colorbalance.c

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#include "widgets/label.h"
/*
    This file is part of darktable,
    Copyright (C) 2013-2016 Roman Lebedev.
    Copyright (C) 2013-2014, 2016-2019 Tobias Ellinghaus.
    Copyright (C) 2013-2014 Ulrich Pegelow.
    Copyright (C) 2015 Pedro Côrte-Real.
    Copyright (C) 2016 johannes hanika.
    Copyright (C) 2017 Heiko Bauke.
    Copyright (C) 2018-2020, 2022-2023, 2025-2026 Aurélien PIERRE.
    Copyright (C) 2018-2019 Edgardo Hoszowski.
    Copyright (C) 2018 Matthieu Moy.
    Copyright (C) 2018 Maurizio Paglia.
    Copyright (C) 2018-2022 Pascal Obry.
    Copyright (C) 2018 rawfiner.
    Copyright (C) 2019 Andreas Schneider.
    Copyright (C) 2019-2020, 2022 Diederik Ter Rahe.
    Copyright (C) 2019 Diederik ter Rahe.
    Copyright (C) 2019 luzpaz.
    Copyright (C) 2019 msdm.
    Copyright (C) 2020 Aldric Renaudin.
    Copyright (C) 2020-2021 Chris Elston.
    Copyright (C) 2020 Marco.
    Copyright (C) 2020-2021 Ralf Brown.
    Copyright (C) 2021 Dan Torop.
    Copyright (C) 2021 Hubert Kowalski.
    Copyright (C) 2021 Miloš Komarčević.
    Copyright (C) 2022 Hanno Schwalm.
    Copyright (C) 2022 Martin Bařinka.
    Copyright (C) 2022 Nicolas Auffray.
    Copyright (C) 2022 Philipp Lutz.
    Copyright (C) 2022 Victor Forsiuk.
    Copyright (C) 2023 Luca Zulberti.
    
    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/>.
*/
/*
http://www.youtube.com/watch?v=JVoUgR6bhBc
 */
 
#ifdef HAVE_CONFIG_H
#include "config.h"
#include "common/conf.h"
#endif
// our includes go first:
#include "widgets/bauhaus.h"
#include "system/target_clones.h"
#include "system/mem_alloc.h"
#include "common/module_versioning.h"
#include "metadata/exif.h"
#include "develop/blend.h"
#include "develop/imageop.h"
#include "develop/imageop_math.h"
#include "develop/imageop_gui.h"
 
#include "gui/presets.h"
#include "gui/color_picker_proxy.h"
#include "iop/iop_api.h"
 
//#include <gtk/gtk.h>
#include <stdlib.h>
#include "control/signal.h"
 
// these are not in a state to be useful. but they look nice. too bad i couldn't map the enhanced mode with
// negative values to the wheels :(
//#define SHOW_COLOR_WHEELS
 
DT_MODULE_INTROSPECTION(3, dt_iop_colorbalance_params_t)
 
/*
 
  Meaning of the values:
   0 --> 100%
  -1 -->   0%
   1 --> 200%
 */
 
typedef enum dt_iop_colorbalance_mode_t
{
  LIFT_GAMMA_GAIN = 0,    // $DESCRIPTION: "lift, gamma, gain (ProPhoto RGB)"
  SLOPE_OFFSET_POWER = 1, // $DESCRIPTION: "slope, offset, power (ProPhoto RGB)"
  LEGACY = 2              // $DESCRIPTION: "lift, gamma, gain (sRGB)"
} dt_iop_colorbalance_mode_t;
 
typedef enum _colorbalance_channel_t
{
  CHANNEL_FACTOR = 0,
  CHANNEL_RED,
  CHANNEL_GREEN,
  CHANNEL_BLUE,
  CHANNEL_SIZE
} _colorbalance_channel_t;
 
typedef enum _colorbalance_levels_t
{
  LIFT = 0,
  GAMMA,
  GAIN,
  LEVELS
} _colorbalance_levels_t;
 
typedef enum _controls_t
{
  HSL,
  RGBL,
  BOTH
} _controls_t;
 
typedef enum _colorbalance_patch_t
{
  INVALID,
  USER_SELECTED,
  AUTO_SELECTED
} _colorbalance_patch_t;
 
typedef struct dt_iop_colorbalance_params_t
{
  dt_iop_colorbalance_mode_t mode; // $DEFAULT: SLOPE_OFFSET_POWER
  float lift[CHANNEL_SIZE], gamma[CHANNEL_SIZE], gain[CHANNEL_SIZE]; // $MIN: 0.0 $MAX: 2.0 $DEFAULT: 1.0
  float saturation;     // $MIN: 0.0 $MAX: 2.0 $DEFAULT: 1.0 $DESCRIPTION: "input saturation"
  float contrast;       // $MIN: 0.01 $MAX: 1.99 $DEFAULT: 1.0
  float grey;           // $MIN: 0.1 $MAX: 100.0 $DEFAULT: 18.0 $DESCRIPTION: "contrast fulcrum"
  float saturation_out; // $MIN: 0.0 $MAX: 2.0 $DEFAULT: 1.0 $DESCRIPTION: "output saturation"
} dt_iop_colorbalance_params_t;
 
typedef struct dt_iop_colorbalance_gui_data_t
{
  GtkWidget *master_box;
  GtkWidget *main_label;
  GtkWidget *main_box;
  GtkWidget *blocks[3];
  GtkWidget *optimizer_box;
  GtkWidget *mode;
  GtkWidget *controls;
  GtkWidget *hue_lift, *hue_gamma, *hue_gain;
  GtkWidget *sat_lift, *sat_gamma, *sat_gain;
  GtkWidget *lift_r, *lift_g, *lift_b, *lift_factor;
  GtkWidget *gamma_r, *gamma_g, *gamma_b, *gamma_factor;
  GtkWidget *gain_r, *gain_g, *gain_b, *gain_factor;
  GtkWidget *saturation, *contrast, *grey, *saturation_out;
  GtkWidget *auto_luma;
  GtkWidget *auto_color;
  float color_patches_lift[3];
  float color_patches_gamma[3];
  float color_patches_gain[3];
  _colorbalance_patch_t color_patches_flags[LEVELS];
  float luma_patches[LEVELS];
  _colorbalance_patch_t luma_patches_flags[LEVELS];
} dt_iop_colorbalance_gui_data_t;
 
typedef struct dt_iop_colorbalance_data_t
{
  dt_iop_colorbalance_mode_t mode;
  float lift[CHANNEL_SIZE], gamma[CHANNEL_SIZE], gain[CHANNEL_SIZE];
  float saturation, contrast, grey, saturation_out;
} dt_iop_colorbalance_data_t;
 
typedef struct dt_iop_colorbalance_global_data_t
{
  int kernel_colorbalance;
  int kernel_colorbalance_cdl;
  int kernel_colorbalance_lgg;
} dt_iop_colorbalance_global_data_t;
 
 
const char *name()
{
  return _("color balance (legacy)");
}
 
const char *aliases()
{
  return _("lift gamma gain|cdl|color grading|contrast|saturation|hue");
}
 
const char **description(struct dt_iop_module_t *self)
{
  return dt_iop_set_description(self, _("affect color, brightness and contrast"),
                                      _("corrective or creative"),
                                      _("linear, Lab, scene-referred"),
                                      _("non-linear, RGB"),
                                      _("non-linear, Lab, scene-referred"));
}
 
int flags()
{
  return IOP_FLAGS_INCLUDE_IN_STYLES | IOP_FLAGS_SUPPORTS_BLENDING| IOP_FLAGS_DEPRECATED;
}
 
int default_group()
{
  return IOP_GROUP_COLOR;
}
 
int default_colorspace(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, const dt_dev_pixelpipe_iop_t *piece)
{
  return IOP_CS_LAB;
}
 
void input_format(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece,
                  dt_iop_buffer_dsc_t *dsc)
{
  default_input_format(self, pipe, piece, dsc);
  dsc->channels = 4;
  dsc->datatype = TYPE_FLOAT;
}
 
int legacy_params(dt_iop_module_t *self, const void *const old_params, const int old_version, void *new_params,
                  const int new_version)
{
  if(old_version == 1 && new_version == 3)
  {
    typedef struct dt_iop_colorbalance_params_v1_t
    {
      float lift[CHANNEL_SIZE], gamma[CHANNEL_SIZE], gain[CHANNEL_SIZE];
    } dt_iop_colorbalance_params_v1_t;
 
    dt_iop_colorbalance_params_v1_t *o = (dt_iop_colorbalance_params_v1_t *)old_params;
    dt_iop_colorbalance_params_t *n = (dt_iop_colorbalance_params_t *)new_params;
    dt_iop_colorbalance_params_t *d = (dt_iop_colorbalance_params_t *)self->default_params;
 
    *n = *d; // start with a fresh copy of default parameters
 
    for(int i = 0; i < CHANNEL_SIZE; i++)
    {
      n->lift[i] = o->lift[i];
      n->gamma[i] = o->gamma[i];
      n->gain[i] = o->gain[i];
    }
    n->mode = LEGACY;
    return 0;
  }
 
  if(old_version == 2 && new_version == 3)
  {
    typedef struct dt_iop_colorbalance_params_v2_t
    {
      dt_iop_colorbalance_mode_t mode;
      float lift[CHANNEL_SIZE], gamma[CHANNEL_SIZE], gain[CHANNEL_SIZE];
      float saturation, contrast, grey;
    } dt_iop_colorbalance_params_v2_t;
 
    dt_iop_colorbalance_params_v2_t *o = (dt_iop_colorbalance_params_v2_t *)old_params;
    dt_iop_colorbalance_params_t *n = (dt_iop_colorbalance_params_t *)new_params;
    dt_iop_colorbalance_params_t *d = (dt_iop_colorbalance_params_t *)self->default_params;
 
    *n = *d; // start with a fresh copy of default parameters
 
    for(int i = 0; i < CHANNEL_SIZE; i++)
    {
      n->lift[i] = o->lift[i];
      n->gamma[i] = o->gamma[i];
      n->gain[i] = o->gain[i];
    }
    n->mode = o->mode;
    n->contrast = o->contrast;
    n->saturation = o->saturation;
    n->contrast = o->contrast;
    n->grey = o->grey;
    return 0;
  }
  return 1;
}
 
