basecurve.c

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/*
    This file is part of darktable,
    Copyright (C) 2009-2017 johannes hanika.
    Copyright (C) 2010 Alexandre Prokoudine.
    Copyright (C) 2010-2011 Bruce Guenter.
    Copyright (C) 2010-2012 Henrik Andersson.
    Copyright (C) 2010 Milan Knížek.
    Copyright (C) 2010-2015 Pascal de Bruijn.
    Copyright (C) 2010-2016, 2019 Tobias Ellinghaus.
    Copyright (C) 2011 Brian Teague.
    Copyright (C) 2011 Jochen Schroeder.
    Copyright (C) 2011 Olivier Tribout.
    Copyright (C) 2011 Robert Bieber.
    Copyright (C) 2011-2012, 2014, 2016, 2019 Ulrich Pegelow.
    Copyright (C) 2012 Richard Wonka.
    Copyright (C) 2013, 2020 Aldric Renaudin.
    Copyright (C) 2013-2014, 2018-2022 Pascal Obry.
    Copyright (C) 2013-2017 Roman Lebedev.
    Copyright (C) 2013 Thomas Pryds.
    Copyright (C) 2014, 2017-2018, 2021 Dan Torop.
    Copyright (C) 2014, 2019 parafin.
    Copyright (C) 2015 Edouard Gomez.
    Copyright (C) 2015 Pedro Côrte-Real.
    Copyright (C) 2015, 2020-2021 Ralf Brown.
    Copyright (C) 2015 Stefan Kauerauf.
    Copyright (C) 2017 Dominik Markiewicz.
    Copyright (C) 2017-2018 Heiko Bauke.
    Copyright (C) 2017 Matthieu Moy.
    Copyright (C) 2017 Peter Budai.
    Copyright (C) 2018 Anders Bennehag.
    Copyright (C) 2018, 2020-2023, 2025-2026 Aurélien PIERRE.
    Copyright (C) 2018-2019 Edgardo Hoszowski.
    Copyright (C) 2018 Lukas Schrangl.
    Copyright (C) 2018 Maurizio Paglia.
    Copyright (C) 2018 rawfiner.
    Copyright (C) 2019 Andreas Schneider.
    Copyright (C) 2019 Andrew Dodd.
    Copyright (C) 2019 Andy Dodd.
    Copyright (C) 2019-2022 Diederik Ter Rahe.
    Copyright (C) 2019 emeikei.
    Copyright (C) 2020 Chris Elston.
    Copyright (C) 2020 GrahamByrnes.
    Copyright (C) 2020 Hubert Kowalski.
    Copyright (C) 2020 Tomasz Golinski.
    Copyright (C) 2021 lhietal.
    Copyright (C) 2022 Hanno Schwalm.
    Copyright (C) 2022 Martin Bařinka.
    Copyright (C) 2022 Philipp Lutz.
    
    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/>.
*/
#ifdef HAVE_CONFIG_H
#include "common/darktable.h"
#include "gui/gdkkeys.h"
#include "config.h"
#endif
#include "bauhaus/bauhaus.h"
#include "common/colorspaces_inline_conversions.h"
#include "common/debug.h"
#include "common/math.h"
#include "common/opencl.h"
#include "common/rgb_norms.h"
#include "control/control.h"
#include "develop/develop.h"
#include "develop/imageop.h"
#include "develop/imageop_math.h"
#include "develop/imageop_gui.h"
#include "develop/tiling.h"
#include "dtgtk/drawingarea.h"
#include "gui/draw.h"
#include "gui/gtk.h"
#include "gui/presets.h"
 
#include "iop/iop_api.h"
 
#include <assert.h>
#include <gtk/gtk.h>
#include <inttypes.h>
#include <stdlib.h>
#include <string.h>
 
#define DT_GUI_CURVE_EDITOR_INSET DT_PIXEL_APPLY_DPI(5)
#define DT_GUI_CURVE_INFL .3f
#define DT_IOP_TONECURVE_RES 256
#define MAXNODES 20
 
 
DT_MODULE_INTROSPECTION(6, dt_iop_basecurve_params_t)
 
typedef struct dt_iop_basecurve_node_t
{
  float x; // $MIN: 0.0 $MAX: 1.0
  float y; // $MIN: 0.0 $MAX: 1.0
} dt_iop_basecurve_node_t;
 
typedef struct dt_iop_basecurve_params_t
{
  // three curves (c, ., .) with max number of nodes
  // the other two are reserved, maybe we'll have cam rgb at some point.
  dt_iop_basecurve_node_t basecurve[3][MAXNODES];
  int basecurve_nodes[3]; // $MIN: 0 $MAX: MAXNODES $DEFAULT: 0
  int basecurve_type[3];  // $MIN: 0 $MAX: MONOTONE_HERMITE $DEFAULT: MONOTONE_HERMITE
  int exposure_fusion;    /* number of exposure fusion steps
                             $DEFAULT: 0 $DESCRIPTION: "fusion" */
  float exposure_stops;   /* number of stops between fusion images
                             $MIN: 0.01 $MAX: 4.0 $DEFAULT: 1.0 $DESCRIPTION: "exposure shift" */
  float exposure_bias;    /* whether to do exposure-fusion with over or under-exposure
                             $MIN: -1.0 $MAX: 1.0 $DEFAULT: 1.0 $DESCRIPTION: "exposure bias" */
  dt_iop_rgb_norms_t preserve_colors; /* $DEFAULT: DT_RGB_NORM_LUMINANCE $DESCRIPTION: "preserve colors" */
} dt_iop_basecurve_params_t;
 
typedef struct dt_iop_basecurve_params5_t
{
  // three curves (c, ., .) with max number of nodes
  // the other two are reserved, maybe we'll have cam rgb at some point.
  dt_iop_basecurve_node_t basecurve[3][MAXNODES];
  int basecurve_nodes[3];
  int basecurve_type[3];
  int exposure_fusion;    // number of exposure fusion steps
  float exposure_stops;   // number of stops between fusion images
  float exposure_bias;    // whether to do exposure-fusion with over or under-exposure
} dt_iop_basecurve_params5_t;
 
typedef struct dt_iop_basecurve_params3_t
{
  // three curves (c, ., .) with max number of nodes
  // the other two are reserved, maybe we'll have cam rgb at some point.
  dt_iop_basecurve_node_t basecurve[3][MAXNODES];
  int basecurve_nodes[3];
  int basecurve_type[3];
  int exposure_fusion;  // number of exposure fusion steps
  float exposure_stops; // number of stops between fusion images
} dt_iop_basecurve_params3_t;
 
// same but semantics/defaults changed
typedef dt_iop_basecurve_params3_t dt_iop_basecurve_params4_t;
 
typedef struct dt_iop_basecurve_params2_t
{
  // three curves (c, ., .) with max number of nodes
  // the other two are reserved, maybe we'll have cam rgb at some point.
  dt_iop_basecurve_node_t basecurve[3][MAXNODES];
  int basecurve_nodes[3];
  int basecurve_type[3];
} dt_iop_basecurve_params2_t;
 
typedef struct dt_iop_basecurve_params1_t
{
  float tonecurve_x[6], tonecurve_y[6];
  int tonecurve_preset;
} dt_iop_basecurve_params1_t;
 
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 == 6)
  {
    dt_iop_basecurve_params1_t *o = (dt_iop_basecurve_params1_t *)old_params;
    dt_iop_basecurve_params_t *n = (dt_iop_basecurve_params_t *)new_params;
 
    // start with a fresh copy of default parameters
    // unfortunately default_params aren't inited at this stage.
    *n = (dt_iop_basecurve_params_t){ {
                                        { { 0.0, 0.0 }, { 1.0, 1.0 } },
                                      },
                                      { 2, 3, 3 },
                                      { MONOTONE_HERMITE, MONOTONE_HERMITE, MONOTONE_HERMITE } , 0, 1};
    for(int k = 0; k < 6; k++) n->basecurve[0][k].x = o->tonecurve_x[k];
    for(int k = 0; k < 6; k++) n->basecurve[0][k].y = o->tonecurve_y[k];
    n->basecurve_nodes[0] = 6;
    n->basecurve_type[0] = CUBIC_SPLINE;
    n->exposure_fusion = 0;
    n->exposure_stops = 1;
    n->exposure_bias = 1.0;
    n->preserve_colors = DT_RGB_NORM_NONE;
    return 0;
  }
  if(old_version == 2 && new_version == 6)
  {
    dt_iop_basecurve_params2_t *o = (dt_iop_basecurve_params2_t *)old_params;
    dt_iop_basecurve_params_t *n = (dt_iop_basecurve_params_t *)new_params;
    memcpy(n, o, sizeof(dt_iop_basecurve_params2_t));
    n->exposure_fusion = 0;
    n->exposure_stops = 1;
    n->exposure_bias = 1.0;
    n->preserve_colors = DT_RGB_NORM_NONE;
    return 0;
  }
  if(old_version == 3 && new_version == 6)
  {
    dt_iop_basecurve_params3_t *o = (dt_iop_basecurve_params3_t *)old_params;
    dt_iop_basecurve_params_t *n = (dt_iop_basecurve_params_t *)new_params;
    memcpy(n, o, sizeof(dt_iop_basecurve_params3_t));
    n->exposure_stops = (o->exposure_fusion == 0 && o->exposure_stops == 0) ? 1.0f : o->exposure_stops;
    n->exposure_bias = 1.0;
    n->preserve_colors = DT_RGB_NORM_NONE;
    return 0;
  }
  if(old_version == 4 && new_version == 6)
  {
    dt_iop_basecurve_params4_t *o = (dt_iop_basecurve_params4_t *)old_params;
    dt_iop_basecurve_params_t *n = (dt_iop_basecurve_params_t *)new_params;
    memcpy(n, o, sizeof(dt_iop_basecurve_params4_t));
    n->exposure_bias = 1.0;
    n->preserve_colors = DT_RGB_NORM_NONE;
    return 0;
  }
  if(old_version == 5 && new_version == 6)
  {
    dt_iop_basecurve_params5_t *o = (dt_iop_basecurve_params5_t *)old_params;
    dt_iop_basecurve_params_t *n = (dt_iop_basecurve_params_t *)new_params;
    memcpy(n, o, sizeof(dt_iop_basecurve_params5_t));
    n->preserve_colors = DT_RGB_NORM_NONE;
    return 0;
  }
  return 1;
}
 
