between its
    // own columns (see _blendop_masks_create_scroll_grid).
    gtk_box_pack_start(GTK_BOX(bd->scroll_cs.container), _blendop_masks_create_scroll_grid(), FALSE, FALSE, 0);
 
    bd->masks_inited = 1;
    _blendop_masks_refresh_lists(module);
  }
  else
  {
    gchar *module_name = dt_history_item_get_name(module);
    gchar *markup = g_markup_printf_escaped(
      _("<i>Drawn masking is disabled because the <b>%s</b> module manages drawn shapes internally.</i>"),
       module_name);
    GtkWidget *label = gtk_label_new(NULL);
    gtk_label_set_markup(GTK_LABEL(label), markup);
    gtk_label_set_xalign(GTK_LABEL(label), 0.0f);
    gtk_label_set_line_wrap(GTK_LABEL(label), TRUE);
    gtk_box_pack_start(GTK_BOX(bd->masks_box), label, FALSE, FALSE, 0);
    dt_free(markup);
    dt_free(module_name);
  }
}
 
typedef struct raster_combo_entry_t
{
  dt_iop_module_t *module;
  int id;
} raster_combo_entry_t;
 
static void _raster_combo_populate(GtkWidget *w, void *m)
{
  dt_iop_module_t *module = (dt_iop_module_t *)m;
  dt_iop_request_focus(module);
 
  dt_bauhaus_combobox_clear(w);
 
  raster_combo_entry_t *entry = (raster_combo_entry_t *)calloc(1, sizeof(raster_combo_entry_t));
  if(IS_NULL_PTR(entry)) return;
  dt_bauhaus_combobox_add_full(w, _("no mask used"), DT_BAUHAUS_COMBOBOX_ALIGN_RIGHT, entry, free, TRUE);
 
  int i = 1;
 
  for(GList* iter = module->dev->iop; iter; iter = g_list_next(iter))
  {
    dt_iop_module_t *iop = (dt_iop_module_t *)iter->data;
    if(iop == module)
      break;
 
    GHashTableIter masks_iter;
    gpointer key, value;
 
    g_hash_table_iter_init(&masks_iter, iop->raster_mask.source.masks);
    while(g_hash_table_iter_next(&masks_iter, &key, &value))
    {
      const int id = GPOINTER_TO_INT(key);
      const char *modulename = (char *)value;
      entry = (raster_combo_entry_t *)malloc(sizeof(raster_combo_entry_t));
      entry->module = iop;
      entry->id = id;
      dt_bauhaus_combobox_add_full(w, modulename, DT_BAUHAUS_COMBOBOX_ALIGN_RIGHT, entry, free, TRUE);
      if(iop == module->raster_mask.sink.source && module->raster_mask.sink.id == id)
        dt_bauhaus_combobox_set(w, i);
      i++;
    }
  }
}
 
static void _raster_value_changed_callback(GtkWidget *widget, struct dt_iop_module_t *module)
{
  raster_combo_entry_t *entry = dt_bauhaus_combobox_get_data(widget);
 
  // nothing to do
  if(entry->module == module->raster_mask.sink.source && entry->id == module->raster_mask.sink.id)
    return;
 
  if(module->raster_mask.sink.source)
  {
    // we no longer use this one
    g_hash_table_remove(module->raster_mask.sink.source->raster_mask.source.users, module);
  }
 
  module->raster_mask.sink.source = entry->module;
  module->raster_mask.sink.id = entry->id;
 
  if(entry->module)
  {
    // The value is the provider-local mask id. dt_iop_is_raster_mask_used()
    // reads it to decide which side-band mask buffers the pixelpipe must
    // publish. g_hash_table_add() stores the consumer pointer as both key and
    // value, making an existing mask visible in the GUI but impossible to
    // retrieve reliably from the pipeline.
    g_hash_table_insert(entry->module->raster_mask.source.users, module,
                        GINT_TO_POINTER(entry->id));
 
    // update blend_params!
    memcpy(module->blend_params->raster_mask_source, entry->module->op, sizeof(module->blend_params->raster_mask_source));
    module->blend_params->raster_mask_instance = entry->module->multi_priority;
    module->blend_params->raster_mask_id = entry->id;
  }
  else
  {
    memset(module->blend_params->raster_mask_source, 0, sizeof(module->blend_params->raster_mask_source));
    module->blend_params->raster_mask_instance = 0;
    module->blend_params->raster_mask_id = 0;
  }
 
  dt_dev_add_history_item(module->dev, module, TRUE, TRUE);
  dt_iop_gui_update_header(module);
}
 
void dt_iop_gui_update_raster(dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  dt_develop_blend_params_t *bp = module->blend_params;
 
  if(IS_NULL_PTR(bd) || !bd->masks_support || !bd->raster_inited) return;
 
  gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->raster_polarity), bp->raster_mask_invert);
 
  _raster_combo_populate(bd->raster_combo, module);
}
 
static void _raster_polarity_callback(GtkToggleButton *togglebutton, dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_develop_blend_params_t *bp = (dt_develop_blend_params_t *)self->blend_params;
 
  bp->raster_mask_invert = gtk_toggle_button_get_active(togglebutton);
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
  dt_iop_gui_update_header(self);
  dt_control_queue_redraw_widget(GTK_WIDGET(togglebutton));
}
 
void dt_iop_gui_init_raster(GtkBox *blendw, dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  bd->raster_box = blendw;
 
  /* create and add raster support if module supports it (it's coupled to masks at the moment) */
  if(bd->masks_support)
  {
    GtkWidget *hbox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
 
    bd->raster_combo = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(module));
    dt_bauhaus_disable_module_list(bd->raster_combo);
    dt_bauhaus_set_use_default_callback(bd->raster_combo);
    dt_bauhaus_widget_set_label(bd->raster_combo, N_("raster mask"));
    dt_bauhaus_combobox_add(bd->raster_combo, _("no mask used"));
    g_signal_connect(G_OBJECT(bd->raster_combo), "value-changed",
                     G_CALLBACK(_raster_value_changed_callback), module);
    dt_bauhaus_combobox_add_populate_fct(bd->raster_combo, _raster_combo_populate);
    gtk_box_pack_start(GTK_BOX(hbox), bd->raster_combo, TRUE, TRUE, 0);
 
    bd->raster_polarity = dtgtk_togglebutton_new(dtgtk_cairo_paint_invert, 0, NULL);
    dt_gui_add_class(bd->raster_polarity, "dt_ignore_fg_state");
    gtk_widget_set_tooltip_text(bd->raster_polarity, _("toggle polarity of raster mask"));
    g_signal_connect(G_OBJECT(bd->raster_polarity), "toggled", G_CALLBACK(_raster_polarity_callback), module);
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(bd->raster_polarity), FALSE);
    gtk_box_pack_start(GTK_BOX(hbox), bd->raster_polarity, FALSE, FALSE, 0);
 