// taken from denoiseprofile.c
static void add_preset(dt_iop_module_so_t *self, const char *name,
                       const char *pi, const int version, const char *bpi, const int blendop_version)
{
  int len, blen;
  uint8_t *p  = dt_exif_xmp_decode(pi, strlen(pi), &len);
  uint8_t *bp = dt_exif_xmp_decode(bpi, strlen(bpi), &blen);
  if(blendop_version != dt_develop_blend_version())
  {
    // update to current blendop params format
    void *bp_new = malloc(sizeof(dt_develop_blend_params_t));
 
    if(dt_develop_blend_legacy_params_from_so(self, bp, blendop_version, bp_new, dt_develop_blend_version(),
      blen) == 0)
    {
      dt_free(bp);
      bp = bp_new;
      blen = sizeof(dt_develop_blend_params_t);
    }
    else
    {
      dt_free(bp);
      dt_free(bp_new);
      bp = NULL;
    }
  }
 
  if(p && bp)
    dt_gui_presets_add_with_blendop(name, self->op, version, p, len, bp, 1);
  dt_free(bp);
  dt_free(p);
}
 
void init_presets(dt_iop_module_so_t *self)
{
  // these blobs were exported as dtstyle and copied from there:
  add_preset(self, _("split-toning teal-orange (2nd instance)"),
             "gz02eJxjZGBg8HhYZX99cYN9kkCDfdCOOnsGhgZ7ruvN9m8CK+yXFNTaz5w50z5PqBku9u9/PVjNv//9jqfP+NgDAHs0HIc=", 3,
             "gz05eJxjZWBgYGUAgRNODFDAzszAxMBQ5cwI4Tow4AUNdkBsD8E3gGwue9x8uB6q8s+c8bEF8Z9Y9Nnt2f3bbluCN03tg/EBIBckVg==", 8);
  add_preset(self, _("split-toning teal-orange (1st instance)"),
             "gz02eJxjZACBBvugHXX2E3fU219f3GAP4n/TqLFvfd1oL8HZaH/2jI/9prn1cLHUtDSwGgaGCY7//tfbAwBRixpm", 3,
             "gz04eJxjZWBgYGUAgRNODFDApgwiq5wZIVyHD4E7bBnwggZ7CIYBRiBbBA8fXT1l/P5DX21i+pnA/Pfv8uw6OzzIMq9I5rgtSH//4wii1AMASbIlcw==", 8);
 
  add_preset(self, _("generic film"),
             "gz02eJxjZACBBntN5gb7op/19u5AGsSX3dFgr+jYaL+vttb+0NcM+1Pnq+3XyFTZr/rYBJZPS0sD0hMcQDQA29kXSQ==", 3,
             "gz11eJxjYGBgkGAAgRNODGiAEV0AJ2iwh+CRxQcA5qIZBA==", 8);
 
  add_preset(self, _("similar to Kodak Portra"),
             "gz02eJxjZACBBnsQfh3YYK8VU28P43s8rLKP6W+yP/Q1w36deyMYLymoBcsZGxcDaQGHs2d87AGnphWu", 3,
             "gz11eJxjYGBgkGAAgRNODGiAEV0AJ2iwh+CRxQcA5qIZBA==", 8);
 
  add_preset(self, _("similar to Kodak Ektar"),
             "gz02eJxjZACBBvvrixvsrXIb7IN21NnD+CA2iOa6nmxvZFxsX15ebp+e1gaWNwbyGRgEHNLS0uwBE7wWhw==", 3,
             "gz11eJxjYGBgkGAAgRNODGiAEV0AJ2iwh+CRxQcA5qIZBA==", 8);
 
  add_preset(self, _("similar to Kodachrome"),
             "gz02eJxjZACBBvvrixvsrXIb7IN21NnD+CA2iG59HWhvZFxsX15ebp+e1gaWT0tLA9ICDrNmRtoDACjOF7c=", 3,
             "gz11eJxjYGBgkGAAgRNODGiAEV0AJ2iwh+CRxQcA5qIZBA==", 8);
}
 
static inline float CDL(float x, float slope, float offset, float power)
{
  float out;
  out = slope * x + offset;
  out = (out <= 0.0f) ? 0.0f : powf(out, power);
  return out;
}
 
// see http://www.brucelindbloom.com/Eqn_RGB_XYZ_Matrix.html for the transformation matrices
__DT_CLONE_TARGETS__
int process(struct dt_iop_module_t *self, const dt_dev_pixelpipe_t *pipe, const dt_dev_pixelpipe_iop_t *piece, const void *const ivoid,
             void *const ovoid)
{
  const dt_iop_roi_t *const roi_in = &piece->roi_in;
  const dt_iop_roi_t *const roi_out = &piece->roi_out;
  dt_iop_colorbalance_data_t *d = (dt_iop_colorbalance_data_t *)piece->data;
  const int ch = 4;
 
  // these are RGB values!
  const dt_aligned_pixel_t gain = { d->gain[CHANNEL_RED] * d->gain[CHANNEL_FACTOR],
                                    d->gain[CHANNEL_GREEN] * d->gain[CHANNEL_FACTOR],
                                    d->gain[CHANNEL_BLUE] * d->gain[CHANNEL_FACTOR] };
  const float contrast = (d->contrast != 0.0f) ? 1.0f / d->contrast : 1000000.0f,
              grey = d->grey / 100.0f;
 
  // For neutral parameters, skip the computations doing x^1 or (x-a)*1 + a to save time
  const int run_contrast = (d->contrast == 1.0f) ? 0 : 1;
  const int run_saturation = (d->saturation == 1.0f) ? 0: 1;
  const int run_saturation_out = (d->saturation_out == 1.0f) ? 0: 1;
 
  switch (d->mode)
  {
    case LEGACY:
    {
      // these are RGB values!
      const dt_aligned_pixel_t lift = { 2.0 - (d->lift[CHANNEL_RED] * d->lift[CHANNEL_FACTOR]),
                                        2.0 - (d->lift[CHANNEL_GREEN] * d->lift[CHANNEL_FACTOR]),
                                        2.0 - (d->lift[CHANNEL_BLUE] * d->lift[CHANNEL_FACTOR]) },
                              gamma = { d->gamma[CHANNEL_RED] * d->gamma[CHANNEL_FACTOR],
                                        d->gamma[CHANNEL_GREEN] * d->gamma[CHANNEL_FACTOR],
                                        d->gamma[CHANNEL_BLUE] * d->gamma[CHANNEL_FACTOR] },
                          gamma_inv = { (gamma[0] != 0.0) ? 1.0 / gamma[0] : 1000000.0,
                                        (gamma[1] != 0.0) ? 1.0 / gamma[1] : 1000000.0,
                                        (gamma[2] != 0.0) ? 1.0 / gamma[2] : 1000000.0 };
      __OMP_PARALLEL_FOR_SIMD__()
      for(size_t k = 0; k < (size_t)ch * roi_in->width * roi_out->height; k += ch)
      {
        float *in = ((float *)ivoid) + k;
        float *out = ((float *)ovoid) + k;
 
        // transform the pixel to sRGB:
        // Lab -> XYZ
        dt_aligned_pixel_t XYZ = { 0.0f };
        dt_Lab_to_XYZ(in, XYZ);
 
        // XYZ -> sRGB
        dt_aligned_pixel_t rgb = { 0.0f };
        dt_XYZ_to_sRGB(XYZ, rgb);
 
        // do the calculation in RGB space
        for(int c = 0; c < 3; c++)
        {
          // lift gamma gain
          rgb[c] = ((( rgb[c]  - 1.0f) * lift[c]) + 1.0f) * gain[c];
          rgb[c] = (rgb[c] < 0.0f) ? 0.0f : powf(rgb[c], gamma_inv[c]);
        }
 
        // transform the result back to Lab
        // sRGB -> XYZ
        dt_sRGB_to_XYZ(rgb, XYZ);
 
        // XYZ -> Lab
        dt_XYZ_to_Lab(XYZ, out);
      }
      break;
    }
    case LIFT_GAMMA_GAIN:
    {
      // these are RGB values!
      const dt_aligned_pixel_t lift = { 2.0 - (d->lift[CHANNEL_RED] * d->lift[CHANNEL_FACTOR]),
                                        2.0 - (d->lift[CHANNEL_GREEN] * d->lift[CHANNEL_FACTOR]),
                                        2.0 - (d->lift[CHANNEL_BLUE] * d->lift[CHANNEL_FACTOR]) },
                              gamma = { d->gamma[CHANNEL_RED] * d->gamma[CHANNEL_FACTOR],
                                        d->gamma[CHANNEL_GREEN] * d->gamma[CHANNEL_FACTOR],
                                        d->gamma[CHANNEL_BLUE] * d->gamma[CHANNEL_FACTOR] },
                          gamma_inv = { (gamma[0] != 0.0) ? 1.0 / gamma[0] : 1000000.0,
                                        (gamma[1] != 0.0) ? 1.0 / gamma[1] : 1000000.0,
                                        (gamma[2] != 0.0) ? 1.0 / gamma[2] : 1000000.0 };
      __OMP_PARALLEL_FOR_SIMD__()
      for(size_t k = 0; k < (size_t)ch * roi_in->width * roi_out->height; k += ch)
      {
        float *in = ((float *)ivoid) + k;
        float *out = ((float *)ovoid) + k;
 
        // transform the pixel to sRGB:
        // Lab -> XYZ
        dt_aligned_pixel_t XYZ = { 0.0f };
        dt_Lab_to_XYZ(in, XYZ);
 
        // XYZ -> sRGB
        dt_aligned_pixel_t rgb = { 0.0f };
        dt_XYZ_to_prophotorgb(XYZ, rgb);
 
        float luma = XYZ[1]; // the Y channel is the relative luminance
 
        // do the calculation in RGB space
        for(int c = 0; c < 3; c++)
        {
          // main saturation input
          if (run_saturation) rgb[c] = luma + d->saturation * (rgb[c] - luma);
 
          // RGB gamma correction
          rgb[c] = (rgb[c] <= 0.0f) ? 0.0f : powf(rgb[c], 1.0f/2.2f);
 
          // lift gamma gain
          rgb[c] = ((( rgb[c]  - 1.0f) * lift[c]) + 1.0f) * gain[c];
          rgb[c] = (rgb[c] <= 0.0f) ? 0.0f : powf(rgb[c], gamma_inv[c] * 2.2f);
        }
 
        // main saturation output
        if (run_saturation_out)
        {
          dt_prophotorgb_to_XYZ(rgb, XYZ);
          luma = XYZ[1];
          for(int c = 0; c < 3; c++) rgb[c] = luma + d->saturation_out * (rgb[c] - luma);
        }
 
        // fulcrum contrat
        if (run_contrast) for(int c = 0; c < 3; c++) rgb[c] = (rgb[c] <= 0.0f) ? 0.0f : powf(rgb[c] / grey, contrast) * grey;
 
        // transform the result back to Lab
        // sRGB -> XYZ
        dt_prophotorgb_to_XYZ(rgb, XYZ);
 
        // XYZ -> Lab
        dt_XYZ_to_Lab(XYZ, out);
      }
      break;
   }
    case SLOPE_OFFSET_POWER:
    {
      // these are RGB values!
 
      const dt_aligned_pixel_t lift = { ( d->lift[CHANNEL_RED] + d->lift[CHANNEL_FACTOR] - 2.0f),
                                        ( d->lift[CHANNEL_GREEN] + d->lift[CHANNEL_FACTOR] - 2.0f),
                                        ( d->lift[CHANNEL_BLUE] + d->lift[CHANNEL_FACTOR] - 2.0f)},
                              gamma = { (2.0f - d->gamma[CHANNEL_RED]) * (2.0f - d->gamma[CHANNEL_FACTOR]),
                                        (2.0f - d->gamma[CHANNEL_GREEN]) * (2.0f - d->gamma[CHANNEL_FACTOR]),
                                        (2.0f - d->gamma[CHANNEL_BLUE]) * (2.0f - d->gamma[CHANNEL_FACTOR])};
      __OMP_PARALLEL_FOR_SIMD__()
      for(size_t k = 0; k < (size_t)ch * roi_in->width * roi_out->height; k += ch)
      {
        float *in = ((float *)ivoid) + k;
        float *out = ((float *)ovoid) + k;
 
