From 3cc1c63274dac90360b8194f66101f86f1a670b6 Mon Sep 17 00:00:00 2001
From: Gaspar Capello <gaspar@igara.com>
Date: Fri, 26 Apr 2024 08:58:36 -0300
Subject: [PATCH] Add different best fit criteria to compare colors for RgbMaps
 (fix #2787, #4416)

---
 data/pref.xml                                |   1 +
 data/strings/en.ini                          |   8 +
 data/widgets/color_mode.xml                  |  12 +-
 data/widgets/options.xml                     |   6 +-
 src/app/CMakeLists.txt                       |   1 +
 src/app/cmd/set_pixel_format.cpp             |  16 +-
 src/app/cmd/set_pixel_format.h               |   9 +-
 src/app/commands/cmd_change_pixel_format.cpp |  50 ++++--
 src/app/commands/cmd_options.cpp             |   7 +
 src/app/script/values.cpp                    |   1 +
 src/app/ui/best_fit_criteria_selector.cpp    |  46 +++++
 src/app/ui/best_fit_criteria_selector.h      |  27 +++
 src/doc/CMakeLists.txt                       |   1 +
 src/doc/fit_criteria.h                       |  23 +++
 src/doc/octree_map.cpp                       |  31 ++--
 src/doc/octree_map.h                         |  38 ++---
 src/doc/palette.cpp                          | 166 +++----------------
 src/doc/rgbmap.h                             |  19 ++-
 src/doc/rgbmap_base.cpp                      | 131 +++++++++++++++
 src/doc/rgbmap_base.h                        |  42 +++++
 src/doc/rgbmap_rgb5a3.cpp                    |  20 +--
 src/doc/rgbmap_rgb5a3.h                      |  21 ++-
 src/doc/sprite.cpp                           |  23 ++-
 src/doc/sprite.h                             |   5 +-
 24 files changed, 476 insertions(+), 228 deletions(-)
 create mode 100644 src/app/ui/best_fit_criteria_selector.cpp
 create mode 100644 src/app/ui/best_fit_criteria_selector.h
 create mode 100644 src/doc/fit_criteria.h
 create mode 100644 src/doc/rgbmap_base.cpp
 create mode 100644 src/doc/rgbmap_base.h

diff --git a/data/pref.xml b/data/pref.xml
index b4e7c81e1..6e7f29e21 100644
--- a/data/pref.xml
+++ b/data/pref.xml
@@ -321,6 +321,7 @@
       <option id="to_gray" type="ToGrayAlgorithm" default="ToGrayAlgorithm::DEFAULT" />
       <option id="advanced" type="bool" default="false" />
       <option id="rgbmap_algorithm" type="doc::RgbMapAlgorithm" default="doc::RgbMapAlgorithm::DEFAULT" />
+      <option id="fit_criteria" type="doc::FitCriteria" default="doc::FitCriteria::DEFAULT" />
     </section>
     <section id="eyedropper" text="Editor">
       <option id="channel" type="EyedropperChannel" default="EyedropperChannel::COLOR_ALPHA" />
diff --git a/data/strings/en.ini b/data/strings/en.ini
index d9ece8cf2..320f08290 100644
--- a/data/strings/en.ini
+++ b/data/strings/en.ini
@@ -1255,6 +1255,14 @@ default = Default (Octree)
 rgb5a3 = Table RGB 5 bits + Alpha 3 bits
 octree = Octree
 
+[best_fit_criteria_selector]
+label = Color Best Fit Criteria:
+default = Default (Euclidean)
+rgb = RGB
+linearized_rgb = Linearized RGB
+cie_xyz = CIEXYZ
+cie_lab = CIELAB
+
 [open_file]
 title = Open
 loading = Loading file
diff --git a/data/widgets/color_mode.xml b/data/widgets/color_mode.xml
index e02ce7fab..83d074e68 100644
--- a/data/widgets/color_mode.xml
+++ b/data/widgets/color_mode.xml
@@ -1,5 +1,5 @@
 <!-- Aseprite -->
-<!-- Copyright (C) 2019-2020  Igara Studio S.A. -->
+<!-- Copyright (C) 2019-2024  Igara Studio S.A. -->
 <!-- Copyright (C) 2017  David Capello -->
 <gui>
 <window id="color_mode" text="@.title">
@@ -23,10 +23,12 @@
     <check text="@.flatten" id="flatten" />
 