    gtk_box_pack_start(GTK_BOX(bd->raster_box), GTK_WIDGET(hbox), FALSE, FALSE, 0);
 
    bd->raster_inited = 1;
  }
}
 
void dt_iop_gui_cleanup_blending(dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  dt_iop_gui_cleanup_blending_body(module);
  DT_DEBUG_CONTROL_SIGNAL_DISCONNECT(dt_control_signal_get_global(), G_CALLBACK(_blendop_masks_handler_callback), module);
 
  dt_pthread_mutex_lock(&bd->lock);
  if(bd->timeout_handle)
    g_source_remove(bd->timeout_handle);
 
  dt_free_align(bd->masks_combo_ids);
  dt_pthread_mutex_unlock(&bd->lock);
  dt_pthread_mutex_destroy(&bd->lock);
 
  dt_free(module->gui->blend_data);
  module->gui->blend_data = NULL;
}
 
 
static gboolean _add_blendmode_combo(GtkWidget *combobox, dt_develop_blend_mode_t mode)
{
  for(const dt_develop_name_value_t *bm = dt_develop_blend_mode_names; *bm->name; bm++)
  {
    if(bm->value == mode)
    {
      dt_bauhaus_combobox_add_full(combobox, g_dpgettext2(NULL, "blendmode", bm->name), DT_BAUHAUS_COMBOBOX_ALIGN_RIGHT, GUINT_TO_POINTER(bm->value), NULL, TRUE);
 
      return TRUE;
    }
  }
 
  return FALSE;
}
 
static GtkWidget *_combobox_new_from_list(dt_iop_module_t *module, const gchar *label,
                                          const dt_develop_name_value_t *list, uint32_t *field, const gchar *tooltip)
{
  GtkWidget *combo = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(module));
  dt_bauhaus_disable_module_list(combo);
  dt_bauhaus_disable_accels(combo);
  dt_bauhaus_set_use_default_callback(combo);
 
  if(field)
    dt_bauhaus_widget_set_field(combo, field, DT_INTROSPECTION_TYPE_ENUM);
  dt_bauhaus_widget_set_label(combo, label);
  gtk_widget_set_tooltip_text(combo, tooltip);
  for(; *list->name; list++)
    dt_bauhaus_combobox_add_full(combo, _(list->name), DT_BAUHAUS_COMBOBOX_ALIGN_RIGHT,
                                 GUINT_TO_POINTER(list->value), NULL, TRUE);
 
  return combo;
}
 
static void _notebook_append_full_width_page(GtkWidget *notebook, GtkWidget *page, const gchar *label)
{
  GtkWidget *tab = gtk_label_new(label);
  gtk_notebook_append_page(GTK_NOTEBOOK(notebook), page, tab);
  gtk_container_child_set(GTK_CONTAINER(notebook), page, "tab-expand", TRUE, "tab-fill", TRUE, NULL);
}
 
static GtkWidget *_blendop_create_enable_toggle(dt_iop_module_t *module, const unsigned int mask_bit)
{
  const gboolean is_disable_toggle = mask_bit == DEVELOP_MASK_RASTER
                                     || mask_bit == DEVELOP_MASK_SHAPE
                                     || mask_bit == DEVELOP_MASK_PARAMETRIC;
  GtkWidget *toggle = gtk_check_button_new_with_label(is_disable_toggle ? _("Disable") : _("Enable"));
  g_object_set_data(G_OBJECT(toggle), "mask-bit", GUINT_TO_POINTER(mask_bit));
  g_signal_connect(G_OBJECT(toggle), "toggled", G_CALLBACK(_blendop_masks_mode_changed), module);
  return toggle;
}
 
static void _blendop_update_top_enable_label(dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module) || !module->gui->blend_data) return;
 
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(!GTK_IS_BUTTON(bd->top_enable)) return;
 
  gchar *clean_name = delete_underscore(module->name());
  const char *multi_name = module->multi_name[0] ? module->multi_name : "0";
  gchar *multi_name_dup = ((g_strcmp0(multi_name, "0") == 0) || (g_strcmp0(multi_name, "") == 0)) ?  g_strdup("") : g_strdup_printf(" (%s)", multi_name);
  GtkWidget *child = gtk_bin_get_child(GTK_BIN(bd->top_enable));
  gchar *label = g_markup_printf_escaped(_("Enable in <b>%s%s</b>"), clean_name, multi_name_dup);
  if(GTK_IS_LABEL(child))
  {
    gtk_label_set_markup(GTK_LABEL(child), label);
    gtk_label_set_line_wrap(GTK_LABEL(child), TRUE);
    gtk_label_set_xalign(GTK_LABEL(child), 0.0f);
  }
  dt_free(label);
  dt_free(clean_name);
  dt_free(multi_name_dup);
}
 
static GtkWidget *_blendop_create_notebook_page(GtkWidget *notebook, const gchar *label,
                                                gchar *help_url, GtkWidget **content)
{
  GtkWidget *page = gtk_event_box_new();
  if(help_url) dt_gui_add_help_link(page, help_url);
  *content = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  gtk_container_add(GTK_CONTAINER(page), *content);
  _notebook_append_full_width_page(notebook, page, label);
  return page;
}
 
static GtkWidget *_blendop_create_toggle_page(GtkWidget *notebook, const gchar *label,
                                              gchar *help_url,
                                              dt_iop_module_t *module, const unsigned int mask_bit,
                                              GtkWidget **toggle, GtkWidget **content)
{
  GtkWidget *page = gtk_event_box_new();
  if(help_url) dt_gui_add_help_link(page, help_url);
  GtkWidget *vbox = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  gtk_container_add(GTK_CONTAINER(page), vbox);
 
  GtkWidget *header = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  *toggle = _blendop_create_enable_toggle(module, mask_bit);
  gtk_box_pack_start(GTK_BOX(header), *toggle, FALSE, FALSE, 0);
  gtk_box_pack_start(GTK_BOX(vbox), header, FALSE, FALSE, 0);
 
  *content = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  gtk_box_pack_start(GTK_BOX(vbox), *content, TRUE, TRUE, 0);
 
