colormanagement.cc

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/* SPDX-FileCopyrightText: 2024 Blender Authors
 *
 * SPDX-License-Identifier: GPL-2.0-or-later */

 
#include "IMB_colormanagement.hh"
#include "IMB_colormanagement_intern.hh"
 
#include <cmath>
#include <cstring>
 
#include "DNA_color_types.h"
#include "DNA_image_types.h"
#include "DNA_movieclip_types.h"
#include "DNA_scene_types.h"
#include "DNA_sequence_types.h"
#include "DNA_space_types.h"
 
#include "IMB_filetype.hh"
#include "IMB_filter.hh"
#include "IMB_imbuf.hh"
#include "IMB_imbuf_types.hh"
#include "IMB_metadata.hh"
#include "IMB_moviecache.hh"
 
#include "MEM_guardedalloc.h"
 
#include "BLI_listbase.h"
#include "BLI_math_color.h"
#include "BLI_math_color.hh"
#include "BLI_math_matrix.hh"
#include "BLI_math_matrix_types.hh"
#include "BLI_math_vector_types.hh"
#include "BLI_path_utils.hh"
#include "BLI_rect.h"
#include "BLI_string.h"
#include "BLI_task.hh"
#include "BLI_threads.h"
#include "BLI_vector_set.hh"
 
#include "BKE_appdir.hh"
#include "BKE_colortools.hh"
#include "BKE_context.hh"
#include "BKE_global.hh"
#include "BKE_image_format.hh"
#include "BKE_main.hh"
 
#include "GPU_capabilities.hh"
 
#include "RNA_define.hh"
 
#include "SEQ_iterator.hh"
 
#include "OCIO_api.hh"
 
using blender::float3;
using blender::float3x3;
using blender::StringRefNull;
 
namespace ocio = blender::ocio;
namespace math = blender::math;
 
/* -------------------------------------------------------------------- */
 
static std::unique_ptr<ocio::Config> g_config = nullptr;
static blender::VectorSet<blender::StringRefNull> g_all_view_names;
 
#define DISPLAY_BUFFER_CHANNELS 4
 
/* ** list of all supported color spaces, displays and views */
static char global_role_data[MAX_COLORSPACE_NAME];
static char global_role_scene_linear[MAX_COLORSPACE_NAME];
static char global_role_color_picking[MAX_COLORSPACE_NAME];
static char global_role_texture_painting[MAX_COLORSPACE_NAME];
static char global_role_default_byte[MAX_COLORSPACE_NAME];
static char global_role_default_float[MAX_COLORSPACE_NAME];
static char global_role_default_sequencer[MAX_COLORSPACE_NAME];
static char global_role_aces_interchange[MAX_COLORSPACE_NAME];
 
/* Luma coefficients and XYZ to RGB to be initialized by OCIO. */
 
float3 imbuf_luma_coefficients(0.0f);
float3x3 imbuf_scene_linear_to_xyz = float3x3::zero();
float3x3 imbuf_xyz_to_scene_linear = float3x3::zero();
float3x3 imbuf_scene_linear_to_rec709 = float3x3::zero();
float3x3 imbuf_rec709_to_scene_linear = float3x3::zero();
float3x3 imbuf_scene_linear_to_aces = float3x3::zero();
float3x3 imbuf_aces_to_scene_linear = float3x3::zero();
 
/* lock used by pre-cached processors getters, so processor wouldn't
 * be created several times
 * LOCK_COLORMANAGE can not be used since this mutex could be needed to
 * be locked before pre-cached processor are creating
 */
static pthread_mutex_t processor_lock = BLI_MUTEX_INITIALIZER;
 
struct ColormanageProcessor {
  std::shared_ptr<const ocio::CPUProcessor> cpu_processor;
  CurveMapping *curve_mapping;
  bool is_data_result;
};
 
static struct GlobalGPUState {
  GlobalGPUState() = default;
 
  ~GlobalGPUState()
  {
    if (curve_mapping) {
      BKE_curvemapping_free(curve_mapping);
    }
  }
 
  /* GPU shader currently bound. */
  bool gpu_shader_bound = false;
 
  /* Curve mapping. */
  CurveMapping *curve_mapping = nullptr, *orig_curve_mapping = nullptr;
  bool use_curve_mapping = false;
  int curve_mapping_timestamp = 0;
} global_gpu_state;
 
static struct GlobalColorPickingState {
  GlobalColorPickingState() = default;
 
  /* Cached processor for color picking conversion. */
  std::shared_ptr<const ocio::CPUProcessor> cpu_processor_to;
  std::shared_ptr<const ocio::CPUProcessor> cpu_processor_from;
  bool failed = false;
} global_color_picking_state;

 
/* -------------------------------------------------------------------- */

 
/* NOTE: ColormanageCacheViewSettings and ColormanageCacheDisplaySettings are
 *       quite the same as ColorManagedViewSettings and ColorManageDisplaySettings
 *       but they holds indexes of all transformations and color spaces, not
 *       their names.
 *
 *       This helps avoid extra colorspace / display / view lookup without
 *       requiring to pass all variables which affects on display buffer
 *       to color management cache system and keeps calls small and nice.
 */
struct ColormanageCacheViewSettings {
  int flag;
  int look;
  int view;
  float exposure;
  float gamma;
  float dither;
  float temperature;
  float tint;
  CurveMapping *curve_mapping;
};
 
struct ColormanageCacheDisplaySettings {
  int display;
};
 
struct ColormanageCacheKey {
  int view;    /* view transformation used for display buffer */
  int display; /* display device name */
};
 
struct ColormanageCacheData {
  int flag;                    /* view flags of cached buffer */
  int look;                    /* Additional artistic transform. */
  float exposure;              /* exposure value cached buffer is calculated with */
  float gamma;                 /* gamma value cached buffer is calculated with */
  float dither;                /* dither value cached buffer is calculated with */
  float temperature;           /* temperature value cached buffer is calculated with */
  float tint;                  /* tint value cached buffer is calculated with */
  CurveMapping *curve_mapping; /* curve mapping used for cached buffer */
  int curve_mapping_timestamp; /* time stamp of curve mapping used for cached buffer */
};
 
struct ColormanageCache {
  MovieCache *moviecache;
 
  ColormanageCacheData *data;
};
 
static MovieCache *colormanage_moviecache_get(const ImBuf *ibuf)
{
  if (!ibuf->colormanage_cache) {
    return nullptr;
  }
 
  return ibuf->colormanage_cache->moviecache;
}
 
static ColormanageCacheData *colormanage_cachedata_get(const ImBuf *ibuf)
{
  if (!ibuf->colormanage_cache) {
    return nullptr;
  }
 
  return ibuf->colormanage_cache->data;
}
 
static uint colormanage_hashhash(const void *key_v)
{
  const ColormanageCacheKey *key = static_cast<const ColormanageCacheKey *>(key_v);
 
  uint rval = (key->display << 16) | (key->view % 0xffff);
 
  return rval;
}
 
static bool colormanage_hashcmp(const void *av, const void *bv)
{
  const ColormanageCacheKey *a = static_cast<const ColormanageCacheKey *>(av);
  const ColormanageCacheKey *b = static_cast<const ColormanageCacheKey *>(bv);
 
  return ((a->view != b->view) || (a->display != b->display));
}
 
static MovieCache *colormanage_moviecache_ensure(ImBuf *ibuf)
{
  if (!ibuf->colormanage_cache) {
    ibuf->colormanage_cache = MEM_callocN<ColormanageCache>("imbuf colormanage cache");
  }
 
  if (!ibuf->colormanage_cache->moviecache) {
    MovieCache *moviecache;
 
    moviecache = IMB_moviecache_create("colormanage cache",
                                       sizeof(ColormanageCacheKey),
                                       colormanage_hashhash,
                                       colormanage_hashcmp);
 
    ibuf->colormanage_cache->moviecache = moviecache;
  }
 
  return ibuf->colormanage_cache->moviecache;
}
 
static void colormanage_cachedata_set(ImBuf *ibuf, ColormanageCacheData *data)
{
  if (!ibuf->colormanage_cache) {
    ibuf->colormanage_cache = MEM_callocN<ColormanageCache>("imbuf colormanage cache");
  }
 
  ibuf->colormanage_cache->data = data;
}
 
static void colormanage_view_settings_to_cache(ImBuf *ibuf,
                                               ColormanageCacheViewSettings *cache_view_settings,
                                               const ColorManagedViewSettings *view_settings)
{
  int look = IMB_colormanagement_look_get_named_index(view_settings->look);
  int view = IMB_colormanagement_view_get_id_by_name(view_settings->view_transform);
 
  cache_view_settings->look = look;
  cache_view_settings->view = view;
  cache_view_settings->exposure = view_settings->exposure;
  cache_view_settings->gamma = view_settings->gamma;
  cache_view_settings->dither = ibuf->dither;
  cache_view_settings->temperature = view_settings->temperature;
  cache_view_settings->tint = view_settings->tint;
  cache_view_settings->flag = view_settings->flag;
  cache_view_settings->curve_mapping = view_settings->curve_mapping;
}
 
static void colormanage_display_settings_to_cache(
    ColormanageCacheDisplaySettings *cache_display_settings,
    const ColorManagedDisplaySettings *display_settings)
{
  int display = IMB_colormanagement_display_get_named_index(display_settings->display_device);
 
  cache_display_settings->display = display;
}
 
static void colormanage_settings_to_key(ColormanageCacheKey *key,
                                        const ColormanageCacheViewSettings *view_settings,
                                        const ColormanageCacheDisplaySettings *display_settings)
{
  key->view = view_settings->view;
  key->display = display_settings->display;
}
 
static ImBuf *colormanage_cache_get_ibuf(ImBuf *ibuf,
                                         ColormanageCacheKey *key,
                                         void **cache_handle)
{
  ImBuf *cache_ibuf;
  MovieCache *moviecache = colormanage_moviecache_get(ibuf);
 
  if (!moviecache) {
    /* If there's no moviecache it means no color management was applied
     * on given image buffer before. */
    return nullptr;
  }
 
  *cache_handle = nullptr;
 
  cache_ibuf = IMB_moviecache_get(moviecache, key, nullptr);
 
  *cache_handle = cache_ibuf;
 
  return cache_ibuf;
}
 
static uchar *colormanage_cache_get(ImBuf *ibuf,
                                    const ColormanageCacheViewSettings *view_settings,
                                    const ColormanageCacheDisplaySettings *display_settings,
                                    void **cache_handle)
{
  ColormanageCacheKey key;
  ImBuf *cache_ibuf;
  int view_flag = 1 << view_settings->view;
  CurveMapping *curve_mapping = view_settings->curve_mapping;
  int curve_mapping_timestamp = curve_mapping ? curve_mapping->changed_timestamp : 0;
 
  colormanage_settings_to_key(&key, view_settings, display_settings);
 
  /* check whether image was marked as dirty for requested transform */
  if ((ibuf->display_buffer_flags[display_settings->display] & view_flag) == 0) {
    return nullptr;
  }
 
  cache_ibuf = colormanage_cache_get_ibuf(ibuf, &key, cache_handle);
 
  if (cache_ibuf) {
 
    BLI_assert(cache_ibuf->x == ibuf->x && cache_ibuf->y == ibuf->y);
 
    /* only buffers with different color space conversions are being stored
     * in cache separately. buffer which were used only different exposure/gamma
     * are re-suing the same cached buffer
     *
     * check here which exposure/gamma/curve was used for cached buffer and if they're
     * different from requested buffer should be re-generated
     */
    const ColormanageCacheData *cache_data = colormanage_cachedata_get(cache_ibuf);
 
    if (cache_data->look != view_settings->look ||
        cache_data->exposure != view_settings->exposure ||
        cache_data->gamma != view_settings->gamma || cache_data->dither != view_settings->dither ||
        cache_data->temperature != view_settings->temperature ||
        cache_data->tint != view_settings->tint || cache_data->flag != view_settings->flag ||
        cache_data->curve_mapping != curve_mapping ||
        cache_data->curve_mapping_timestamp != curve_mapping_timestamp)
    {
      *cache_handle = nullptr;
 
      IMB_freeImBuf(cache_ibuf);
 
      return nullptr;
    }
 
    return (uchar *)cache_ibuf->byte_buffer.data;
  }
 
  return nullptr;
}
 
static void colormanage_cache_put(ImBuf *ibuf,
                                  const ColormanageCacheViewSettings *view_settings,
                                  const ColormanageCacheDisplaySettings *display_settings,
                                  uchar *display_buffer,
                                  void **cache_handle)
{
  ColormanageCacheKey key;
  ImBuf *cache_ibuf;
  ColormanageCacheData *cache_data;
  int view_flag = 1 << view_settings->view;
  MovieCache *moviecache = colormanage_moviecache_ensure(ibuf);
  CurveMapping *curve_mapping = view_settings->curve_mapping;
  int curve_mapping_timestamp = curve_mapping ? curve_mapping->changed_timestamp : 0;
 
  colormanage_settings_to_key(&key, view_settings, display_settings);
 
  /* mark display buffer as valid */
  ibuf->display_buffer_flags[display_settings->display] |= view_flag;
 
  /* buffer itself */
  cache_ibuf = IMB_allocImBuf(ibuf->x, ibuf->y, ibuf->planes, 0);
  IMB_assign_byte_buffer(cache_ibuf, display_buffer, IB_TAKE_OWNERSHIP);
 
  /* Store data which is needed to check whether cached buffer
   * could be used for color managed display settings. */
  cache_data = MEM_callocN<ColormanageCacheData>("color manage cache imbuf data");
  cache_data->look = view_settings->look;
  cache_data->exposure = view_settings->exposure;
  cache_data->gamma = view_settings->gamma;
  cache_data->dither = view_settings->dither;
  cache_data->temperature = view_settings->temperature;
  cache_data->tint = view_settings->tint;
  cache_data->flag = view_settings->flag;
  cache_data->curve_mapping = curve_mapping;
  cache_data->curve_mapping_timestamp = curve_mapping_timestamp;
 
  colormanage_cachedata_set(cache_ibuf, cache_data);
 
  *cache_handle = cache_ibuf;
 
  IMB_moviecache_put(moviecache, &key, cache_ibuf);
}
 
static void colormanage_cache_handle_release(void *cache_handle)
{
  ImBuf *cache_ibuf = static_cast<ImBuf *>(cache_handle);
 
  IMB_freeImBuf(cache_ibuf);
}

 
/* -------------------------------------------------------------------- */
 
static bool colormanage_role_color_space_name_get(ocio::Config &config,
                                                  char *colorspace_name,
                                                  const char *role,
                                                  const char *backup_role,
                                                  const bool optional = false)
{
  const ColorSpace *ociocs = config.get_color_space(role);
 
  if (ociocs == nullptr && backup_role) {
    ociocs = config.get_color_space(backup_role);
  }
 
  if (ociocs == nullptr) {
    /* Overall fallback role. */
    ociocs = config.get_color_space("default");
  }
 
  if (ociocs == nullptr) {
    if (!optional && !G.quiet) {
      printf("Color management: Error, could not find role \"%s\"\n", role);
    }
    colorspace_name[0] = '\0';
    return false;
  }
 
  /* assume function was called with buffer properly allocated to MAX_COLORSPACE_NAME chars */
  BLI_strncpy(colorspace_name, ociocs->name().c_str(), MAX_COLORSPACE_NAME);
  return true;
}
 
static bool colormanage_load_config(ocio::Config &config)
{
  bool ok = true;
 