typedef struct dt_iop_basecurve_gui_data_t
{
  dt_draw_curve_t *minmax_curve; // curve for gui to draw
  int minmax_curve_type, minmax_curve_nodes;
  GtkBox *hbox;
  GtkDrawingArea *area;
  GtkWidget *fusion, *exposure_step, *exposure_bias;
  GtkWidget *cmb_preserve_colors;
  double mouse_x, mouse_y;
  int selected;
  double selected_offset, selected_y, selected_min, selected_max;
  float draw_xs[DT_IOP_TONECURVE_RES], draw_ys[DT_IOP_TONECURVE_RES];
  float draw_min_xs[DT_IOP_TONECURVE_RES], draw_min_ys[DT_IOP_TONECURVE_RES];
  float draw_max_xs[DT_IOP_TONECURVE_RES], draw_max_ys[DT_IOP_TONECURVE_RES];
  float loglogscale;
  GtkWidget *logbase;
} dt_iop_basecurve_gui_data_t;
 
static const char neutral[] = N_("neutral");
static const char canon_eos[] = N_("canon eos like");
static const char canon_eos_alt[] = N_("canon eos like alternate");
static const char nikon[] = N_("nikon like");
static const char nikon_alt[] = N_("nikon like alternate");
static const char sony_alpha[] = N_("sony alpha like");
static const char pentax[] = N_("pentax like");
static const char ricoh[] = N_("ricoh like");
static const char olympus[] = N_("olympus like");
static const char olympus_alt[] = N_("olympus like alternate");
static const char panasonic[] = N_("panasonic like");
static const char leica[] = N_("leica like");
static const char kodak_easyshare[] = N_("kodak easyshare like");
static const char konica_minolta[] = N_("konica minolta like");
static const char samsung[] = N_("samsung like");
static const char fujifilm[] = N_("fujifilm like");
static const char nokia[] = N_("nokia like");
 
typedef struct basecurve_preset_t
{
  const char *name;
  const char *maker;
  const char *model;
  int iso_min;
  float iso_max;
  dt_iop_basecurve_params_t params;
  int autoapply;
  int filter;
} basecurve_preset_t;
 
#define m MONOTONE_HERMITE
 
static const basecurve_preset_t basecurve_camera_presets[] = {
  // copy paste your measured basecurve line at the top here, like so (note the exif data and the last 1):
  // clang-format off
 
  // nikon d750 by Edouard Gomez
  {"Nikon D750", "NIKON CORPORATION", "NIKON D750", 0, FLT_MAX, {{{{0.000000, 0.000000}, {0.018124, 0.026126}, {0.143357, 0.370145}, {0.330116, 0.730507}, {0.457952, 0.853462}, {0.734950, 0.965061}, {0.904758, 0.985699}, {1.000000, 1.000000}}}, {8}, {m}, 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1},
  // contributed by Stefan Kauerauf
  {"Nikon D5100", "NIKON CORPORATION", "NIKON D5100", 0, FLT_MAX, {{{{0.000000, 0.000000}, {0.001113, 0.000506}, {0.002842, 0.001338}, {0.005461, 0.002470}, {0.011381, 0.006099}, {0.013303, 0.007758}, {0.034638, 0.041119}, {0.044441, 0.063882}, {0.070338, 0.139639}, {0.096068, 0.210915}, {0.137693, 0.310295}, {0.206041, 0.432674}, {0.255508, 0.504447}, {0.302770, 0.569576}, {0.425625, 0.726755}, {0.554526, 0.839541}, {0.621216, 0.882839}, {0.702662, 0.927072}, {0.897426, 0.990984}, {1.000000, 1.000000}}}, {20}, {m}, 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1},
  // nikon d7000 by Edouard Gomez
  {"Nikon D7000", "NIKON CORPORATION", "NIKON D7000", 0, FLT_MAX, {{{{0.000000, 0.000000}, {0.001943, 0.003040}, {0.019814, 0.028810}, {0.080784, 0.210476}, {0.145700, 0.383873}, {0.295961, 0.654041}, {0.651915, 0.952819}, {1.000000, 1.000000}}}, {8}, {m}, 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1},
  // nikon d7200 standard by Ralf Brown (firmware 1.00)
  {"Nikon D7200", "NIKON CORPORATION", "NIKON D7200", 0, FLT_MAX, {{{{0.000000, 0.000000}, {0.001604, 0.001334}, {0.007401, 0.005237}, {0.009474, 0.006890}, {0.017348, 0.017176}, {0.032782, 0.044336}, {0.048033, 0.086548}, {0.075803, 0.168331}, {0.109539, 0.273539}, {0.137373, 0.364645}, {0.231651, 0.597511}, {0.323797, 0.736475}, {0.383796, 0.805797}, {0.462284, 0.872247}, {0.549844, 0.918328}, {0.678855, 0.962361}, {0.817445, 0.990406}, {1.000000, 1.000000}}}, {18}, {m}, 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1},
  // nikon d7500 by Anders Bennehag (firmware C 1.00, LD 2.016)
  {"NIKON D7500", "NIKON CORPORATION", "NIKON D7500", 0, FLT_MAX, {{{{0.000000, 0.000000}, {0.000892, 0.001062}, {0.002280, 0.001768}, {0.013983, 0.011368}, {0.032597, 0.044700}, {0.050065, 0.097131}, {0.084129, 0.219954}, {0.120975, 0.336806}, {0.170730, 0.473752}, {0.258677, 0.647113}, {0.409997, 0.827417}, {0.499979, 0.889468}, {0.615564, 0.941960}, {0.665272, 0.957736}, {0.832126, 0.991968}, {1.000000, 1.000000}}}, {16}, {m}, 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1},
  // sony rx100m2 by Günther R.
  { "Sony DSC-RX100M2", "SONY", "DSC-RX100M2", 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.015106, 0.008116 }, { 0.070077, 0.093725 }, { 0.107484, 0.170723 }, { 0.191528, 0.341093 }, { 0.257996, 0.458453 }, { 0.305381, 0.537267 }, { 0.326367, 0.569257 }, { 0.448067, 0.723742 }, { 0.509627, 0.777966 }, { 0.676751, 0.898797 }, { 1.000000, 1.000000 } } }, { 12 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  // contributed by matthias bodenbinder
  { "Canon EOS 6D", "Canon", "Canon EOS 6D", 0, FLT_MAX, { { { { 0.000000, 0.002917 }, { 0.000751, 0.001716 }, { 0.006011, 0.004438 }, { 0.020286, 0.021725 }, { 0.048084, 0.085918 }, { 0.093914, 0.233804 }, { 0.162284, 0.431375 }, { 0.257701, 0.629218 }, { 0.384673, 0.800332 }, { 0.547709, 0.917761 }, { 0.751315, 0.988132 }, { 1.000000, 0.999943 } } }, { 12 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  // contributed by Dan Torop
  { "Fujifilm X100S", "Fujifilm", "X100S", 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.009145, 0.007905 }, { 0.026570, 0.032201 }, { 0.131526, 0.289717 }, { 0.175858, 0.395263 }, { 0.350981, 0.696899 }, { 0.614997, 0.959451 }, { 1.000000, 1.000000 } } }, { 8 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  { "Fujifilm X100T", "Fujifilm", "X100T", 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.009145, 0.007905 }, { 0.026570, 0.032201 }, { 0.131526, 0.289717 }, { 0.175858, 0.395263 }, { 0.350981, 0.696899 }, { 0.614997, 0.959451 }, { 1.000000, 1.000000 } } }, { 8 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  // contributed by Johannes Hanika
  { "Canon EOS 5D Mark II", "Canon", "Canon EOS 5D Mark II", 0, FLT_MAX, { { { { 0.000000, 0.000366 }, { 0.006560, 0.003504 }, { 0.027310, 0.029834 }, { 0.045915, 0.070230 }, { 0.206554, 0.539895 }, { 0.442337, 0.872409 }, { 0.673263, 0.971703 }, { 1.000000, 0.999832 } } }, { 8 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  // contributed by chrik5
  { "Pentax K-5", "Pentax", "Pentax K-5", 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.004754, 0.002208 }, { 0.009529, 0.004214 }, { 0.023713, 0.013508 }, { 0.031866, 0.020352 }, { 0.046734, 0.034063 }, { 0.059989, 0.052413 }, { 0.088415, 0.096030 }, { 0.136610, 0.190629 }, { 0.174480, 0.256484 }, { 0.205192, 0.307430 }, { 0.228896, 0.348447 }, { 0.286411, 0.428680 }, { 0.355314, 0.513527 }, { 0.440014, 0.607651 }, { 0.567096, 0.732791 }, { 0.620597, 0.775968 }, { 0.760355, 0.881828 }, { 0.875139, 0.960682 }, { 1.000000, 1.000000 } } }, { 20 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  // contributed by Togan Muftuoglu - ed: slope is too aggressive on shadows
  //{ "Nikon D90", "NIKON", "D90", 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.015520, 0.012248 }, { 0.097950, 0.251013 }, { 0.301515, 0.621951 }, { 0.415513, 0.771384 }, { 0.547326, 0.843079 }, { 0.819769, 0.956678 }, { 1.000000, 1.000000 } } }, { 8 }, { m } }, 0, 1 },
  // contributed by Edouard Gomez
  {"Nikon D90", "NIKON CORPORATION", "NIKON D90", 0, FLT_MAX, {{{{0.000000, 0.000000}, {0.011702, 0.012659}, {0.122918, 0.289973}, {0.153642, 0.342731}, {0.246855, 0.510114}, {0.448958, 0.733820}, {0.666759, 0.894290}, {1.000000, 1.000000}}}, {8}, {m}, 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1},
  // contributed by Pascal Obry
  { "Nikon D800", "NIKON", "NIKON D800", 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.001773, 0.001936 }, { 0.009671, 0.009693 }, { 0.016754, 0.020617 }, { 0.024884, 0.037309 }, { 0.048174, 0.107768 }, { 0.056932, 0.139532 }, { 0.085504, 0.233303 }, { 0.130378, 0.349747 }, { 0.155476, 0.405445 }, { 0.175245, 0.445918 }, { 0.217657, 0.516873 }, { 0.308475, 0.668608 }, { 0.375381, 0.754058 }, { 0.459858, 0.839909 }, { 0.509567, 0.881543 }, { 0.654394, 0.960877 }, { 0.783380, 0.999161 }, { 0.859310, 1.000000 }, { 1.000000, 1.000000 } } }, { 20 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  // contributed by Lukas Schrangl
  {"Olympus OM-D E-M10 II", "OLYMPUS CORPORATION    ", "E-M10MarkII     ", 0, FLT_MAX, {{{{0.000000, 0.000000}, {0.005707, 0.004764}, {0.018944, 0.024456}, {0.054501, 0.129992}, {0.075665, 0.211873}, {0.119641, 0.365771}, {0.173148, 0.532024}, {0.247979, 0.668989}, {0.357597, 0.780138}, {0.459003, 0.839829}, {0.626844, 0.904426}, {0.769425, 0.948541}, {0.820429, 0.964715}, {1.000000, 1.000000}}}, {14}, {m}, 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1},
  // clang-format on
};
static const int basecurve_camera_presets_cnt = sizeof(basecurve_camera_presets) / sizeof(basecurve_preset_t);
 