  _notebook_append_full_width_page(notebook, page, label);
  return header;
}
 
static void _blendop_toggle_button_set_active(GtkWidget *toggle, const gboolean enabled)
{
  if(GTK_IS_TOGGLE_BUTTON(toggle))
  {
    const unsigned int bit = GPOINTER_TO_UINT(g_object_get_data(G_OBJECT(toggle), "mask-bit"));
    const gboolean is_disable_toggle = bit == DEVELOP_MASK_RASTER
                                       || bit == DEVELOP_MASK_SHAPE
                                       || bit == DEVELOP_MASK_PARAMETRIC;
    gtk_toggle_button_set_active(GTK_TOGGLE_BUTTON(toggle), is_disable_toggle ? !enabled : enabled);
  }
}
 
static void _blendop_sync_toggle_state(GtkWidget *toggle, const gboolean available,
                                       const gboolean enabled, GtkWidget *content)
{
  _blendop_toggle_button_set_active(toggle, enabled);
  if(GTK_IS_WIDGET(toggle))
    gtk_widget_set_sensitive(toggle, available);
  if(GTK_IS_WIDGET(content))
    gtk_widget_set_sensitive(content, available && enabled);
}
 
void dt_iop_gui_update_blending(dt_iop_module_t *module)
{
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  if(!(module->flags() & IOP_FLAGS_SUPPORTS_BLENDING) || IS_NULL_PTR(bd)) return;
 
  dt_gui_freeze_begin();
 
  // update color space from parameters
  const dt_develop_blend_colorspace_t default_csp = dt_develop_blend_default_module_blend_colorspace(module);
  switch(default_csp)
  {
    case DEVELOP_BLEND_CS_RAW:
      bd->csp = DEVELOP_BLEND_CS_RAW;
      break;
    case DEVELOP_BLEND_CS_LAB:
    case DEVELOP_BLEND_CS_RGB_DISPLAY:
    case DEVELOP_BLEND_CS_RGB_SCENE:
      switch(module->blend_params->blend_cst)
      {
        case DEVELOP_BLEND_CS_LAB:
        case DEVELOP_BLEND_CS_RGB_DISPLAY:
        case DEVELOP_BLEND_CS_RGB_SCENE:
          bd->csp = module->blend_params->blend_cst;
          break;
        default:
          bd->csp = default_csp;
          break;
      }
      break;
    case DEVELOP_BLEND_CS_NONE:
    default:
      bd->csp = DEVELOP_BLEND_CS_NONE;
      break;
  }
 
  // (un)set the mask indicator
  dt_iop_add_remove_mask_indicator(module);
 
  if(!bd->blending_box)
  {
    dt_gui_freeze_end();
    return;
  }
 
  // initialization of blending modes
  if(bd->csp != bd->blend_modes_csp)
  {
    dt_bauhaus_combobox_clear(bd->blend_modes_combo);
 
    if(bd->csp == DEVELOP_BLEND_CS_LAB
       || bd->csp == DEVELOP_BLEND_CS_RGB_DISPLAY
       || bd->csp == DEVELOP_BLEND_CS_RAW )
    {
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_NORMAL2);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_BOUNDED);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_AVERAGE);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_DIFFERENCE2);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LIGHTEN);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_ADD);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_SCREEN);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_DARKEN);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_SUBTRACT);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_MULTIPLY);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_OVERLAY);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_SOFTLIGHT);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_HARDLIGHT);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_VIVIDLIGHT);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LINEARLIGHT);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_PINLIGHT);
 
      if(bd->csp == DEVELOP_BLEND_CS_LAB)
      {
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LAB_LIGHTNESS);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LAB_A);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LAB_B);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LAB_COLOR);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LIGHTNESS);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_CHROMATICITY);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_HUE);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_COLOR);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_COLORADJUST);
      }
      else if(bd->csp == DEVELOP_BLEND_CS_RGB_DISPLAY)
      {
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_RGB_R);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_RGB_G);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_RGB_B);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LIGHTNESS);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_HSV_VALUE);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_CHROMATICITY);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_HSV_COLOR);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_HUE);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_COLOR);
        _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_COLORADJUST);
      }
    }
    else if(bd->csp == DEVELOP_BLEND_CS_RGB_SCENE)
    {
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_NORMAL2);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_MULTIPLY);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_DIVIDE);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_ADD);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_SUBTRACT);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_DIFFERENCE2);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_AVERAGE);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_GEOMETRIC_MEAN);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_HARMONIC_MEAN);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_RGB_R);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_RGB_G);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_RGB_B);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_LIGHTNESS);
      _add_blendmode_combo(bd->blend_modes_combo, DEVELOP_BLEND_CHROMATICITY);
    }
    bd->blend_modes_csp = bd->csp;
  }
 
  dt_develop_blend_mode_t blend_mode = module->blend_params->blend_mode & DEVELOP_BLEND_MODE_MASK;
  // module->blend_params->mask_mode
  if(!dt_bauhaus_combobox_set_from_value(bd->blend_modes_combo, blend_mode))
  {
    // add deprecated blend mode
    if(!_add_blendmode_combo(bd->blend_modes_combo, blend_mode))
    {
      // should never happen: unknown blend mode
      dt_control_log("unknown blend mode '%d' in module '%s'", blend_mode, module->op);
      module->blend_params->blend_mode = DEVELOP_BLEND_NORMAL2;
      blend_mode = DEVELOP_BLEND_NORMAL2;
    }
 
    dt_bauhaus_combobox_set_from_value(bd->blend_modes_combo, blend_mode);
  }
 
  gboolean blend_mode_reversed = (module->blend_params->blend_mode & DEVELOP_BLEND_REVERSE) == DEVELOP_BLEND_REVERSE;
  dt_bauhaus_combobox_set_from_value(bd->blend_modes_blend_order, blend_mode_reversed);
 
  dt_bauhaus_slider_set(bd->blend_mode_parameter_slider, module->blend_params->blend_parameter);
  const gboolean show_param = (bd->blend_modes_csp == DEVELOP_BLEND_CS_RGB_SCENE) &&
                              _blendif_blend_parameter_enabled(bd->blend_modes_csp, module->blend_params->blend_mode);
  if(!show_param)
  {
    module->blend_params->blend_parameter = 0.0f;
    dt_bauhaus_slider_set(bd->blend_mode_parameter_slider, module->blend_params->blend_parameter);
  }
  gtk_widget_set_visible(bd->blend_mode_parameter_slider, show_param);
 
  dt_bauhaus_combobox_set_from_value(bd->masks_combine_combo,
                                     module->blend_params->mask_combine & (DEVELOP_COMBINE_INV | DEVELOP_COMBINE_INCL));
  dt_bauhaus_combobox_set_from_value(bd->masks_invert_combo,
                                     module->blend_params->mask_combine & DEVELOP_COMBINE_INV);
  dt_bauhaus_slider_set(bd->opacity_slider, module->blend_params->opacity);
  dt_bauhaus_combobox_set_from_value(bd->masks_feathering_guide_combo,
                                     module->blend_params->feathering_guide);
  dt_bauhaus_slider_set(bd->feathering_radius_slider, module->blend_params->feathering_radius);
  dt_bauhaus_slider_set(bd->blur_radius_slider, module->blend_params->blur_radius);
  dt_bauhaus_slider_set(bd->brightness_slider, module->blend_params->brightness);
  dt_bauhaus_slider_set(bd->contrast_slider, module->blend_params->contrast);
  dt_bauhaus_slider_set(bd->details_slider, module->blend_params->details);
 