  /* get roles */
  ok &= colormanage_role_color_space_name_get(config, global_role_data, OCIO_ROLE_DATA, nullptr);
  ok &= colormanage_role_color_space_name_get(
      config, global_role_scene_linear, OCIO_ROLE_SCENE_LINEAR, nullptr);
  ok &= colormanage_role_color_space_name_get(
      config, global_role_color_picking, OCIO_ROLE_COLOR_PICKING, nullptr);
  ok &= colormanage_role_color_space_name_get(
      config, global_role_texture_painting, OCIO_ROLE_TEXTURE_PAINT, nullptr);
  ok &= colormanage_role_color_space_name_get(
      config, global_role_default_sequencer, OCIO_ROLE_DEFAULT_SEQUENCER, OCIO_ROLE_SCENE_LINEAR);
  ok &= colormanage_role_color_space_name_get(
      config, global_role_default_byte, OCIO_ROLE_DEFAULT_BYTE, OCIO_ROLE_TEXTURE_PAINT);
  ok &= colormanage_role_color_space_name_get(
      config, global_role_default_float, OCIO_ROLE_DEFAULT_FLOAT, OCIO_ROLE_SCENE_LINEAR);
 
  colormanage_role_color_space_name_get(
      config, global_role_aces_interchange, OCIO_ROLE_ACES_INTERCHANGE, nullptr, true);
 
  if (g_config->get_num_displays() == 0) {
    if (!G.quiet) {
      printf("Color management: Error, could not find any displays\n");
    }
    ok = false;
  }
  /* NOTE: The look "None" is expected to be hard-coded to exist in the OpenColorIO integration. */
  if (g_config->get_num_looks() == 0) {
    if (!G.quiet) {
      printf("Color management: Error, could not find any looks\n");
    }
    ok = false;
  }
 
  for (const int display_index : blender::IndexRange(g_config->get_num_displays())) {
    const ocio::Display *display = g_config->get_display_by_index(display_index);
    const int num_views = display->get_num_views();
    if (num_views <= 0) {
      if (!G.quiet) {
        printf("Color management: Error, could not find any views for display %s\n",
               display->name().c_str());
      }
      ok = false;
      break;
    }
 
    for (const int view_index : blender::IndexRange(num_views)) {
      const ocio::View *view = display->get_view_by_index(view_index);
      g_all_view_names.add(view->name());
    }
  }
 
  /* Load luminance coefficients. */
  imbuf_luma_coefficients = config.get_default_luma_coefs();
 
  /* Load standard color spaces. */
  imbuf_xyz_to_scene_linear = config.get_xyz_to_scene_linear_matrix();
  imbuf_scene_linear_to_xyz = math::invert(imbuf_xyz_to_scene_linear);
 
  imbuf_scene_linear_to_rec709 = ocio::XYZ_TO_REC709 * imbuf_scene_linear_to_xyz;
  imbuf_rec709_to_scene_linear = math::invert(imbuf_scene_linear_to_rec709);
 
  imbuf_aces_to_scene_linear = imbuf_xyz_to_scene_linear * ocio::ACES_TO_XYZ;
  imbuf_scene_linear_to_aces = math::invert(imbuf_aces_to_scene_linear);
 
  return ok;
}
 
static void colormanage_free_config()
{
  g_config = nullptr;
  g_all_view_names.clear();
}
 
void colormanagement_init()
{
  /* First try config from environment variable. */
  const char *ocio_env = BLI_getenv("OCIO");
 
  if (ocio_env && ocio_env[0] != '\0') {
    g_config = ocio::Config::create_from_environment();
    if (g_config != nullptr) {
      if (!G.quiet) {
        printf("Color management: Using %s as a configuration file\n", ocio_env);
      }
      const bool ok = colormanage_load_config(*g_config);
 
      if (!ok) {
        if (!G.quiet) {
          printf("Color management: Failed to load config from environment\n");
        }
        colormanage_free_config();
      }
    }
  }
 
  /* Then try bundled configuration file. */
  if (g_config == nullptr) {
    const std::optional<std::string> configdir = BKE_appdir_folder_id(BLENDER_DATAFILES,
                                                                      "colormanagement");
    if (configdir.has_value()) {
      char configfile[FILE_MAX];
      BLI_path_join(configfile, sizeof(configfile), configdir->c_str(), BCM_CONFIG_FILE);
 
      g_config = ocio::Config::create_from_file(configfile);
 
      if (g_config != nullptr) {
        const bool ok = colormanage_load_config(*g_config);
 
        if (!ok) {
          if (!G.quiet) {
            printf("Color management: Failed to load bundled config\n");
          }
          colormanage_free_config();
        }
      }
    }
  }
 
  /* Then use fallback. */
  if (g_config == nullptr) {
    if (!G.quiet) {
      printf("Color management: Using fallback mode for management\n");
    }
    g_config = ocio::Config::create_fallback();
    colormanage_load_config(*g_config);
  }
 
  BLI_init_srgb_conversion();
}
 
void colormanagement_exit()
{
  global_gpu_state = GlobalGPUState();
  global_color_picking_state = GlobalColorPickingState();
 
  colormanage_free_config();
}

 
/* -------------------------------------------------------------------- */
 
static bool has_explicit_look_for_view(const char *view_name)
{
  if (!view_name) {
    return false;
  }
 
  for (const int look_index : blender::IndexRange(g_config->get_num_looks())) {
    const ocio::Look *look = g_config->get_look_by_index(look_index);
    if (look->view() == view_name) {
      return true;
    }
  }
 
  return false;
}
 
static bool colormanage_compatible_look(const ocio::Look *look,
                                        const char *view_name,
                                        const bool has_explicit_look)
{
  if (look->is_noop) {
    return true;
  }
 
  /* Skip looks only relevant to specific view transforms.
   * If the view transform has view-specific look ignore non-specific looks. */
 
  if (view_name && look->view() == view_name) {
    return true;
  }
 
  if (has_explicit_look) {
    return false;
  }
 
  return look->view().is_empty();
}
 
static bool colormanage_compatible_look(const ocio::Look *look, const char *view_name)
{
  const bool has_explicit_look = has_explicit_look_for_view(view_name);
  return colormanage_compatible_look(look, view_name, has_explicit_look);
}
 
static bool colormanage_use_look(const char *look_name, const char *view_name)
{
  const ocio::Look *look = g_config->get_look_by_name(look_name);
  return (look->is_noop == false && colormanage_compatible_look(look, view_name));
}
 
void colormanage_cache_free(ImBuf *ibuf)
{
  MEM_SAFE_FREE(ibuf->display_buffer_flags);
 
  if (ibuf->colormanage_cache) {
    ColormanageCacheData *cache_data = colormanage_cachedata_get(ibuf);
    MovieCache *moviecache = colormanage_moviecache_get(ibuf);
 
    if (cache_data) {
      MEM_freeN(cache_data);
    }
 
    if (moviecache) {
      IMB_moviecache_free(moviecache);
    }
 
    MEM_freeN(ibuf->colormanage_cache);
 
    ibuf->colormanage_cache = nullptr;
  }
}
 
void IMB_colormanagement_display_settings_from_ctx(
    const bContext *C,
    ColorManagedViewSettings **r_view_settings,
    ColorManagedDisplaySettings **r_display_settings)
{
  Scene *scene = CTX_data_scene(C);
  SpaceImage *sima = CTX_wm_space_image(C);
 
  *r_view_settings = &scene->view_settings;
  *r_display_settings = &scene->display_settings;
 
  if (sima && sima->image) {
    if ((sima->image->flag & IMA_VIEW_AS_RENDER) == 0) {
      *r_view_settings = nullptr;
    }
  }
}
 
static const ColorSpace *get_display_colorspace(
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings)
{
  return g_config->get_display_view_color_space(display_settings->display_device,
                                                view_settings->view_transform);
}
 
static std::shared_ptr<const ocio::CPUProcessor> get_display_buffer_processor(
    const char *look,
    const char *view_transform,
    const char *display,
    const float exposure,
    const float gamma,
    const float temperature,
    const float tint,
    const bool use_white_balance,
    const char *from_colorspace)
{
  ocio::DisplayParameters display_parameters;
  display_parameters.from_colorspace = from_colorspace;
  display_parameters.view = view_transform;
  display_parameters.display = display;
  display_parameters.look = (colormanage_use_look(look, view_transform)) ? look : "";
  display_parameters.scale = (exposure == 0.0f) ? 1.0f : powf(2.0f, exposure);
  display_parameters.exponent = (gamma == 1.0f) ? 1.0f : 1.0f / max_ff(FLT_EPSILON, gamma);
  display_parameters.temperature = temperature;
  display_parameters.tint = tint;
  display_parameters.use_white_balance = use_white_balance;
  display_parameters.inverse = false;
 
  return g_config->get_display_cpu_processor(display_parameters);
}
 
void IMB_colormanagement_init_default_view_settings(
    ColorManagedViewSettings *view_settings, const ColorManagedDisplaySettings *display_settings)
{
  /* First, try use "Standard" view transform of the requested device. */
  const ocio::Display *display = g_config->get_display_by_name(display_settings->display_device);
  if (!display) {
    return;
  }
  const ocio::View *default_view = display->get_view_by_name("Standard");
  /* If that fails, we fall back to the default view transform of the display
   * as per OCIO configuration. */
  if (default_view == nullptr) {
    default_view = display->get_default_view();
  }
  if (default_view != nullptr) {
    STRNCPY(view_settings->view_transform, default_view->name().c_str());
  }
  else {
    view_settings->view_transform[0] = '\0';
  }
  /* TODO(sergey): Find a way to safely/reliable un-hardcode this. */
  STRNCPY(view_settings->look, "None");
  /* Initialize rest of the settings. */
  view_settings->flag = 0;
  view_settings->gamma = 1.0f;
  view_settings->exposure = 0.0f;
  view_settings->temperature = 6500.0f;
  view_settings->tint = 10.0f;
  view_settings->curve_mapping = nullptr;
}
 
static void curve_mapping_apply_pixel(const CurveMapping *curve_mapping,
                                      float *pixel,
                                      int channels)
{
  if (channels == 1) {
    pixel[0] = BKE_curvemap_evaluateF(curve_mapping, curve_mapping->cm, pixel[0]);
  }
  else if (channels == 2) {
    pixel[0] = BKE_curvemap_evaluateF(curve_mapping, curve_mapping->cm, pixel[0]);
    pixel[1] = BKE_curvemap_evaluateF(curve_mapping, curve_mapping->cm, pixel[1]);
  }
  else {
    BKE_curvemapping_evaluate_premulRGBF(curve_mapping, pixel, pixel);
  }
}
 
void colormanage_imbuf_set_default_spaces(ImBuf *ibuf)
{
  /* Regression tests are allocating ImBuf. Guard against access of uninitialized color
   * management configuration. */
  /* TODO(sergey): Always allocate the fallback color management configuration for such cases? */
  if (!g_config) {
    return;
  }
  ibuf->byte_buffer.colorspace = g_config->get_color_space(global_role_default_byte);
}
 
void colormanage_imbuf_make_linear(ImBuf *ibuf, const char *from_colorspace)
{
  const ColorSpace *colorspace = g_config->get_color_space(from_colorspace);
 
  if (colorspace && colorspace->is_data()) {
    ibuf->colormanage_flag |= IMB_COLORMANAGE_IS_DATA;
    return;
  }
 
  if (ibuf->float_buffer.data) {
    const char *to_colorspace = global_role_scene_linear;
    const bool predivide = IMB_alpha_affects_rgb(ibuf);
 
    if (ibuf->byte_buffer.data) {
      IMB_free_byte_pixels(ibuf);
    }
 
    IMB_colormanagement_transform_float(ibuf->float_buffer.data,
                                        ibuf->x,
                                        ibuf->y,
                                        ibuf->channels,
                                        from_colorspace,
                                        to_colorspace,
                                        predivide);
    ibuf->float_buffer.colorspace = nullptr;
  }
}

 
/* -------------------------------------------------------------------- */
 
static void colormanage_check_display_settings(ColorManagedDisplaySettings *display_settings,
                                               const char *what,
                                               const ocio::Display *default_display)
{
  if (display_settings->display_device[0] == '\0') {
    STRNCPY(display_settings->display_device, default_display->name().c_str());
  }
  else {
    const ocio::Display *display = g_config->get_display_by_name(display_settings->display_device);
 
    if (!display) {
      if (!G.quiet) {
        printf(
            "Color management: display \"%s\" used by %s not found, setting to default "
            "(\"%s\").\n",
            display_settings->display_device,
            what,
            default_display->name().c_str());
      }
 
      STRNCPY(display_settings->display_device, default_display->name().c_str());
    }
  }
}
 
static void colormanage_check_view_settings(ColorManagedDisplaySettings *display_settings,
                                            ColorManagedViewSettings *view_settings,
                                            const char *what)
{
  const ocio::Display *display = g_config->get_display_by_name(display_settings->display_device);
  if (!display) {
    return;
  }
  const char *default_look_name = IMB_colormanagement_look_get_default_name();
 
  if (view_settings->view_transform[0] == '\0') {
    const ocio::View *default_view = display->get_default_view();
    if (default_view) {
      STRNCPY(view_settings->view_transform, default_view->name().c_str());
    }
  }
  else {
    const ocio::View *view = display->get_view_by_name(view_settings->view_transform);
    if (!view) {
      const ocio::View *default_view = display->get_default_view();
      if (default_view) {
        if (!G.quiet) {
          printf("Color management: %s view \"%s\" not found, setting default \"%s\".\n",
                 what,
                 view_settings->view_transform,
                 default_view->name().c_str());
        }
        STRNCPY(view_settings->view_transform, default_view->name().c_str());
      }
    }
  }
 
  if (view_settings->look[0] == '\0') {
    STRNCPY(view_settings->look, default_look_name);
  }
  else {
    const ocio::Look *look = g_config->get_look_by_name(view_settings->look);
    if (look == nullptr) {
      if (!G.quiet) {
        printf("Color management: %s look \"%s\" not found, setting default \"%s\".\n",
               what,
               view_settings->look,
               default_look_name);
      }
 
      STRNCPY(view_settings->look, default_look_name);
    }
    else if (!colormanage_compatible_look(look, view_settings->view_transform)) {
      if (!G.quiet) {
        printf(
            "Color management: %s look \"%s\" is not compatible with view \"%s\", setting "
            "default "
            "\"%s\".\n",
            what,
            view_settings->look,
            view_settings->view_transform,
            default_look_name);
      }
 
      STRNCPY(view_settings->look, default_look_name);
    }
  }
 
  /* OCIO_TODO: move to do_versions() */
  if (view_settings->exposure == 0.0f && view_settings->gamma == 0.0f) {
    view_settings->exposure = 0.0f;
    view_settings->gamma = 1.0f;
  }
}
 
static void colormanage_check_colorspace_settings(
    ColorManagedColorspaceSettings *colorspace_settings, const char *what)
{
  if (colorspace_settings->name[0] == '\0') {
    /* pass */
  }
  else {
    const ColorSpace *colorspace = g_config->get_color_space(colorspace_settings->name);
 
    if (!colorspace) {
      if (!G.quiet) {
        printf("Color management: %s colorspace \"%s\" not found, will use default instead.\n",
               what,
               colorspace_settings->name);
      }
 
      STRNCPY(colorspace_settings->name, "");
    }
  }
 
  (void)what;
}
 
static bool strip_callback(Strip *strip, void * /*user_data*/)
{
  if (strip->data) {
    colormanage_check_colorspace_settings(&strip->data->colorspace_settings, "sequencer strip");
  }
  return true;
}
 
void IMB_colormanagement_check_file_config(Main *bmain)
{
  const ocio::Display *default_display = g_config->get_default_display();
  if (!default_display) {
    /* happens when OCIO configuration is incorrect */
    return;
  }
 
  LISTBASE_FOREACH (Scene *, scene, &bmain->scenes) {
    ColorManagedColorspaceSettings *sequencer_colorspace_settings;
 
    /* check scene color management settings */
    colormanage_check_display_settings(&scene->display_settings, "scene", default_display);
    colormanage_check_view_settings(&scene->display_settings, &scene->view_settings, "scene");
 
    sequencer_colorspace_settings = &scene->sequencer_colorspace_settings;
 
    colormanage_check_colorspace_settings(sequencer_colorspace_settings, "sequencer");
 
    if (sequencer_colorspace_settings->name[0] == '\0') {
      STRNCPY(sequencer_colorspace_settings->name, global_role_default_sequencer);
    }
 
    /* check sequencer strip input color space settings */
    if (scene->ed != nullptr) {
      blender::seq::for_each_callback(&scene->ed->seqbase, strip_callback, nullptr);
    }
  }
 