static const basecurve_preset_t basecurve_presets[] = {
  // clang-format off
  // smoother cubic spline curve
  { N_("cubic spline"), "", "", 0, FLT_MAX, { { { { 0.0, 0.0}, { 1.0, 1.0 }, { 0., 0.}, { 0., 0.}, { 0., 0.}, { 0., 0.}, { 0., 0.}, { 0., 0.} } }, { 2 }, { CUBIC_SPLINE }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { neutral,         "", "",                      0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.005000, 0.002500 }, { 0.150000, 0.300000 }, { 0.400000, 0.700000 }, { 0.750000, 0.950000 }, { 1.000000, 1.000000 } } }, { 6 }, { m } , 0, 0, 0, DT_RGB_NORM_LUMINANCE}, 0, 1 },
  { canon_eos,       "Canon", "",                 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.028226, 0.029677 }, { 0.120968, 0.232258 }, { 0.459677, 0.747581 }, { 0.858871, 0.967742 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { canon_eos_alt,   "Canon", "EOS 5D Mark%",      0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.026210, 0.029677 }, { 0.108871, 0.232258 }, { 0.350806, 0.747581 }, { 0.669355, 0.967742 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { nikon,           "NIKON", "",                 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.036290, 0.036532 }, { 0.120968, 0.228226 }, { 0.459677, 0.759678 }, { 0.858871, 0.983468 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { nikon_alt,       "NIKON", "%D____%",            0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.012097, 0.007322 }, { 0.072581, 0.130742 }, { 0.310484, 0.729291 }, { 0.611321, 0.951613 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { sony_alpha,      "SONY", "",                  0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.031949, 0.036532 }, { 0.105431, 0.228226 }, { 0.434505, 0.759678 }, { 0.855738, 0.983468 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { pentax,          "PENTAX", "",                0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.032258, 0.024596 }, { 0.120968, 0.166419 }, { 0.205645, 0.328527 }, { 0.604839, 0.790171 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { ricoh,           "RICOH", "",                 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.032259, 0.024596 }, { 0.120968, 0.166419 }, { 0.205645, 0.328527 }, { 0.604839, 0.790171 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { olympus,         "OLYMPUS", "",               0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.033962, 0.028226 }, { 0.249057, 0.439516 }, { 0.501887, 0.798387 }, { 0.750943, 0.955645 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { olympus_alt,     "OLYMPUS", "E-M%",            0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.012097, 0.010322 }, { 0.072581, 0.167742 }, { 0.310484, 0.711291 }, { 0.645161, 0.956855 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { panasonic,       "Panasonic", "",             0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.036290, 0.024596 }, { 0.120968, 0.166419 }, { 0.205645, 0.328527 }, { 0.604839, 0.790171 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { leica,           "Leica", "",                 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.036291, 0.024596 }, { 0.120968, 0.166419 }, { 0.205645, 0.328527 }, { 0.604839, 0.790171 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { kodak_easyshare, "EASTMAN KODAK COMPANY", "", 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.044355, 0.020967 }, { 0.133065, 0.154322 }, { 0.209677, 0.300301 }, { 0.572581, 0.753477 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { konica_minolta,  "MINOLTA", "",               0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.020161, 0.010322 }, { 0.112903, 0.167742 }, { 0.500000, 0.711291 }, { 0.899194, 0.956855 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { samsung,         "SAMSUNG", "",               0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.040323, 0.029677 }, { 0.133065, 0.232258 }, { 0.447581, 0.747581 }, { 0.842742, 0.967742 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { fujifilm,        "FUJIFILM", "",              0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.028226, 0.029677 }, { 0.104839, 0.232258 }, { 0.387097, 0.747581 }, { 0.754032, 0.967742 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  { nokia,           "Nokia", "",                 0, FLT_MAX, { { { { 0.000000, 0.000000 }, { 0.041825, 0.020161 }, { 0.117871, 0.153226 }, { 0.319392, 0.500000 }, { 0.638783, 0.842742 }, { 1.000000, 1.000000 } } }, { 6 }, { m }, 0, 0, 0, DT_RGB_NORM_LUMINANCE }, 0, 0 },
  // clang-format on
};
#undef m
static const int basecurve_presets_cnt = sizeof(basecurve_presets) / sizeof(basecurve_preset_t);
 
typedef struct dt_iop_basecurve_data_t
{
  dt_draw_curve_t *curve; // curve for pixelpipe piece and pixel processing
  int basecurve_type;
  int basecurve_nodes;
  float table[0x10000];      // precomputed look-up table for tone curve
  float unbounded_coeffs[3]; // approximation for extrapolation
  int exposure_fusion;
  float exposure_stops;
  float exposure_bias;
  int preserve_colors;
} dt_iop_basecurve_data_t;
 
 
const char *name()
{
  return _("base curve");
}
 
const char **description(struct dt_iop_module_t *self)
{
  return dt_iop_set_description(self, _("apply a view transform based on personal or camera manufacturer look,\n"
                                        "for corrective purposes, to prepare images for display"),
                                      _("corrective"),
                                      _("linear, RGB, display-referred"),
                                      _("non-linear, RGB"),
                                      _("non-linear, RGB, display-referred"));
}
 
int default_group()
{
  return IOP_GROUP_TONES;
}
 
int flags()
{
  return IOP_FLAGS_SUPPORTS_BLENDING | IOP_FLAGS_ALLOW_TILING | IOP_FLAGS_DEPRECATED;
}
 
int default_colorspace(dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, const dt_dev_pixelpipe_iop_t *piece)
{
  return IOP_CS_RGB;
}
 
static void set_presets(dt_iop_module_so_t *self, const basecurve_preset_t *presets, int count, gboolean camera)
{
  const gboolean autoapply_percamera = FALSE;
 
  const gboolean force_autoapply = (autoapply_percamera || !camera);
 
  // transform presets above to db entries.
  for(int k = 0; k < count; k++)
  {
    // disable exposure fusion if not explicitly inited in params struct definition above:
    dt_iop_basecurve_params_t tmp = presets[k].params;
    if(tmp.exposure_fusion == 0 && tmp.exposure_stops == 0.0f)
    {
      tmp.exposure_fusion = 0;
      tmp.exposure_stops = 1.0f;
      tmp.exposure_bias = 1.0f;
    }
    // add the preset.
    dt_gui_presets_add_generic(_(presets[k].name), self->op, self->version(),
                               &tmp, sizeof(dt_iop_basecurve_params_t), 1,
                               DEVELOP_BLEND_CS_RGB_DISPLAY);
    // and restrict it to model, maker, iso, and raw images
    dt_gui_presets_update_mml(_(presets[k].name), self->op, self->version(),
                              presets[k].maker, presets[k].model, "");
    dt_gui_presets_update_iso(_(presets[k].name), self->op, self->version(),
                              presets[k].iso_min, presets[k].iso_max);
    dt_gui_presets_update_ldr(_(presets[k].name), self->op, self->version(), FOR_RAW);
    // make it auto-apply for matching images:
    dt_gui_presets_update_autoapply(_(presets[k].name), self->op, self->version(),
                                    force_autoapply ? 1 : presets[k].autoapply);
    // hide all non-matching presets in case the model string is set.
    // When force_autoapply was given always filter (as these are per-camera presets)
    dt_gui_presets_update_filter(_(presets[k].name), self->op, self->version(), camera || presets[k].filter);
  }
}
 
void init_presets(dt_iop_module_so_t *self)
{
  // sql begin
  dt_database_start_transaction(darktable.db);
 
  set_presets(self, basecurve_presets, basecurve_presets_cnt, FALSE);
  set_presets(self, basecurve_camera_presets, basecurve_camera_presets_cnt, TRUE);
 