  /* reset all alternative display modes for blendif */
  memset(bd->altmode, 0, sizeof(bd->altmode));
 
  // force the visibility of output channels if they contain some setting
  bd->output_channels_shown = bd->output_channels_shown
      || _blendif_are_output_channels_used(module->blend_params, bd->csp);
 
  dt_iop_gui_update_blendif(module);
  dt_iop_gui_blend_masks_update(module);
  dt_iop_gui_update_raster(module);
 
  /* sync page states from mask mode */
  uint32_t mask_mode = module->blend_params->mask_mode;
  const gboolean top_enabled = (mask_mode & DEVELOP_MASK_ENABLED) != 0;
  const gboolean masks_enabled = (mask_mode & DEVELOP_MASK_SHAPE) != 0;
  const gboolean raster_enabled = (mask_mode & DEVELOP_MASK_RASTER) != 0;
  const gboolean blendif_enabled = (mask_mode & DEVELOP_MASK_PARAMETRIC) != 0;
  const gboolean bottom_enabled = top_enabled && ((bd->masks_inited && masks_enabled)
                                                  || (bd->raster_inited && raster_enabled)
                                                  || (bd->blendif_inited && blendif_enabled));
 
  _blendop_update_top_enable_label(module);
  _blendop_toggle_button_set_active(bd->top_enable, top_enabled);
 
  if(GTK_IS_WIDGET(bd->blending_box))
  {
    gtk_widget_set_sensitive(bd->blending_box, top_enabled);
    // Note: the showmask toggle is outside the blending box.
    gtk_widget_set_sensitive(bd->showmask, top_enabled);
  }
 
  _blendop_sync_toggle_state(bd->masks_enable, bd->masks_inited, masks_enabled, bd->masks_content);
  _blendop_sync_toggle_state(bd->raster_enable, bd->raster_inited, raster_enabled, bd->raster_content);
  _blendop_sync_toggle_state(bd->blendif_enable, bd->blendif_inited, blendif_enabled, bd->blendif_content);
 
  // The Contours page has no enable/disable toggle of its own (unlike the three pages above),
  // so unlike them it never gets its own explicit gtk_widget_set_sensitive() call and relies
  // entirely on inherited state propagated from bd->blending_box. Give it the same explicit
  // sync so its tab content doesn't get stuck rendering with a stale insensitive (dimmed) style.
  // It refines whatever mask raster/drawn/parametric produces, so it has nothing to act on
  // unless at least one of those three is actually enabled.
  if(GTK_IS_WIDGET(bd->contours_content))
    gtk_widget_set_sensitive(bd->contours_content, bottom_enabled);
 
  if(bd->blendif_inited && !IS_NULL_PTR(bd->channel))
  {
    /* The parametric page may have made the whole content insensitive before
     * `_blendop_blendif_update_tab()` restored the channel-local state.
     * Reapply the final contract after the page toggle is synchronized:
     * boost factor is editable only for an enabled parametric mask and a
     * channel whose descriptor explicitly supports boosting. */
    gtk_widget_set_sensitive(
        bd->channel_boost_factor_slider,
        blendif_enabled && bd->channel[bd->tab].boost_factor_enabled);
  }
 
  if(bd->blendif_inited && blendif_enabled)
  {
    gtk_widget_hide(GTK_WIDGET(bd->masks_invert_combo));
    gtk_widget_show(GTK_WIDGET(bd->masks_combine_combo));
  }
  else
  {
    gtk_widget_show(GTK_WIDGET(bd->masks_invert_combo));
    gtk_widget_hide(GTK_WIDGET(bd->masks_combine_combo));
  }
 
  /*
   * if this iop is operating in raw space, it has only 1 channel per pixel,
   * thus there is no alpha channel where we would normally store mask
   * that would get displayed if following button have been pressed.
   */
  if(module->blend_colorspace(module, NULL, NULL) == IOP_CS_RAW)
  {
    module->request_mask_display = DT_DEV_PIXELPIPE_DISPLAY_NONE;
    dt_iop_set_cache_bypass(module, FALSE);
    _blendop_toggle_button_set_active(bd->showmask, FALSE);
    gtk_widget_hide(GTK_WIDGET(bd->showmask));
 
    // disable also guided filters on RAW based color space
    gtk_widget_set_sensitive(bd->masks_feathering_guide_combo, FALSE);
    gtk_widget_hide(bd->masks_feathering_guide_combo);
    gtk_widget_set_sensitive(bd->feathering_radius_slider, FALSE);
    gtk_widget_hide(bd->feathering_radius_slider);
    gtk_widget_set_sensitive(bd->brightness_slider, FALSE);
    gtk_widget_hide(bd->brightness_slider);
    gtk_widget_set_sensitive(bd->contrast_slider, FALSE);
    gtk_widget_hide(bd->contrast_slider);
    gtk_widget_set_sensitive(bd->details_slider, FALSE);
    gtk_widget_hide(bd->details_slider);
  }
  else
  {
    gtk_widget_show(GTK_WIDGET(bd->showmask));
    gtk_widget_set_sensitive(bd->masks_feathering_guide_combo, TRUE);
    gtk_widget_show(bd->masks_feathering_guide_combo);
    gtk_widget_set_sensitive(bd->feathering_radius_slider, TRUE);
    gtk_widget_show(bd->feathering_radius_slider);
    gtk_widget_set_sensitive(bd->brightness_slider, TRUE);
    gtk_widget_show(bd->brightness_slider);
    gtk_widget_set_sensitive(bd->contrast_slider, TRUE);
    gtk_widget_show(bd->contrast_slider);
    /* show details slider only if it was used in an old edit (non-zero) */
    const gboolean show_details = (module->blend_params->details != 0.0f);
    gtk_widget_set_visible(bd->details_slider, show_details);
  }
 
  if(!bottom_enabled)
  {
    module->request_mask_display = DT_DEV_PIXELPIPE_DISPLAY_NONE;
    dt_iop_set_cache_bypass(module, FALSE);
    _blendop_toggle_button_set_active(bd->showmask, FALSE);
  }
 
  if(bd->masks_inited && !masks_enabled)
  {
    dt_masks_set_edit_mode(module, DT_MASKS_EDIT_OFF);
    _blendop_toggle_button_set_active(bd->masks_edit, FALSE);
  }
 
  if(bd->masks_support && !masks_enabled)
  {
    dt_masks_shape_buttons_deactivate_all(NULL);
  }
 
  if(bd->blendif_inited && !blendif_enabled)
  {
    dt_iop_color_picker_reset(module, FALSE);
  }
 
  _blendop_blendif_sync_channel_display_buttons(module);
 