        // transform the pixel to RGB:
        // Lab -> XYZ
        dt_aligned_pixel_t XYZ;
        dt_Lab_to_XYZ(in, XYZ);
 
        // XYZ -> RGB
        dt_aligned_pixel_t rgb;
        dt_XYZ_to_prophotorgb(XYZ, rgb);
 
        float luma = XYZ[1]; // the Y channel is the RGB luminance
 
        // do the calculation in RGB space
        for(int c = 0; c < 3; c++)
        {
          // main saturation input
          if (run_saturation) rgb[c] = luma + d->saturation * (rgb[c] - luma);
 
          // channel CDL
          rgb[c] = CDL(rgb[c], gain[c], lift[c], gamma[c]);
        }
 
        // main saturation output
        if (run_saturation_out)
        {
          dt_prophotorgb_to_XYZ(rgb, XYZ);
          luma = XYZ[1];
          for(int c = 0; c < 3; c++) rgb[c] = luma + d->saturation_out * (rgb[c] - luma);
        }
 
        // fulcrum contrat
        if (run_contrast) for(int c = 0; c < 3; c++) rgb[c] = (rgb[c] <= 0.0f) ? 0.0f : powf(rgb[c] / grey, contrast) * grey;
 
        // transform the result back to Lab
        // sRGB -> XYZ
        dt_prophotorgb_to_XYZ(rgb , XYZ);
 
        // XYZ -> Lab
        dt_XYZ_to_Lab(XYZ, out);
      }
      break;
    }
  }
  if(pipe->mask_display & DT_DEV_PIXELPIPE_DISPLAY_MASK) dt_iop_alpha_copy(ivoid, ovoid, roi_out->width, roi_out->height);
  return 0;
}
 
#ifdef HAVE_OPENCL
int process_cl(struct dt_iop_module_t *self, const dt_dev_pixelpipe_t *pipe, const dt_dev_pixelpipe_iop_t *piece, cl_mem dev_in, cl_mem dev_out)
{
  const dt_iop_roi_t *const roi_in = &piece->roi_in;
  dt_iop_colorbalance_data_t *d = (dt_iop_colorbalance_data_t *)piece->data;
  dt_iop_colorbalance_global_data_t *gd = (dt_iop_colorbalance_global_data_t *)self->global_data;
 
  cl_int err = -999;
  const int devid = pipe->devid;
  const int width = roi_in->width;
  const int height = roi_in->height;
  size_t sizes[] = { ROUNDUPDWD(width, devid), ROUNDUPDHT(height, devid), 1 };
 
  switch (d->mode)
  {
    case LEGACY:
    {
      const float lift[4] = { 2.0f - (d->lift[CHANNEL_RED] * d->lift[CHANNEL_FACTOR]),
                              2.0f - (d->lift[CHANNEL_GREEN] * d->lift[CHANNEL_FACTOR]),
                              2.0f - (d->lift[CHANNEL_BLUE] * d->lift[CHANNEL_FACTOR]), 0.0f },
                  gamma[4] = { d->gamma[CHANNEL_RED] * d->gamma[CHANNEL_FACTOR],
                               d->gamma[CHANNEL_GREEN] * d->gamma[CHANNEL_FACTOR],
                               d->gamma[CHANNEL_BLUE] * d->gamma[CHANNEL_FACTOR], 0.0f },
                  gamma_inv[4] = { (gamma[0] != 0.0f) ? 1.0f / gamma[0] : 1000000.0f,
                                   (gamma[1] != 0.0f) ? 1.0f / gamma[1] : 1000000.0f,
                                   (gamma[2] != 0.0f) ? 1.0f / gamma[2] : 1000000.0f, 0.0f },
                  gain[4] = { d->gain[CHANNEL_RED] * d->gain[CHANNEL_FACTOR],
                              d->gain[CHANNEL_GREEN] * d->gain[CHANNEL_FACTOR],
                              d->gain[CHANNEL_BLUE] * d->gain[CHANNEL_FACTOR], 0.0f },
                  contrast = (d->contrast != 0.0f) ? 1.0f / d->contrast : 1000000.0f,
                  grey = d->grey / 100.0f,
                  saturation = d->saturation;
 
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 0, sizeof(cl_mem), (void *)&dev_in);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 1, sizeof(cl_mem), (void *)&dev_out);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 2, sizeof(int), (void *)&width);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 3, sizeof(int), (void *)&height);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 4, 4 * sizeof(float), (void *)&lift);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 5, 4 * sizeof(float), (void *)&gain);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 6, 4 * sizeof(float), (void *)&gamma_inv);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 7, sizeof(float), (void *)&saturation);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 8, sizeof(float), (void *)&contrast);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance, 9, sizeof(float), (void *)&grey);
      err = dt_opencl_enqueue_kernel_2d(devid, gd->kernel_colorbalance, sizes);
      if(err != CL_SUCCESS) goto error;
      return TRUE;
 
      break;
    }
    case LIFT_GAMMA_GAIN:
    {
      const float lift[4] = { 2.0f - (d->lift[CHANNEL_RED] * d->lift[CHANNEL_FACTOR]),
                              2.0f - (d->lift[CHANNEL_GREEN] * d->lift[CHANNEL_FACTOR]),
                              2.0f - (d->lift[CHANNEL_BLUE] * d->lift[CHANNEL_FACTOR]), 0.0f },
                  gamma[4] = { d->gamma[CHANNEL_RED] * d->gamma[CHANNEL_FACTOR],
                               d->gamma[CHANNEL_GREEN] * d->gamma[CHANNEL_FACTOR],
                               d->gamma[CHANNEL_BLUE] * d->gamma[CHANNEL_FACTOR], 0.0f },
                  gamma_inv[4] = { (gamma[0] != 0.0f) ? 1.0f / gamma[0] : 1000000.0f,
                                   (gamma[1] != 0.0f) ? 1.0f / gamma[1] : 1000000.0f,
                                   (gamma[2] != 0.0f) ? 1.0f / gamma[2] : 1000000.0f, 0.0f },
                  gain[4] = { d->gain[CHANNEL_RED] * d->gain[CHANNEL_FACTOR],
                              d->gain[CHANNEL_GREEN] * d->gain[CHANNEL_FACTOR],
                              d->gain[CHANNEL_BLUE] * d->gain[CHANNEL_FACTOR], 0.0f },
                  contrast = (d->contrast != 0.0f) ? 1.0f / d->contrast : 1000000.0f,
                  grey = d->grey / 100.0f,
                  saturation = d->saturation,
                  saturation_out = d->saturation_out;
 
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 0, sizeof(cl_mem), (void *)&dev_in);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 1, sizeof(cl_mem), (void *)&dev_out);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 2, sizeof(int), (void *)&width);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 3, sizeof(int), (void *)&height);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 4, 4 * sizeof(float), (void *)&lift);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 5, 4 * sizeof(float), (void *)&gain);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 6, 4 * sizeof(float), (void *)&gamma_inv);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 7, sizeof(float), (void *)&saturation);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 8, sizeof(float), (void *)&contrast);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 9, sizeof(float), (void *)&grey);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_lgg, 10, sizeof(float), (void *)&saturation_out);
      err = dt_opencl_enqueue_kernel_2d(devid, gd->kernel_colorbalance_lgg, sizes);
      if(err != CL_SUCCESS) goto error;
      return TRUE;
 
      break;
    }
    case SLOPE_OFFSET_POWER:
    {
      const float lift[4] = { ( d->lift[CHANNEL_RED] + d->lift[CHANNEL_FACTOR] - 2.0f ),
                              ( d->lift[CHANNEL_GREEN] + d->lift[CHANNEL_FACTOR] - 2.0f ),
                              ( d->lift[CHANNEL_BLUE] + d->lift[CHANNEL_FACTOR] - 2.0f ),
                              0.0f },
                  gamma[4] = { (2.0f - d->gamma[CHANNEL_RED]) * (2.0f - d->gamma[CHANNEL_FACTOR]),
                               (2.0f - d->gamma[CHANNEL_GREEN]) * (2.0f - d->gamma[CHANNEL_FACTOR]),
                               (2.0f - d->gamma[CHANNEL_BLUE]) * (2.0f - d->gamma[CHANNEL_FACTOR]),
                               0.0f },
                  gain[4] = { d->gain[CHANNEL_RED] * d->gain[CHANNEL_FACTOR],
                              d->gain[CHANNEL_GREEN] * d->gain[CHANNEL_FACTOR],
                              d->gain[CHANNEL_BLUE] * d->gain[CHANNEL_FACTOR],
                              0.0f },
                  contrast = (d->contrast != 0.0f) ? 1.0f / d->contrast : 1000000.0f,
                  grey = d->grey / 100.0f,
                  saturation = d->saturation,
                  saturation_out = d->saturation_out;
 
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 0, sizeof(cl_mem), (void *)&dev_in);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 1, sizeof(cl_mem), (void *)&dev_out);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 2, sizeof(int), (void *)&width);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 3, sizeof(int), (void *)&height);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 4, 4 * sizeof(float), (void *)&lift);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 5, 4 * sizeof(float), (void *)&gain);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 6, 4 * sizeof(float), (void *)&gamma);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 7, sizeof(float), (void *)&saturation);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 8, sizeof(float), (void *)&contrast);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 9, sizeof(float), (void *)&grey);
      dt_opencl_set_kernel_arg(devid, gd->kernel_colorbalance_cdl, 10, sizeof(float), (void *)&saturation_out);
      err = dt_opencl_enqueue_kernel_2d(devid, gd->kernel_colorbalance_cdl, sizes);
      if(err != CL_SUCCESS) goto error;
      return TRUE;
 
      break;
    }
  }
 
error:
  dt_print(DT_DEBUG_OPENCL, "[opencl_colorbalance] couldn't enqueue kernel! %d\n", err);
  return FALSE;
}
#endif
 
static inline void update_saturation_slider_color(GtkWidget *slider, float hue)
{
  dt_aligned_pixel_t rgb;
  if(hue != -1)
  {
    hsl2rgb(rgb, hue, 1.0, 0.5);
    dt_bauhaus_slider_set_stop(slider, 1.0, rgb[0], rgb[1], rgb[2]);
    hsl2rgb(rgb, hue, 0.0, 0.5);
    dt_bauhaus_slider_set_stop(slider, 0.0, rgb[0], rgb[1], rgb[2]);
    gtk_widget_queue_draw(GTK_WIDGET(slider));
  }
}
 
static inline void set_RGB_sliders(GtkWidget *R, GtkWidget *G, GtkWidget *B, float hsl[3], float *p, int mode)
{
 
  dt_aligned_pixel_t rgb = { 0.0f };
  hsl2rgb(rgb, hsl[0], hsl[1], hsl[2]);
 
  if(hsl[0] != -1)
  {
    p[CHANNEL_RED] = rgb[0] * 2.0f;
    p[CHANNEL_GREEN] = rgb[1] * 2.0f;
    p[CHANNEL_BLUE] = rgb[2] * 2.0f;
 
    dt_gui_freeze_begin();
    dt_bauhaus_slider_set(R, p[CHANNEL_RED]);
    dt_bauhaus_slider_set(G, p[CHANNEL_GREEN]);
    dt_bauhaus_slider_set(B, p[CHANNEL_BLUE]);
    dt_gui_freeze_end();
  }
}
 