  // sql commit
  dt_database_release_transaction(darktable.db);
}
 
static inline __attribute__((always_inline)) float exposure_increment(float stops, int e, float fusion, float bias)
{
  float offset = stops * fusion * (bias - 1.0f) / 2.0f;
  return powf(2.0f, stops * e + offset);
}
 
void tiling_callback(struct dt_iop_module_t *self, const struct dt_dev_pixelpipe_t *pipe, const struct dt_dev_pixelpipe_iop_t *piece, struct dt_develop_tiling_t *tiling)
{
  const dt_iop_roi_t *const roi_in = &piece->roi_in;
  dt_iop_basecurve_data_t *const d = (dt_iop_basecurve_data_t *)piece->data;
 
  if(d->exposure_fusion)
  {
    const int rad = MIN(roi_in->width, (int)ceilf(256 * roi_in->scale));
 
    tiling->factor = 6.666f;                 // in + out + col[] + comb[] + 2*tmp
    tiling->maxbuf = 1.0f;
    tiling->overhead = 0;
    tiling->xalign = 1;
    tiling->yalign = 1;
    tiling->overlap = rad;
  }
  else
  {
    tiling->factor = 2.0f;                   // in + out
    tiling->maxbuf = 1.0f;
    tiling->overhead = 0;
    tiling->xalign = 1;
    tiling->yalign = 1;
    tiling->overlap = 0;
  }
}
 
// See comments of opencl version in data/kernels/basecurve.cl for description of the meaning of "legacy"
__DT_CLONE_TARGETS__
static inline void apply_legacy_curve(
    const float *const in,
    float *const out,
    const int width,
    const int height,
    const float mul,
    const float *const table,
    const float *const unbounded_coeffs)
{
  const size_t npixels = (size_t)width * height;
  __OMP_PARALLEL_FOR__()
  for(size_t k = 0; k < 4*npixels; k += 4)
  {
    for(int i = 0; i < 3; i++)
    {
      const float f = in[k+i] * mul;
      // use base curve for values < 1, else use extrapolation.
      if(f < 1.0f)
        out[k+i] = fmaxf(table[CLAMP((int)(f * 0x10000ul), 0, 0xffff)], 0.f);
      else
        out[k+i] = fmaxf(dt_iop_eval_exp(unbounded_coeffs, f), 0.f);
    }
    out[k+3] = in[k+3];
  }
}
 
// See description of the equivalent OpenCL function in data/kernels/basecurve.cl
__DT_CLONE_TARGETS__
static inline void apply_curve(
    const float *const in,
    float *const out,
    const int width,
    const int height,
    const int preserve_colors,
    const float mul,
    const float *const table,
    const float *const unbounded_coeffs,
    const dt_iop_order_iccprofile_info_t *const work_profile)
{
  const size_t npixels = (size_t)width * height;
  __OMP_PARALLEL_FOR__()
  for(size_t k = 0; k < 4*npixels; k += 4)
  {
    float ratio = 1.f;
    // FIXME: Determine if we can get rid of the conditionals within this function in some way to improve performance.
    // However, solving this one is much harder than the conditional for legacy vs. current
    const float lum = mul * dt_rgb_norm(in+k, preserve_colors, work_profile);
    if(lum > 0.f)
    {
      const float curve_lum = (lum < 1.0f)
        ? table[CLAMP((int)(lum * 0x10000ul), 0, 0xffff)]
        : dt_iop_eval_exp(unbounded_coeffs, lum);
      ratio = mul * curve_lum / lum;
    }
    for(size_t c = 0; c < 3; c++)
    {
      out[k+c] = fmaxf(ratio * in[k+c], 0.f);
    }
    out[k+3] = in[k+3];
  }
}
 
__DT_CLONE_TARGETS__
static inline void compute_features(
    float *const col,
    const int wd,
    const int ht)
{
  // features are product of
  // 1) well exposedness
  // 2) saturation
  // 3) local contrast (handled in laplacian form later)
  const size_t npixels = (size_t)wd * ht;
  __OMP_PARALLEL_FOR__()
  for(size_t x = 0; x < 4*npixels; x += 4)
  {
    const float max = MAX(col[x], MAX(col[x+1], col[x+2]));
    const float min = MIN(col[x], MIN(col[x+1], col[x+2]));
    const float sat = .1f + .1f*(max-min)/MAX(1e-4f, max);
 
    const float c = 0.54f;
    float v = fabsf(col[x]-c);
    v = MAX(fabsf(col[x+1]-c), v);
    v = MAX(fabsf(col[x+2]-c), v);
    const float var = 0.5;
    const float exp = .2f + dt_fast_expf(-v*v/(var*var));
    col[x+3] = sat * exp;
  }
}
 
__DT_CLONE_TARGETS__
static inline int gauss_blur(
    const float *const input,
    float *const output,
    const size_t wd,
    const size_t ht)
{
  const float w[5] = { 1.f / 16.f, 4.f / 16.f, 6.f / 16.f, 4.f / 16.f, 1.f / 16.f };
  float *tmp = dt_pixelpipe_cache_alloc_align_float_cache((size_t)4 * wd * ht, 0);
  if(IS_NULL_PTR(tmp)) return 1;
 
  memset(tmp, 0, sizeof(float) * 4 * wd * ht);
  __OMP_PARALLEL_FOR__()
  for(int j=0;j<ht;j++)
  { // horizontal pass
    // left borders
    for(int i=0;i<2;i++) for(int c=0;c<4;c++)
      for(int ii=-2;ii<=2;ii++)
        tmp[4*(j*wd+i)+c] += input[4*(j*wd+MAX(-i-ii,i+ii))+c] * w[ii+2];
    // most pixels
    for(int i=2;i<wd-2;i++) for(int c=0;c<4;c++)
      for(int ii=-2;ii<=2;ii++)
        tmp[4*(j*wd+i)+c] += input[4*(j*wd+i+ii)+c] * w[ii+2];
    // right borders
    for(int i=wd-2;i<wd;i++) for(int c=0;c<4;c++)
      for(int ii=-2;ii<=2;ii++)
        tmp[4*(j*wd+i)+c] += input[4*(j*wd+MIN(i+ii, wd-(i+ii-wd+1) ))+c] * w[ii+2];
  }
  memset(output, 0, sizeof(float) * 4 * wd * ht);
  __OMP_PARALLEL_FOR__()
  for(int i=0;i<wd;i++)
  { // vertical pass
    for(int j=0;j<2;j++) for(int c=0;c<4;c++)
      for(int jj=-2;jj<=2;jj++)
        output[4*(j*wd+i)+c] += tmp[4*(MAX(-j-jj,j+jj)*wd+i)+c] * w[jj+2];
    for(int j=2;j<ht-2;j++) for(int c=0;c<4;c++)
      for(int jj=-2;jj<=2;jj++)
        output[4*(j*wd+i)+c] += tmp[4*((j+jj)*wd+i)+c] * w[jj+2];
    for(int j=ht-2;j<ht;j++) for(int c=0;c<4;c++)
      for(int jj=-2;jj<=2;jj++)
        output[4*(j*wd+i)+c] += tmp[4*(MIN(j+jj, ht-(j+jj-ht+1))*wd+i)+c] * w[jj+2];
  }
  dt_pixelpipe_cache_free_align(tmp);
  return 0;
}
 
__DT_CLONE_TARGETS__
static inline int gauss_expand(
    const float *const input, // coarse input
    float *const fine,        // upsampled, blurry output
    const size_t wd,          // fine res
    const size_t ht)
{
  const size_t cw = (wd-1)/2+1;
  // fill numbers in even pixels, zero odd ones
  memset(fine, 0, sizeof(float) * 4 * wd * ht);
  __OMP_PARALLEL_FOR__(collapse(2))
  for(int j=0;j<ht;j+=2)
    for(int i=0;i<wd;i+=2)
      for(int c=0;c<4;c++)
        fine[4*(j*wd+i)+c] = 4.0f * input[4*(j/2*cw + i/2)+c];
 
  // convolve with same kernel weights mul by 4:
  if(gauss_blur(fine, fine, wd, ht)) return 1;
  return 0;
}
 
// XXX FIXME: we'll need to pad up the image to get a good boundary condition!
// XXX FIXME: downsampling will not result in an energy conserving pattern (every 4 pixels one sample)
// XXX FIXME: neither will a mirror boundary condition (mirrors in subsampled values at random density)
// TODO: copy laplacian code from local laplacian filters, it's faster.
static inline int gauss_reduce(
    const float *const input, // fine input buffer
    float *const coarse,      // coarse scale, blurred input buf
    float *const detail,      // detail/laplacian, fine scale, or 0
    const size_t wd,
    const size_t ht)
{
  // blur, store only coarse res
  const size_t cw = (wd-1)/2+1, ch = (ht-1)/2+1;
 
  float *blurred = dt_pixelpipe_cache_alloc_align_float_cache((size_t)4 * wd * ht, 0);
  if(IS_NULL_PTR(blurred)) return 1;
 
  if(gauss_blur(input, blurred, wd, ht))
  {
    dt_pixelpipe_cache_free_align(blurred);
    return 1;
  }
  for(size_t j=0;j<ch;j++) for(size_t i=0;i<cw;i++)
    for(int c=0;c<4;c++) coarse[4*(j*cw+i)+c] = blurred[4*(2*j*wd+2*i)+c];
  dt_pixelpipe_cache_free_align(blurred);
 
  if(!IS_NULL_PTR(detail))
  {
    // compute laplacian/details: expand coarse buffer into detail
    // buffer subtract expanded buffer from input in place
    if(gauss_expand(coarse, detail, wd, ht)) return 1;
    for(size_t k=0;k<wd*ht*4;k++)
      detail[k] = input[k] - detail[k];
  }
  return 0;
}
 
__DT_CLONE_TARGETS__
int process_fusion(struct dt_iop_module_t *self, const dt_dev_pixelpipe_iop_t *piece, const void *const ivoid,
                   void *const ovoid, const dt_iop_roi_t *const roi_in, const dt_iop_roi_t *const roi_out)
{
  const float *const in = (const float *)ivoid;
  float *const out = (float *)ovoid;
  dt_iop_basecurve_data_t *const d = (dt_iop_basecurve_data_t *)(piece->data);
  const dt_iop_order_iccprofile_info_t *const work_profile = dt_ioppr_get_iop_work_profile_info(piece->module, piece->module->dev->iop);
  int err = 0;
 