  /* ** check input color space settings ** */
 
  LISTBASE_FOREACH (Image *, image, &bmain->images) {
    colormanage_check_colorspace_settings(&image->colorspace_settings, "image");
  }
 
  LISTBASE_FOREACH (MovieClip *, clip, &bmain->movieclips) {
    colormanage_check_colorspace_settings(&clip->colorspace_settings, "clip");
  }
}
 
void IMB_colormanagement_validate_settings(const ColorManagedDisplaySettings *display_settings,
                                           ColorManagedViewSettings *view_settings)
{
  const ocio::Display *display = g_config->get_display_by_name(display_settings->display_device);
  const ocio::View *default_view = display->get_default_view();
 
  bool found = false;
  for (const int view_index : blender::IndexRange(display->get_num_views())) {
    const ocio::View *view = display->get_view_by_index(view_index);
    if (view->name() == view_settings->view_transform) {
      found = true;
      break;
    }
  }
 
  if (!found && default_view) {
    STRNCPY(view_settings->view_transform, default_view->name().c_str());
  }
}
 
const char *IMB_colormanagement_role_colorspace_name_get(int role)
{
  switch (role) {
    case COLOR_ROLE_DATA:
      return global_role_data;
    case COLOR_ROLE_SCENE_LINEAR:
      return global_role_scene_linear;
    case COLOR_ROLE_COLOR_PICKING:
      return global_role_color_picking;
    case COLOR_ROLE_TEXTURE_PAINTING:
      return global_role_texture_painting;
    case COLOR_ROLE_DEFAULT_SEQUENCER:
      return global_role_default_sequencer;
    case COLOR_ROLE_DEFAULT_FLOAT:
      return global_role_default_float;
    case COLOR_ROLE_DEFAULT_BYTE:
      return global_role_default_byte;
    case COLOR_ROLE_ACES_INTERCHANGE:
      return global_role_aces_interchange;
    default:
      if (!G.quiet) {
        printf("Unknown role was passed to %s\n", __func__);
      }
      BLI_assert(0);
      break;
  }
 
  return nullptr;
}
 
void IMB_colormanagement_check_is_data(ImBuf *ibuf, const char *name)
{
  const ColorSpace *colorspace = g_config->get_color_space(name);
 
  if (colorspace && colorspace->is_data()) {
    ibuf->colormanage_flag |= IMB_COLORMANAGE_IS_DATA;
  }
  else {
    ibuf->colormanage_flag &= ~IMB_COLORMANAGE_IS_DATA;
  }
}
 
void IMB_colormanagegent_copy_settings(ImBuf *ibuf_src, ImBuf *ibuf_dst)
{
  IMB_colormanagement_assign_byte_colorspace(ibuf_dst,
                                             IMB_colormanagement_get_rect_colorspace(ibuf_src));
  IMB_colormanagement_assign_float_colorspace(ibuf_dst,
                                              IMB_colormanagement_get_float_colorspace(ibuf_src));
  if (ibuf_src->flags & IB_alphamode_premul) {
    ibuf_dst->flags |= IB_alphamode_premul;
  }
  else if (ibuf_src->flags & IB_alphamode_channel_packed) {
    ibuf_dst->flags |= IB_alphamode_channel_packed;
  }
  else if (ibuf_src->flags & IB_alphamode_ignore) {
    ibuf_dst->flags |= IB_alphamode_ignore;
  }
}
 
void IMB_colormanagement_assign_float_colorspace(ImBuf *ibuf, const char *name)
{
  const ColorSpace *colorspace = g_config->get_color_space(name);
 
  ibuf->float_buffer.colorspace = colorspace;
 
  if (colorspace && colorspace->is_data()) {
    ibuf->colormanage_flag |= IMB_COLORMANAGE_IS_DATA;
  }
  else {
    ibuf->colormanage_flag &= ~IMB_COLORMANAGE_IS_DATA;
  }
}
 
void IMB_colormanagement_assign_byte_colorspace(ImBuf *ibuf, const char *name)
{
  const ColorSpace *colorspace = g_config->get_color_space(name);
 
  ibuf->byte_buffer.colorspace = colorspace;
 
  if (colorspace && colorspace->is_data()) {
    ibuf->colormanage_flag |= IMB_COLORMANAGE_IS_DATA;
  }
  else {
    ibuf->colormanage_flag &= ~IMB_COLORMANAGE_IS_DATA;
  }
}
 
const char *IMB_colormanagement_get_float_colorspace(ImBuf *ibuf)
{
  if (ibuf->float_buffer.colorspace) {
    return ibuf->float_buffer.colorspace->name().c_str();
  }
 
  return IMB_colormanagement_role_colorspace_name_get(COLOR_ROLE_SCENE_LINEAR);
}
 
const char *IMB_colormanagement_get_rect_colorspace(ImBuf *ibuf)
{
  if (ibuf->byte_buffer.colorspace) {
    return ibuf->byte_buffer.colorspace->name().c_str();
  }
 
  return IMB_colormanagement_role_colorspace_name_get(COLOR_ROLE_DEFAULT_BYTE);
}
 
const char *IMB_colormanagement_space_from_filepath_rules(const char *filepath)
{
  return g_config->get_color_space_from_filepath(filepath);
}
 
const ColorSpace *IMB_colormanagement_space_get_named(const char *name)
{
  return g_config->get_color_space(name);
}
 
bool IMB_colormanagement_space_is_data(const ColorSpace *colorspace)
{
  return (colorspace && colorspace->is_data());
}
 
bool IMB_colormanagement_space_is_scene_linear(const ColorSpace *colorspace)
{
  return (colorspace && colorspace->is_scene_linear());
}
 
bool IMB_colormanagement_space_is_srgb(const ColorSpace *colorspace)
{
  return (colorspace && colorspace->is_srgb());
}
 
bool IMB_colormanagement_space_name_is_data(const char *name)
{
  const ColorSpace *colorspace = g_config->get_color_space(name);
  return (colorspace && colorspace->is_data());
}
 
bool IMB_colormanagement_space_name_is_scene_linear(const char *name)
{
  const ColorSpace *colorspace = g_config->get_color_space(name);
  return (colorspace && IMB_colormanagement_space_is_scene_linear(colorspace));
}
 
bool IMB_colormanagement_space_name_is_srgb(const char *name)
{
  const ColorSpace *colorspace = g_config->get_color_space(name);
  return (colorspace && IMB_colormanagement_space_is_srgb(colorspace));
}
 
const char *IMB_colormanagement_srgb_colorspace_name_get()
{
  /* Make a best effort to find by common names. First two are from the ColorInterop forum. */
  const char *names[] = {"sRGB Encoded Rec.709 (sRGB)",
                         "srgb_rec709_scene",
                         "Utility - sRGB - Texture",
                         "sRGB - Texture",
                         "sRGB",
                         nullptr};
  for (int i = 0; names[i]; i++) {
    const ColorSpace *colorspace = g_config->get_color_space(names[i]);
    if (colorspace) {
      return colorspace->name().c_str();
    }
  }
 
  /* Fallback if nothing can be found. */
  return global_role_default_byte;
}
 
blender::float3x3 IMB_colormanagement_get_xyz_to_scene_linear()
{
  return blender::float3x3(imbuf_xyz_to_scene_linear);
}
 
blender::float3x3 IMB_colormanagement_get_scene_linear_to_xyz()
{
  return blender::float3x3(imbuf_scene_linear_to_xyz);
}

 
/* -------------------------------------------------------------------- */
 
void IMB_colormanagement_get_whitepoint(const float temperature,
                                        const float tint,
                                        float whitepoint[3])
{
  blender::float3 xyz = blender::math::whitepoint_from_temp_tint(temperature, tint);
  IMB_colormanagement_xyz_to_scene_linear(whitepoint, xyz);
}
 
bool IMB_colormanagement_set_whitepoint(const float whitepoint[3], float &temperature, float &tint)
{
  blender::float3 xyz;
  IMB_colormanagement_scene_linear_to_xyz(xyz, whitepoint);
  return blender::math::whitepoint_to_temp_tint(xyz, temperature, tint);
}

 
/* -------------------------------------------------------------------- */
 
struct DisplayBufferThread {
  ColormanageProcessor *cm_processor;
 
  const float *buffer;
  uchar *byte_buffer;
 
  float *display_buffer;
  uchar *display_buffer_byte;
 
  int width;
  int start_line;
  int tot_line;
 
  int channels;
  float dither;
  bool is_data;
  bool predivide;
 
  const char *byte_colorspace;
  const char *float_colorspace;
};
 
struct DisplayBufferInitData {
  ImBuf *ibuf;
  ColormanageProcessor *cm_processor;
  const float *buffer;
  uchar *byte_buffer;
 
  float *display_buffer;
  uchar *display_buffer_byte;
 
  int width;
 
  const char *byte_colorspace;
  const char *float_colorspace;
};
 
static void display_buffer_init_handle(DisplayBufferThread *handle,
                                       int start_line,
                                       int tot_line,
                                       DisplayBufferInitData *init_data)
{
  ImBuf *ibuf = init_data->ibuf;
 
  int channels = ibuf->channels;
  float dither = ibuf->dither;
  bool is_data = (ibuf->colormanage_flag & IMB_COLORMANAGE_IS_DATA) != 0;
 
  size_t offset = size_t(channels) * start_line * ibuf->x;
  size_t display_buffer_byte_offset = size_t(DISPLAY_BUFFER_CHANNELS) * start_line * ibuf->x;
 
  memset(handle, 0, sizeof(DisplayBufferThread));
 
  handle->cm_processor = init_data->cm_processor;
 
  if (init_data->buffer) {
    handle->buffer = init_data->buffer + offset;
  }
 
  if (init_data->byte_buffer) {
    handle->byte_buffer = init_data->byte_buffer + offset;
  }
 
  if (init_data->display_buffer) {
    handle->display_buffer = init_data->display_buffer + offset;
  }
 
  if (init_data->display_buffer_byte) {
    handle->display_buffer_byte = init_data->display_buffer_byte + display_buffer_byte_offset;
  }
 
  handle->width = ibuf->x;
 
  handle->start_line = start_line;
  handle->tot_line = tot_line;
 
  handle->channels = channels;
  handle->dither = dither;
  handle->is_data = is_data;
  handle->predivide = IMB_alpha_affects_rgb(ibuf);
 
  handle->byte_colorspace = init_data->byte_colorspace;
  handle->float_colorspace = init_data->float_colorspace;
}
 
static void display_buffer_apply_get_linear_buffer(DisplayBufferThread *handle,
                                                   int height,
                                                   float *linear_buffer,
                                                   bool *is_straight_alpha)
{
  int channels = handle->channels;
  int width = handle->width;
 
  size_t buffer_size = size_t(channels) * width * height;
 
  bool is_data = handle->is_data;
  bool is_data_display = handle->cm_processor->is_data_result;
  bool predivide = handle->predivide;
 
  if (!handle->buffer) {
    uchar *byte_buffer = handle->byte_buffer;
 
    const char *from_colorspace = handle->byte_colorspace;
    const char *to_colorspace = global_role_scene_linear;
 
    float *fp;
    uchar *cp;
    const size_t i_last = size_t(width) * height;
    size_t i;
 
    /* first convert byte buffer to float, keep in image space */
    for (i = 0, fp = linear_buffer, cp = byte_buffer; i != i_last;
         i++, fp += channels, cp += channels)
    {
      if (channels == 3) {
        rgb_uchar_to_float(fp, cp);
      }
      else if (channels == 4) {
        rgba_uchar_to_float(fp, cp);
      }
      else {
        BLI_assert_msg(0, "Buffers of 3 or 4 channels are only supported here");
      }
    }
 
    if (!is_data && !is_data_display) {
      /* convert float buffer to scene linear space */
      IMB_colormanagement_transform_float(
          linear_buffer, width, height, channels, from_colorspace, to_colorspace, false);
    }
 
    *is_straight_alpha = true;
  }
  else if (handle->float_colorspace) {
    /* currently float is non-linear only in sequencer, which is working
     * in its own color space even to handle float buffers.
     * This color space is the same for byte and float images.
     * Need to convert float buffer to linear space before applying display transform
     */
 
    const char *from_colorspace = handle->float_colorspace;
    const char *to_colorspace = global_role_scene_linear;
 
    memcpy(linear_buffer, handle->buffer, buffer_size * sizeof(float));
 
    if (!is_data && !is_data_display) {
      IMB_colormanagement_transform_float(
          linear_buffer, width, height, channels, from_colorspace, to_colorspace, predivide);
    }
 
    *is_straight_alpha = false;
  }
  else {
    /* some processors would want to modify float original buffer
     * before converting it into display byte buffer, so we need to
     * make sure original's ImBuf buffers wouldn't be modified by
     * using duplicated buffer here
     */
 
    memcpy(linear_buffer, handle->buffer, buffer_size * sizeof(float));
 
    *is_straight_alpha = false;
  }
}
 
static void do_display_buffer_apply_no_processor(DisplayBufferThread *handle)
{
  const int width = handle->width;
  const int height = handle->tot_line;
  if (handle->display_buffer_byte && handle->display_buffer_byte != handle->byte_buffer) {
    if (handle->byte_buffer) {
      IMB_buffer_byte_from_byte(handle->display_buffer_byte,
                                handle->byte_buffer,
                                IB_PROFILE_SRGB,
                                IB_PROFILE_SRGB,
                                false,
                                width,
                                height,
                                width,
                                width);
    }
    else if (handle->buffer) {
      IMB_buffer_byte_from_float(handle->display_buffer_byte,
                                 handle->buffer,
                                 handle->channels,
                                 handle->dither,
                                 IB_PROFILE_SRGB,
                                 IB_PROFILE_SRGB,
                                 handle->predivide,
                                 width,
                                 height,
                                 width,
                                 width,
                                 handle->start_line);
    }
  }
 
  if (handle->display_buffer) {
    if (handle->byte_buffer) {
      IMB_buffer_float_from_byte(handle->display_buffer,
                                 handle->byte_buffer,
                                 IB_PROFILE_SRGB,
                                 IB_PROFILE_SRGB,
                                 false,
                                 width,
                                 height,
                                 width,
                                 width);
    }
    else if (handle->buffer) {
      IMB_buffer_float_from_float(handle->display_buffer,
                                  handle->buffer,
                                  handle->channels,
                                  IB_PROFILE_SRGB,
                                  IB_PROFILE_SRGB,
                                  handle->predivide,
                                  width,
                                  height,
                                  width,
                                  width);
    }
  }
}
 
static void do_display_buffer_apply_thread(DisplayBufferThread *handle)
{
  ColormanageProcessor *cm_processor = handle->cm_processor;
  if (cm_processor == nullptr) {
    do_display_buffer_apply_no_processor(handle);
    return;
  }
 
  float *display_buffer = handle->display_buffer;
  uchar *display_buffer_byte = handle->display_buffer_byte;
  int channels = handle->channels;
  int width = handle->width;
  int height = handle->tot_line;
  float *linear_buffer = MEM_malloc_arrayN<float>(
      size_t(channels) * size_t(width) * size_t(height), "color conversion linear buffer");
 
  bool is_straight_alpha;
  display_buffer_apply_get_linear_buffer(handle, height, linear_buffer, &is_straight_alpha);
 
  bool predivide = handle->predivide && (is_straight_alpha == false);
 
  /* Apply processor (note: data buffers never get color space conversions). */
  if (!handle->is_data) {
    IMB_colormanagement_processor_apply(
        cm_processor, linear_buffer, width, height, channels, predivide);
  }
 
  /* copy result to output buffers */
  if (display_buffer_byte) {
    /* do conversion */
    IMB_buffer_byte_from_float(display_buffer_byte,
                               linear_buffer,
                               channels,
                               handle->dither,
                               IB_PROFILE_SRGB,
                               IB_PROFILE_SRGB,
                               predivide,
                               width,
                               height,
                               width,
                               width,
                               handle->start_line);
  }
 
  if (display_buffer) {
    memcpy(display_buffer, linear_buffer, size_t(width) * height * channels * sizeof(float));
 
    if (is_straight_alpha && channels == 4) {
      const size_t i_last = size_t(width) * height;
      size_t i;
      float *fp;
 
      for (i = 0, fp = display_buffer; i != i_last; i++, fp += channels) {
        straight_to_premul_v4(fp);
      }
    }
  }
 