static inline void set_HSL_sliders(GtkWidget *hue, GtkWidget *sat, float RGB[4])
{
  dt_aligned_pixel_t RGB_norm = { (RGB[CHANNEL_RED] / 2.0f), (RGB[CHANNEL_GREEN] / 2.0f), (RGB[CHANNEL_BLUE] / 2.0f) };
 
  float h, s, l;
  rgb2hsl(RGB_norm, &h, &s, &l);
 
  if(h != -1.0f)
  {
    dt_bauhaus_slider_set(hue, h * 360.0f);
    dt_bauhaus_slider_set(sat, s * 100.0f);
    update_saturation_slider_color(GTK_WIDGET(sat), h);
    gtk_widget_queue_draw(GTK_WIDGET(sat));
  }
  else
  {
    dt_bauhaus_slider_set(hue, -1.0f);
    dt_bauhaus_slider_set(sat, 0.0f);
    gtk_widget_queue_draw(GTK_WIDGET(sat));
  }
}
 
static inline void _check_tuner_picker_labels(dt_iop_module_t *self)
{
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  if(g->luma_patches_flags[GAIN] == USER_SELECTED && g->luma_patches_flags[GAMMA] == USER_SELECTED
     && g->luma_patches_flags[LIFT] == USER_SELECTED)
    dt_bauhaus_widget_set_label(g->auto_luma, N_("optimize luma from patches"));
  else
    dt_bauhaus_widget_set_label(g->auto_luma, N_("optimize luma"));
 
  if(g->color_patches_flags[GAIN] == USER_SELECTED && g->color_patches_flags[GAMMA] == USER_SELECTED
     && g->color_patches_flags[LIFT] == USER_SELECTED)
    dt_bauhaus_widget_set_label(g->auto_color, N_("neutralize colors from patches"));
  else
    dt_bauhaus_widget_set_label(g->auto_color, N_("neutralize colors"));
}
 
 
static void apply_autogrey(dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  dt_aligned_pixel_t XYZ = { 0.0f };
  dt_aligned_pixel_t rgb = { 0.0f };
  dt_Lab_to_XYZ((const float *)self->picked_color, XYZ);
  dt_XYZ_to_prophotorgb((const float *)XYZ, rgb);
 
  const dt_aligned_pixel_t lift
      = { (p->lift[CHANNEL_RED] + p->lift[CHANNEL_FACTOR] - 2.0f),
          (p->lift[CHANNEL_GREEN] + p->lift[CHANNEL_FACTOR] - 2.0f),
          (p->lift[CHANNEL_BLUE] + p->lift[CHANNEL_FACTOR] - 2.0f) },
      gamma
      = { p->gamma[CHANNEL_RED] * p->gamma[CHANNEL_FACTOR],
          p->gamma[CHANNEL_GREEN] * p->gamma[CHANNEL_FACTOR],
          p->gamma[CHANNEL_BLUE] * p->gamma[CHANNEL_FACTOR] },
      gain = { p->gain[CHANNEL_RED] * p->gain[CHANNEL_FACTOR], p->gain[CHANNEL_GREEN] * p->gain[CHANNEL_FACTOR],
               p->gain[CHANNEL_BLUE] * p->gain[CHANNEL_FACTOR] };
 
  for(int c = 0; c < 3; c++)
  {
    rgb[c] = CDL(rgb[c], gain[c], lift[c], 2.0f - gamma[c]);
    rgb[c] = CLAMP(rgb[c], 0.0f, 1.0f);
  }
 
  dt_prophotorgb_to_XYZ((const float *)rgb, XYZ);
 
  p->grey = XYZ[1] * 100.0f;
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->grey, p->grey);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_lift_neutralize(dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  dt_aligned_pixel_t XYZ = { 0.0f };
  dt_Lab_to_XYZ((const float *)self->picked_color, XYZ);
  dt_aligned_pixel_t RGB = { 0.0f };
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
// Save the patch color for the optimization
  for(int c = 0; c < 3; ++c) g->color_patches_lift[c] = RGB[c];
  g->color_patches_flags[LIFT] = USER_SELECTED;
 
  // Compute the RGB values after the CDL factors
  for(int c = 0; c < 3; ++c)
    RGB[c] = CDL(RGB[c], p->gain[CHANNEL_FACTOR], p->lift[CHANNEL_FACTOR] - 1.0f, 2.0f - p->gamma[CHANNEL_FACTOR]);
 
  // Compute the luminance of the average grey
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
  // Get the parameter
  for(int c = 0; c < 3; ++c) RGB[c] = powf(XYZ[1], 1.0f/(2.0f - p->gamma[c+1])) - RGB[c] * p->gain[c+1];
 
  p->lift[CHANNEL_RED] = RGB[0] + 1.0f;
  p->lift[CHANNEL_GREEN] = RGB[1] + 1.0f;
  p->lift[CHANNEL_BLUE] = RGB[2] + 1.0f;
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->lift_r, p->lift[CHANNEL_RED]);
  dt_bauhaus_slider_set(g->lift_g, p->lift[CHANNEL_GREEN]);
  dt_bauhaus_slider_set(g->lift_b, p->lift[CHANNEL_BLUE]);
  set_HSL_sliders(g->hue_lift, g->sat_lift, p->lift);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_gamma_neutralize(dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  dt_aligned_pixel_t XYZ = { 0.0f };
  dt_Lab_to_XYZ((const float *)self->picked_color, XYZ);
  dt_aligned_pixel_t RGB = { 0.0f };
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
// Save the patch color for the optimization
  for(int c = 0; c < 3; ++c) g->color_patches_gamma[c] = RGB[c];
  g->color_patches_flags[GAMMA] = USER_SELECTED;
 
  // Compute the RGB values after the CDL factors
  for(int c = 0; c < 3; ++c)
    RGB[c] = CDL(RGB[c], p->gain[CHANNEL_FACTOR], p->lift[CHANNEL_FACTOR] - 1.0f, 2.0f - p->gamma[CHANNEL_FACTOR]);
 
  // Compute the luminance of the average grey
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
  // Get the parameter
  for(int c = 0; c < 3; ++c) RGB[c] = logf(XYZ[1])/ logf(RGB[c] * p->gain[c + 1] + p->lift[c + 1] - 1.0f);
 
  p->gamma[CHANNEL_RED] = CLAMP(2.0 - RGB[0], 0.0001f, 2.0f);
  p->gamma[CHANNEL_GREEN] = CLAMP(2.0 - RGB[1], 0.0001f, 2.0f);
  p->gamma[CHANNEL_BLUE] = CLAMP(2.0 - RGB[2], 0.0001f, 2.0f);
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->gamma_r, p->gamma[CHANNEL_RED]);
  dt_bauhaus_slider_set(g->gamma_g, p->gamma[CHANNEL_GREEN]);
  dt_bauhaus_slider_set(g->gamma_b, p->gamma[CHANNEL_BLUE]);
  set_HSL_sliders(g->hue_gamma, g->sat_gamma, p->gamma);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_gain_neutralize(dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  dt_aligned_pixel_t XYZ = { 0.0f };
  dt_Lab_to_XYZ((const float *)self->picked_color, XYZ);
  dt_aligned_pixel_t RGB = { 0.0f };
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
// Save the patch color for the optimization
  for(int c = 0; c < 3; c++) g->color_patches_gain[c] = RGB[c];
  g->color_patches_flags[GAIN] = USER_SELECTED;
 
  // Compute the RGB values after the CDL factors
  for(int c = 0; c < 3; ++c)
    RGB[c] = CDL(RGB[c], p->gain[CHANNEL_FACTOR], p->lift[CHANNEL_FACTOR] - 1.0f, 2.0f - p->gamma[CHANNEL_FACTOR]);
 
  // Compute the luminance of the average grey
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
  // Get the parameter
  for(int c = 0; c < 3; ++c) RGB[c] = (powf(XYZ[1], 1.0f/(2.0f - p->gamma[c+1])) - p->lift[c+1] + 1.0f) / MAX(RGB[c], 0.000001f);
 
  p->gain[CHANNEL_RED] = RGB[0];
  p->gain[CHANNEL_GREEN] = RGB[1];
  p->gain[CHANNEL_BLUE] = RGB[2];
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->gain_r, p->gain[CHANNEL_RED]);
  dt_bauhaus_slider_set(g->gain_g, p->gain[CHANNEL_GREEN]);
  dt_bauhaus_slider_set(g->gain_b, p->gain[CHANNEL_BLUE]);
  set_HSL_sliders(g->hue_gain, g->sat_gain, p->gain);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_lift_auto(dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  dt_aligned_pixel_t XYZ = { 0.0f };
  dt_Lab_to_XYZ((const float *)self->picked_color_min, XYZ);
 
  g->luma_patches[LIFT] = XYZ[1];
  g->luma_patches_flags[LIFT] = USER_SELECTED;
 
  dt_aligned_pixel_t RGB = { 0.0f };
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
  p->lift[CHANNEL_FACTOR] = -p->gain[CHANNEL_FACTOR] * XYZ[1] + 1.0f;
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->lift_factor, p->lift[CHANNEL_FACTOR]);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_gamma_auto(dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  dt_aligned_pixel_t XYZ = { 0.0f };
  dt_Lab_to_XYZ((const float *)self->picked_color, XYZ);
 
  g->luma_patches[GAMMA] = XYZ[1];
  g->luma_patches_flags[GAMMA] = USER_SELECTED;
 
  dt_aligned_pixel_t RGB = { 0.0f };
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
  p->gamma[CHANNEL_FACTOR]
      = 2.0f - logf(0.1842f) / logf(MAX(p->gain[CHANNEL_FACTOR] * XYZ[1] + p->lift[CHANNEL_FACTOR] - 1.0f, 0.000001f));
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->gamma_factor, p->gamma[CHANNEL_FACTOR]);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_gain_auto(dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  dt_aligned_pixel_t XYZ = { 0.0f };
  dt_Lab_to_XYZ((const float *)self->picked_color_max, XYZ);
 
  g->luma_patches[GAIN] = XYZ[1];
  g->luma_patches_flags[GAIN] = USER_SELECTED;
 
  dt_aligned_pixel_t RGB = { 0.0f };
  dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
  p->gain[CHANNEL_FACTOR] = p->lift[CHANNEL_FACTOR] / (XYZ[1]);
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->gain_factor, p->gain[CHANNEL_FACTOR]);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_autocolor(dt_iop_module_t *self)
{
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  if(g->color_patches_flags[GAIN] == INVALID || g->color_patches_flags[GAMMA] == INVALID
     || g->color_patches_flags[LIFT] == INVALID)
  {
    /*
     * Some color patches were not picked by the user. Take a
     * picture-wide patch for these.
     */
    dt_aligned_pixel_t XYZ = { 0.0f };
    dt_Lab_to_XYZ((const float *)self->picked_color, XYZ);
    dt_aligned_pixel_t RGB = { 0.0f };
    dt_XYZ_to_prophotorgb((const float *)XYZ, RGB);
 