  // allocate temporary buffer for wavelet transform + blending
  const int wd = roi_in->width, ht = roi_in->height;
  int num_levels = 8;
  float **col = calloc(num_levels, sizeof(float *));
  float **comb = calloc(num_levels, sizeof(float *));
  if(IS_NULL_PTR(col) || IS_NULL_PTR(comb))
  {
    err = 1;
    goto error;
  }
  int w = wd, h = ht;
  const int rad = MIN(wd, (int)ceilf(256 * roi_in->scale));
  int step = 1;
  for(int k = 0; k < num_levels; k++)
  {
    // coarsest step is some % of image width.
    col[k]  = dt_pixelpipe_cache_alloc_align_float_cache((size_t)4 * w * h, 0);
    if(col[k] == NULL)
    {
      err = 1;
      goto error;
    }
    comb[k] = dt_pixelpipe_cache_alloc_align_float_cache((size_t)4 * w * h, 0);
    if(comb[k] == NULL)
    {
      err = 1;
      goto error;
    }
 
    memset(comb[k], 0, sizeof(float) * 4 * w * h);
    w = (w - 1) / 2 + 1;
    h = (h - 1) / 2 + 1;
    step *= 2;
    if(step > rad || w < 4 || h < 4)
    {
      num_levels = k + 1;
      break;
    }
  }
 
  for(int e = 0; e < d->exposure_fusion + 1; e++)
  {
    // for every exposure fusion image:
    // push by some ev, apply base curve:
    if(d->preserve_colors == DT_RGB_NORM_NONE)
      apply_legacy_curve(in, col[0], wd, ht, exposure_increment(d->exposure_stops, e, d->exposure_fusion, d->exposure_bias),
                         d->table, d->unbounded_coeffs);
    else
      apply_curve(in, col[0], wd, ht, d->preserve_colors, exposure_increment(d->exposure_stops, e, d->exposure_fusion, d->exposure_bias),
                  d->table, d->unbounded_coeffs, work_profile);
 
    // compute features
    compute_features(col[0], wd, ht);
 
    // create gaussian pyramid of colour buffer
    w = wd;
    h = ht;
    if(gauss_reduce(col[0], col[1], out, w, h))
    {
      err = 1;
      goto error;
    }
    __OMP_PARALLEL_FOR__()
    for(size_t k = 0; k < 4ul * wd * ht; k += 4)
      col[0][k + 3] *= .1f + sqrtf(out[k] * out[k] + out[k + 1] * out[k + 1] + out[k + 2] * out[k + 2]);
 
// #define DEBUG_VIS2
#ifdef DEBUG_VIS2 // transform weights in channels
    for(size_t k = 0; k < 4ul * w * h; k += 4) col[0][k + e] = col[0][k + 3];
#endif
 
// #define DEBUG_VIS
#ifdef DEBUG_VIS // DEBUG visualise weight buffer
    for(size_t k = 0; k < 4ul * w * h; k += 4) comb[0][k + e] = col[0][k + 3];
    continue;
#endif
 
    for(int k = 1; k < num_levels; k++)
    {
      if(gauss_reduce(col[k - 1], col[k], 0, w, h))
      {
        err = 1;
        goto error;
      }
      w = (w - 1) / 2 + 1;
      h = (h - 1) / 2 + 1;
    }
 
    // update pyramid coarse to fine
    for(int k = num_levels - 1; k >= 0; k--)
    {
      w = wd;
      h = ht;
      for(int i = 0; i < k; i++)
      {
        w = (w - 1) / 2 + 1;
        h = (h - 1) / 2 + 1;
      }
      // abuse output buffer as temporary memory:
      if(k != num_levels - 1)
      {
        if(gauss_expand(col[k + 1], out, w, h))
        {
          err = 1;
          goto error;
        }
      }
      __OMP_PARALLEL_FOR__()
      for(size_t x = 0; x < (size_t)4 * h * w; x += 4)
      {
        // blend images into output pyramid
        if(k == num_levels - 1) // blend gaussian base
#ifdef DEBUG_VIS2
          ;
#else
        {
        for(int c = 0; c < 3; c++)
          comb[k][x + c] += col[k][x + 3] * col[k][x + c];
        }
#endif
        else // laplacian
        {
          for(int c = 0; c < 3; c++)
            comb[k][x + c] += col[k][x + 3] * (col[k][x + c] - out[x + c]);
        }
        comb[k][x + 3] += col[k][x + 3];
      }
    }
  }
 
#ifndef DEBUG_VIS // DEBUG: switch off when visualising weight buf
  // normalise and reconstruct output pyramid buffer coarse to fine
  for(int k = num_levels - 1; k >= 0; k--)
  {
    w = wd;
    h = ht;
    for(int i = 0; i < k; i++)
    {
      w = (w - 1) / 2 + 1;
      h = (h - 1) / 2 + 1;
    }
 
    // normalise both gaussian base and laplacians:
    __OMP_PARALLEL_FOR__()
    for(size_t i = 0; i < (size_t)4 * w * h; i += 4)
      if(comb[k][i + 3] > 1e-8f)
        for(int c = 0; c < 3; c++) comb[k][i + c] /= comb[k][i + 3];
 
    if(k < num_levels - 1)
    { // reconstruct output image
      if(gauss_expand(comb[k + 1], out, w, h))
      {
        err = 1;
        goto error;
      }
      __OMP_PARALLEL_FOR__()
      for(size_t x = 0; x < (size_t)4 * h * w; x += 4)
        {
        for(int c = 0; c < 3; c++)
          comb[k][x + c] += out[x + c];
        }
    }
  }
#endif
  // copy output buffer
  __OMP_PARALLEL_FOR__()
  for(size_t k = 0; k < (size_t)4 * wd * ht; k += 4)
  {
    out[k + 0] = fmaxf(comb[0][k + 0], 0.f);
    out[k + 1] = fmaxf(comb[0][k + 1], 0.f);
    out[k + 2] = fmaxf(comb[0][k + 2], 0.f);
    out[k + 3] = in[k + 3]; // pass on 4th channel
  }
 
error:;
  // free temp buffers
  for(int k = 0; k < num_levels; k++)
  {
    dt_pixelpipe_cache_free_align(col[k]);
    dt_pixelpipe_cache_free_align(comb[k]);
  }
  dt_free(col);
  dt_free(comb);
  return err;
}
 
void process_lut(struct dt_iop_module_t *self, const dt_dev_pixelpipe_iop_t *piece, const void *const ivoid,
                 void *const ovoid, const dt_iop_roi_t *const roi_in, const dt_iop_roi_t *const roi_out)
{
  const float *const in = (const float *)ivoid;
  float *const out = (float *)ovoid;
  //const int ch = piece->dsc_in.channels; <-- it appears someone was trying to make this handle monochrome data,
  //however the for loops only handled RGBA - FIXME, determine what possible data formats and channel
  //configurations we might encounter here and handle those too
  dt_iop_basecurve_data_t *const d = (dt_iop_basecurve_data_t *)(piece->data);
  const dt_iop_order_iccprofile_info_t *const work_profile = dt_ioppr_get_iop_work_profile_info(piece->module, piece->module->dev->iop);
 
  const int wd = roi_in->width, ht = roi_in->height;
 
  // Compared to previous implementation, we've at least moved this conditional outside of the image processing loops
  // so that it is evaluated only once.  See FIXME comments in apply_curve for more potential performance improvements
  if(d->preserve_colors == DT_RGB_NORM_NONE)
    apply_legacy_curve(in, out, wd, ht, 1.0, d->table, d->unbounded_coeffs);
  else
    apply_curve(in, out, wd, ht, d->preserve_colors, 1.0, d->table, d->unbounded_coeffs, work_profile);
}
 
 
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_basecurve_data_t *const d = (dt_iop_basecurve_data_t *)(piece->data);
 
  // are we doing exposure fusion?
  if(d->exposure_fusion)
    return process_fusion(self, piece, ivoid, ovoid, roi_in, roi_out);
  else
    process_lut(self, piece, ivoid, ovoid, roi_in, roi_out);
  return 0;
}
 
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_basecurve_data_t *d = (dt_iop_basecurve_data_t *)(piece->data);
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)p1;
 
  d->exposure_fusion = p->exposure_fusion;
  d->exposure_stops = p->exposure_stops;
  d->exposure_bias = p->exposure_bias;
  d->preserve_colors = p->preserve_colors;
 
  const int ch = 0;
  // take care of possible change of curve type or number of nodes (not yet implemented in UI)
  if(d->basecurve_type != p->basecurve_type[ch] || d->basecurve_nodes != p->basecurve_nodes[ch])
  {
    if(d->curve) // catch initial init_pipe case
      dt_draw_curve_destroy(d->curve);
    d->curve = dt_draw_curve_new(0.0, 1.0, p->basecurve_type[ch]);
    d->basecurve_nodes = p->basecurve_nodes[ch];
    d->basecurve_type = p->basecurve_type[ch];
    for(int k = 0; k < p->basecurve_nodes[ch]; k++)
    {
      // printf("p->basecurve[%i][%i].x = %f;\n", ch, k, p->basecurve[ch][k].x);
      // printf("p->basecurve[%i][%i].y = %f;\n", ch, k, p->basecurve[ch][k].y);
      (void)dt_draw_curve_add_point(d->curve, p->basecurve[ch][k].x, p->basecurve[ch][k].y);
    }
  }
  else
  {
    for(int k = 0; k < p->basecurve_nodes[ch]; k++)
      dt_draw_curve_set_point(d->curve, k, p->basecurve[ch][k].x, p->basecurve[ch][k].y);
  }
  dt_draw_curve_calc_values(d->curve, 0.0f, 1.0f, 0x10000, NULL, d->table);
 