  MEM_freeN(linear_buffer);
}
 
static void display_buffer_apply_threaded(ImBuf *ibuf,
                                          const float *buffer,
                                          uchar *byte_buffer,
                                          float *display_buffer,
                                          uchar *display_buffer_byte,
                                          ColormanageProcessor *cm_processor)
{
  using namespace blender;
  DisplayBufferInitData init_data;
 
  init_data.ibuf = ibuf;
  init_data.cm_processor = cm_processor;
  init_data.buffer = buffer;
  init_data.byte_buffer = byte_buffer;
  init_data.display_buffer = display_buffer;
  init_data.display_buffer_byte = display_buffer_byte;
 
  if (ibuf->byte_buffer.colorspace != nullptr) {
    init_data.byte_colorspace = ibuf->byte_buffer.colorspace->name().c_str();
  }
  else {
    /* happens for viewer images, which are not so simple to determine where to
     * set image buffer's color spaces
     */
    init_data.byte_colorspace = global_role_default_byte;
  }
 
  if (ibuf->float_buffer.colorspace != nullptr) {
    /* sequencer stores float buffers in non-linear space */
    init_data.float_colorspace = ibuf->float_buffer.colorspace->name().c_str();
  }
  else {
    init_data.float_colorspace = nullptr;
  }
 
  threading::parallel_for(IndexRange(ibuf->y), 64, [&](const IndexRange y_range) {
    DisplayBufferThread handle;
    display_buffer_init_handle(&handle, y_range.first(), y_range.size(), &init_data);
    do_display_buffer_apply_thread(&handle);
  });
}
 
/* Checks if given colorspace can be used for display as-is:
 * - View settings do not have extra curves, exposure, gamma or look applied, and
 * - Display colorspace is the same as given colorspace. */
static bool is_colorspace_same_as_display(const ColorSpace *colorspace,
                                          const ColorManagedViewSettings *view_settings,
                                          const ColorManagedDisplaySettings *display_settings)
{
  if ((view_settings->flag & COLORMANAGE_VIEW_USE_CURVES) != 0 ||
      (view_settings->flag & COLORMANAGE_VIEW_USE_WHITE_BALANCE) != 0 ||
      view_settings->exposure != 0.0f || view_settings->gamma != 1.0f)
  {
    return false;
  }
 
  const ocio::Look *look = g_config->get_look_by_name(view_settings->look);
  if (look != nullptr && !look->process_space().is_empty()) {
    return false;
  }
 
  const ColorSpace *display_colorspace = get_display_colorspace(view_settings, display_settings);
  if (display_colorspace == colorspace) {
    return true;
  }
 
  return false;
}
 
static void colormanage_display_buffer_process_ex(
    ImBuf *ibuf,
    float *display_buffer,
    uchar *display_buffer_byte,
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings)
{
  ColormanageProcessor *cm_processor = nullptr;
  /* Check if we can skip colorspace transforms. */
  bool skip_transform = false;
  if (ibuf->float_buffer.data == nullptr && ibuf->byte_buffer.colorspace) {
    skip_transform = is_colorspace_same_as_display(
        ibuf->byte_buffer.colorspace, view_settings, display_settings);
  }
  if (ibuf->byte_buffer.data == nullptr && ibuf->float_buffer.colorspace) {
    skip_transform = is_colorspace_same_as_display(
        ibuf->float_buffer.colorspace, view_settings, display_settings);
  }
 
  if (skip_transform == false) {
    cm_processor = IMB_colormanagement_display_processor_new(view_settings, display_settings);
  }
 
  display_buffer_apply_threaded(ibuf,
                                ibuf->float_buffer.data,
                                ibuf->byte_buffer.data,
                                display_buffer,
                                display_buffer_byte,
                                cm_processor);
 
  if (cm_processor) {
    IMB_colormanagement_processor_free(cm_processor);
  }
}
 
static void colormanage_display_buffer_process(ImBuf *ibuf,
                                               uchar *display_buffer,
                                               const ColorManagedViewSettings *view_settings,
                                               const ColorManagedDisplaySettings *display_settings)
{
  colormanage_display_buffer_process_ex(
      ibuf, nullptr, display_buffer, view_settings, display_settings);
}

 
/* -------------------------------------------------------------------- */
 
struct ProcessorTransformThread {
  ColormanageProcessor *cm_processor;
  uchar *byte_buffer;
  float *float_buffer;
  int width;
  int start_line;
  int tot_line;
  int channels;
  bool predivide;
  bool float_from_byte;
};
 
struct ProcessorTransformInitData {
  ColormanageProcessor *cm_processor;
  uchar *byte_buffer;
  float *float_buffer;
  int width;
  int height;
  int channels;
  bool predivide;
  bool float_from_byte;
};
 
static void processor_transform_init_handle(ProcessorTransformThread *handle,
                                            int start_line,
                                            int tot_line,
                                            ProcessorTransformInitData *init_data)
{
  const int channels = init_data->channels;
  const int width = init_data->width;
  const bool predivide = init_data->predivide;
  const bool float_from_byte = init_data->float_from_byte;
 
  const size_t offset = size_t(channels) * start_line * width;
 
  memset(handle, 0, sizeof(ProcessorTransformThread));
 
  handle->cm_processor = init_data->cm_processor;
 
  if (init_data->byte_buffer != nullptr) {
    /* TODO(serge): Offset might be different for byte and float buffers. */
    handle->byte_buffer = init_data->byte_buffer + offset;
  }
  if (init_data->float_buffer != nullptr) {
    handle->float_buffer = init_data->float_buffer + offset;
  }
 
  handle->width = width;
 
  handle->start_line = start_line;
  handle->tot_line = tot_line;
 
  handle->channels = channels;
  handle->predivide = predivide;
  handle->float_from_byte = float_from_byte;
}
 
static void do_processor_transform_thread(ProcessorTransformThread *handle)
{
  uchar *byte_buffer = handle->byte_buffer;
  float *float_buffer = handle->float_buffer;
  const int channels = handle->channels;
  const int width = handle->width;
  const int height = handle->tot_line;
  const bool predivide = handle->predivide;
  const bool float_from_byte = handle->float_from_byte;
 
  if (float_from_byte) {
    IMB_buffer_float_from_byte(float_buffer,
                               byte_buffer,
                               IB_PROFILE_SRGB,
                               IB_PROFILE_SRGB,
                               false,
                               width,
                               height,
                               width,
                               width);
    IMB_colormanagement_processor_apply(
        handle->cm_processor, float_buffer, width, height, channels, predivide);
    IMB_premultiply_rect_float(float_buffer, 4, width, height);
  }
  else {
    if (byte_buffer != nullptr) {
      IMB_colormanagement_processor_apply_byte(
          handle->cm_processor, byte_buffer, width, height, channels);
    }
    if (float_buffer != nullptr) {
      IMB_colormanagement_processor_apply(
          handle->cm_processor, float_buffer, width, height, channels, predivide);
    }
  }
}
 
static void processor_transform_apply_threaded(uchar *byte_buffer,
                                               float *float_buffer,
                                               const int width,
                                               const int height,
                                               const int channels,
                                               ColormanageProcessor *cm_processor,
                                               const bool predivide,
                                               const bool float_from_byte)
{
  using namespace blender;
  ProcessorTransformInitData init_data;
 
  init_data.cm_processor = cm_processor;
  init_data.byte_buffer = byte_buffer;
  init_data.float_buffer = float_buffer;
  init_data.width = width;
  init_data.height = height;
  init_data.channels = channels;
  init_data.predivide = predivide;
  init_data.float_from_byte = float_from_byte;
 
  threading::parallel_for(IndexRange(height), 64, [&](const IndexRange y_range) {
    ProcessorTransformThread handle;
    processor_transform_init_handle(&handle, y_range.first(), y_range.size(), &init_data);
    do_processor_transform_thread(&handle);
  });
}

 
/* -------------------------------------------------------------------- */
 
/* Convert the whole buffer from specified by name color space to another -
 * internal implementation. */
static void colormanagement_transform_ex(uchar *byte_buffer,
                                         float *float_buffer,
                                         int width,
                                         int height,
                                         int channels,
                                         const char *from_colorspace,
                                         const char *to_colorspace,
                                         bool predivide)
{
  if (from_colorspace[0] == '\0') {
    return;
  }
 
  if (STREQ(from_colorspace, to_colorspace)) {
    /* if source and destination color spaces are identical, do nothing. */
    return;
  }
 
  ColormanageProcessor *cm_processor = IMB_colormanagement_colorspace_processor_new(
      from_colorspace, to_colorspace);
  if (IMB_colormanagement_processor_is_noop(cm_processor)) {
    IMB_colormanagement_processor_free(cm_processor);
    return;
  }
 
  processor_transform_apply_threaded(
      byte_buffer, float_buffer, width, height, channels, cm_processor, predivide, false);
  IMB_colormanagement_processor_free(cm_processor);
}
 
void IMB_colormanagement_transform_float(float *buffer,
                                         int width,
                                         int height,
                                         int channels,
                                         const char *from_colorspace,
                                         const char *to_colorspace,
                                         bool predivide)
{
  colormanagement_transform_ex(
      nullptr, buffer, width, height, channels, from_colorspace, to_colorspace, predivide);
}
 
void IMB_colormanagement_transform_byte(uchar *buffer,
                                        int width,
                                        int height,
                                        int channels,
                                        const char *from_colorspace,
                                        const char *to_colorspace)
{
  colormanagement_transform_ex(
      buffer, nullptr, width, height, channels, from_colorspace, to_colorspace, false);
}
 
void IMB_colormanagement_transform_byte_to_float(float *float_buffer,
                                                 uchar *byte_buffer,
                                                 int width,
                                                 int height,
                                                 int channels,
                                                 const char *from_colorspace,
                                                 const char *to_colorspace)
{
  using namespace blender;
  ColormanageProcessor *cm_processor;
  if (from_colorspace == nullptr || from_colorspace[0] == '\0') {
    return;
  }
  if (STREQ(from_colorspace, to_colorspace) && channels == 4) {
    /* Color spaces are the same, just do a simple byte->float conversion. */
    int64_t pixel_count = int64_t(width) * height;
    threading::parallel_for(IndexRange(pixel_count), 256 * 1024, [&](IndexRange pix_range) {
      float *dst_ptr = float_buffer + pix_range.first() * channels;
      uchar *src_ptr = byte_buffer + pix_range.first() * channels;
      for ([[maybe_unused]] const int i : pix_range) {
        /* Equivalent of rgba_uchar_to_float + premultiply. */
        float cr = float(src_ptr[0]) * (1.0f / 255.0f);
        float cg = float(src_ptr[1]) * (1.0f / 255.0f);
        float cb = float(src_ptr[2]) * (1.0f / 255.0f);
        float ca = float(src_ptr[3]) * (1.0f / 255.0f);
        dst_ptr[0] = cr * ca;
        dst_ptr[1] = cg * ca;
        dst_ptr[2] = cb * ca;
        dst_ptr[3] = ca;
        src_ptr += 4;
        dst_ptr += 4;
      }
    });
    return;
  }
  cm_processor = IMB_colormanagement_colorspace_processor_new(from_colorspace, to_colorspace);
  processor_transform_apply_threaded(
      byte_buffer, float_buffer, width, height, channels, cm_processor, false, true);
  IMB_colormanagement_processor_free(cm_processor);
}
 
void IMB_colormanagement_transform_v4(float pixel[4],
                                      const char *from_colorspace,
                                      const char *to_colorspace)
{
  ColormanageProcessor *cm_processor;
 
  if (from_colorspace[0] == '\0') {
    return;
  }
 
  if (STREQ(from_colorspace, to_colorspace)) {
    /* if source and destination color spaces are identical, skip
     * threading overhead and simply do nothing
     */
    return;
  }
 
  cm_processor = IMB_colormanagement_colorspace_processor_new(from_colorspace, to_colorspace);
 
  IMB_colormanagement_processor_apply_v4(cm_processor, pixel);
 
  IMB_colormanagement_processor_free(cm_processor);
}
 
void IMB_colormanagement_colorspace_to_scene_linear_v3(float pixel[3],
                                                       const ColorSpace *colorspace)
{
  if (colorspace == nullptr) { /* should never happen */
    printf("%s: perform conversion from unknown color space\n", __func__);
    return;
  }
  const ocio::CPUProcessor *processor = colorspace->get_to_scene_linear_cpu_processor();
  if (processor == nullptr) {
    return;
  }
  processor->apply_rgb(pixel);
}
 
void IMB_colormanagement_scene_linear_to_colorspace_v3(float pixel[3],
                                                       const ColorSpace *colorspace)
{
  if (colorspace == nullptr) { /* should never happen */
    printf("%s: perform conversion from unknown color space\n", __func__);
    return;
  }
  const ocio::CPUProcessor *processor = colorspace->get_from_scene_linear_cpu_processor();
  if (processor == nullptr) {
    return;
  }
  processor->apply_rgb(pixel);
}
 
void IMB_colormanagement_colorspace_to_scene_linear_v4(float pixel[4],
                                                       const bool predivide,
                                                       const ColorSpace *colorspace)
{
  if (colorspace == nullptr) { /* should never happen */
    printf("%s: perform conversion from unknown color space\n", __func__);
    return;
  }
  const ocio::CPUProcessor *processor = colorspace->get_to_scene_linear_cpu_processor();
  if (processor == nullptr) {
    return;
  }
  if (predivide) {
    processor->apply_rgba_predivide(pixel);
  }
  else {
    processor->apply_rgba(pixel);
  }
}
 
void IMB_colormanagement_colorspace_to_scene_linear(float *buffer,
                                                    const int width,
                                                    const int height,
                                                    const int channels,
                                                    const ColorSpace *colorspace,
                                                    const bool predivide)
{
  if (colorspace == nullptr) { /* should never happen */
    printf("%s: perform conversion from unknown color space\n", __func__);
    return;
  }
  const ocio::CPUProcessor *processor = colorspace->get_to_scene_linear_cpu_processor();
  if (processor == nullptr) {
    return;
  }
  ocio::PackedImage img(buffer,
                        width,
                        height,
                        channels,
                        ocio::BitDepth::BIT_DEPTH_F32,
                        sizeof(float),
                        size_t(channels) * sizeof(float),
                        size_t(channels) * sizeof(float) * width);
 
  if (predivide) {
    processor->apply_predivide(img);
  }
  else {
    processor->apply(img);
  }
}
 
void IMB_colormanagement_scene_linear_to_colorspace(float *buffer,
                                                    const int width,
                                                    const int height,
                                                    const int channels,
                                                    const ColorSpace *colorspace)
{
  if (colorspace == nullptr) { /* should never happen */
    printf("%s: perform conversion from unknown color space\n", __func__);
    return;
  }
  const ocio::CPUProcessor *processor = colorspace->get_from_scene_linear_cpu_processor();
  if (processor == nullptr) {
    return;
  }
  const ocio::PackedImage img(buffer,
                              width,
                              height,
                              channels,
                              ocio::BitDepth::BIT_DEPTH_F32,
                              sizeof(float),
                              size_t(channels) * sizeof(float),
                              size_t(channels) * sizeof(float) * width);
  processor->apply(img);
}
 
void IMB_colormanagement_imbuf_to_byte_texture(uchar *out_buffer,
                                               const int offset_x,
                                               const int offset_y,
                                               const int width,
                                               const int height,
                                               const ImBuf *ibuf,
                                               const bool store_premultiplied)
{
  /* Byte buffer storage, only for sRGB, scene linear and data texture since other
   * color space conversions can't be done on the GPU. */
  BLI_assert(ibuf->byte_buffer.data);
  BLI_assert(ibuf->float_buffer.data == nullptr);
  BLI_assert(IMB_colormanagement_space_is_srgb(ibuf->byte_buffer.colorspace) ||
             IMB_colormanagement_space_is_scene_linear(ibuf->byte_buffer.colorspace) ||
             IMB_colormanagement_space_is_data(ibuf->byte_buffer.colorspace));
 
  const uchar *in_buffer = ibuf->byte_buffer.data;
  const bool use_premultiply = IMB_alpha_affects_rgb(ibuf) && store_premultiplied;
 
  for (int y = 0; y < height; y++) {
    const size_t in_offset = (offset_y + y) * ibuf->x + offset_x;
    const size_t out_offset = y * width;
    const uchar *in = in_buffer + in_offset * 4;
    uchar *out = out_buffer + out_offset * 4;
 
    if (use_premultiply) {
      /* Premultiply only. */
      for (int x = 0; x < width; x++, in += 4, out += 4) {
        out[0] = (in[0] * in[3]) >> 8;
        out[1] = (in[1] * in[3]) >> 8;
        out[2] = (in[2] * in[3]) >> 8;
        out[3] = in[3];
      }
    }
    else {
      /* Copy only. */
      for (int x = 0; x < width; x++, in += 4, out += 4) {
        out[0] = in[0];
        out[1] = in[1];
        out[2] = in[2];
        out[3] = in[3];
      }
    }
  }
}
 
void IMB_colormanagement_imbuf_to_float_texture(float *out_buffer,
                                                const int offset_x,
                                                const int offset_y,
                                                const int width,
                                                const int height,
                                                const ImBuf *ibuf,
                                                const bool store_premultiplied)
{
  using namespace blender;
 