    // Save the patch color for the optimization
    if(g->color_patches_flags[LIFT] == INVALID)
    {
      for(int c = 0; c < 3; c++) g->color_patches_lift[c] = RGB[c];
      g->color_patches_flags[LIFT] = AUTO_SELECTED;
    }
    if(g->color_patches_flags[GAMMA] == INVALID)
    {
      for(int c = 0; c < 3; c++) g->color_patches_gamma[c] = RGB[c];
      g->color_patches_flags[GAMMA] = AUTO_SELECTED;
    }
    if(g->color_patches_flags[GAIN] == INVALID)
    {
      for(int c = 0; c < 3; c++) g->color_patches_gain[c] = RGB[c];
      g->color_patches_flags[GAIN] = AUTO_SELECTED;
    }
  }
 
  dt_iop_color_picker_reset(self, TRUE);
 
  // Build the CDL-corrected samples (after the factors)
  dt_aligned_pixel_t samples_lift = { 0.f };
  dt_aligned_pixel_t samples_gamma = { 0.f };
  dt_aligned_pixel_t samples_gain = { 0.f };
 
  for (int c = 0; c < 3; ++c)
  {
    samples_lift[c] = CDL(g->color_patches_lift[c], p->gain[CHANNEL_FACTOR], p->lift[CHANNEL_FACTOR] - 1.0f, 2.0f - p->gamma[CHANNEL_FACTOR]);
    samples_gamma[c] = CDL(g->color_patches_gamma[c], p->gain[CHANNEL_FACTOR], p->lift[CHANNEL_FACTOR] - 1.0f, 2.0f - p->gamma[CHANNEL_FACTOR]);
    samples_gain[c] = CDL(g->color_patches_gain[c], p->gain[CHANNEL_FACTOR], p->lift[CHANNEL_FACTOR] - 1.0f, 2.0f - p->gamma[CHANNEL_FACTOR]);
  }
 
  // Get the average patches luma value (= neutral grey equivalents) after the CDL factors
  dt_aligned_pixel_t greys = { 0.0 };
  dt_aligned_pixel_t XYZ = { 0.0 };
  dt_prophotorgb_to_XYZ((const float *)samples_lift, (float *)XYZ);
  greys[0] = XYZ[1];
  dt_prophotorgb_to_XYZ((const float *)samples_gamma, (float *)XYZ);
  greys[1] = XYZ[1];
  dt_prophotorgb_to_XYZ((const float *)samples_gain, (float *)XYZ);
  greys[2] = XYZ[1];
 
  // Get the current params
  dt_aligned_pixel_t RGB_lift = { p->lift[CHANNEL_RED] - 1.0f, p->lift[CHANNEL_GREEN] - 1.0f, p->lift[CHANNEL_BLUE] - 1.0f };
  dt_aligned_pixel_t RGB_gamma = { p->gamma[CHANNEL_RED], p->gamma[CHANNEL_GREEN], p->gamma[CHANNEL_BLUE] };
  dt_aligned_pixel_t RGB_gain = { p->gain[CHANNEL_RED], p->gain[CHANNEL_GREEN], p->gain[CHANNEL_BLUE] };
 
  for (int runs = 0 ; runs < 1000 ; ++runs)
  {
    // compute RGB slope/gain (powf(XYZ[1], 1.0f/(2.0f - p->gamma[c+1])) - p->lift[c+1] + 1.0f) / MAX(RGB[c], 0.000001f);
    for (int c = 0; c < 3; ++c) RGB_gain[c] = CLAMP((powf(greys[GAIN], 1.0f / (2.0f - RGB_gamma[c])) - RGB_lift[c]) / MAX(samples_gain[c], 0.000001f), 0.75f, 1.25f);
    // compute RGB offset/lift powf(XYZ[1], 1.0f/(2.0f - p->gamma[c+1])) - RGB[c] * p->gain[c+1];
    for (int c = 0; c < 3; ++c) RGB_lift[c] = CLAMP(powf(greys[LIFT], 1.0f / (2.0f - RGB_gamma[c])) - samples_lift[c] * RGB_gain[c], -0.025f, 0.025f);
    // compute  power/gamma 2.0f - logf(0.1842f) / logf(MAX(p->gain[CHANNEL_FACTOR] * XYZ[1] + p->lift[CHANNEL_FACTOR] - 1.0f, 0.000001f));
    for (int c = 0; c < 3; ++c) RGB_gamma[c] = 2.0f - CLAMP(logf(MAX(greys[GAMMA], 0.000001f)) / logf(MAX(RGB_gain[c] * samples_gamma[c] + RGB_lift[c], 0.000001f)), 0.75f, 1.25f);
  }
 
  // save
  p->lift[CHANNEL_RED] = RGB_lift[0] + 1.0f;
  p->lift[CHANNEL_GREEN] = RGB_lift[1] + 1.0f;
  p->lift[CHANNEL_BLUE] = RGB_lift[2] + 1.0f;
  p->gamma[CHANNEL_RED] = RGB_gamma[0];
  p->gamma[CHANNEL_GREEN] = RGB_gamma[1];
  p->gamma[CHANNEL_BLUE] = RGB_gamma[2];
  p->gain[CHANNEL_RED] = RGB_gain[0];
  p->gain[CHANNEL_GREEN] = RGB_gain[1];
  p->gain[CHANNEL_BLUE] = RGB_gain[2];
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->lift_r, p->lift[CHANNEL_RED]);
  dt_bauhaus_slider_set(g->lift_g, p->lift[CHANNEL_GREEN]);
  dt_bauhaus_slider_set(g->lift_b, p->lift[CHANNEL_BLUE]);
 
  dt_bauhaus_slider_set(g->gamma_r, p->gamma[CHANNEL_RED]);
  dt_bauhaus_slider_set(g->gamma_g, p->gamma[CHANNEL_GREEN]);
  dt_bauhaus_slider_set(g->gamma_b, p->gamma[CHANNEL_BLUE]);
 
  dt_bauhaus_slider_set(g->gain_r, p->gain[CHANNEL_RED]);
  dt_bauhaus_slider_set(g->gain_g, p->gain[CHANNEL_GREEN]);
  dt_bauhaus_slider_set(g->gain_b, p->gain[CHANNEL_BLUE]);
 
  set_HSL_sliders(g->hue_lift, g->sat_lift, p->lift);
  set_HSL_sliders(g->hue_gamma, g->sat_gamma, p->gamma);
  set_HSL_sliders(g->hue_gain, g->sat_gain, p->gain);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
static void apply_autoluma(dt_iop_module_t *self)
{
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  /*
   * If some luma patches were not picked by the user, take a
   * picture-wide patch for these.
   */
  if(g->luma_patches_flags[LIFT] == INVALID)
  {
    dt_aligned_pixel_t XYZ = { 0.0f };
    dt_Lab_to_XYZ((const float *)self->picked_color_min, XYZ);
    g->luma_patches[LIFT] = XYZ[1];
    g->luma_patches_flags[LIFT] = AUTO_SELECTED;
  }
  if(g->luma_patches_flags[GAMMA] == INVALID)
  {
    dt_aligned_pixel_t XYZ = { 0.0f };
    dt_Lab_to_XYZ((const float *)self->picked_color, XYZ);
    g->luma_patches[GAMMA] = XYZ[1];
    g->luma_patches_flags[GAMMA] = AUTO_SELECTED;
  }
  if(g->luma_patches_flags[GAIN] == INVALID)
  {
    dt_aligned_pixel_t XYZ = { 0.0f };
    dt_Lab_to_XYZ((const float *)self->picked_color_max, XYZ);
    g->luma_patches[GAIN] = XYZ[1];
    g->luma_patches_flags[GAIN] = AUTO_SELECTED;
  }
 
  dt_iop_color_picker_reset(self, TRUE);
 
  for (int runs = 0 ; runs < 100 ; ++runs)
  {
    p->gain[CHANNEL_FACTOR] = CLAMP(p->lift[CHANNEL_FACTOR] / g->luma_patches[GAIN], 0.0f, 2.0f);
    p->lift[CHANNEL_FACTOR] = CLAMP(-p->gain[CHANNEL_FACTOR] * g->luma_patches[LIFT] + 1.0f, 0.0f, 2.0f);
    p->gamma[CHANNEL_FACTOR] = CLAMP(2.0f - logf(0.1842f) / logf(MAX(p->gain[CHANNEL_FACTOR] * g->luma_patches[GAMMA] + p->lift[CHANNEL_FACTOR] - 1.0f, 0.000001f)), 0.0f, 2.0f);
  }
 
  dt_gui_freeze_begin();
  dt_bauhaus_slider_set(g->lift_factor, p->lift[CHANNEL_FACTOR]);
  dt_bauhaus_slider_set(g->gamma_factor, p->gamma[CHANNEL_FACTOR]);
  dt_bauhaus_slider_set(g->gain_factor, p->gain[CHANNEL_FACTOR]);
  dt_gui_freeze_end();
 
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);
}
 
void color_picker_apply(dt_iop_module_t *self, GtkWidget *picker, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
  if     (picker == g->hue_lift)
    apply_lift_neutralize(self);
  else if(picker == g->hue_gamma)
    apply_gamma_neutralize(self);
  else if(picker == g->hue_gain)
    apply_gain_neutralize(self);
  else if(picker == g->lift_factor)
    apply_lift_auto(self);
  else if(picker == g->gamma_factor)
    apply_gamma_auto(self);
  else if(picker == g->gain_factor)
    apply_gain_auto(self);
  else if(picker == g->grey)
    apply_autogrey(self);
  else if(picker == g->auto_luma)
    apply_autoluma(self);
  else if(picker == g->auto_color)
    apply_autocolor(self);
  else
    fprintf(stderr, "[colorbalance] unknown color picker\n");
 
  _check_tuner_picker_labels(self);
}
 
void init_global(dt_iop_module_so_t *module)
{
  const int program = 8; // extended.cl, from programs.conf
  dt_iop_colorbalance_global_data_t *gd
      = (dt_iop_colorbalance_global_data_t *)malloc(sizeof(dt_iop_colorbalance_global_data_t));
  module->data = gd;
  gd->kernel_colorbalance = dt_opencl_create_kernel(program, "colorbalance");
  gd->kernel_colorbalance_lgg = dt_opencl_create_kernel(program, "colorbalance_lgg");
  gd->kernel_colorbalance_cdl = dt_opencl_create_kernel(program, "colorbalance_cdl");
}
 
void cleanup_global(dt_iop_module_so_t *module)
{
  dt_iop_colorbalance_global_data_t *gd = (dt_iop_colorbalance_global_data_t *)module->data;
  dt_opencl_free_kernel(gd->kernel_colorbalance);
  dt_opencl_free_kernel(gd->kernel_colorbalance_lgg);
  dt_opencl_free_kernel(gd->kernel_colorbalance_cdl);
  dt_free(module->data);
}
 
void commit_params(struct dt_iop_module_t *self, dt_iop_params_t *p1, dt_dev_pixelpipe_t *pipe,
                   dt_dev_pixelpipe_iop_t *piece)
{
  dt_iop_colorbalance_data_t *d = (dt_iop_colorbalance_data_t *)(piece->data);
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)p1;
 
  d->mode = p->mode;
 
  const dt_aligned_pixel_t lift = { p->lift[CHANNEL_RED], p->lift[CHANNEL_GREEN], p->lift[CHANNEL_BLUE] };
  const dt_aligned_pixel_t gamma = { p->gamma[CHANNEL_RED], p->gamma[CHANNEL_GREEN], p->gamma[CHANNEL_BLUE] };
  const dt_aligned_pixel_t gain = { p->gain[CHANNEL_RED], p->gain[CHANNEL_GREEN], p->gain[CHANNEL_BLUE] };
 