     <check id="advanced_check" text="@general.advanced_options" cell_hspan="2" />
-    <hbox id="advanced" cell_hspan="2">
-      <label text="@rgbmap_algorithm_selector.label" />
-      <hbox id="rgbmap_algorithm_placeholder" />
-    </hbox>
+    <vbox id="advanced" cell_hspan="2">
+      <label text="@rgbmap_algorithm_selector.label" cell_hspan="1" />
+      <hbox id="rgbmap_algorithm_placeholder" cell_hspan="1" />
+      <label text="@best_fit_criteria_selector.label" cell_hspan="1" />
+      <hbox id="best_fit_criteria_placeholder" cell_hspan="1" />
+    </vbox>
 
     <separator horizontal="true" />
     <hbox>
diff --git a/data/widgets/options.xml b/data/widgets/options.xml
index fbd339960..9d04d39ab 100644
--- a/data/widgets/options.xml
+++ b/data/widgets/options.xml
@@ -587,10 +587,12 @@
             <slider id="nonactive_layers_opacity" min="0" max="255" width="128" />
           </hbox>
           <separator text="@.color_quantization" horizontal="true" />
-          <hbox>
+          <grid columns="2">
             <label text="@rgbmap_algorithm_selector.label" />
             <hbox id="rgbmap_algorithm_placeholder" />
-          </hbox>
+            <label text="@best_fit_criteria_selector.label" />
+            <hbox id="best_fit_criteria_placeholder" />
+          </grid>
           <separator text="@.performance" horizontal="true" />
           <hbox>
             <check id="shaders_for_color_selectors"
diff --git a/src/app/CMakeLists.txt b/src/app/CMakeLists.txt
index 44249ecb7..f35d6510e 100644
--- a/src/app/CMakeLists.txt
+++ b/src/app/CMakeLists.txt
@@ -579,6 +579,7 @@ target_sources(app-lib PRIVATE
   ui/alpha_slider.cpp
   ui/app_menuitem.cpp
   ui/backup_indicator.cpp
+  ui/best_fit_criteria_selector.cpp
   ui/browser_view.cpp
   ui/brush_popup.cpp
   ui/button_set.cpp
diff --git a/src/app/cmd/set_pixel_format.cpp b/src/app/cmd/set_pixel_format.cpp
index f69613ad6..f9233d59e 100644
--- a/src/app/cmd/set_pixel_format.cpp
+++ b/src/app/cmd/set_pixel_format.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2023  Igara Studio S.A.
+// Copyright (C) 2019-2024  Igara Studio S.A.
 // Copyright (C) 2001-2018  David Capello
 //
 // This program is distributed under the terms of
@@ -73,7 +73,8 @@ SetPixelFormat::SetPixelFormat(Sprite* sprite,
                                const render::Dithering& dithering,
                                const doc::RgbMapAlgorithm mapAlgorithm,
                                doc::rgba_to_graya_func toGray,
-                               render::TaskDelegate* delegate)
+                               render::TaskDelegate* delegate,
+                               const FitCriteria fitCriteria)
   : WithSprite(sprite)
   , m_oldFormat(sprite->pixelFormat())
   , m_newFormat(newFormat)
@@ -108,7 +109,8 @@ SetPixelFormat::SetPixelFormat(Sprite* sprite,
                  cel->layer()->isBackground(),
                  mapAlgorithm,
                  toGray,
-                 &superDel);
+                 &superDel,
+                 fitCriteria);
 