  // now the extrapolation stuff:
  const float xm = p->basecurve[0][p->basecurve_nodes[0] - 1].x;
  const float x[4] = { 0.7f * xm, 0.8f * xm, 0.9f * xm, 1.0f * xm };
  const float y[4] = { d->table[CLAMP((int)(x[0] * 0x10000ul), 0, 0xffff)],
                       d->table[CLAMP((int)(x[1] * 0x10000ul), 0, 0xffff)],
                       d->table[CLAMP((int)(x[2] * 0x10000ul), 0, 0xffff)],
                       d->table[CLAMP((int)(x[3] * 0x10000ul), 0, 0xffff)] };
  dt_iop_estimate_exp(x, y, 4, d->unbounded_coeffs);
}
 
void init_pipe(struct dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  // create part of the pixelpipe
  piece->data = dt_calloc_align(sizeof(dt_iop_basecurve_data_t));
  piece->data_size = sizeof(dt_iop_basecurve_data_t);
}
 
void cleanup_pipe(struct dt_iop_module_t *self, dt_dev_pixelpipe_t *pipe, dt_dev_pixelpipe_iop_t *piece)
{
  // clean up everything again.
  dt_iop_basecurve_data_t *d = (dt_iop_basecurve_data_t *)(piece->data);
  if(d->curve) dt_draw_curve_destroy(d->curve);
  dt_free_align(piece->data);
  piece->data = NULL;
}
 
void gui_update(struct dt_iop_module_t *self)
{
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->params;
  dt_iop_basecurve_gui_data_t *g = (dt_iop_basecurve_gui_data_t *)self->gui_data;
 
  gtk_widget_set_visible(g->exposure_step, p->exposure_fusion != 0);
  gtk_widget_set_visible(g->exposure_bias, p->exposure_fusion != 0);
 
  dt_gui_throttle_cancel(self);
  // gui curve is read directly from params during expose event.
  gtk_widget_queue_draw(self->widget);
}
 
static float eval_grey(float x)
{
  // "log base" is a combined scaling and offset change so that x->[0,1], with
  // the left side of the histogram expanded (slider->right) or not (slider left, linear)
  return x;
}
 
void init(dt_iop_module_t *module)
{
  dt_iop_default_init(module);
  dt_iop_basecurve_params_t *d = module->default_params;
  d->basecurve[0][1].x = d->basecurve[0][1].y = 1.0;
  d->basecurve_nodes[0] = 2;
}
 
static gboolean dt_iop_basecurve_enter_notify(GtkWidget *widget, GdkEventCrossing *event, gpointer user_data)
{
  gtk_widget_queue_draw(widget);
  return TRUE;
}
 
static gboolean dt_iop_basecurve_leave_notify(GtkWidget *widget, GdkEventCrossing *event, gpointer user_data)
{
  gtk_widget_queue_draw(widget);
  return TRUE;
}
 
static float to_log(const float x, const float base)
{
  if(base > 0.0f)
    return logf(x * base + 1.0f) / logf(base + 1.0f);
  else
    return x;
}
 
static float to_lin(const float x, const float base)
{
  if(base > 0.0f)
    return (powf(base - 1.0f, x) - 1.0f) / base;
  else
    return x;
}
 
static gboolean dt_iop_basecurve_draw(GtkWidget *widget, cairo_t *crf, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->params;
 
  int nodes = p->basecurve_nodes[0];
  dt_iop_basecurve_node_t *basecurve = p->basecurve[0];
  if(c->minmax_curve_type != p->basecurve_type[0] || c->minmax_curve_nodes != p->basecurve_nodes[0])
  {
    dt_draw_curve_destroy(c->minmax_curve);
    c->minmax_curve = dt_draw_curve_new(0.0, 1.0, p->basecurve_type[0]);
    c->minmax_curve_nodes = p->basecurve_nodes[0];
    c->minmax_curve_type = p->basecurve_type[0];
    for(int k = 0; k < p->basecurve_nodes[0]; k++)
      (void)dt_draw_curve_add_point(c->minmax_curve, p->basecurve[0][k].x, p->basecurve[0][k].y);
  }
  else
  {
    for(int k = 0; k < p->basecurve_nodes[0]; k++)
      dt_draw_curve_set_point(c->minmax_curve, k, p->basecurve[0][k].x, p->basecurve[0][k].y);
  }
  dt_draw_curve_t *minmax_curve = c->minmax_curve;
  dt_draw_curve_calc_values(minmax_curve, 0.0, 1.0, DT_IOP_TONECURVE_RES, c->draw_xs, c->draw_ys);
 
  float unbounded_coeffs[3];
  const float xm = basecurve[nodes - 1].x;
  {
    const float x[4] = { 0.7f * xm, 0.8f * xm, 0.9f * xm, 1.0f * xm };
    const float y[4] = { c->draw_ys[CLAMP((int)(x[0] * DT_IOP_TONECURVE_RES), 0, DT_IOP_TONECURVE_RES - 1)],
                         c->draw_ys[CLAMP((int)(x[1] * DT_IOP_TONECURVE_RES), 0, DT_IOP_TONECURVE_RES - 1)],
                         c->draw_ys[CLAMP((int)(x[2] * DT_IOP_TONECURVE_RES), 0, DT_IOP_TONECURVE_RES - 1)],
                         c->draw_ys[CLAMP((int)(x[3] * DT_IOP_TONECURVE_RES), 0, DT_IOP_TONECURVE_RES - 1)] };
    dt_iop_estimate_exp(x, y, 4, unbounded_coeffs);
  }
 
  const int inset = DT_GUI_CURVE_EDITOR_INSET;
  GtkAllocation allocation;
  gtk_widget_get_allocation(widget, &allocation);
  int width = allocation.width, height = allocation.height;
  cairo_surface_t *cst = dt_cairo_image_surface_create(CAIRO_FORMAT_ARGB32, width, height);
  cairo_t *cr = cairo_create(cst);
  // clear bg
  cairo_set_source_rgb(cr, .2, .2, .2);
  cairo_paint(cr);
 
  cairo_translate(cr, inset, inset);
  width -= 2 * inset;
  height -= 2 * inset;
 
#if 0
  // draw shadow around
  float alpha = 1.0f;
  for(int k=0; k<inset; k++)
  {
    cairo_rectangle(cr, -k, -k, width + 2*k, height + 2*k);
    cairo_set_source_rgba(cr, 0, 0, 0, alpha);
    alpha *= 0.6f;
    cairo_fill(cr);
  }
#else
  cairo_set_line_width(cr, DT_PIXEL_APPLY_DPI(1.0));
  cairo_set_source_rgb(cr, .1, .1, .1);
  cairo_rectangle(cr, 0, 0, width, height);
  cairo_stroke(cr);
#endif
 
  cairo_set_source_rgb(cr, .3, .3, .3);
  cairo_rectangle(cr, 0, 0, width, height);
  cairo_fill(cr);
 
  cairo_translate(cr, 0, height);
  if(c->selected >= 0)
  {
    char text[30];
    // draw information about current selected node
    PangoLayout *layout;
    PangoRectangle ink;
    PangoFontDescription *desc = pango_font_description_copy_static(darktable.bauhaus->pango_font_desc);
    pango_font_description_set_weight(desc, PANGO_WEIGHT_BOLD);
    pango_font_description_set_absolute_size(desc, PANGO_SCALE);
    layout = pango_cairo_create_layout(cr);
    pango_layout_set_font_description(layout, desc);
 
    const float x_node_value = basecurve[c->selected].x * 100;
    const float y_node_value = basecurve[c->selected].y * 100;
    const float d_node_value = y_node_value - x_node_value;
    // scale conservatively to 100% of width:
    snprintf(text, sizeof(text), "100.00 / 100.00 ( +100.00)");
    pango_layout_set_text(layout, text, -1);
    pango_layout_get_pixel_extents(layout, &ink, NULL);
    pango_font_description_set_absolute_size(desc, (double)width / ink.width * PANGO_SCALE);
    pango_layout_set_font_description(layout, desc);
 
    snprintf(text, sizeof(text), "%.2f / %.2f ( %+.2f)", x_node_value, y_node_value, d_node_value);
 
    cairo_set_source_rgb(cr, 0.1, 0.1, 0.1);
    pango_layout_set_text(layout, text, -1);
    pango_layout_get_pixel_extents(layout, &ink, NULL);
    cairo_move_to(cr, 0.98f * width - ink.width - ink.x, -0.02 * height - ink.height - ink.y);
    pango_cairo_show_layout(cr, layout);
    cairo_stroke(cr);
    pango_font_description_free(desc);
    g_object_unref(layout);
  }
  cairo_scale(cr, 1.0f, -1.0f);
 
  // draw grid
  cairo_set_line_width(cr, DT_PIXEL_APPLY_DPI(.4));
  cairo_set_source_rgb(cr, .1, .1, .1);
  if(c->loglogscale)
    dt_draw_loglog_grid(cr, 4, 0, 0, width, height, c->loglogscale + 1.0f);
  else
    dt_draw_grid(cr, 4, 0, 0, width, height);
 
  // draw nodes positions
  cairo_set_line_width(cr, DT_PIXEL_APPLY_DPI(1.));
  cairo_set_source_rgb(cr, 0.6, 0.6, 0.6);
  for(int k = 0; k < nodes; k++)
  {
    const float x = to_log(basecurve[k].x, c->loglogscale), y = to_log(basecurve[k].y, c->loglogscale);
    cairo_arc(cr, x * width, y * height, DT_PIXEL_APPLY_DPI(3), 0, 2. * M_PI);
    cairo_stroke(cr);
  }
 
  // draw selected cursor
  cairo_set_line_width(cr, DT_PIXEL_APPLY_DPI(1.));
 
  if(c->selected >= 0)
  {
    cairo_set_source_rgb(cr, .9, .9, .9);
    const float x = to_log(basecurve[c->selected].x, c->loglogscale),
                y = to_log(basecurve[c->selected].y, c->loglogscale);
    cairo_arc(cr, x * width, y * height, DT_PIXEL_APPLY_DPI(4), 0, 2. * M_PI);
    cairo_stroke(cr);
  }
 