  switch(d->mode)
  {
    case SLOPE_OFFSET_POWER:
    {
      // Correct the luminance in RGB parameters so we don't affect it
      dt_aligned_pixel_t XYZ;
 
      dt_prophotorgb_to_XYZ(lift, XYZ);
      d->lift[CHANNEL_FACTOR] = p->lift[CHANNEL_FACTOR];
      d->lift[CHANNEL_RED] = (p->lift[CHANNEL_RED] - XYZ[1]) + 1.f;
      d->lift[CHANNEL_GREEN] = (p->lift[CHANNEL_GREEN] - XYZ[1]) + 1.f;
      d->lift[CHANNEL_BLUE] = (p->lift[CHANNEL_BLUE] - XYZ[1]) + 1.f;
 
      dt_prophotorgb_to_XYZ(gamma, XYZ);
      d->gamma[CHANNEL_FACTOR] = p->gamma[CHANNEL_FACTOR];
      d->gamma[CHANNEL_RED] = (p->gamma[CHANNEL_RED] - XYZ[1]) + 1.f;
      d->gamma[CHANNEL_GREEN] = (p->gamma[CHANNEL_GREEN] - XYZ[1]) + 1.f;
      d->gamma[CHANNEL_BLUE] = (p->gamma[CHANNEL_BLUE] - XYZ[1]) + 1.f;
 
      dt_prophotorgb_to_XYZ(gain, XYZ);
      d->gain[CHANNEL_FACTOR] = p->gain[CHANNEL_FACTOR];
      d->gain[CHANNEL_RED] = (p->gain[CHANNEL_RED] - XYZ[1]) + 1.f;
      d->gain[CHANNEL_GREEN] = (p->gain[CHANNEL_GREEN] - XYZ[1]) + 1.f;
      d->gain[CHANNEL_BLUE] = (p->gain[CHANNEL_BLUE] - XYZ[1]) + 1.f;
 
      break;
    }
 
    case LEGACY:
    {
      // Luminance is not corrected in lift/gamma/gain for compatibility
      for(int i = 0; i < CHANNEL_SIZE; i++)
      {
        d->lift[i] = p->lift[i];
        d->gamma[i] = p->gamma[i];
        d->gain[i] = p->gain[i];
      }
 
      break;
    }
 
    case LIFT_GAMMA_GAIN:
    {
      // Correct the luminance in RGB parameters so we don't affect it
      dt_aligned_pixel_t XYZ;
 
      dt_prophotorgb_to_XYZ(lift, XYZ);
      d->lift[CHANNEL_FACTOR] = p->lift[CHANNEL_FACTOR];
      d->lift[CHANNEL_RED] = (p->lift[CHANNEL_RED] - XYZ[1]) + 1.f;
      d->lift[CHANNEL_GREEN] = (p->lift[CHANNEL_GREEN] - XYZ[1]) + 1.f;
      d->lift[CHANNEL_BLUE] = (p->lift[CHANNEL_BLUE] - XYZ[1]) + 1.f;
 
      dt_prophotorgb_to_XYZ(gamma, XYZ);
      d->gamma[CHANNEL_FACTOR] = p->gamma[CHANNEL_FACTOR];
      d->gamma[CHANNEL_RED] = (p->gamma[CHANNEL_RED] - XYZ[1]) + 1.f;
      d->gamma[CHANNEL_GREEN] = (p->gamma[CHANNEL_GREEN] - XYZ[1]) + 1.f;
      d->gamma[CHANNEL_BLUE] = (p->gamma[CHANNEL_BLUE] - XYZ[1]) + 1.f;
 
      dt_prophotorgb_to_XYZ(gain, XYZ);
      d->gain[CHANNEL_FACTOR] = p->gain[CHANNEL_FACTOR];
      d->gain[CHANNEL_RED] = (p->gain[CHANNEL_RED] - XYZ[1]) + 1.f;
      d->gain[CHANNEL_GREEN] = (p->gain[CHANNEL_GREEN] - XYZ[1]) + 1.f;
      d->gain[CHANNEL_BLUE] = (p->gain[CHANNEL_BLUE] - XYZ[1]) + 1.f;
 
      break;
    }
  }
 
  d->grey = p->grey;
  d->saturation = p->saturation;
  d->saturation_out = p->saturation_out;
  d->contrast = p->contrast;
}
 
void init_pipe(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  piece->data = dt_calloc_align(sizeof(dt_iop_colorbalance_data_t));
  piece->data_size = sizeof(dt_iop_colorbalance_data_t);
}
 
void cleanup_pipe(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  dt_free_align(piece->data);
  piece->data = NULL;
}
 
void set_visible_widgets(dt_iop_colorbalance_gui_data_t *g)
{
  const int mode = dt_bauhaus_combobox_get(g->mode);
  const int control_mode = dt_bauhaus_combobox_get(g->controls);
 
  gtk_widget_set_visible(g->master_box, mode != LEGACY);
 
  dt_conf_set_string("plugins/darkroom/colorbalance/controls",
                     control_mode == RGBL ? "RGBL" :
                     control_mode == BOTH ? "BOTH" : "HSL");
  gboolean show_rgbl = (control_mode == RGBL) || (control_mode == BOTH);
  gboolean show_hsl  = (control_mode == HSL)  || (control_mode == BOTH);
 
  gtk_widget_set_visible(g->lift_r,  show_rgbl);
  gtk_widget_set_visible(g->lift_g,  show_rgbl);
  gtk_widget_set_visible(g->lift_b,  show_rgbl);
  gtk_widget_set_visible(g->gamma_r, show_rgbl);
  gtk_widget_set_visible(g->gamma_g, show_rgbl);
  gtk_widget_set_visible(g->gamma_b, show_rgbl);
  gtk_widget_set_visible(g->gain_r,  show_rgbl);
  gtk_widget_set_visible(g->gain_g,  show_rgbl);
  gtk_widget_set_visible(g->gain_b,  show_rgbl);
 
  gtk_widget_set_visible(g->hue_lift,  show_hsl);
  gtk_widget_set_visible(g->sat_lift,  show_hsl);
  gtk_widget_set_visible(g->hue_gamma, show_hsl);
  gtk_widget_set_visible(g->sat_gamma, show_hsl);
  gtk_widget_set_visible(g->hue_gain,  show_hsl);
  gtk_widget_set_visible(g->sat_gain,  show_hsl);
 
  gtk_widget_set_visible(g->optimizer_box, mode == SLOPE_OFFSET_POWER);
}
 
void gui_update(dt_iop_module_t *self)
{
  dt_iop_color_picker_reset(self, TRUE);
  _check_tuner_picker_labels(self);
 
  gui_changed(self, NULL, NULL);
}
 
void gui_reset(dt_iop_module_t *self)
{
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  for (int k=0; k<LEVELS; k++)
  {
    g->color_patches_flags[k] = INVALID;
    g->luma_patches_flags[k] = INVALID;
  }
  _check_tuner_picker_labels(self);
 
  dt_bauhaus_combobox_set(g->controls, HSL);
 
  set_visible_widgets(g);
 
  dt_iop_color_picker_reset(self, TRUE);
}
 
static void _configure_slider_blocks(gpointer instance, dt_iop_module_t *self);
 
void gui_changed(dt_iop_module_t *self, GtkWidget *w, void *previous)
{
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  if(IS_NULL_PTR(w) || w == g->mode)
  {
    set_visible_widgets(g);
    _configure_slider_blocks(NULL, self);
  }
 
  dt_gui_freeze_begin();
 
  if(IS_NULL_PTR(w) || w == g->lift_r  || w == g->lift_g  || w == g->lift_b)
    set_HSL_sliders(g->hue_lift, g->sat_lift, p->lift);
  if(IS_NULL_PTR(w) || w == g->gamma_r || w == g->gamma_g || w == g->gamma_b)
    set_HSL_sliders(g->hue_gamma, g->sat_gamma, p->gamma);
  if(IS_NULL_PTR(w) || w == g->gain_r  || w == g->gain_g  || w == g->gain_b)
    set_HSL_sliders(g->hue_gain, g->sat_gain, p->gain);
 
  dt_gui_freeze_end();
}
 
static void controls_callback(GtkWidget *combo, dt_iop_module_t *self)
{
  if(dt_gui_widgets_suppressed()) return;
 
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  set_visible_widgets(g);
 
  dt_iop_color_picker_reset(self, TRUE);
}
 
#ifdef SHOW_COLOR_WHEELS
static gboolean dt_iop_area_draw(GtkWidget *widget, cairo_t *cr, dt_iop_module_t *self)
{
  float flt_bg = 0.5;
  if(gtk_widget_get_state_flags(widget) & GTK_STATE_FLAG_SELECTED) flt_bg = 0.6;
  float flt_dark = flt_bg / 1.5, flt_light = flt_bg * 1.5;
 
  uint32_t bg = ((255 << 24) | ((int)floor(flt_bg * 255 + 0.5) << 16) | ((int)floor(flt_bg * 255 + 0.5) << 8)
                 | (int)floor(flt_bg * 255 + 0.5));
  // bg = 0xffffffff;
  //   uint32_t dark = ((255 << 24) |
  //                  ((int)floor(flt_dark * 255 + 0.5) << 16) |
  //                  ((int)floor(flt_dark * 255 + 0.5) << 8) |
  //                  (int)floor(flt_dark * 255 + 0.5));
  uint32_t light = ((255 << 24) | ((int)floor(flt_light * 255 + 0.5) << 16)
                    | ((int)floor(flt_light * 255 + 0.5) << 8) | (int)floor(flt_light * 255 + 0.5));
 
  GtkAllocation allocation;
  gtk_widget_get_allocation(widget, &allocation);
  int width = allocation.width, height = allocation.height;
  if(width % 2 == 0) width--;
  if(height % 2 == 0) height--;
  double center_x = (float)width / 2.0, center_y = (float)height / 2.0;
  double diameter = MIN(width, height) - 4;
  double r_outside = diameter / 2.0, r_inside = r_outside * 0.87;
  double r_outside_2 = r_outside * r_outside, r_inside_2 = r_inside * r_inside;
 
  // clear the background
  cairo_set_source_rgb(cr, flt_bg, flt_bg, flt_bg);
  cairo_paint(cr);
 
  /* Create an image initialized with the ring colors */
  gint stride = cairo_format_stride_for_width(CAIRO_FORMAT_RGB24, width);
  guint32 *buf = (guint32 *)malloc(sizeof(guint32) * height * stride / 4);
 
  for(int y = 0; y < height; y++)
  {
    guint32 *p = buf + y * width;
 
    double dy = -(y + 0.5 - center_y);
 
    for(int x = 0; x < width; x++)
    {
      double dx = x + 0.5 - center_x;
      double dist = dx * dx + dy * dy;
      if(dist < r_inside_2 || dist > r_outside_2)
      {
        uint32_t col = bg;
        if((abs(dx) < 1 && abs(dy) < 3) || (abs(dx) < 3 && abs(dy) < 1)) col = light;
        *p++ = col;
        continue;
      }
 
      double angle = atan2(dy, dx) - M_PI_2;
      if(angle < 0.0) angle += 2.0 * M_PI;
 
      double hue = angle / (2.0 * M_PI);
 
      dt_aligned_pixel_t rgb;
      hsl2rgb(rgb, hue, 1.0, 0.5);
 