  /* Float texture are stored in scene linear color space, with premultiplied
   * alpha depending on the image alpha mode. */
  if (ibuf->float_buffer.data) {
    /* Float source buffer. */
    const float *in_buffer = ibuf->float_buffer.data;
    const int in_channels = ibuf->channels;
    const bool use_unpremultiply = IMB_alpha_affects_rgb(ibuf) && !store_premultiplied;
 
    for (int y = 0; y < height; y++) {
      const size_t in_offset = (offset_y + y) * ibuf->x + offset_x;
      const size_t out_offset = y * width;
      const float *in = in_buffer + in_offset * in_channels;
      float *out = out_buffer + out_offset * 4;
 
      if (in_channels == 1) {
        /* Copy single channel. */
        for (int x = 0; x < width; x++, in += 1, out += 4) {
          out[0] = in[0];
          out[1] = in[0];
          out[2] = in[0];
          out[3] = in[0];
        }
      }
      else if (in_channels == 3) {
        /* Copy RGB. */
        for (int x = 0; x < width; x++, in += 3, out += 4) {
          out[0] = in[0];
          out[1] = in[1];
          out[2] = in[2];
          out[3] = 1.0f;
        }
      }
      else if (in_channels == 4) {
        /* Copy or convert RGBA. */
        if (use_unpremultiply) {
          for (int x = 0; x < width; x++, in += 4, out += 4) {
            premul_to_straight_v4_v4(out, in);
          }
        }
        else {
          memcpy(out, in, sizeof(float[4]) * width);
        }
      }
    }
  }
  else {
    /* Byte source buffer. */
    const uchar *in_buffer = ibuf->byte_buffer.data;
    const bool use_premultiply = IMB_alpha_affects_rgb(ibuf) && store_premultiplied;
 
    const ocio::CPUProcessor *processor =
        (ibuf->byte_buffer.colorspace) ?
            ibuf->byte_buffer.colorspace->get_to_scene_linear_cpu_processor() :
            nullptr;
 
    threading::parallel_for(IndexRange(height), 128, [&](const IndexRange y_range) {
      for (const int y : y_range) {
        const size_t in_offset = (offset_y + y) * ibuf->x + offset_x;
        const size_t out_offset = y * width;
        const uchar *in = in_buffer + in_offset * 4;
        float *out = out_buffer + out_offset * 4;
        for (int x = 0; x < width; x++, in += 4, out += 4) {
          /* Convert to scene linear and premultiply. */
          float pixel[4];
          rgba_uchar_to_float(pixel, in);
          if (processor) {
            processor->apply_rgb(pixel);
          }
          else {
            srgb_to_linearrgb_v3_v3(pixel, pixel);
          }
          if (use_premultiply) {
            mul_v3_fl(pixel, pixel[3]);
          }
          copy_v4_v4(out, pixel);
        }
      }
    });
  }
}
 
void IMB_colormanagement_scene_linear_to_color_picking_v3(float color_picking[3],
                                                          const float scene_linear[3])
{
  if (!global_color_picking_state.cpu_processor_to && !global_color_picking_state.failed) {
    /* Create processor if none exists. */
    BLI_mutex_lock(&processor_lock);
 
    if (!global_color_picking_state.cpu_processor_to && !global_color_picking_state.failed) {
      std::shared_ptr<const ocio::CPUProcessor> cpu_processor = g_config->get_cpu_processor(
          global_role_scene_linear, global_role_color_picking);
 
      if (cpu_processor) {
        global_color_picking_state.cpu_processor_to = cpu_processor;
      }
      else {
        global_color_picking_state.failed = true;
      }
    }
 
    BLI_mutex_unlock(&processor_lock);
  }
 
  copy_v3_v3(color_picking, scene_linear);
 
  if (global_color_picking_state.cpu_processor_to) {
    global_color_picking_state.cpu_processor_to->apply_rgb(color_picking);
  }
}
 
void IMB_colormanagement_color_picking_to_scene_linear_v3(float scene_linear[3],
                                                          const float color_picking[3])
{
  if (!global_color_picking_state.cpu_processor_from && !global_color_picking_state.failed) {
    /* Create processor if none exists. */
    BLI_mutex_lock(&processor_lock);
 
    if (!global_color_picking_state.cpu_processor_from && !global_color_picking_state.failed) {
      std::shared_ptr<const ocio::CPUProcessor> cpu_processor = g_config->get_cpu_processor(
          global_role_color_picking, global_role_scene_linear);
 
      if (cpu_processor) {
        global_color_picking_state.cpu_processor_from = cpu_processor;
      }
      else {
        global_color_picking_state.failed = true;
      }
    }
 
    BLI_mutex_unlock(&processor_lock);
  }
 
  copy_v3_v3(scene_linear, color_picking);
 
  if (global_color_picking_state.cpu_processor_from) {
    global_color_picking_state.cpu_processor_from->apply_rgb(scene_linear);
  }
}
 
void IMB_colormanagement_scene_linear_to_display_v3(float pixel[3],
                                                    const ColorManagedDisplay *display)
{
  const ocio::CPUProcessor *processor = display->get_from_scene_linear_cpu_processor();
  if (processor != nullptr) {
    processor->apply_rgb(pixel);
  }
}
 
void IMB_colormanagement_display_to_scene_linear_v3(float pixel[3],
                                                    const ColorManagedDisplay *display)
{
  const ocio::CPUProcessor *processor = display->get_to_scene_linear_cpu_processor();
  if (processor != nullptr) {
    processor->apply_rgb(pixel);
  }
}
 
void IMB_colormanagement_pixel_to_display_space_v4(
    float result[4],
    const float pixel[4],
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings)
{
  ColormanageProcessor *cm_processor;
 
  copy_v4_v4(result, pixel);
 
  cm_processor = IMB_colormanagement_display_processor_new(view_settings, display_settings);
  IMB_colormanagement_processor_apply_v4(cm_processor, result);
  IMB_colormanagement_processor_free(cm_processor);
}
 
void IMB_colormanagement_pixel_to_display_space_v3(
    float result[3],
    const float pixel[3],
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings)
{
  ColormanageProcessor *cm_processor;
 
  copy_v3_v3(result, pixel);
 
  cm_processor = IMB_colormanagement_display_processor_new(view_settings, display_settings);
  IMB_colormanagement_processor_apply_v3(cm_processor, result);
  IMB_colormanagement_processor_free(cm_processor);
}
 
static void colormanagement_imbuf_make_display_space(
    ImBuf *ibuf,
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings,
    bool make_byte)
{
  if (!ibuf->byte_buffer.data && make_byte) {
    IMB_alloc_byte_pixels(ibuf);
  }
 
  colormanage_display_buffer_process_ex(
      ibuf, ibuf->float_buffer.data, ibuf->byte_buffer.data, view_settings, display_settings);
}
 
void IMB_colormanagement_imbuf_make_display_space(
    ImBuf *ibuf,
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings)
{
  colormanagement_imbuf_make_display_space(ibuf, view_settings, display_settings, false);
}
 
static ImBuf *imbuf_ensure_editable(ImBuf *ibuf, ImBuf *colormanaged_ibuf, bool allocate_result)
{
  if (colormanaged_ibuf != ibuf) {
    /* Is already an editable copy. */
    return colormanaged_ibuf;
  }
 
  if (allocate_result) {
    /* Copy full image buffer. */
    colormanaged_ibuf = IMB_dupImBuf(ibuf);
    IMB_metadata_copy(colormanaged_ibuf, ibuf);
    return colormanaged_ibuf;
  }
 
  /* Render pipeline is constructing image buffer itself,
   * but it's re-using byte and float buffers from render result make copy of this buffers
   * here sine this buffers would be transformed to other color space here. */
  IMB_make_writable_byte_buffer(ibuf);
  IMB_make_writable_float_buffer(ibuf);
 
  return ibuf;
}
 
ImBuf *IMB_colormanagement_imbuf_for_write(ImBuf *ibuf,
                                           bool save_as_render,
                                           bool allocate_result,
                                           const ImageFormatData *image_format)
{
  ImBuf *colormanaged_ibuf = ibuf;
 
  /* Update byte buffer if exists but invalid. */
  if (ibuf->float_buffer.data && ibuf->byte_buffer.data &&
      (ibuf->userflags & (IB_DISPLAY_BUFFER_INVALID | IB_RECT_INVALID)) != 0)
  {
    IMB_byte_from_float(ibuf);
    ibuf->userflags &= ~(IB_RECT_INVALID | IB_DISPLAY_BUFFER_INVALID);
  }
 
  /* Detect if we are writing to a file format that needs a linear float buffer. */
  const bool linear_float_output = BKE_imtype_requires_linear_float(image_format->imtype);
 
  /* Detect if we are writing output a byte buffer, which we would need to create
   * with color management conversions applied. This may be for either applying the
   * display transform for renders, or a user specified color space for the file. */
  const bool byte_output = BKE_image_format_is_byte(image_format);
 
  /* If we're saving from RGBA to RGB buffer then it's not so much useful to just ignore alpha --
   * it leads to bad artifacts especially when saving byte images.
   *
   * What we do here is we're overlaying our image on top of background color (which is currently
   * black). This is quite much the same as what Gimp does and it seems to be what artists
   * expects from saving.
   *
   * Do a conversion here, so image format writers could happily assume all the alpha tricks were
   * made already. helps keep things locally here, not spreading it to all possible image writers
   * we've got.
   */
  if (image_format->planes != R_IMF_PLANES_RGBA) {
    float color[3] = {0, 0, 0};
 
    colormanaged_ibuf = imbuf_ensure_editable(ibuf, colormanaged_ibuf, allocate_result);
 
    if (colormanaged_ibuf->float_buffer.data && colormanaged_ibuf->channels == 4) {
      IMB_alpha_under_color_float(
          colormanaged_ibuf->float_buffer.data, colormanaged_ibuf->x, colormanaged_ibuf->y, color);
    }
 
    if (colormanaged_ibuf->byte_buffer.data) {
      IMB_alpha_under_color_byte(
          colormanaged_ibuf->byte_buffer.data, colormanaged_ibuf->x, colormanaged_ibuf->y, color);
    }
  }
 
  if (save_as_render && !linear_float_output) {
    /* Render output: perform conversion to display space using view transform. */
    colormanaged_ibuf = imbuf_ensure_editable(ibuf, colormanaged_ibuf, allocate_result);
 
    colormanagement_imbuf_make_display_space(colormanaged_ibuf,
                                             &image_format->view_settings,
                                             &image_format->display_settings,
                                             byte_output);
 
    if (colormanaged_ibuf->float_buffer.data) {
      /* Float buffer isn't linear anymore,
       * image format write callback should check for this flag and assume
       * no space conversion should happen if ibuf->float_buffer.colorspace != nullptr. */
      colormanaged_ibuf->float_buffer.colorspace = get_display_colorspace(
          &image_format->view_settings, &image_format->display_settings);
      if (byte_output) {
        colormanaged_ibuf->byte_buffer.colorspace = colormanaged_ibuf->float_buffer.colorspace;
      }
    }
  }
  else {
    /* Linear render or regular file output: conversion between two color spaces. */
 
    /* Detect which color space we need to convert between. */
    const char *from_colorspace = (ibuf->float_buffer.data &&
                                   !(byte_output && ibuf->byte_buffer.data)) ?
                                      /* From float buffer. */
                                      (ibuf->float_buffer.colorspace) ?
                                      ibuf->float_buffer.colorspace->name().c_str() :
                                      global_role_scene_linear :
                                      /* From byte buffer. */
                                      (ibuf->byte_buffer.colorspace) ?
                                      ibuf->byte_buffer.colorspace->name().c_str() :
                                      global_role_default_byte;
 
    const char *to_colorspace = image_format->linear_colorspace_settings.name;
 
    /* TODO: can we check with OCIO if color spaces are the same but have different names? */
    if (to_colorspace[0] == '\0' || STREQ(from_colorspace, to_colorspace)) {
      /* No conversion needed, but may still need to allocate byte buffer for output. */
      if (byte_output && !ibuf->byte_buffer.data) {
        ibuf->byte_buffer.colorspace = ibuf->float_buffer.colorspace;
        IMB_byte_from_float(ibuf);
      }
    }
    else {
      /* Color space conversion needed. */
      colormanaged_ibuf = imbuf_ensure_editable(ibuf, colormanaged_ibuf, allocate_result);
 
      if (byte_output) {
        colormanaged_ibuf->byte_buffer.colorspace = colormanage_colorspace_get_named(
            to_colorspace);
 
        if (colormanaged_ibuf->byte_buffer.data) {
          /* Byte to byte. */
          IMB_colormanagement_transform_byte(colormanaged_ibuf->byte_buffer.data,
                                             colormanaged_ibuf->x,
                                             colormanaged_ibuf->y,
                                             colormanaged_ibuf->channels,
                                             from_colorspace,
                                             to_colorspace);
        }
        else {
          /* Float to byte. */
          IMB_byte_from_float(colormanaged_ibuf);
        }
      }
      else {
        if (!colormanaged_ibuf->float_buffer.data) {
          /* Byte to float. */
          IMB_float_from_byte(colormanaged_ibuf);
          IMB_free_byte_pixels(colormanaged_ibuf);
 
          /* This conversion always goes to scene linear. */
          from_colorspace = global_role_scene_linear;
        }
 
        if (colormanaged_ibuf->float_buffer.data) {
          /* Float to float. */
          IMB_colormanagement_transform_float(colormanaged_ibuf->float_buffer.data,
                                              colormanaged_ibuf->x,
                                              colormanaged_ibuf->y,
                                              colormanaged_ibuf->channels,
                                              from_colorspace,
                                              to_colorspace,
                                              false);
 
          colormanaged_ibuf->float_buffer.colorspace = colormanage_colorspace_get_named(
              to_colorspace);
        }
      }
    }
  }
 
  return colormanaged_ibuf;
}

 
/* -------------------------------------------------------------------- */
 
uchar *IMB_display_buffer_acquire(ImBuf *ibuf,
                                  const ColorManagedViewSettings *view_settings,
                                  const ColorManagedDisplaySettings *display_settings,
                                  void **cache_handle)
{
  uchar *display_buffer;
  ColormanageCacheViewSettings cache_view_settings;
  ColormanageCacheDisplaySettings cache_display_settings;
  ColorManagedViewSettings default_view_settings;
  const ColorManagedViewSettings *applied_view_settings;
 
  *cache_handle = nullptr;
 
  if (!ibuf->x || !ibuf->y) {
    return nullptr;
  }
 
  if (view_settings) {
    applied_view_settings = view_settings;
  }
  else {
    /* If no view settings were specified, use default ones, which will
     * attempt not to do any extra color correction. */
    IMB_colormanagement_init_default_view_settings(&default_view_settings, display_settings);
    applied_view_settings = &default_view_settings;
  }
 