  // draw curve
  cairo_set_line_width(cr, DT_PIXEL_APPLY_DPI(2.));
  cairo_set_source_rgb(cr, .9, .9, .9);
  // cairo_set_line_cap  (cr, CAIRO_LINE_CAP_SQUARE);
  cairo_move_to(cr, 0, height * to_log(c->draw_ys[0], c->loglogscale));
  for(int k = 1; k < DT_IOP_TONECURVE_RES; k++)
  {
    const float xx = k / (DT_IOP_TONECURVE_RES - 1.0f);
    if(xx > xm)
    {
      const float yy = dt_iop_eval_exp(unbounded_coeffs, xx);
      const float x = to_log(xx, c->loglogscale), y = to_log(yy, c->loglogscale);
      cairo_line_to(cr, x * width, height * y);
    }
    else
    {
      const float yy = c->draw_ys[k];
      const float x = to_log(xx, c->loglogscale), y = to_log(yy, c->loglogscale);
      cairo_line_to(cr, x * width, height * y);
    }
  }
  cairo_stroke(cr);
 
  cairo_destroy(cr);
  cairo_set_source_surface(crf, cst, 0, 0);
  cairo_paint(crf);
  cairo_surface_destroy(cst);
  return TRUE;
}
 
static inline int _add_node(dt_iop_basecurve_node_t *basecurve, int *nodes, float x, float y)
{
  int selected = -1;
  if(basecurve[0].x > x)
    selected = 0;
  else
  {
    for(int k = 1; k < *nodes; k++)
    {
      if(basecurve[k].x > x)
      {
        selected = k;
        break;
      }
    }
  }
  if(selected == -1) selected = *nodes;
  for(int i = *nodes; i > selected; i--)
  {
    basecurve[i].x = basecurve[i - 1].x;
    basecurve[i].y = basecurve[i - 1].y;
  }
  // found a new point
  basecurve[selected].x = x;
  basecurve[selected].y = y;
  (*nodes)++;
  return selected;
}
 
static void dt_iop_basecurve_sanity_check(dt_iop_module_t *self, GtkWidget *widget)
{
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->params;
 
  int ch = 0;
  int nodes = p->basecurve_nodes[ch];
  dt_iop_basecurve_node_t *basecurve = p->basecurve[ch];
 
  if(nodes <= 2) return;
 
  const float mx = basecurve[c->selected].x;
 
  // delete vertex if order has changed
  // for all points, x coordinate of point must be strictly larger than
  // the x coordinate of the previous point
  if((c->selected > 0 && (basecurve[c->selected - 1].x >= mx))
     || (c->selected < nodes - 1 && (basecurve[c->selected + 1].x <= mx)))
  {
    for(int k = c->selected; k < nodes - 1; k++)
    {
      basecurve[k].x = basecurve[k + 1].x;
      basecurve[k].y = basecurve[k + 1].y;
    }
    c->selected = -2; // avoid re-insertion of that point immediately after this
    p->basecurve_nodes[ch]--;
  }
}
 
static gboolean _move_point_internal(dt_iop_module_t *self, GtkWidget *widget, float dx, float dy, guint state);
 
static gboolean dt_iop_basecurve_motion_notify(GtkWidget *widget, GdkEventMotion *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->params;
  int ch = 0;
  int nodes = p->basecurve_nodes[ch];
  dt_iop_basecurve_node_t *basecurve = p->basecurve[ch];
 
  GtkAllocation allocation;
  gtk_widget_get_allocation(widget, &allocation);
  const int inset = DT_GUI_CURVE_EDITOR_INSET;
  int height = allocation.height - 2 * inset, width = allocation.width - 2 * inset;
  const double old_m_x = c->mouse_x;
  const double old_m_y = c->mouse_y;
  c->mouse_x = event->x - inset;
  c->mouse_y = event->y - inset;
 
  const float mx = CLAMP(c->mouse_x, 0, width) / (float)width;
  const float my = 1.0f - CLAMP(c->mouse_y, 0, height) / (float)height;
  const float linx = to_lin(mx, c->loglogscale), liny = to_lin(my, c->loglogscale);
 
  if(event->state & GDK_BUTTON1_MASK)
  {
    // got a vertex selected:
    if(c->selected >= 0)
    {
      // this is used to translate mause position in loglogscale to make this behavior unified with linear scale.
      const float translate_mouse_x = old_m_x / width - to_log(basecurve[c->selected].x, c->loglogscale);
      const float translate_mouse_y = 1 - old_m_y / height - to_log(basecurve[c->selected].y, c->loglogscale);
      // dx & dy are in linear coordinates
      const float dx = to_lin(c->mouse_x / width - translate_mouse_x, c->loglogscale)
                       - to_lin(old_m_x / width - translate_mouse_x, c->loglogscale);
      const float dy = to_lin(1 - c->mouse_y / height - translate_mouse_y, c->loglogscale)
                       - to_lin(1 - old_m_y / height - translate_mouse_y, c->loglogscale);
 
      return _move_point_internal(self, widget, dx, dy, event->state);
    }
    else if(nodes < MAXNODES && c->selected >= -1)
    {
      // no vertex was close, create a new one!
      c->selected = _add_node(basecurve, &p->basecurve_nodes[ch], linx, liny);
      dt_dev_add_history_item(darktable.develop, self, TRUE, TRUE);
    }
  }
  else
  {
    // minimum area around the node to select it:
    float min = .04f;
    min *= min; // comparing against square
    int nearest = -1;
    for(int k = 0; k < nodes; k++)
    {
      float dist
          = (my - to_log(basecurve[k].y, c->loglogscale)) * (my - to_log(basecurve[k].y, c->loglogscale))
            + (mx - to_log(basecurve[k].x, c->loglogscale)) * (mx - to_log(basecurve[k].x, c->loglogscale));
      if(dist < min)
      {
        min = dist;
        nearest = k;
      }
    }
    c->selected = nearest;
  }
  if(c->selected >= 0) gtk_widget_grab_focus(widget);
  gtk_widget_queue_draw(widget);
  return TRUE;
}
 
static gboolean dt_iop_basecurve_button_press(GtkWidget *widget, GdkEventButton *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->params;
  dt_iop_basecurve_params_t *d = (dt_iop_basecurve_params_t *)self->default_params;
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
 
  int ch = 0;
  int nodes = p->basecurve_nodes[ch];
  dt_iop_basecurve_node_t *basecurve = p->basecurve[ch];
 
  if(event->button == 1)
  {
    if(event->type == GDK_BUTTON_PRESS && dt_modifier_is(event->state, GDK_CONTROL_MASK)
      && nodes < MAXNODES && c->selected == -1)
    {
      // if we are not on a node -> add a new node at the current x of the pointer and y of the curve at that x
      const int inset = DT_GUI_CURVE_EDITOR_INSET;
      GtkAllocation allocation;
      gtk_widget_get_allocation(widget, &allocation);
      int width = allocation.width - 2 * inset;
      c->mouse_x = event->x - inset;
      c->mouse_y = event->y - inset;
 
      const float mx = CLAMP(c->mouse_x, 0, width) / (float)width;
      const float linx = to_lin(mx, c->loglogscale);
 
      // don't add a node too close to others in x direction, it can crash dt
      int selected = -1;
      if(basecurve[0].x > linx)
        selected = 0;
      else
      {
        for(int k = 1; k < nodes; k++)
        {
          if(basecurve[k].x > linx)
          {
            selected = k;
            break;
          }
        }
      }
      if(selected == -1) selected = nodes;
      // > 0 -> check distance to left neighbour
      // < nodes -> check distance to right neighbour
      if(!((selected > 0 && linx - basecurve[selected - 1].x <= 0.025) ||
           (selected < nodes && basecurve[selected].x - linx <= 0.025)))
      {
        // evaluate the curve at the current x position
        const float y = dt_draw_curve_calc_value(c->minmax_curve, linx);
 
        if(y >= 0.0 && y <= 1.0) // never add something outside the viewport, you couldn't change it afterwards
        {
          // create a new node
          selected = _add_node(basecurve, &p->basecurve_nodes[ch], linx, y);
 
          // maybe set the new one as being selected
          float min = .04f;
          min *= min; // comparing against square
          for(int k = 0; k < nodes; k++)
          {
            float other_y = to_log(basecurve[k].y, c->loglogscale);
            float dist = (y - other_y) * (y - other_y);
            if(dist < min) c->selected = selected;
          }
 
          dt_dev_add_history_item(darktable.develop, self, TRUE, TRUE);
          gtk_widget_queue_draw(self->widget);
        }
      }
      return TRUE;
    }
    else if(event->type == GDK_2BUTTON_PRESS)
    {
      // reset current curve
      p->basecurve_nodes[ch] = d->basecurve_nodes[ch];
      p->basecurve_type[ch] = d->basecurve_type[ch];
      for(int k = 0; k < d->basecurve_nodes[ch]; k++)
      {
        p->basecurve[ch][k].x = d->basecurve[ch][k].x;
        p->basecurve[ch][k].y = d->basecurve[ch][k].y;
      }
      c->selected = -2; // avoid motion notify re-inserting immediately.
      dt_dev_add_history_item(darktable.develop, self, TRUE, TRUE);
      gtk_widget_queue_draw(self->widget);
      return TRUE;
    }
  }
  else if(event->button == 3 && c->selected >= 0)
  {
    if(c->selected == 0 || c->selected == nodes - 1)
    {
      float reset_value = c->selected == 0 ? 0 : 1;
      basecurve[c->selected].y = basecurve[c->selected].x = reset_value;
      gtk_widget_queue_draw(self->widget);
      dt_dev_add_history_item(darktable.develop, self, TRUE, TRUE);
      return TRUE;
    }
 
    for(int k = c->selected; k < nodes - 1; k++)
    {
      basecurve[k].x = basecurve[k + 1].x;
      basecurve[k].y = basecurve[k + 1].y;
    }
    basecurve[nodes - 1].x = basecurve[nodes - 1].y = 0;
    c->selected = -2; // avoid re-insertion of that point immediately after this
    p->basecurve_nodes[ch]--;
    gtk_widget_queue_draw(self->widget);
    dt_dev_add_history_item(darktable.develop, self, TRUE, TRUE);
    return TRUE;
  }
  return FALSE;
}
 
static gboolean area_resized(GtkWidget *widget, GdkEvent *event, gpointer user_data)
{
  GtkAllocation allocation;
  gtk_widget_get_allocation(widget, &allocation);
  GtkRequisition r;
  r.width = allocation.width;
  r.height = allocation.width;
  gtk_widget_get_preferred_size(widget, &r, NULL);
  return TRUE;
}
 
static gboolean _move_point_internal(dt_iop_module_t *self, GtkWidget *widget, float dx, float dy, guint state)
{
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->params;
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
 
  int ch = 0;
  dt_iop_basecurve_node_t *basecurve = p->basecurve[ch];
 
  basecurve[c->selected].x = CLAMP(basecurve[c->selected].x + dx, 0.0f, 1.0f);
  basecurve[c->selected].y = CLAMP(basecurve[c->selected].y + dy, 0.0f, 1.0f);
 
  dt_iop_basecurve_sanity_check(self, widget);
 
  gtk_widget_queue_draw(widget);
  dt_gui_throttle_queue(self, dt_iop_throttled_history_update, self);
  return TRUE;
}
 