      *p++ = (((int)floor(rgb[0] * 255 + 0.5) << 16) | ((int)floor(rgb[1] * 255 + 0.5) << 8)
              | (int)floor(rgb[2] * 255 + 0.5));
    }
  }
 
  cairo_surface_t *source
      = cairo_image_surface_create_for_data((unsigned char *)buf, CAIRO_FORMAT_RGB24, width, height, stride);
 
  cairo_set_source_surface(cr, source, 0.0, 0.0);
  cairo_paint(cr);
  dt_free(buf);
 
  // draw border
  float line_width = 1;
  cairo_set_line_width(cr, line_width);
 
  cairo_set_source_rgb(cr, flt_bg, flt_bg, flt_bg);
  cairo_new_path(cr);
  cairo_arc(cr, center_x, center_y, r_outside, 0.0, 2.0 * M_PI);
  cairo_stroke(cr);
  cairo_arc(cr, center_x, center_y, r_inside, 0.0, 2.0 * M_PI);
  cairo_stroke(cr);
 
  cairo_set_source_rgb(cr, flt_dark, flt_dark, flt_dark);
  cairo_new_path(cr);
  cairo_arc(cr, center_x, center_y, r_outside, M_PI, 1.5 * M_PI);
  cairo_stroke(cr);
  cairo_arc(cr, center_x, center_y, r_inside, 0.0, 0.5 * M_PI);
  cairo_stroke(cr);
 
  cairo_set_source_rgb(cr, flt_light, flt_light, flt_light);
  cairo_new_path(cr);
  cairo_arc(cr, center_x, center_y, r_outside, 0.0, 0.5 * M_PI);
  cairo_stroke(cr);
  cairo_arc(cr, center_x, center_y, r_inside, M_PI, 1.5 * M_PI);
  cairo_stroke(cr);
 
  // draw selector
  double r = 255 / 255.0, g = 155 / 255.0, b = 40 / 255.0;
  double h, s, v;
 
  gtk_rgb_to_hsv(r, g, b, &h, &s, &v);
 
  cairo_save(cr);
  cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, 0.7);
 
  cairo_translate(cr, center_x, center_y);
  cairo_rotate(cr, h * 2.0 * M_PI - M_PI_2);
 
  cairo_arc(cr, r_inside * v, 0.0, 3.0, 0, 2.0 * M_PI);
  cairo_stroke(cr);
 
  cairo_restore(cr);
 
  cairo_surface_destroy(source);
 
  return TRUE;
}
#endif
 
static void _configure_slider_blocks(gpointer instance, dt_iop_module_t *self)
{
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self);
 
  GtkWidget *new_container = NULL;
  GtkWidget *old_container = gtk_bin_get_child(GTK_BIN(g->main_box));
 
  for(int i=0; i<3; i++)
  {
    g_object_ref(G_OBJECT(g->blocks[i]));
    if(old_container) gtk_container_remove(GTK_CONTAINER(old_container), g->blocks[i]);
  }
 
  if(old_container) gtk_widget_destroy(old_container);
 
  const gchar *long_label[]
     = { N_("shadows: lift / offset"),
         N_("mid-tones: gamma / power"),
         N_("highlights: gain / slope") };
 
  gchar *layout = dt_conf_get_string("plugins/darkroom/colorbalance/layout");
  new_container = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
 
  for(int i=0; i<3; i++)
  {
    if(i == 0)
      gtk_label_set_text(GTK_LABEL(g->main_label), _(long_label[0]));
    else
    {
      GtkWidget *label = dt_ui_section_label_new(_(long_label[i]));
      gtk_container_add(GTK_CONTAINER(new_container), label);
      if(old_container) gtk_widget_show(label);
    }
 
    gtk_container_add(GTK_CONTAINER(new_container), g->blocks[i]);
  }
 
  dt_free(layout);
 
  for(int i=0; i<3; i++) g_object_unref(G_OBJECT(g->blocks[i]));
 
  gtk_container_add(GTK_CONTAINER(g->main_box), new_container);
  if(old_container) gtk_widget_show(new_container);
}
 
static void _cycle_layout_callback(GtkWidget *label, GdkEventButton *event, dt_iop_module_t *self)
{
  _configure_slider_blocks(NULL, self);
}
 
#define HSL_CALLBACK(which)                                                             \
static void which##_callback(GtkWidget *slider, gpointer user_data)                     \
{                                                                                       \
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;                                 \
  dt_iop_colorbalance_params_t *p = (dt_iop_colorbalance_params_t *)self->params;       \
  dt_iop_colorbalance_gui_data_t *g = (dt_iop_colorbalance_gui_data_t *)dt_iop_gui_data(self); \
                                                                                        \
  if(dt_gui_widgets_suppressed()) return;                                                      \
                                                                                        \
  dt_iop_color_picker_reset(self, TRUE);                                                \
                                                                                        \
  float hsl[3] = {dt_bauhaus_slider_get(g->hue_##which) / 360.0f,                       \
                  dt_bauhaus_slider_get(g->sat_##which) / 100.0f,                       \
                  0.5f};                                                                \
                                                                                        \
  if(slider == g->hue_##which)                                                          \
    update_saturation_slider_color(g->sat_##which, hsl[0]);                             \
  set_RGB_sliders(g->which##_r, g->which##_g, g->which##_b, hsl, p->which, p->mode);    \
  dt_dev_add_history_item(self->dev, self, TRUE, TRUE);                               \
}
 
HSL_CALLBACK(lift)
HSL_CALLBACK(gamma)
HSL_CALLBACK(gain)
 
void gui_init(dt_iop_module_t *self)
{
  dt_iop_colorbalance_gui_data_t *g = IOP_GUI_ALLOC(colorbalance);
 
  g->mode = NULL;
 
  for (int k=0; k<LEVELS; k++)
  {
    g->color_patches_flags[k] = INVALID;
    g->luma_patches_flags[k] = INVALID;
  }
 
  GtkWidget *mode_box = self->gui->widget = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
 
  // mode choice
  g->mode = dt_bauhaus_combobox_from_params(self, N_("mode"));
  gtk_widget_set_tooltip_text(g->mode, _("color-grading mapping method"));
 
  // control choice
  g->controls = dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(self));
  dt_bauhaus_widget_set_label(g->controls, N_("color control sliders"));
  dt_bauhaus_combobox_add(g->controls, _("HSL"));
  dt_bauhaus_combobox_add(g->controls, _("RGBL"));
  dt_bauhaus_combobox_add(g->controls, _("both"));
  gtk_box_pack_start(GTK_BOX(self->gui->widget), GTK_WIDGET(g->controls), TRUE, TRUE, 0);
  gtk_widget_set_tooltip_text(g->controls, _("color-grading mapping method"));
  g_signal_connect(G_OBJECT(g->controls), "value-changed", G_CALLBACK(controls_callback), self);
 
  const char *mode = dt_conf_get_string_const("plugins/darkroom/colorbalance/controls");
  dt_bauhaus_combobox_set(g->controls, !g_strcmp0(mode, "RGBL") ? RGBL :
                                       !g_strcmp0(mode, "BOTH") ? BOTH : HSL);
 
  g->master_box = self->gui->widget = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
 
  gtk_box_pack_start(GTK_BOX(g->master_box), dt_ui_section_label_new(_("master")), FALSE, FALSE, 0);
 
  g->saturation = dt_bauhaus_slider_from_params(self, "saturation");
  dt_bauhaus_slider_set_soft_range(g->saturation, 0.5f, 1.5f);
  dt_bauhaus_slider_set_digits(g->saturation, 4);
  dt_bauhaus_slider_set_format(g->saturation, "%");
  gtk_widget_set_tooltip_text(g->saturation, _("saturation correction before the color balance"));
 
  g->saturation_out = dt_bauhaus_slider_from_params(self, "saturation_out");
  dt_bauhaus_slider_set_soft_range(g->saturation_out, 0.5f, 1.5f);
  dt_bauhaus_slider_set_digits(g->saturation_out, 4);
  dt_bauhaus_slider_set_format(g->saturation_out, "%");
  gtk_widget_set_tooltip_text(g->saturation_out, _("saturation correction after the color balance"));
 
  g->grey = dt_color_picker_new(self, DT_COLOR_PICKER_AREA,
            dt_bauhaus_slider_from_params(self, "grey"));
  dt_bauhaus_slider_set_format(g->grey, "%");
  gtk_widget_set_tooltip_text(g->grey, _("adjust to match a neutral tone"));
 
  g->contrast = dt_bauhaus_slider_from_params(self, N_("contrast"));
  dt_bauhaus_slider_set_soft_range(g->contrast, 0.5f, 1.5f);
  dt_bauhaus_slider_set_digits(g->contrast, 4);
  dt_bauhaus_slider_set_factor(g->contrast, -100.0f);
  dt_bauhaus_slider_set_offset(g->contrast, 100.0f);
  dt_bauhaus_slider_set_format(g->contrast, "%");
  gtk_widget_set_tooltip_text(g->contrast, _("contrast"));
 
#ifdef SHOW_COLOR_WHEELS
  GtkWidget *hbox = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, DT_GUI_BOX_SPACING);
  gtk_box_pack_start(GTK_BOX(self->widget), hbox, FALSE, FALSE, 0);
 
  GtkWidget *area = dtgtk_drawing_area_new_with_aspect_ratio(1.0);
  gtk_box_pack_start(GTK_BOX(hbox), area, TRUE, TRUE, 0);
 
  //   gtk_widget_add_events(g->area,
  //                         GDK_POINTER_MOTION_MASK |
  //                         GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK | GDK_LEAVE_NOTIFY_MASK);
  g_signal_connect(G_OBJECT(area), "draw", G_CALLBACK(dt_iop_area_draw), self);
  //   g_signal_connect (G_OBJECT (area), "button-press-event",
  //                     G_CALLBACK (dt_iop_colorbalance_button_press), self);
  //   g_signal_connect (G_OBJECT (area), "motion-notify-event",
  //                     G_CALLBACK (dt_iop_colorbalance_motion_notify), self);
  //   g_signal_connect (G_OBJECT (area), "leave-notify-event",
  //                     G_CALLBACK (dt_iop_colorbalance_leave_notify), self);
 
  area = dtgtk_drawing_area_new_with_aspect_ratio(1.0);
  gtk_box_pack_start(GTK_BOX(hbox), area, TRUE, TRUE, 0);
 
  //   gtk_widget_add_events(g->area,
  //                         GDK_POINTER_MOTION_MASK |
  //                         GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK | GDK_LEAVE_NOTIFY_MASK);
  g_signal_connect(G_OBJECT(area), "draw", G_CALLBACK(dt_iop_area_draw), self);
  //   g_signal_connect (G_OBJECT (area), "button-press-event",
  //                     G_CALLBACK (dt_iop_colorbalance_button_press), self);
  //   g_signal_connect (G_OBJECT (area), "motion-notify-event",
  //                     G_CALLBACK (dt_iop_colorbalance_motion_notify), self);
  //   g_signal_connect (G_OBJECT (area), "leave-notify-event",
  //                     G_CALLBACK (dt_iop_colorbalance_leave_notify), self);
 
  area = dtgtk_drawing_area_new_with_aspect_ratio(1.0);
  gtk_box_pack_start(GTK_BOX(hbox), area, TRUE, TRUE, 0);
 