  /* No float buffer and byte buffer is already in display space, let's just use it. */
  if (ibuf->float_buffer.data == nullptr && ibuf->byte_buffer.colorspace && ibuf->channels == 4) {
    if (is_colorspace_same_as_display(
            ibuf->byte_buffer.colorspace, applied_view_settings, display_settings))
    {
      return ibuf->byte_buffer.data;
    }
  }
 
  colormanage_view_settings_to_cache(ibuf, &cache_view_settings, applied_view_settings);
  colormanage_display_settings_to_cache(&cache_display_settings, display_settings);
 
  if (ibuf->invalid_rect.xmin != ibuf->invalid_rect.xmax) {
    if ((ibuf->userflags & IB_DISPLAY_BUFFER_INVALID) == 0) {
      IMB_partial_display_buffer_update_threaded(ibuf,
                                                 ibuf->float_buffer.data,
                                                 ibuf->byte_buffer.data,
                                                 ibuf->x,
                                                 0,
                                                 0,
                                                 applied_view_settings,
                                                 display_settings,
                                                 ibuf->invalid_rect.xmin,
                                                 ibuf->invalid_rect.ymin,
                                                 ibuf->invalid_rect.xmax,
                                                 ibuf->invalid_rect.ymax);
    }
 
    BLI_rcti_init(&ibuf->invalid_rect, 0, 0, 0, 0);
  }
 
  BLI_thread_lock(LOCK_COLORMANAGE);
 
  /* ensure color management bit fields exists */
  if (!ibuf->display_buffer_flags) {
    ibuf->display_buffer_flags = MEM_calloc_arrayN<uint>(g_config->get_num_displays(),
                                                         "imbuf display_buffer_flags");
  }
  else if (ibuf->userflags & IB_DISPLAY_BUFFER_INVALID) {
    /* all display buffers were marked as invalid from other areas,
     * now propagate this flag to internal color management routines
     */
    memset(ibuf->display_buffer_flags, 0, g_config->get_num_displays() * sizeof(uint));
 
    ibuf->userflags &= ~IB_DISPLAY_BUFFER_INVALID;
  }
 
  display_buffer = colormanage_cache_get(
      ibuf, &cache_view_settings, &cache_display_settings, cache_handle);
 
  if (display_buffer) {
    BLI_thread_unlock(LOCK_COLORMANAGE);
    return display_buffer;
  }
 
  display_buffer = MEM_malloc_arrayN<uchar>(
      DISPLAY_BUFFER_CHANNELS * size_t(ibuf->x) * size_t(ibuf->y), "imbuf display buffer");
 
  colormanage_display_buffer_process(
      ibuf, display_buffer, applied_view_settings, display_settings);
 
  colormanage_cache_put(
      ibuf, &cache_view_settings, &cache_display_settings, display_buffer, cache_handle);
 
  BLI_thread_unlock(LOCK_COLORMANAGE);
 
  return display_buffer;
}
 
uchar *IMB_display_buffer_acquire_ctx(const bContext *C, ImBuf *ibuf, void **cache_handle)
{
  ColorManagedViewSettings *view_settings;
  ColorManagedDisplaySettings *display_settings;
 
  IMB_colormanagement_display_settings_from_ctx(C, &view_settings, &display_settings);
 
  return IMB_display_buffer_acquire(ibuf, view_settings, display_settings, cache_handle);
}
 
void IMB_display_buffer_transform_apply(uchar *display_buffer,
                                        float *linear_buffer,
                                        int width,
                                        int height,
                                        int channels,
                                        const ColorManagedViewSettings *view_settings,
                                        const ColorManagedDisplaySettings *display_settings,
                                        bool predivide)
{
  float *buffer;
  ColormanageProcessor *cm_processor = IMB_colormanagement_display_processor_new(view_settings,
                                                                                 display_settings);
 
  buffer = MEM_malloc_arrayN<float>(size_t(channels) * size_t(width) * size_t(height),
                                    "display transform temp buffer");
  memcpy(buffer, linear_buffer, size_t(channels) * width * height * sizeof(float));
 
  IMB_colormanagement_processor_apply(cm_processor, buffer, width, height, channels, predivide);
 
  IMB_colormanagement_processor_free(cm_processor);
 
  IMB_buffer_byte_from_float(display_buffer,
                             buffer,
                             channels,
                             0.0f,
                             IB_PROFILE_SRGB,
                             IB_PROFILE_SRGB,
                             false,
                             width,
                             height,
                             width,
                             width);
 
  MEM_freeN(buffer);
}
 
void IMB_display_buffer_transform_apply_float(float *float_display_buffer,
                                              float *linear_buffer,
                                              int width,
                                              int height,
                                              int channels,
                                              const ColorManagedViewSettings *view_settings,
                                              const ColorManagedDisplaySettings *display_settings,
                                              bool predivide)
{
  float *buffer;
  ColormanageProcessor *cm_processor = IMB_colormanagement_display_processor_new(view_settings,
                                                                                 display_settings);
 
  buffer = MEM_malloc_arrayN<float>(size_t(channels) * size_t(width) * size_t(height),
                                    "display transform temp buffer");
  memcpy(buffer, linear_buffer, size_t(channels) * width * height * sizeof(float));
 
  IMB_colormanagement_processor_apply(cm_processor, buffer, width, height, channels, predivide);
 
  IMB_colormanagement_processor_free(cm_processor);
 
  memcpy(float_display_buffer, buffer, size_t(channels) * width * height * sizeof(float));
  MEM_freeN(buffer);
}
 
void IMB_display_buffer_release(void *cache_handle)
{
  if (cache_handle) {
    BLI_thread_lock(LOCK_COLORMANAGE);
 
    colormanage_cache_handle_release(cache_handle);
 
    BLI_thread_unlock(LOCK_COLORMANAGE);
  }
}

 
/* -------------------------------------------------------------------- */
 
int IMB_colormanagement_display_get_named_index(const char *name)
{
  const ocio::Display *display = g_config->get_display_by_name(name);
  if (display) {
    return display->index;
  }
  return -1;
}
 
const char *IMB_colormanagement_display_get_indexed_name(const int index)
{
  const ocio::Display *display = g_config->get_display_by_index(index);
  if (!display) {
    return "";
  }
  return display->name().c_str();
}
 
const char *IMB_colormanagement_display_get_default_name()
{
  const ocio::Display *display = g_config->get_default_display();
  return display->name().c_str();
}
 
const ColorManagedDisplay *IMB_colormanagement_display_get_named(const char *name)
{
  return g_config->get_display_by_name(name);
}
 
const char *IMB_colormanagement_display_get_none_name()
{
  if (g_config->get_display_by_name("None") != nullptr) {
    return "None";
  }
  return IMB_colormanagement_display_get_default_name();
}
 
const char *IMB_colormanagement_display_get_default_view_transform_name(
    const ColorManagedDisplay *display)
{
  const ocio::View *default_view = display->get_default_view();
  if (!default_view) {
    return "";
  }
  return default_view->name().c_str();
}

 
/* -------------------------------------------------------------------- */
 
int IMB_colormanagement_view_get_id_by_name(const char *name)
{
  return g_all_view_names.index_of_try(name);
}
 
const char *IMB_colormanagement_view_get_name_by_id(const int index)
{
  /* The code is expected to be used for the purposes of the EnumPropertyItem and maintaining the
   * DNA values from RNA's get() and set(). It is unexpected that an invalid index will be passed
   * here, as it will indicate a coding error somewhere else. */
  if (index < 0 || index >= g_all_view_names.size()) {
    BLI_assert(0);
    return "";
  }
 
  return g_all_view_names[index].c_str();
}
 
const char *IMB_colormanagement_view_get_default_name(const char *display_name)
{
  const ocio::Display *display = g_config->get_display_by_name(display_name);
  if (!display) {
    return "";
  }
 
  const ocio::View *view = display->get_default_view();
  if (!view) {
    return "";
  }
 
  return view->name().c_str();
}
 
const char *IMB_colormanagement_view_get_raw_or_default_name(const char *display_name)
{
  const ocio::Display *display = g_config->get_display_by_name(display_name);
  if (!display) {
    return "";
  }
 
  const ocio::View *view = nullptr;
 
  if (!view) {
    view = display->get_view_by_name("Raw");
  }
 
  if (!view) {
    view = display->get_default_view();
  }
 
  if (!view) {
    return "";
  }
 
  return view->name().c_str();
}

 
/* -------------------------------------------------------------------- */
 
const ColorSpace *colormanage_colorspace_get_named(const char *name)
{
  return g_config->get_color_space(name);
}
 
const ColorSpace *colormanage_colorspace_get_roled(const int role)
{
  const char *role_colorspace = IMB_colormanagement_role_colorspace_name_get(role);
 
  return colormanage_colorspace_get_named(role_colorspace);
}
 
int IMB_colormanagement_colorspace_get_named_index(const char *name)
{
  const ColorSpace *colorspace = colormanage_colorspace_get_named(name);
  if (colorspace) {
    return colorspace->index;
  }
  return -1;
}
 
const char *IMB_colormanagement_colorspace_get_indexed_name(const int index)
{
  const ColorSpace *colorspace = g_config->get_color_space_by_index(index);
  if (colorspace) {
    return colorspace->name().c_str();
  }
  return "";
}
 
const char *IMB_colormanagement_colorspace_get_name(const ColorSpace *colorspace)
{
  return colorspace->name().c_str();
}
 
void IMB_colormanagement_colorspace_from_ibuf_ftype(
    ColorManagedColorspaceSettings *colorspace_settings, ImBuf *ibuf)
{
  /* Don't modify non-color data space, it does not change with file type. */
  const ColorSpace *colorspace = g_config->get_color_space(colorspace_settings->name);
 
  if (colorspace && colorspace->is_data()) {
    return;
  }
 
  /* Get color space from file type. */
  const ImFileType *type = IMB_file_type_from_ibuf(ibuf);
  if (type != nullptr) {
    if (type->save != nullptr) {
      const char *role_colorspace = IMB_colormanagement_role_colorspace_name_get(
          type->default_save_role);
      STRNCPY(colorspace_settings->name, role_colorspace);
    }
  }
}

 
/* -------------------------------------------------------------------- */
 
int IMB_colormanagement_look_get_named_index(const char *name)
{
  const ocio::Look *look = g_config->get_look_by_name(name);
  if (look) {
    return look->index;
  }
  return -1;
}
 
const char *IMB_colormanagement_look_get_indexed_name(const int index)
{
  const ocio::Look *look = g_config->get_look_by_index(index);
  if (!look) {
    return "";
  }
  return look->name().c_str();
}
 
const char *IMB_colormanagement_look_get_default_name()
{
  const ocio::Look *look = g_config->get_look_by_index(0);
  if (!look) {
    return "";
  }
  return look->name().c_str();
}
 
const char *IMB_colormanagement_look_validate_for_view(const char *view_name,
                                                       const char *look_name)
{
  const ocio::Look *look = g_config->get_look_by_name(look_name);
  if (!look) {
    return look_name;
  }
 
  /* Keep same look if compatible. */
  if (colormanage_compatible_look(look, view_name)) {
    return look_name;
  }
 
  /* Try to find another compatible look with the same UI name, in case of looks specialized for
   * view transform, */
  for (const int other_look_index : blender::IndexRange(g_config->get_num_looks())) {
    const ocio::Look *other_look = g_config->get_look_by_index(other_look_index);
    if (look->ui_name() == other_look->ui_name() &&
        colormanage_compatible_look(other_look, view_name))
    {
      return other_look->name().c_str();
    }
  }
 
  return IMB_colormanagement_look_get_default_name();
}

 
/* -------------------------------------------------------------------- */
 
void IMB_colormanagement_display_items_add(EnumPropertyItem **items, int *totitem)
{
  for (const int display_index : blender::IndexRange(g_config->get_num_displays())) {
    const ocio::Display *display = g_config->get_display_by_index(display_index);
 
    EnumPropertyItem item;
 
    item.value = display->index;
    item.name = display->name().c_str();
    item.identifier = display->name().c_str();
    item.icon = 0;
    item.description = "";
 
    RNA_enum_item_add(items, totitem, &item);
  }
}
 
void IMB_colormanagement_view_items_add(EnumPropertyItem **items,
                                        int *totitem,
                                        const char *display_name)
{
  const ocio::Display *display = g_config->get_display_by_name(display_name);
  if (!display) {
    return;
  }
 
  for (const int view_index : blender::IndexRange(display->get_num_views())) {
    const ocio::View *view = display->get_view_by_index(view_index);
 
    EnumPropertyItem item;
 
    item.value = IMB_colormanagement_view_get_id_by_name(view->name().c_str());
    item.name = view->name().c_str();
    item.identifier = view->name().c_str();
    item.icon = 0;
    item.description = "";
 
    RNA_enum_item_add(items, totitem, &item);
  }
}
 
void IMB_colormanagement_look_items_add(EnumPropertyItem **items,
                                        int *totitem,
                                        const char *view_name)
{
  const bool has_explicit_look = has_explicit_look_for_view(view_name);
 
  for (const int look_index : blender::IndexRange(g_config->get_num_looks())) {
    const ocio::Look *look = g_config->get_look_by_index(look_index);
    if (!colormanage_compatible_look(look, view_name, has_explicit_look)) {
      continue;
    }
 
    EnumPropertyItem item;
 
    item.value = look->index;
    item.name = look->ui_name().c_str();
    item.identifier = look->name().c_str();
    item.icon = 0;
    item.description = "";
 
    RNA_enum_item_add(items, totitem, &item);
  }
}
 
void IMB_colormanagement_colorspace_items_add(EnumPropertyItem **items, int *totitem)
{
  for (const int colorspace_index : blender::IndexRange(g_config->get_num_color_spaces())) {
    const ColorSpace *colorspace = g_config->get_sorted_color_space_by_index(colorspace_index);
    if (!colorspace->is_invertible()) {
      continue;
    }
 
    EnumPropertyItem item;
 
    item.value = colorspace->index;
    item.name = colorspace->name().c_str();
    item.identifier = colorspace->name().c_str();
    item.icon = 0;
    item.description = colorspace->description().c_str();
 