#define BASECURVE_DEFAULT_STEP (0.001f)
 
static gboolean _scrolled(GtkWidget *widget, GdkEventScroll *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
 
  if(c->selected < 0) return TRUE;
 
  gdouble delta_y;
  if(dt_gui_get_scroll_delta(event, &delta_y))
  {
    delta_y *= -BASECURVE_DEFAULT_STEP;
    return _move_point_internal(self, widget, 0.0, delta_y, event->state);
  }
 
  return TRUE;
}
 
static gboolean dt_iop_basecurve_key_press(GtkWidget *widget, GdkEventKey *event, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
 
  if(c->selected < 0) return TRUE;
  guint key = dt_keys_mainpad_alternatives(event->keyval);
 
  int handled = 0;
  float dx = 0.0f, dy = 0.0f;
  if(key == GDK_KEY_Up)
  {
    handled = 1;
    dy = BASECURVE_DEFAULT_STEP;
  }
  else if(key == GDK_KEY_Down)
  {
    handled = 1;
    dy = -BASECURVE_DEFAULT_STEP;
  }
  else if(key == GDK_KEY_Right)
  {
    handled = 1;
    dx = BASECURVE_DEFAULT_STEP;
  }
  else if(key == GDK_KEY_Left)
  {
    handled = 1;
    dx = -BASECURVE_DEFAULT_STEP;
  }
 
  if(!handled) return FALSE;
 
  return _move_point_internal(self, widget, dx, dy, event->state);
}
 
#undef BASECURVE_DEFAULT_STEP
 
void gui_changed(dt_iop_module_t *self, GtkWidget *w, void *previous)
{
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->params;
  dt_iop_basecurve_gui_data_t *g = (dt_iop_basecurve_gui_data_t *)self->gui_data;
 
  if(w == g->fusion)
  {
    int prev = *(int *)previous;
    if(p->exposure_fusion != 0 && prev == 0)
    {
      gtk_widget_set_visible(g->exposure_step, TRUE);
      gtk_widget_set_visible(g->exposure_bias, TRUE);
    }
    if(p->exposure_fusion == 0 && prev != 0)
    {
      gtk_widget_set_visible(g->exposure_step, FALSE);
      gtk_widget_set_visible(g->exposure_bias, FALSE);
    }
  }
}
 
static void logbase_callback(GtkWidget *slider, gpointer user_data)
{
  dt_iop_module_t *self = (dt_iop_module_t *)user_data;
  dt_iop_basecurve_gui_data_t *g = (dt_iop_basecurve_gui_data_t *)self->gui_data;
  g->loglogscale = eval_grey(dt_bauhaus_slider_get(g->logbase));
  gtk_widget_queue_draw(GTK_WIDGET(g->area));
}
 
void gui_init(struct dt_iop_module_t *self)
{
  dt_iop_basecurve_gui_data_t *c = IOP_GUI_ALLOC(basecurve);
  dt_iop_basecurve_params_t *p = (dt_iop_basecurve_params_t *)self->default_params;
 
  c->minmax_curve = dt_draw_curve_new(0.0, 1.0, p->basecurve_type[0]);
  c->minmax_curve_type = p->basecurve_type[0];
  c->minmax_curve_nodes = p->basecurve_nodes[0];
  for(int k = 0; k < p->basecurve_nodes[0]; k++)
    (void)dt_draw_curve_add_point(c->minmax_curve, p->basecurve[0][k].x, p->basecurve[0][k].y);
  c->mouse_x = c->mouse_y = -1.0;
  c->selected = -1;
  c->loglogscale = 0;
  self->timeout_handle = 0;
 
  self->widget = gtk_box_new(GTK_ORIENTATION_VERTICAL, DT_GUI_BOX_SPACING);
 
  c->area = GTK_DRAWING_AREA(gtk_drawing_area_new());
  gtk_widget_set_hexpand(GTK_WIDGET(c->area), TRUE);
  gtk_widget_set_tooltip_text(GTK_WIDGET(c->area), _("abscissa: input, ordinate: output. works on RGB channels"));
  g_object_set_data(G_OBJECT(c->area), "iop-instance", self);
  gtk_box_pack_start(GTK_BOX(self->widget),
                     dt_ui_resizable_drawing_area(GTK_WIDGET(c->area),
                                                  "plugins/darkroom/basecurve/graphheight", 280, 100),
                     FALSE, FALSE, 0);
 
  c->cmb_preserve_colors = dt_bauhaus_combobox_from_params(self, "preserve_colors");
  gtk_widget_set_tooltip_text(c->cmb_preserve_colors, _("method to preserve colors when applying contrast"));
 
  c->fusion = dt_bauhaus_combobox_from_params(self, "exposure_fusion");
  dt_bauhaus_combobox_add(c->fusion, _("none"));
  dt_bauhaus_combobox_add(c->fusion, _("two exposures"));
  dt_bauhaus_combobox_add(c->fusion, _("three exposures"));
  gtk_widget_set_tooltip_text(c->fusion, _("fuse this image stopped up/down a couple of times with itself, to "
                                           "compress high dynamic range. expose for the highlights before use."));
 
  c->exposure_step = dt_bauhaus_slider_from_params(self, "exposure_stops");
  dt_bauhaus_slider_set_digits(c->exposure_step, 3);
  gtk_widget_set_tooltip_text(c->exposure_step, _("how many stops to shift the individual exposures apart"));
  gtk_widget_set_no_show_all(c->exposure_step, TRUE);
  gtk_widget_set_visible(c->exposure_step, p->exposure_fusion != 0 ? TRUE : FALSE);
 
  // initially set to 1 (consistency with previous versions), but double-click resets to 0
  // to get a quick way to reach 0 with the mouse.
  c->exposure_bias = dt_bauhaus_slider_from_params(self, "exposure_bias");
  dt_bauhaus_slider_set_default(c->exposure_bias, 0.0f);
  dt_bauhaus_slider_set_digits(c->exposure_bias, 3);
  gtk_widget_set_tooltip_text(c->exposure_bias, _("whether to shift exposure up or down "
                                                  "(-1: reduce highlight, +1: reduce shadows)"));
  gtk_widget_set_no_show_all(c->exposure_bias, TRUE);
  gtk_widget_set_visible(c->exposure_bias, p->exposure_fusion != 0 ? TRUE : FALSE);
  c->logbase = dt_bauhaus_slider_new_with_range(darktable.bauhaus, DT_GUI_MODULE(self), 0.0f, 40.0f, 0, 0.0f, 2);
  dt_bauhaus_widget_set_label(c->logbase, N_("scale for graph"));
  gtk_box_pack_start(GTK_BOX(self->widget), c->logbase , TRUE, TRUE, 0);  g_signal_connect(G_OBJECT(c->logbase), "value-changed", G_CALLBACK(logbase_callback), self);
 
  gtk_widget_add_events(GTK_WIDGET(c->area), GDK_POINTER_MOTION_MASK | darktable.gui->scroll_mask
                                           | GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK
                                           | GDK_ENTER_NOTIFY_MASK | GDK_LEAVE_NOTIFY_MASK);
  gtk_widget_set_can_focus(GTK_WIDGET(c->area), TRUE);
  g_signal_connect(G_OBJECT(c->area), "draw", G_CALLBACK(dt_iop_basecurve_draw), self);
  g_signal_connect(G_OBJECT(c->area), "button-press-event", G_CALLBACK(dt_iop_basecurve_button_press), self);
  g_signal_connect(G_OBJECT(c->area), "motion-notify-event", G_CALLBACK(dt_iop_basecurve_motion_notify), self);
  g_signal_connect(G_OBJECT(c->area), "leave-notify-event", G_CALLBACK(dt_iop_basecurve_leave_notify), self);
  g_signal_connect(G_OBJECT(c->area), "enter-notify-event", G_CALLBACK(dt_iop_basecurve_enter_notify), self);
  g_signal_connect(G_OBJECT(c->area), "configure-event", G_CALLBACK(area_resized), self);
  g_signal_connect(G_OBJECT(c->area), "scroll-event", G_CALLBACK(_scrolled), self);
  g_signal_connect(G_OBJECT(c->area), "key-press-event", G_CALLBACK(dt_iop_basecurve_key_press), self);
}
 
void gui_cleanup(struct dt_iop_module_t *self)
{
  dt_iop_basecurve_gui_data_t *c = (dt_iop_basecurve_gui_data_t *)self->gui_data;
  dt_draw_curve_destroy(c->minmax_curve);
  dt_gui_throttle_cancel(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