  // Re-evaluate header state after notebook toggle synchronization.
  dt_iop_add_remove_mask_indicator(module);
 
  dt_gui_freeze_end();
}
 
void dt_iop_gui_blending_lose_focus(dt_iop_module_t *module)
{
  // FIXME : there are more than 3 functions getting clever about how to setup module->request_mask_display depending on user input.
  // These should all use an uniform setter function.
  //
  // The lack of setter implies we don't guaranty that only 1 module can request mask display at a time.
  // The consequence is pipeline needs to check if module->request_mask_display AND module == dev->gui_module,
  // but the global pipe->mask_display is set from *_blend_process() at runtime, so it's a pipe property
  // that changes over the pipe lifecycle.
  //
  // This is a self-feeding loop of madness because it ties the pipeline to GUI states
  // (but not all pipes are connected to a GUI, so you need to cover all cases all the time and don't forget to test everything),
  // and because the pipeline is executed recursively from the end, but pipe->mask_display is set in the middle,
  // when it reaches the process() method of the module capturing mask preview, so you don't have this info when
  // planning for pipeline execution.
  // And you need to plan for mask preview ahead in pipe because mask preview needs to work
  // without using the pixelpipe cache, at least between the module requiring mask preview and gamma.c, which will actually render
  // the preview at the far end of the pipe.
  // So the not-so-clever workaround inherited from darktable was to flush all cache lines when requesting mask preview,
  // which flushed lines that could be reused later and were only temporarily not needed.
 
  if(dt_gui_widgets_suppressed()) return;
  if(IS_NULL_PTR(module)) return;
 
  const int has_mask_display = module->request_mask_display & (DT_DEV_PIXELPIPE_DISPLAY_MASK | DT_DEV_PIXELPIPE_DISPLAY_CHANNEL);
 
  if((module->flags() & IOP_FLAGS_SUPPORTS_BLENDING) && module->gui->blend_data)
  {
    dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
    if(bd->showmask)
      _blendop_toggle_button_set_active(bd->showmask, FALSE);
    module->request_mask_display = DT_DEV_PIXELPIPE_DISPLAY_NONE;
    dt_iop_set_cache_bypass(module, FALSE);
    _blendop_blendif_sync_channel_display_buttons(module);
 
    // (re)set the header mask indicator too
    if(bd->masks_support && bd->masks_edit)
    {
      // unselect all tools
      _blendop_toggle_button_set_active(bd->masks_edit, FALSE);
      dt_masks_set_edit_mode(module, DT_MASKS_EDIT_OFF);
 
      dt_masks_shape_buttons_deactivate_all(NULL);
    }
 
    dt_pthread_mutex_lock(&bd->lock);
    bd->save_for_leave = DT_DEV_PIXELPIPE_DISPLAY_NONE;
    if(bd->timeout_handle)
    {
      // purge any remaining timeout handlers
      g_source_remove(bd->timeout_handle);
      bd->timeout_handle = 0;
    }
    dt_pthread_mutex_unlock(&bd->lock);
 
    // reprocess main center image if needed
    if (has_mask_display)
      dt_dev_pixelpipe_update_history_main(module->dev);
  }
}
 
void dt_iop_gui_blending_reload_defaults(dt_iop_module_t *module)
{
  // reached from dt_iop_load_default_params() -- the module-defaults path, which runs
  // headless too; every other entry in this file exists only under a live GUI
  if(IS_NULL_PTR(module) || IS_NULL_PTR(module->gui)) return;
  dt_iop_gui_blend_data_t *bd = module->gui->blend_data;
  if(IS_NULL_PTR(bd) || !bd->blendif_support || !bd->blendif_inited) return;
  bd->output_channels_shown = FALSE;
}
 
void dt_iop_gui_cleanup_blending_body(dt_iop_module_t *module)
{
  if(IS_NULL_PTR(module) || !module->gui->blend_data) return;
 
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(IS_NULL_PTR(bd->blending_box)) return;
  dt_pthread_mutex_lock(&bd->lock);
  if(bd->timeout_handle)
  {
    g_source_remove(bd->timeout_handle);
    bd->timeout_handle = 0;
  }
  dt_free_align(bd->masks_combo_ids);
  dt_pthread_mutex_unlock(&bd->lock);
 
  if(bd->masks_ic_inverse) g_object_unref(bd->masks_ic_inverse);
  if(bd->masks_ic_union) g_object_unref(bd->masks_ic_union);
  if(bd->masks_ic_intersection) g_object_unref(bd->masks_ic_intersection);
  if(bd->masks_ic_difference) g_object_unref(bd->masks_ic_difference);
  if(bd->masks_ic_exclusion) g_object_unref(bd->masks_ic_exclusion);
  if(bd->group_shapes_store) g_object_unref(bd->group_shapes_store);
  if(bd->all_shapes_store) g_object_unref(bd->all_shapes_store);
 
  gtk_widget_destroy(bd->blending_box);
 
  bd->blending_box = NULL;
  bd->blending_notebook = NULL;
  bd->top_enable = NULL;
  bd->masks_enable = NULL;
  bd->raster_enable = NULL;
  bd->blendif_enable = NULL;
  bd->blending_box = NULL;
  bd->masks_content = NULL;
  bd->raster_content = NULL;
  bd->blendif_content = NULL;
  bd->contours_content = NULL;
  bd->blendif_box = NULL;
  bd->masks_box = NULL;
  bd->raster_box = NULL;
  bd->colorpicker = NULL;
  bd->colorpicker_set_values = NULL;
  memset(bd->filter, 0, sizeof(bd->filter));
  bd->showmask = NULL;
  bd->masks_combine_combo = NULL;
  bd->blend_modes_combo = NULL;
  bd->blend_modes_blend_order = NULL;
  bd->blend_mode_parameter_slider = NULL;
  bd->masks_invert_combo = NULL;
  bd->opacity_slider = NULL;
  bd->masks_feathering_guide_combo = NULL;
  bd->feathering_radius_slider = NULL;
  bd->blur_radius_slider = NULL;
  bd->contrast_slider = NULL;
  bd->brightness_slider = NULL;
  bd->channel_boost_factor_slider = NULL;
  bd->details_slider = NULL;
  bd->masks_combo = NULL;
  memset(bd->masks_shapes, 0, sizeof(bd->masks_shapes));
  bd->masks_edit = NULL;
  bd->group_shapes_label = NULL;
  bd->masks_polarity = NULL;
  bd->wire_shape_toggle = NULL;
  bd->masks_treeview = NULL;
  bd->masks_group_treeview = NULL;
  bd->group_shapes_store = NULL;
  bd->group_shapes_col = NULL;
  bd->group_unlink_col = NULL;
  bd->group_delete_col = NULL;
  bd->all_shapes_store = NULL;
  bd->group_shapes_sw = NULL;
  bd->all_shapes_col = NULL;
  bd->all_shapes_delete_col = NULL;
  bd->all_shapes_sw = NULL;
  bd->lists_stack = NULL;
  bd->all_shapes_buttons = NULL;
  bd->lists_box = NULL;
  bd->masks_ic_inverse = NULL;
  bd->masks_ic_union = NULL;
  bd->masks_ic_intersection = NULL;
  bd->masks_ic_difference = NULL;
  bd->masks_ic_exclusion = NULL;
  bd->raster_combo = NULL;
  bd->raster_polarity = NULL;
  bd->picker_set_values_box_valid = FALSE;
  memset(bd->picker_set_values_box, 0, sizeof(bd->picker_set_values_box));
  bd->picker_set_values_manual_boost_lock = FALSE;
  bd->channel_tabs = NULL;
  bd->blendif_inited = 0;
  bd->masks_inited = 0;
  bd->raster_inited = 0;
  bd->blend_modes_csp = DEVELOP_BLEND_CS_NONE;
  bd->channel_tabs_csp = DEVELOP_BLEND_CS_NONE;
  module->gui->fusion_slider = NULL;
}
 