  //   gtk_widget_add_events(g->area,
  //                         GDK_POINTER_MOTION_MASK |
  //                         GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK | GDK_LEAVE_NOTIFY_MASK);
  g_signal_connect(G_OBJECT(area), "draw", G_CALLBACK(dt_iop_area_draw), self);
//   g_signal_connect (G_OBJECT (area), "button-press-event",
//                     G_CALLBACK (dt_iop_colorbalance_button_press), self);
//   g_signal_connect (G_OBJECT (area), "motion-notify-event",
//                     G_CALLBACK (dt_iop_colorbalance_motion_notify), self);
//   g_signal_connect (G_OBJECT (area), "leave-notify-event",
//                     G_CALLBACK (dt_iop_colorbalance_leave_notify), self);
#endif
 
  g->main_label = dt_ui_section_label_new(""); // is set in _configure_slider_blocks
  gtk_widget_set_tooltip_text(g->main_label, _("click to cycle layout"));
  GtkWidget *main_label_box = gtk_event_box_new();
  gtk_container_add(GTK_CONTAINER(main_label_box), g->main_label);
  g_signal_connect(G_OBJECT(main_label_box), "button-release-event", G_CALLBACK(_cycle_layout_callback), self);
 
  g->main_box = gtk_event_box_new(); // is filled in _configure_slider_blocks
 
  char field_name[10];
 
#define ADD_CHANNEL(which, section, c, n, N, text, span)                    \
  sprintf(field_name, "%s[%d]", #which, CHANNEL_##N);                       \
  g->which##_##c = dt_bauhaus_slider_from_params(self, field_name);         \
  dt_bauhaus_slider_set_soft_range(g->which##_##c, -span+1.0, span+1.0);    \
  dt_bauhaus_slider_set_digits(g->which##_##c, 5);                          \
  dt_bauhaus_slider_set_offset(g->which##_##c, -1.0);                       \
  dt_bauhaus_slider_set_feedback(g->which##_##c, 0);                        \
  gtk_widget_set_tooltip_text(g->which##_##c, _(text[CHANNEL_##N]));        \
  dt_bauhaus_widget_set_label(g->which##_##c, #n);                 \
 
#define ADD_BLOCK(blk, which, section, text, span, satspan)                 \
  g->blocks[blk] = self->gui->widget = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING); \
                                                                            \
  sprintf(field_name, "%s[%d]", #which, CHANNEL_FACTOR);                    \
  g->which##_factor = dt_color_picker_new(self, DT_COLOR_PICKER_AREA,       \
                      dt_bauhaus_slider_from_params(self, field_name));     \
  dt_bauhaus_slider_set_soft_range(g->which##_factor, -span+1.0, span+1.0); \
  dt_bauhaus_slider_set_digits(g->which##_factor, 4);                       \
  dt_bauhaus_slider_set_factor(g->which##_factor, 100.0);                   \
  dt_bauhaus_slider_set_offset(g->which##_factor, - 100.0);                 \
  dt_bauhaus_slider_set_format(g->which##_factor,"%");                      \
  dt_bauhaus_slider_set_feedback(g->which##_factor, 0);                     \
  dt_bauhaus_slider_set_stop(g->which##_factor, 0.0, 0.0, 0.0, 0.0);        \
  dt_bauhaus_slider_set_stop(g->which##_factor, 1.0, 1.0, 1.0, 1.0);        \
  gtk_widget_set_tooltip_text(g->which##_factor, _(text[CHANNEL_FACTOR]));  \
  dt_bauhaus_widget_set_label(g->which##_factor, N_("factor"));    \
                                                                            \
  g->hue_##which = dt_color_picker_new(self, DT_COLOR_PICKER_AREA,          \
                   dt_bauhaus_slider_new_with_range_and_feedback(dt_bauhaus_get_global(), DT_GUI_MODULE(self),      \
                   0.0f, 360.0f, 0, 0.0f, 2, 0));                           \
  dt_bauhaus_widget_set_label(g->hue_##which, N_("hue"));          \
  dt_bauhaus_slider_set_format(g->hue_##which, "\302\260");                        \
  dt_bauhaus_slider_set_stop(g->hue_##which, 0.0f,   1.0f, 0.0f, 0.0f);     \
  dt_bauhaus_slider_set_stop(g->hue_##which, 0.166f, 1.0f, 1.0f, 0.0f);     \
  dt_bauhaus_slider_set_stop(g->hue_##which, 0.322f, 0.0f, 1.0f, 0.0f);     \
  dt_bauhaus_slider_set_stop(g->hue_##which, 0.498f, 0.0f, 1.0f, 1.0f);     \
  dt_bauhaus_slider_set_stop(g->hue_##which, 0.664f, 0.0f, 0.0f, 1.0f);     \
  dt_bauhaus_slider_set_stop(g->hue_##which, 0.830f, 1.0f, 0.0f, 1.0f);     \
  dt_bauhaus_slider_set_stop(g->hue_##which, 1.0f,   1.0f, 0.0f, 0.0f);     \
  gtk_widget_set_tooltip_text(g->hue_##which, _("select the hue"));         \
  g_signal_connect(G_OBJECT(g->hue_##which), "value-changed",               \
                   G_CALLBACK(which##_callback), self);                     \
  gtk_box_pack_start(GTK_BOX(self->gui->widget), g->hue_##which, TRUE, TRUE, 0); \
                                                                            \
  g->sat_##which = dt_bauhaus_slider_new_with_range_and_feedback(dt_bauhaus_get_global(), DT_GUI_MODULE(self),      \
                   0.0f, 100.0f, 0, 0.0f, 2, 0);                            \
  dt_bauhaus_slider_set_soft_max(g->sat_##which, satspan);                  \
  dt_bauhaus_widget_set_label(g->sat_##which, N_("saturation"));   \
  dt_bauhaus_slider_set_format(g->sat_##which, "%");                        \
  dt_bauhaus_slider_set_stop(g->sat_##which, 0.0f, 0.2f, 0.2f, 0.2f);       \
  dt_bauhaus_slider_set_stop(g->sat_##which, 1.0f, 1.0f, 1.0f, 1.0f);       \
  gtk_widget_set_tooltip_text(g->sat_##which, _("select the saturation"));  \
  g_signal_connect(G_OBJECT(g->sat_##which), "value-changed",               \
                   G_CALLBACK(which##_callback), self);                     \
  gtk_box_pack_start(GTK_BOX(self->gui->widget), g->sat_##which, TRUE, TRUE, 0); \
                                                                            \
  ADD_CHANNEL(which, section, r, red, RED, text, span)                      \
  dt_bauhaus_slider_set_stop(g->which##_r, 0.0, 0.0, 1.0, 1.0);             \
  dt_bauhaus_slider_set_stop(g->which##_r, 0.5, 1.0, 1.0, 1.0);             \
  dt_bauhaus_slider_set_stop(g->which##_r, 1.0, 1.0, 0.0, 0.0);             \
  ADD_CHANNEL(which, section, g, green, GREEN, text, span)                  \
  dt_bauhaus_slider_set_stop(g->which##_g, 0.0, 1.0, 0.0, 1.0);             \
  dt_bauhaus_slider_set_stop(g->which##_g, 0.5, 1.0, 1.0, 1.0);             \
  dt_bauhaus_slider_set_stop(g->which##_g, 1.0, 0.0, 1.0, 0.0);             \
  ADD_CHANNEL(which, section, b, blue, BLUE, text, span)                    \
  dt_bauhaus_slider_set_stop(g->which##_b, 0.0, 1.0, 1.0, 0.0);             \
  dt_bauhaus_slider_set_stop(g->which##_b, 0.5, 1.0, 1.0, 1.0);             \
  dt_bauhaus_slider_set_stop(g->which##_b, 1.0, 0.0, 0.0, 1.0);             \
 
  static const char *lift_messages[]
    = { N_("factor of lift/offset"),
        N_("factor of red for lift/offset"),
        N_("factor of green for lift/offset"),
        N_("factor of blue for lift/offset") };
 
  static const char *gamma_messages[]
    = { N_("factor of gamma/power"),
        N_("factor of red for gamma/power"),
        N_("factor of green for gamma/power"),
        N_("factor of blue for gamma/power") };
 
  static const char *gain_messages[]
    = { N_("factor of gain/slope"),
        N_("factor of red for gain/slope"),
        N_("factor of green for gain/slope"),
        N_("factor of blue for gain/slope") };
 
  ADD_BLOCK(0, lift,  N_("shadows"), lift_messages, 0.05f,  5.0f)
  ADD_BLOCK(1, gamma, N_("mid-tones"), gamma_messages, 0.5f, 20.0f)
  ADD_BLOCK(2, gain,  N_("highlights"), gain_messages,  0.5f, 25.0f)
  _configure_slider_blocks(NULL, self);
 
  g->optimizer_box = self->gui->widget = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
 
  gtk_box_pack_start(GTK_BOX(self->gui->widget), dt_ui_section_label_new(_("auto optimizers")), FALSE, FALSE, 0);
 
  g->auto_luma = dt_color_picker_new(self, DT_COLOR_PICKER_AREA,
                 dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(self)));
  dt_bauhaus_widget_set_label(g->auto_luma, N_("optimize luma"));
  gtk_widget_set_tooltip_text(g->auto_luma, _("fit the whole histogram and center the average luma"));
  gtk_box_pack_start(GTK_BOX(self->gui->widget), g->auto_luma, FALSE, FALSE, 0);
 
  g->auto_color = dt_color_picker_new(self, DT_COLOR_PICKER_AREA,
                  dt_bauhaus_combobox_new(dt_bauhaus_get_global(), DT_GUI_MODULE(self)));
  dt_bauhaus_widget_set_label(g->auto_color, N_("neutralize colors"));
  gtk_widget_set_tooltip_text(g->auto_color, _("optimize the RGB curves to remove color casts"));
  gtk_box_pack_start(GTK_BOX(self->gui->widget), g->auto_color, FALSE, FALSE, 0);
 
  // start building top level widget
  self->gui->widget = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
 
  gtk_box_pack_start(GTK_BOX(self->gui->widget), GTK_WIDGET(mode_box), TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(self->gui->widget), GTK_WIDGET(g->master_box), TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(self->gui->widget), GTK_WIDGET(main_label_box), TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(self->gui->widget), GTK_WIDGET(g->main_box), TRUE, TRUE, 0);
  gtk_box_pack_start(GTK_BOX(self->gui->widget), GTK_WIDGET(g->optimizer_box), TRUE, TRUE, 0);
 
  DT_DEBUG_CONTROL_SIGNAL_CONNECT(dt_control_signal_get_global(), DT_SIGNAL_PREFERENCES_CHANGE,
                                  G_CALLBACK(_configure_slider_blocks), (gpointer)self);
}
 
void gui_cleanup(struct dt_iop_module_t *self)
{
  DT_DEBUG_CONTROL_SIGNAL_DISCONNECT(dt_control_signal_get_global(), G_CALLBACK(_configure_slider_blocks), self);
 
  IOP_GUI_FREE;
}
 
// clang-format off
// 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