    RNA_enum_item_add(items, totitem, &item);
  }
}

 
/* -------------------------------------------------------------------- */
 
/*
 * Partial display update is supposed to be used by such areas as
 * compositor and renderer, This areas are calculating tiles of the
 * images and because of performance reasons only this tiles should
 * be color managed.
 * This gives nice visual feedback without slowing things down.
 *
 * Updating happens for active display transformation only, all
 * the rest buffers would be marked as dirty
 */
 
static void partial_buffer_update_rect(ImBuf *ibuf,
                                       uchar *display_buffer,
                                       const float *linear_buffer,
                                       const uchar *byte_buffer,
                                       int display_stride,
                                       int linear_stride,
                                       int linear_offset_x,
                                       int linear_offset_y,
                                       ColormanageProcessor *cm_processor,
                                       const int xmin,
                                       const int ymin,
                                       const int xmax,
                                       const int ymax)
{
  int x, y;
  int channels = ibuf->channels;
  float dither = ibuf->dither;
  const ColorSpace *rect_colorspace = ibuf->byte_buffer.colorspace;
  float *display_buffer_float = nullptr;
  const int width = xmax - xmin;
  const int height = ymax - ymin;
  bool is_data = (ibuf->colormanage_flag & IMB_COLORMANAGE_IS_DATA) != 0;
 
  if (dither != 0.0f) {
    /* cm_processor is nullptr in cases byte_buffer's space matches display
     * buffer's space
     * in this case we could skip extra transform and only apply dither
     * use 4 channels for easier byte->float->byte conversion here so
     * (this is only needed to apply dither, in other cases we'll convert
     * byte buffer to display directly)
     */
    if (!cm_processor) {
      channels = 4;
    }
 
    display_buffer_float = MEM_malloc_arrayN<float>(
        size_t(channels) * size_t(width) * size_t(height), "display buffer for dither");
  }
 
  if (cm_processor) {
    for (y = ymin; y < ymax; y++) {
      for (x = xmin; x < xmax; x++) {
        size_t display_index = (size_t(y) * display_stride + x) * 4;
        size_t linear_index = (size_t(y - linear_offset_y) * linear_stride +
                               (x - linear_offset_x)) *
                              channels;
        float pixel[4];
 
        if (linear_buffer) {
          if (channels == 4) {
            copy_v4_v4(pixel, (float *)linear_buffer + linear_index);
          }
          else if (channels == 3) {
            copy_v3_v3(pixel, (float *)linear_buffer + linear_index);
            pixel[3] = 1.0f;
          }
          else if (channels == 1) {
            pixel[0] = linear_buffer[linear_index];
          }
          else {
            BLI_assert_msg(0, "Unsupported number of channels in partial buffer update");
          }
        }
        else if (byte_buffer) {
          rgba_uchar_to_float(pixel, byte_buffer + linear_index);
          IMB_colormanagement_colorspace_to_scene_linear_v3(pixel, rect_colorspace);
          straight_to_premul_v4(pixel);
        }
 
        if (!is_data) {
          IMB_colormanagement_processor_apply_pixel(cm_processor, pixel, channels);
        }
 
        if (display_buffer_float) {
          size_t index = (size_t(y - ymin) * width + (x - xmin)) * channels;
 
          if (channels == 4) {
            copy_v4_v4(display_buffer_float + index, pixel);
          }
          else if (channels == 3) {
            copy_v3_v3(display_buffer_float + index, pixel);
          }
          else /* if (channels == 1) */ {
            display_buffer_float[index] = pixel[0];
          }
        }
        else {
          if (channels == 4) {
            float pixel_straight[4];
            premul_to_straight_v4_v4(pixel_straight, pixel);
            rgba_float_to_uchar(display_buffer + display_index, pixel_straight);
          }
          else if (channels == 3) {
            rgb_float_to_uchar(display_buffer + display_index, pixel);
            display_buffer[display_index + 3] = 255;
          }
          else /* if (channels == 1) */ {
            display_buffer[display_index] = display_buffer[display_index + 1] =
                display_buffer[display_index + 2] = display_buffer[display_index + 3] =
                    unit_float_to_uchar_clamp(pixel[0]);
          }
        }
      }
    }
  }
  else {
    if (display_buffer_float) {
      /* huh, for dither we need float buffer first, no cheaper way. currently */
      IMB_buffer_float_from_byte(display_buffer_float,
                                 byte_buffer,
                                 IB_PROFILE_SRGB,
                                 IB_PROFILE_SRGB,
                                 true,
                                 width,
                                 height,
                                 width,
                                 display_stride);
    }
    else {
      int i;
 
      for (i = ymin; i < ymax; i++) {
        size_t byte_offset = (size_t(linear_stride) * i + xmin) * 4;
        size_t display_offset = (size_t(display_stride) * i + xmin) * 4;
 
        memcpy(
            display_buffer + display_offset, byte_buffer + byte_offset, sizeof(char[4]) * width);
      }
    }
  }
 
  if (display_buffer_float) {
    size_t display_index = (size_t(ymin) * display_stride + xmin) * channels;
 
    IMB_buffer_byte_from_float(display_buffer + display_index,
                               display_buffer_float,
                               channels,
                               dither,
                               IB_PROFILE_SRGB,
                               IB_PROFILE_SRGB,
                               true,
                               width,
                               height,
                               display_stride,
                               width,
                               ymin);
 
    MEM_freeN(display_buffer_float);
  }
}
 
static void imb_partial_display_buffer_update_ex(
    ImBuf *ibuf,
    const float *linear_buffer,
    const uchar *byte_buffer,
    int stride,
    int offset_x,
    int offset_y,
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings,
    int xmin,
    int ymin,
    int xmax,
    int ymax,
    bool do_threads)
{
  using namespace blender;
  ColormanageCacheViewSettings cache_view_settings;
  ColormanageCacheDisplaySettings cache_display_settings;
  void *cache_handle = nullptr;
  uchar *display_buffer = nullptr;
  int buffer_width = ibuf->x;
 
  if (ibuf->display_buffer_flags) {
    int view_flag, display_index;
 
    colormanage_view_settings_to_cache(ibuf, &cache_view_settings, view_settings);
    colormanage_display_settings_to_cache(&cache_display_settings, display_settings);
 
    view_flag = 1 << cache_view_settings.view;
    display_index = cache_display_settings.display;
 
    BLI_thread_lock(LOCK_COLORMANAGE);
 
    if ((ibuf->userflags & IB_DISPLAY_BUFFER_INVALID) == 0) {
      display_buffer = colormanage_cache_get(
          ibuf, &cache_view_settings, &cache_display_settings, &cache_handle);
    }
 
    /* In some rare cases buffer's dimension could be changing directly from
     * different thread
     * this i.e. happens when image editor acquires render result
     */
    buffer_width = ibuf->x;
 
    /* Mark all other buffers as invalid. */
    memset(ibuf->display_buffer_flags, 0, g_config->get_num_displays() * sizeof(uint));
    ibuf->display_buffer_flags[display_index] |= view_flag;
 
    BLI_thread_unlock(LOCK_COLORMANAGE);
  }
 
  if (display_buffer) {
    ColormanageProcessor *cm_processor = nullptr;
    bool skip_transform = false;
 
    /* If we only have a byte or a float buffer, and color space already
     * matches display, there's no need to do color transforms.
     * However if both float and byte buffers exist, it is likely that
     * some operation was performed on float buffer first, and the byte
     * buffer is out of date. */
    if (linear_buffer == nullptr && byte_buffer != nullptr) {
      skip_transform = is_colorspace_same_as_display(
          ibuf->byte_buffer.colorspace, view_settings, display_settings);
    }
    if (byte_buffer == nullptr && linear_buffer != nullptr) {
      skip_transform = is_colorspace_same_as_display(
          ibuf->float_buffer.colorspace, view_settings, display_settings);
    }
 
    if (!skip_transform) {
      cm_processor = IMB_colormanagement_display_processor_new(view_settings, display_settings);
    }
 
    threading::parallel_for(IndexRange(ymin, ymax - ymin),
                            do_threads ? 64 : ymax - ymin,
                            [&](const IndexRange y_range) {
                              partial_buffer_update_rect(ibuf,
                                                         display_buffer,
                                                         linear_buffer,
                                                         byte_buffer,
                                                         buffer_width,
                                                         stride,
                                                         offset_x,
                                                         offset_y,
                                                         cm_processor,
                                                         xmin,
                                                         y_range.first(),
                                                         xmax,
                                                         y_range.one_after_last());
                            });
 
    if (cm_processor) {
      IMB_colormanagement_processor_free(cm_processor);
    }
 
    IMB_display_buffer_release(cache_handle);
  }
}
 
void IMB_partial_display_buffer_update(ImBuf *ibuf,
                                       const float *linear_buffer,
                                       const uchar *byte_buffer,
                                       int stride,
                                       int offset_x,
                                       int offset_y,
                                       const ColorManagedViewSettings *view_settings,
                                       const ColorManagedDisplaySettings *display_settings,
                                       int xmin,
                                       int ymin,
                                       int xmax,
                                       int ymax)
{
  imb_partial_display_buffer_update_ex(ibuf,
                                       linear_buffer,
                                       byte_buffer,
                                       stride,
                                       offset_x,
                                       offset_y,
                                       view_settings,
                                       display_settings,
                                       xmin,
                                       ymin,
                                       xmax,
                                       ymax,
                                       false);
}
 
void IMB_partial_display_buffer_update_threaded(
    ImBuf *ibuf,
    const float *linear_buffer,
    const uchar *byte_buffer,
    int stride,
    int offset_x,
    int offset_y,
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings,
    int xmin,
    int ymin,
    int xmax,
    int ymax)
{
  int width = xmax - xmin;
  int height = ymax - ymin;
  bool do_threads = (size_t(width) * height >= 64 * 64);
  imb_partial_display_buffer_update_ex(ibuf,
                                       linear_buffer,
                                       byte_buffer,
                                       stride,
                                       offset_x,
                                       offset_y,
                                       view_settings,
                                       display_settings,
                                       xmin,
                                       ymin,
                                       xmax,
                                       ymax,
                                       do_threads);
}
 
void IMB_partial_display_buffer_update_delayed(ImBuf *ibuf, int xmin, int ymin, int xmax, int ymax)
{
  if (ibuf->invalid_rect.xmin == ibuf->invalid_rect.xmax) {
    BLI_rcti_init(&ibuf->invalid_rect, xmin, xmax, ymin, ymax);
  }
  else {
    rcti rect;
    BLI_rcti_init(&rect, xmin, xmax, ymin, ymax);
    BLI_rcti_union(&ibuf->invalid_rect, &rect);
  }
}

 
/* -------------------------------------------------------------------- */
 
ColormanageProcessor *IMB_colormanagement_display_processor_new(
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings)
{
  ColormanageProcessor *cm_processor;
  ColorManagedViewSettings default_view_settings;
  const ColorManagedViewSettings *applied_view_settings;
  const ColorSpace *display_space;
 
  cm_processor = MEM_new<ColormanageProcessor>("colormanagement processor");
 
  if (view_settings) {
    applied_view_settings = view_settings;
  }
  else {
    IMB_colormanagement_init_default_view_settings(&default_view_settings, display_settings);
    applied_view_settings = &default_view_settings;
  }
 
  display_space = get_display_colorspace(applied_view_settings, display_settings);
  if (display_space) {
    cm_processor->is_data_result = display_space->is_data();
  }
 
  const bool use_white_balance = applied_view_settings->flag & COLORMANAGE_VIEW_USE_WHITE_BALANCE;
  cm_processor->cpu_processor = get_display_buffer_processor(applied_view_settings->look,
                                                             applied_view_settings->view_transform,
                                                             display_settings->display_device,
                                                             applied_view_settings->exposure,
                                                             applied_view_settings->gamma,
                                                             applied_view_settings->temperature,
                                                             applied_view_settings->tint,
                                                             use_white_balance,
                                                             global_role_scene_linear);
 
  if (applied_view_settings->flag & COLORMANAGE_VIEW_USE_CURVES) {
    cm_processor->curve_mapping = BKE_curvemapping_copy(applied_view_settings->curve_mapping);
    BKE_curvemapping_premultiply(cm_processor->curve_mapping, false);
  }
 
  return cm_processor;
}
 
ColormanageProcessor *IMB_colormanagement_colorspace_processor_new(const char *from_colorspace,
                                                                   const char *to_colorspace)
{
  ColormanageProcessor *cm_processor;
 
  cm_processor = MEM_new<ColormanageProcessor>("colormanagement processor");
  cm_processor->is_data_result = IMB_colormanagement_space_name_is_data(to_colorspace);
 
  cm_processor->cpu_processor = g_config->get_cpu_processor(from_colorspace, to_colorspace);
 
  return cm_processor;
}
 
bool IMB_colormanagement_processor_is_noop(ColormanageProcessor *cm_processor)
{
  if (cm_processor->curve_mapping) {
    /* Consider processor which has curve mapping as a non no-op.
     * This is mainly for the simplicity of the check, since the current cases where this
     * function is used the curve mapping is never assigned. */
    return false;
  }
 
  if (!cm_processor->cpu_processor) {
    /* The CPU processor might have failed to be created, for example when the requested color
     * space does not exist in the configuration, or if there is a missing lookup table, or the
     * configuration is invalid due to other reasons.
     *
     * The actual processing checks for the cpu_processor not being null pointer, and it if is
     * then processing does not apply it. However, processing could still apply curve mapping.
     *
     * Hence a null-pointer here, which happens after the curve mapping check, but before
     * accessing cpu_processor. */
    return true;
  }
 
  return cm_processor->cpu_processor->is_noop();
}
 
void IMB_colormanagement_processor_apply_v4(ColormanageProcessor *cm_processor, float pixel[4])
{
  if (cm_processor->curve_mapping) {
    BKE_curvemapping_evaluate_premulRGBF(cm_processor->curve_mapping, pixel, pixel);
  }
 
  if (cm_processor->cpu_processor) {
    cm_processor->cpu_processor->apply_rgba(pixel);
  }
}
 
void IMB_colormanagement_processor_apply_v4_predivide(ColormanageProcessor *cm_processor,
                                                      float pixel[4])
{
  if (cm_processor->curve_mapping) {
    BKE_curvemapping_evaluate_premulRGBF(cm_processor->curve_mapping, pixel, pixel);
  }
 
  if (cm_processor->cpu_processor) {
    cm_processor->cpu_processor->apply_rgba_predivide(pixel);
    ;
  }
}
 
void IMB_colormanagement_processor_apply_v3(ColormanageProcessor *cm_processor, float pixel[3])
{
  if (cm_processor->curve_mapping) {
    BKE_curvemapping_evaluate_premulRGBF(cm_processor->curve_mapping, pixel, pixel);
  }
 
  if (cm_processor->cpu_processor) {
    cm_processor->cpu_processor->apply_rgb(pixel);
  }
}
 
void IMB_colormanagement_processor_apply_pixel(ColormanageProcessor *cm_processor,
                                               float *pixel,
                                               int channels)
{
  if (channels == 4) {
    IMB_colormanagement_processor_apply_v4_predivide(cm_processor, pixel);
  }
  else if (channels == 3) {
    IMB_colormanagement_processor_apply_v3(cm_processor, pixel);
  }
  else if (channels == 1) {
    if (cm_processor->curve_mapping) {
      curve_mapping_apply_pixel(cm_processor->curve_mapping, pixel, 1);
    }
  }
  else {
    BLI_assert_msg(
        false, "Incorrect number of channels passed to IMB_colormanagement_processor_apply_pixel");
  }
}
 
void IMB_colormanagement_processor_apply(ColormanageProcessor *cm_processor,
                                         float *buffer,
                                         int width,
                                         int height,
                                         int channels,
                                         bool predivide)
{
  /* apply curve mapping */
  if (cm_processor->curve_mapping) {
    int x, y;
 
    for (y = 0; y < height; y++) {
      for (x = 0; x < width; x++) {
        float *pixel = buffer + channels * (size_t(y) * width + x);
 
        curve_mapping_apply_pixel(cm_processor->curve_mapping, pixel, channels);
      }
    }
  }
 
  if (cm_processor->cpu_processor && channels >= 3) {
    /* apply OCIO processor */
    const ocio::PackedImage img(buffer,
                                width,
                                height,
                                channels,
                                ocio::BitDepth::BIT_DEPTH_F32,
                                sizeof(float),
                                size_t(channels) * sizeof(float),
                                size_t(channels) * sizeof(float) * width);
 
    if (predivide) {
      cm_processor->cpu_processor->apply_predivide(img);
    }
    else {
      cm_processor->cpu_processor->apply(img);
    }
  }
}
 
void IMB_colormanagement_processor_apply_byte(
    ColormanageProcessor *cm_processor, uchar *buffer, int width, int height, int channels)
{
  /* TODO(sergey): Would be nice to support arbitrary channels configurations,
   * but for now it's not so important.
   */
  BLI_assert(channels == 4);
  float pixel[4];
  for (int y = 0; y < height; y++) {
    for (int x = 0; x < width; x++) {
      size_t offset = channels * (size_t(y) * width + x);
      rgba_uchar_to_float(pixel, buffer + offset);
      IMB_colormanagement_processor_apply_v4(cm_processor, pixel);
      rgba_float_to_uchar(buffer + offset, pixel);
    }
  }
}
 
void IMB_colormanagement_processor_free(ColormanageProcessor *cm_processor)
{
  if (cm_processor->curve_mapping) {
    BKE_curvemapping_free(cm_processor->curve_mapping);
  }
 
  MEM_delete(cm_processor);
}
 
/* **** OpenGL drawing routines using GLSL for color space transform ***** */
 
static CurveMapping *update_glsl_curve_mapping(const ColorManagedViewSettings *view_settings)
{
  /* Using curve mapping? */
  const bool use_curve_mapping = (view_settings->flag & COLORMANAGE_VIEW_USE_CURVES) != 0;
  if (!use_curve_mapping) {
    return nullptr;
  }
 