void dt_iop_gui_init_blending_body(GtkWidget *container, dt_iop_module_t *module)
{
  if(IS_NULL_PTR(container) || !GTK_IS_WIDGET(container)) return;
  if(!(module->flags() & IOP_FLAGS_SUPPORTS_BLENDING)) return;
  if(IS_NULL_PTR(module->gui) || IS_NULL_PTR(module->gui->blend_data)) return;
 
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
  if(bd->blending_box) return;
 
  dt_gui_freeze_begin();
 
  /* NOTE: we attach 2 modules to the parent container:
      1. the on/off global switch,
      2. the box containing all other options (recursively nested).
    This is just a trick so we can hide/insensitize the whole content
    in one shot, on main disabling, except for the main switch.
  */
 
  /* Global ON/OFF switch + show/hide toggle */
  GtkWidget *display_box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  dt_gui_add_help_link(display_box, dt_get_help_url("masks_blending"));
  gtk_widget_set_name(display_box, "blending-main-switch");
 
  bd->top_enable = _blendop_create_enable_toggle(module, DEVELOP_MASK_ENABLED);
  _blendop_update_top_enable_label(module);
  gtk_box_pack_start(GTK_BOX(display_box), bd->top_enable, FALSE, FALSE, 0);
 
  bd->showmask = dt_iop_togglebutton_new_no_register(module, "blend`tools", N_("display mask and/or color channel"), NULL, 
                                                     G_CALLBACK(_blendop_blendif_showmask_clicked),
                                                     FALSE, 0, 0, dtgtk_cairo_paint_showmask, display_box);
  gtk_widget_set_tooltip_text(bd->showmask, _("display mask and/or color channel. ctrl+click to display mask, "
                                              "shift+click to display channel. hover over parametric mask slider to "
                                              "select channel for display"));
 
  gtk_box_pack_start(GTK_BOX(container), display_box, FALSE, FALSE, 0);
  gtk_widget_show_all(display_box);
 
  /* Main widget container */
  bd->blending_box = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
  gtk_box_pack_start(GTK_BOX(container), bd->blending_box, TRUE, TRUE, 0);
  gtk_widget_set_name(bd->blending_box, "blending-box");
 
  /* Blend mode */
  bd->blend_modes_combo = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(module));
  dt_bauhaus_disable_module_list(bd->blend_modes_combo);
  dt_bauhaus_set_use_default_callback(bd->blend_modes_combo);
  dt_bauhaus_disable_accels(bd->blend_modes_combo);
  dt_bauhaus_widget_set_label(bd->blend_modes_combo, N_("Blend mode"));
  g_signal_connect(G_OBJECT(bd->blend_modes_combo), "value-changed",
                   G_CALLBACK(_blendop_blend_mode_callback), bd);
  dt_gui_add_help_link(GTK_WIDGET(bd->blend_modes_combo), dt_get_help_url("masks_blending_op"));
  gtk_box_pack_start(GTK_BOX(bd->blending_box), bd->blend_modes_combo, TRUE, TRUE, 0);
 
  /* Compositing combobox: choose compositing order */
  bd->blend_modes_blend_order = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(module));
  dt_bauhaus_widget_set_label(bd->blend_modes_blend_order, N_("Compositing"));
  dt_bauhaus_combobox_add_full(bd->blend_modes_blend_order, _("Output over input"), DT_BAUHAUS_COMBOBOX_ALIGN_RIGHT,
                               GINT_TO_POINTER(0), NULL, TRUE);
  dt_bauhaus_combobox_add_full(bd->blend_modes_blend_order, _("Input over output"), DT_BAUHAUS_COMBOBOX_ALIGN_RIGHT,
                               GINT_TO_POINTER(1), NULL, TRUE);
  dt_bauhaus_disable_module_list(bd->blend_modes_blend_order);
  dt_bauhaus_disable_accels(bd->blend_modes_blend_order);
  gtk_widget_set_tooltip_text(bd->blend_modes_blend_order, _("choose compositing order: which layer is placed on top"));
  g_signal_connect(G_OBJECT(bd->blend_modes_blend_order), "value-changed",
                   G_CALLBACK(_blendop_compositing_changed), bd);
  gtk_box_pack_start(GTK_BOX(bd->blending_box), bd->blend_modes_blend_order, TRUE, TRUE, 0);
 
  /* Optional fulcrum parameter for blend modes supporting it */
  bd->blend_mode_parameter_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), -18.0f, 18.0f, 0, 0.0f, 3);
  dt_bauhaus_disable_module_list(bd->blend_mode_parameter_slider);
  dt_bauhaus_set_use_default_callback(bd->blend_mode_parameter_slider);
  dt_bauhaus_disable_accels(bd->blend_mode_parameter_slider);
  dt_bauhaus_widget_set_field(bd->blend_mode_parameter_slider, &module->blend_params->blend_parameter, DT_INTROSPECTION_TYPE_FLOAT);
  dt_bauhaus_widget_set_label(bd->blend_mode_parameter_slider, N_("blend fulcrum"));
  dt_bauhaus_slider_set_format(bd->blend_mode_parameter_slider, _(" EV"));
  dt_bauhaus_slider_set_soft_range(bd->blend_mode_parameter_slider, -3.0, 3.0);
  gtk_widget_set_tooltip_text(bd->blend_mode_parameter_slider, _("adjust the fulcrum used by some blending"
                                                                 " operations"));
  g_object_set_data(G_OBJECT(bd->blend_mode_parameter_slider), "dt-blendop-header-update", GINT_TO_POINTER(TRUE));
  gtk_widget_set_visible(bd->blend_mode_parameter_slider, FALSE);
  gtk_box_pack_start(GTK_BOX(bd->blending_box), bd->blend_mode_parameter_slider, TRUE, TRUE, 0);
 
  /* mask combine control: how to combine drawn/parametric masks */
  bd->masks_combine_combo = _combobox_new_from_list(module, _("Combine drawn & parametric"), dt_develop_combine_masks_names, NULL,
                                                    _("how to combine drawn and parametric masks"));
  g_signal_connect(G_OBJECT(bd->masks_combine_combo), "value-changed",
                   G_CALLBACK(_blendop_masks_combine_callback), bd);
  dt_gui_add_help_link(GTK_WIDGET(bd->masks_combine_combo), dt_get_help_url("masks_combined"));
  gtk_box_pack_start(GTK_BOX(bd->blending_box), GTK_WIDGET(bd->masks_combine_combo), TRUE, TRUE, 0);
 
  /* mask invert control: single checkbox to invert masks */
  bd->masks_invert_combo = gtk_check_button_new_with_label(_("Invert mask"));
  gtk_widget_set_tooltip_text(bd->masks_invert_combo, _("invert the resulting mask (apply mask in inverted mode)"));
  g_signal_connect(G_OBJECT(bd->masks_invert_combo), "toggled",
                   G_CALLBACK(_blendop_masks_invert_toggled), bd);
  gtk_box_pack_start(GTK_BOX(bd->blending_box), GTK_WIDGET(bd->masks_invert_combo), TRUE, TRUE, 0);
 
  /* Global mask output opacity */
  bd->opacity_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), 0.0, 100.0, 0, 100.0, 0);
  dt_bauhaus_disable_module_list(bd->opacity_slider);
  dt_bauhaus_set_use_default_callback(bd->opacity_slider);
  dt_bauhaus_disable_accels(bd->opacity_slider);
  dt_bauhaus_widget_set_field(bd->opacity_slider, &module->blend_params->opacity, DT_INTROSPECTION_TYPE_FLOAT);
  dt_bauhaus_widget_set_label(bd->opacity_slider, N_("opacity"));
  dt_bauhaus_slider_set_format(bd->opacity_slider, "%");
  module->gui->fusion_slider = bd->opacity_slider;
  gtk_widget_set_tooltip_text(bd->opacity_slider, _("set the opacity of the blending"));
  g_object_set_data(G_OBJECT(bd->opacity_slider), "dt-blendop-header-update", GINT_TO_POINTER(TRUE));
  gtk_box_pack_start(GTK_BOX(bd->blending_box), bd->opacity_slider, TRUE, TRUE, 0);
 
  bd->details_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), -1.0f, 1.0f, 0, 0.0f, 2);
  dt_bauhaus_disable_module_list(bd->details_slider);
  dt_bauhaus_set_use_default_callback(bd->details_slider);
  dt_bauhaus_disable_accels(bd->details_slider);
  dt_bauhaus_widget_set_label(bd->details_slider, N_("details threshold"));
  dt_bauhaus_slider_set_format(bd->details_slider, "%");
  gtk_widget_set_tooltip_text(bd->details_slider, _("adjust the threshold for the details mask, "
                                                    "\npositive values selects areas with strong details, "
                                                    "\nnegative values select flat areas"));
  g_signal_connect(G_OBJECT(bd->details_slider), "value-changed", G_CALLBACK(_blendop_blendif_details_callback), bd);
  gtk_widget_hide(bd->details_slider);
 
  bd->blur_radius_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), 0.0, 100.0, 0, 0.0, 1);
  dt_bauhaus_disable_module_list(bd->blur_radius_slider);
  dt_bauhaus_set_use_default_callback(bd->blur_radius_slider);
  dt_bauhaus_disable_accels(bd->blur_radius_slider);
  dt_bauhaus_widget_set_field(bd->blur_radius_slider, &module->blend_params->blur_radius, DT_INTROSPECTION_TYPE_FLOAT);
  dt_bauhaus_widget_set_label(bd->blur_radius_slider, N_("blurring radius"));
  dt_bauhaus_slider_set_format(bd->blur_radius_slider, " px");
  gtk_widget_set_tooltip_text(bd->blur_radius_slider, _("radius for gaussian blur of blend mask"));
  g_object_set_data(G_OBJECT(bd->blur_radius_slider), "dt-blendop-header-update", GINT_TO_POINTER(TRUE));
 
  bd->masks_feathering_guide_combo = _combobox_new_from_list(module, _("feathering guide"), dt_develop_feathering_guide_names,
                                                             &module->blend_params->feathering_guide,
                                                             _("choose to guide mask by input or output image and"
                                                               "\nchoose to apply feathering before or after mask blur"));
  g_object_set_data(G_OBJECT(bd->masks_feathering_guide_combo), "dt-blendop-header-update", GINT_TO_POINTER(TRUE));
 
  bd->feathering_radius_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), 0.0, 250.0, 0, 0.0, 1);
  dt_bauhaus_disable_module_list(bd->feathering_radius_slider);
  dt_bauhaus_set_use_default_callback(bd->feathering_radius_slider);
  dt_bauhaus_disable_accels(bd->feathering_radius_slider);
  dt_bauhaus_widget_set_field(bd->feathering_radius_slider, &module->blend_params->feathering_radius, DT_INTROSPECTION_TYPE_FLOAT);
  dt_bauhaus_widget_set_label(bd->feathering_radius_slider, N_("feathering radius"));
  dt_bauhaus_slider_set_format(bd->feathering_radius_slider, " px");
  gtk_widget_set_tooltip_text(bd->feathering_radius_slider, _("spatial radius of feathering"));
  g_object_set_data(G_OBJECT(bd->feathering_radius_slider), "dt-blendop-header-update", GINT_TO_POINTER(TRUE));
 
  bd->brightness_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), -1.0, 1.0, 0, 0.0, 2);
  dt_bauhaus_disable_module_list(bd->brightness_slider);
  dt_bauhaus_set_use_default_callback(bd->brightness_slider);
  dt_bauhaus_disable_accels(bd->brightness_slider);
  dt_bauhaus_widget_set_field(bd->brightness_slider, &module->blend_params->brightness, DT_INTROSPECTION_TYPE_FLOAT);
  dt_bauhaus_widget_set_label(bd->brightness_slider, N_("Feathering mask opacity"));
  dt_bauhaus_slider_set_format(bd->brightness_slider, "%");
  gtk_widget_set_tooltip_text(bd->brightness_slider, _("shifts and tilts the tone curve of the blend mask to adjust its "
                                                       "brightness without affecting fully transparent/fully opaque "
                                                       "regions"));
  g_object_set_data(G_OBJECT(bd->brightness_slider), "dt-blendop-header-update", GINT_TO_POINTER(TRUE));
 
  bd->contrast_slider = dt_bauhaus_slider_new_with_range(dt_bauhaus_get_global(), DT_GUI_MODULE(module), -1.0, 1.0, 0, 0.0, 2);
  dt_bauhaus_disable_module_list(bd->contrast_slider);
  dt_bauhaus_set_use_default_callback(bd->contrast_slider);
  dt_bauhaus_disable_accels(bd->contrast_slider);
  dt_bauhaus_widget_set_field(bd->contrast_slider, &module->blend_params->contrast, DT_INTROSPECTION_TYPE_FLOAT);
  dt_bauhaus_widget_set_label(bd->contrast_slider, N_("Feathering mask contrast"));
  dt_bauhaus_slider_set_format(bd->contrast_slider, "%");
  gtk_widget_set_tooltip_text(bd->contrast_slider, _("gives the tone curve of the blend mask an s-like shape to "
                                                     "adjust its contrast"));
  g_object_set_data(G_OBJECT(bd->contrast_slider), "dt-blendop-header-update", GINT_TO_POINTER(TRUE));
 