  /* Already up to date? */
  if (view_settings->curve_mapping->changed_timestamp ==
          global_gpu_state.curve_mapping_timestamp &&
      view_settings->curve_mapping == global_gpu_state.orig_curve_mapping)
  {
    return view_settings->curve_mapping;
  }
 
  /* We're using curve mapping's address as a cache ID, so we need to make sure re-allocation
   * gives new address here. We do this by allocating new curve mapping before freeing old one.
   */
  CurveMapping *new_curve_mapping = BKE_curvemapping_copy(view_settings->curve_mapping);
 
  if (global_gpu_state.curve_mapping) {
    BKE_curvemapping_free(global_gpu_state.curve_mapping);
    global_gpu_state.curve_mapping = nullptr;
  }
 
  /* Fill in OCIO's curve mapping settings. */
  global_gpu_state.curve_mapping = new_curve_mapping;
  global_gpu_state.curve_mapping_timestamp = view_settings->curve_mapping->changed_timestamp;
  global_gpu_state.orig_curve_mapping = view_settings->curve_mapping;
  global_gpu_state.use_curve_mapping = true;
 
  return global_gpu_state.curve_mapping;
}
 
bool IMB_colormanagement_setup_glsl_draw_from_space(
    const ColorManagedViewSettings *view_settings,
    const ColorManagedDisplaySettings *display_settings,
    const ColorSpace *from_colorspace,
    float dither,
    bool predivide,
    bool do_overlay_merge)
{
  ColorManagedViewSettings default_view_settings;
  const ColorManagedViewSettings *applied_view_settings;
 
  if (view_settings) {
    applied_view_settings = view_settings;
  }
  else {
    /* If no view settings were specified, use default ones, which will attempt not to do any
     * extra color correction. */
    IMB_colormanagement_init_default_view_settings(&default_view_settings, display_settings);
    applied_view_settings = &default_view_settings;
  }
 
  /* Ensure curve mapping is up to date. */
  CurveMapping *applied_curve_mapping = update_glsl_curve_mapping(applied_view_settings);
 
  /* GPU shader parameters. */
  const bool use_look = colormanage_use_look(applied_view_settings->look,
                                             applied_view_settings->view_transform);
  const float exposure = applied_view_settings->exposure;
  const float gamma = applied_view_settings->gamma;
 
  /* TODO)sergey): Use designated initializer. */
  ocio::GPUDisplayParameters display_parameters;
  display_parameters.from_colorspace = from_colorspace ? from_colorspace->name().c_str() :
                                                         global_role_scene_linear;
  display_parameters.view = applied_view_settings->view_transform;
  display_parameters.display = display_settings->display_device;
  display_parameters.look = (use_look) ? applied_view_settings->look : "";
  display_parameters.curve_mapping = applied_curve_mapping;
  display_parameters.scale = (exposure == 0.0f) ? 1.0f : powf(2.0f, exposure);
  display_parameters.exponent = (gamma == 1.0f) ? 1.0f : 1.0f / max_ff(FLT_EPSILON, gamma);
  display_parameters.dither = dither;
  display_parameters.temperature = applied_view_settings->temperature;
  display_parameters.tint = applied_view_settings->tint;
  display_parameters.use_white_balance = (applied_view_settings->flag &
                                          COLORMANAGE_VIEW_USE_WHITE_BALANCE) != 0;
  display_parameters.use_predivide = predivide;
  display_parameters.do_overlay_merge = do_overlay_merge;
  display_parameters.use_hdr = GPU_hdr_support() &&
                               (applied_view_settings->flag & COLORMANAGE_VIEW_USE_HDR) != 0;
 
  /* Bind shader. Internally GPU shaders are created and cached on demand. */
  global_gpu_state.gpu_shader_bound = g_config->get_gpu_shader_binder().display_bind(
      display_parameters);
 
  return global_gpu_state.gpu_shader_bound;
}
 
bool IMB_colormanagement_setup_glsl_draw(const ColorManagedViewSettings *view_settings,
                                         const ColorManagedDisplaySettings *display_settings,
                                         float dither,
                                         bool predivide)
{
  return IMB_colormanagement_setup_glsl_draw_from_space(
      view_settings, display_settings, nullptr, dither, predivide, false);
}
 
bool IMB_colormanagement_setup_glsl_draw_from_space_ctx(const bContext *C,
                                                        const ColorSpace *from_colorspace,
                                                        float dither,
                                                        bool predivide)
{
  ColorManagedViewSettings *view_settings;
  ColorManagedDisplaySettings *display_settings;
 
  IMB_colormanagement_display_settings_from_ctx(C, &view_settings, &display_settings);
 
  return IMB_colormanagement_setup_glsl_draw_from_space(
      view_settings, display_settings, from_colorspace, dither, predivide, false);
}
 
bool IMB_colormanagement_setup_glsl_draw_ctx(const bContext *C, float dither, bool predivide)
{
  return IMB_colormanagement_setup_glsl_draw_from_space_ctx(C, nullptr, dither, predivide);
}
 
bool IMB_colormanagement_setup_glsl_draw_to_scene_linear(const char *from_colorspace_name,
                                                         const bool predivide)
{
  global_gpu_state.gpu_shader_bound = g_config->get_gpu_shader_binder().to_scene_linear_bind(
      from_colorspace_name, predivide);
  return global_gpu_state.gpu_shader_bound;
}
 
void IMB_colormanagement_finish_glsl_draw()
{
  if (global_gpu_state.gpu_shader_bound) {
    g_config->get_gpu_shader_binder().unbind();
    global_gpu_state.gpu_shader_bound = false;
  }
}

 
/* -------------------------------------------------------------------- */
 
/* Calculate color in range 800..12000 using an approximation
 * a/x+bx+c for R and G and ((at + b)t + c)t + d) for B
 *
 * The result of this can be negative to support gamut wider than
 * than rec.709, just needs to be clamped. */
 
static const float blackbody_table_r[7][3] = {{1.61919106e+03f, -2.05010916e-03f, 5.02995757e+00f},
                                              {2.48845471e+03f, -1.11330907e-03f, 3.22621544e+00f},
                                              {3.34143193e+03f, -4.86551192e-04f, 1.76486769e+00f},
                                              {4.09461742e+03f, -1.27446582e-04f, 7.25731635e-01f},
                                              {4.67028036e+03f, 2.91258199e-05f, 1.26703442e-01f},
                                              {4.59509185e+03f, 2.87495649e-05f, 1.50345020e-01f},
                                              {3.78717450e+03f, 9.35907826e-06f, 3.99075871e-01f}};
 
static const float blackbody_table_g[7][3] = {
    {-4.88999748e+02f, 6.04330754e-04f, -7.55807526e-02f},
    {-7.55994277e+02f, 3.16730098e-04f, 4.78306139e-01f},
    {-1.02363977e+03f, 1.20223470e-04f, 9.36662319e-01f},
    {-1.26571316e+03f, 4.87340896e-06f, 1.27054498e+00f},
    {-1.42529332e+03f, -4.01150431e-05f, 1.43972784e+00f},
    {-1.17554822e+03f, -2.16378048e-05f, 1.30408023e+00f},
    {-5.00799571e+02f, -4.59832026e-06f, 1.09098763e+00f}};
 
static const float blackbody_table_b[7][4] = {
    {5.96945309e-11f, -4.85742887e-08f, -9.70622247e-05f, -4.07936148e-03f},
    {2.40430366e-11f, 5.55021075e-08f, -1.98503712e-04f, 2.89312858e-02f},
    {-1.40949732e-11f, 1.89878968e-07f, -3.56632824e-04f, 9.10767778e-02f},
    {-3.61460868e-11f, 2.84822009e-07f, -4.93211319e-04f, 1.56723440e-01f},
    {-1.97075738e-11f, 1.75359352e-07f, -2.50542825e-04f, -2.22783266e-02f},
    {-1.61997957e-13f, -1.64216008e-08f, 3.86216271e-04f, -7.38077418e-01f},
    {6.72650283e-13f, -2.73078809e-08f, 4.24098264e-04f, -7.52335691e-01f}};
 
static void blackbody_temperature_to_rec709(float rec709[3], float t)
{
  if (t >= 12000.0f) {
    rec709[0] = 0.8262954810464208f;
    rec709[1] = 0.9945080501520986f;
    rec709[2] = 1.566307710274283f;
  }
  else if (t < 800.0f) {
    rec709[0] = 5.413294490189271f;
    rec709[1] = -0.20319390035873933f;
    rec709[2] = -0.0822535242887164f;
  }
  else {
    int i = (t >= 6365.0f) ? 6 :
            (t >= 3315.0f) ? 5 :
            (t >= 1902.0f) ? 4 :
            (t >= 1449.0f) ? 3 :
            (t >= 1167.0f) ? 2 :
            (t >= 965.0f)  ? 1 :
                             0;
 
    const float *r = blackbody_table_r[i];
    const float *g = blackbody_table_g[i];
    const float *b = blackbody_table_b[i];
 
    const float t_inv = 1.0f / t;
    rec709[0] = r[0] * t_inv + r[1] * t + r[2];
    rec709[1] = g[0] * t_inv + g[1] * t + g[2];
    rec709[2] = ((b[0] * t + b[1]) * t + b[2]) * t + b[3];
  }
}
 
void IMB_colormanagement_blackbody_temperature_to_rgb(float r_dest[4], float value)
{
  float rec709[3];
  blackbody_temperature_to_rec709(rec709, value);
 
  float rgb[3];
  IMB_colormanagement_rec709_to_scene_linear(rgb, rec709);
  clamp_v3(rgb, 0.0f, FLT_MAX);
 
  copy_v3_v3(r_dest, rgb);
  r_dest[3] = 1.0f;
}
 
void IMB_colormanagement_blackbody_temperature_to_rgb_table(float *r_table,
                                                            const int width,
                                                            const float min,
                                                            const float max)
{
  for (int i = 0; i < width; i++) {
    float temperature = min + (max - min) / float(width) * float(i);
    IMB_colormanagement_blackbody_temperature_to_rgb(&r_table[i * 4], temperature);
  }
}

 
static float cie_color_match[81][3] = {
    {0.0014f, 0.0000f, 0.0065f}, {0.0022f, 0.0001f, 0.0105f}, {0.0042f, 0.0001f, 0.0201f},
    {0.0076f, 0.0002f, 0.0362f}, {0.0143f, 0.0004f, 0.0679f}, {0.0232f, 0.0006f, 0.1102f},
    {0.0435f, 0.0012f, 0.2074f}, {0.0776f, 0.0022f, 0.3713f}, {0.1344f, 0.0040f, 0.6456f},
    {0.2148f, 0.0073f, 1.0391f}, {0.2839f, 0.0116f, 1.3856f}, {0.3285f, 0.0168f, 1.6230f},
    {0.3483f, 0.0230f, 1.7471f}, {0.3481f, 0.0298f, 1.7826f}, {0.3362f, 0.0380f, 1.7721f},
    {0.3187f, 0.0480f, 1.7441f}, {0.2908f, 0.0600f, 1.6692f}, {0.2511f, 0.0739f, 1.5281f},
    {0.1954f, 0.0910f, 1.2876f}, {0.1421f, 0.1126f, 1.0419f}, {0.0956f, 0.1390f, 0.8130f},
    {0.0580f, 0.1693f, 0.6162f}, {0.0320f, 0.2080f, 0.4652f}, {0.0147f, 0.2586f, 0.3533f},
    {0.0049f, 0.3230f, 0.2720f}, {0.0024f, 0.4073f, 0.2123f}, {0.0093f, 0.5030f, 0.1582f},
    {0.0291f, 0.6082f, 0.1117f}, {0.0633f, 0.7100f, 0.0782f}, {0.1096f, 0.7932f, 0.0573f},
    {0.1655f, 0.8620f, 0.0422f}, {0.2257f, 0.9149f, 0.0298f}, {0.2904f, 0.9540f, 0.0203f},
    {0.3597f, 0.9803f, 0.0134f}, {0.4334f, 0.9950f, 0.0087f}, {0.5121f, 1.0000f, 0.0057f},
    {0.5945f, 0.9950f, 0.0039f}, {0.6784f, 0.9786f, 0.0027f}, {0.7621f, 0.9520f, 0.0021f},
    {0.8425f, 0.9154f, 0.0018f}, {0.9163f, 0.8700f, 0.0017f}, {0.9786f, 0.8163f, 0.0014f},
    {1.0263f, 0.7570f, 0.0011f}, {1.0567f, 0.6949f, 0.0010f}, {1.0622f, 0.6310f, 0.0008f},
    {1.0456f, 0.5668f, 0.0006f}, {1.0026f, 0.5030f, 0.0003f}, {0.9384f, 0.4412f, 0.0002f},
    {0.8544f, 0.3810f, 0.0002f}, {0.7514f, 0.3210f, 0.0001f}, {0.6424f, 0.2650f, 0.0000f},
    {0.5419f, 0.2170f, 0.0000f}, {0.4479f, 0.1750f, 0.0000f}, {0.3608f, 0.1382f, 0.0000f},
    {0.2835f, 0.1070f, 0.0000f}, {0.2187f, 0.0816f, 0.0000f}, {0.1649f, 0.0610f, 0.0000f},
    {0.1212f, 0.0446f, 0.0000f}, {0.0874f, 0.0320f, 0.0000f}, {0.0636f, 0.0232f, 0.0000f},
    {0.0468f, 0.0170f, 0.0000f}, {0.0329f, 0.0119f, 0.0000f}, {0.0227f, 0.0082f, 0.0000f},
    {0.0158f, 0.0057f, 0.0000f}, {0.0114f, 0.0041f, 0.0000f}, {0.0081f, 0.0029f, 0.0000f},
    {0.0058f, 0.0021f, 0.0000f}, {0.0041f, 0.0015f, 0.0000f}, {0.0029f, 0.0010f, 0.0000f},
    {0.0020f, 0.0007f, 0.0000f}, {0.0014f, 0.0005f, 0.0000f}, {0.0010f, 0.0004f, 0.0000f},
    {0.0007f, 0.0002f, 0.0000f}, {0.0005f, 0.0002f, 0.0000f}, {0.0003f, 0.0001f, 0.0000f},
    {0.0002f, 0.0001f, 0.0000f}, {0.0002f, 0.0001f, 0.0000f}, {0.0001f, 0.0000f, 0.0000f},
    {0.0001f, 0.0000f, 0.0000f}, {0.0001f, 0.0000f, 0.0000f}, {0.0000f, 0.0000f, 0.0000f}};
 
static void wavelength_to_xyz(float xyz[3], float lambda_nm)
{
  float ii = (lambda_nm - 380.0f) * (1.0f / 5.0f); /* Scaled 0..80. */
  int i = int(ii);
 
  if (i < 0 || i >= 80) {
    xyz[0] = 0.0f;
    xyz[1] = 0.0f;
    xyz[2] = 0.0f;
  }
  else {
    ii -= float(i);
    const float *c = cie_color_match[i];
    xyz[0] = c[0] + ii * (c[3] - c[0]);
    xyz[1] = c[1] + ii * (c[4] - c[1]);
    xyz[2] = c[2] + ii * (c[5] - c[2]);
  }
}
 
void IMB_colormanagement_wavelength_to_rgb(float r_dest[4], float value)
{
  float xyz[3];
  wavelength_to_xyz(xyz, value);
 
  float rgb[3];
  IMB_colormanagement_xyz_to_scene_linear(rgb, xyz);
  clamp_v3(rgb, 0.0f, FLT_MAX);
 
  copy_v3_v3(r_dest, rgb);
  r_dest[3] = 1.0f;
}
 
void IMB_colormanagement_wavelength_to_rgb_table(float *r_table, const int width)
{
  for (int i = 0; i < width; i++) {
    float wavelength = 380 + 400 / float(width) * float(i);
    IMB_colormanagement_wavelength_to_rgb(&r_table[i * 4], wavelength);
  }
}