  /* separator between global blending options and the masking sub-modes notebook */
  GtkWidget *blend_separator = gtk_separator_new(GTK_ORIENTATION_HORIZONTAL);
  gtk_widget_set_name(blend_separator, "blending-separator");
  gtk_box_pack_start(GTK_BOX(bd->blending_box), blend_separator, FALSE, FALSE, 0);
 
  GtkWidget *presets_button = dtgtk_button_new(dtgtk_cairo_paint_presets, 0, NULL);
  gtk_widget_set_tooltip_text(presets_button, _("blending options"));
  if(bd->blendif_support)
    g_signal_connect(G_OBJECT(presets_button), "button-press-event", G_CALLBACK(_blendif_options_callback), module);
  else
    gtk_widget_set_sensitive(GTK_WIDGET(presets_button), FALSE);
 
  /* Blending submodes notebook */
  bd->blending_notebook = gtk_notebook_new();
  gtk_notebook_set_scrollable(GTK_NOTEBOOK(bd->blending_notebook), TRUE);
  gtk_notebook_set_action_widget(GTK_NOTEBOOK(bd->blending_notebook), presets_button, GTK_PACK_END);
  gtk_widget_show(presets_button);
  gtk_box_pack_start(GTK_BOX(bd->blending_box), bd->blending_notebook, TRUE, TRUE, 0);
 
  /* Raster page */
  _blendop_create_toggle_page(bd->blending_notebook, _("Raster"), dt_get_help_url("masks_raster"),
                              module, DEVELOP_MASK_RASTER, &bd->raster_enable, &bd->raster_content);
  dt_iop_gui_init_raster(GTK_BOX(bd->raster_content), module);
 
  /* Drawn page */
  _blendop_create_toggle_page(bd->blending_notebook, _("Drawn"), dt_get_help_url("masks_drawn"),
                              module, DEVELOP_MASK_SHAPE, &bd->masks_enable, &bd->masks_content);
  dt_iop_gui_init_masks(GTK_BOX(bd->masks_content), module);
 
  /* Parametric page */
  GtkWidget *blendif_header = _blendop_create_toggle_page(bd->blending_notebook, _("Parametric"),
                              dt_get_help_url("masks_parametric"),
                              module, DEVELOP_MASK_PARAMETRIC, &bd->blendif_enable,
                              &bd->blendif_content);
  dt_iop_gui_init_blendif(GTK_BOX(bd->blendif_content), module, blendif_header);
 
  /* Contours page */
  _blendop_create_notebook_page(bd->blending_notebook, _("Contours"), dt_get_help_url("masks_refinement"), &bd->contours_content);
  dt_iop_gui_init_contours(GTK_BOX(bd->contours_content), module);
 
  /* Init all GUI states from module params */
  const unsigned int mask_mode = module->blend_params->mask_mode;
  _blendop_toggle_button_set_active(bd->top_enable, (mask_mode & DEVELOP_MASK_ENABLED) != 0);
  _blendop_toggle_button_set_active(bd->masks_enable, (mask_mode & DEVELOP_MASK_SHAPE) != 0);
  _blendop_toggle_button_set_active(bd->raster_enable, (mask_mode & DEVELOP_MASK_RASTER) != 0);
  _blendop_toggle_button_set_active(bd->blendif_enable, (mask_mode & DEVELOP_MASK_PARAMETRIC) != 0);
 
  gtk_widget_show_all(GTK_WIDGET(bd->blending_box));
  // show_all overrides the visibility the collapsible section set at init; re-apply config state.
  if(bd->masks_inited)
  {
    dt_gui_update_collapsible_section(&bd->masks_cs);
    dt_gui_update_collapsible_section(&bd->scroll_cs);
  }
  gtk_widget_set_sensitive(bd->blending_box, (mask_mode & DEVELOP_MASK_ENABLED) != 0);
 
  g_signal_connect(G_OBJECT(bd->blending_notebook), "switch_page", G_CALLBACK(_blendop_blending_notebook_switch), bd);
  const int page_count = gtk_notebook_get_n_pages(GTK_NOTEBOOK(bd->blending_notebook));
  if(page_count > 0)
  {
    // Restore the last-used tab after the notebook has been fully realized.
    int page = dt_conf_get_int(BLEND_MASKMODE_CONF_KEY);
    page = CLAMP(page, 0, page_count - 1);
    gtk_notebook_set_current_page(GTK_NOTEBOOK(bd->blending_notebook), page);
  }
 
  dt_gui_freeze_end();
}
 
void dt_iop_gui_init_blending(dt_iop_module_t *module)
{
  if(!(module->flags() & IOP_FLAGS_SUPPORTS_BLENDING) || module->gui->blend_data) return;
 
  module->gui->blend_data = g_malloc0(sizeof(dt_iop_gui_blend_data_t));
  dt_iop_gui_blend_data_t *bd = (dt_iop_gui_blend_data_t *)module->gui->blend_data;
 
  bd->module = module;
  bd->csp = DEVELOP_BLEND_CS_NONE;
  bd->blend_modes_csp = DEVELOP_BLEND_CS_NONE;
  bd->channel_tabs_csp = DEVELOP_BLEND_CS_NONE;
 
  const dt_iop_colorspace_type_t cst = module->blend_colorspace(module, NULL, NULL);
  bd->blendif_support = (cst == IOP_CS_LAB || dt_iop_colorspace_is_rgb(cst));
  bd->masks_support = !(module->flags() & IOP_FLAGS_NO_MASKS);
 
  dt_pthread_mutex_init(&bd->lock, NULL);
  dt_pthread_mutex_lock(&bd->lock);
  dt_pthread_mutex_unlock(&bd->lock);
 
  if(bd->masks_support)
  {
    DT_DEBUG_CONTROL_SIGNAL_CONNECT(dt_control_signal_get_global(), DT_SIGNAL_MASK_CHANGED,
                                    G_CALLBACK(_blendop_masks_handler_callback), module);
  }
}
 
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// modelines: These editor modelines have been set for all relevant files by tools/update_modelines.py
// vim: shiftwidth=2 expandtab tabstop=2 cindent
// kate: tab-indents: off; indent-width 2; replace-tabs on; indent-mode cstyle; remove-trailing-spaces modified;
// clang-format on