     superDel.nextImage();
   }
@@ -208,7 +210,8 @@ void SetPixelFormat::convertImage(doc::Sprite* sprite,
                                   const bool isBackground,
                                   const doc::RgbMapAlgorithm mapAlgorithm,
                                   doc::rgba_to_graya_func toGray,
-                                  render::TaskDelegate* delegate)
+                                  render::TaskDelegate* delegate,
+                                  const doc::FitCriteria fitCriteria)
 {
   ASSERT(oldImage);
   ASSERT(oldImage->pixelFormat() != IMAGE_TILEMAP);
@@ -218,7 +221,10 @@ void SetPixelFormat::convertImage(doc::Sprite* sprite,
   RgbMap* rgbmap;
   int newMaskIndex = (isBackground ? -1 : 0);
   if (m_newFormat == IMAGE_INDEXED) {
-    rgbmap = sprite->rgbMap(frame, sprite->rgbMapForSprite(), mapAlgorithm);
+    rgbmap = sprite->rgbMap(frame,
+                            sprite->rgbMapForSprite(),
+                            mapAlgorithm,
+                            fitCriteria);
     if (m_oldFormat == IMAGE_INDEXED)
       newMaskIndex = sprite->transparentColor();
     else
diff --git a/src/app/cmd/set_pixel_format.h b/src/app/cmd/set_pixel_format.h
index db817a033..d02cc4db4 100644
--- a/src/app/cmd/set_pixel_format.h
+++ b/src/app/cmd/set_pixel_format.h
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (C) 2019-2020  Igara Studio S.A.
+// Copyright (C) 2019-2024  Igara Studio S.A.
 // Copyright (C) 2001-2017  David Capello
 //
 // This program is distributed under the terms of
@@ -12,6 +12,7 @@
 #include "app/cmd/with_sprite.h"
 #include "app/cmd_sequence.h"
 #include "doc/color.h"
+#include "doc/fit_criteria.h"
 #include "doc/frame.h"
 #include "doc/image_ref.h"
 #include "doc/pixel_format.h"
@@ -37,7 +38,8 @@ namespace cmd {
                    const render::Dithering& dithering,
                    const doc::RgbMapAlgorithm mapAlgorithm,
                    doc::rgba_to_graya_func toGray,
-                   render::TaskDelegate* delegate);
+                   render::TaskDelegate* delegate,
+                   const doc::FitCriteria fitCriteria = doc::FitCriteria::DEFAULT);
 
   protected:
     void onExecute() override;
@@ -56,7 +58,8 @@ namespace cmd {
                       const bool isBackground,
                       const doc::RgbMapAlgorithm mapAlgorithm,
                       doc::rgba_to_graya_func toGray,
-                      render::TaskDelegate* delegate);
+                      render::TaskDelegate* delegate,
+                      const doc::FitCriteria fitCriteria = doc::FitCriteria::DEFAULT);
 
     doc::PixelFormat m_oldFormat;
     doc::PixelFormat m_newFormat;
diff --git a/src/app/commands/cmd_change_pixel_format.cpp b/src/app/commands/cmd_change_pixel_format.cpp
index 341f6c4b4..541f1ce15 100644
--- a/src/app/commands/cmd_change_pixel_format.cpp
+++ b/src/app/commands/cmd_change_pixel_format.cpp
@@ -23,6 +23,7 @@
 #include "app/modules/palettes.h"
 #include "app/sprite_job.h"
 #include "app/transaction.h"
+#include "app/ui/best_fit_criteria_selector.h"
 #include "app/ui/dithering_selector.h"
 #include "app/ui/editor/editor.h"
 #include "app/ui/editor/editor_render.h"
@@ -69,7 +70,6 @@ public:
                 const doc::frame_t frame,
                 const doc::PixelFormat pixelFormat,
                 const render::Dithering& dithering,
-                const doc::RgbMapAlgorithm rgbMapAlgorithm,
                 const gen::ToGrayAlgorithm toGray,
                 const gfx::Point& pos,
                 const bool newBlend)
@@ -83,13 +83,11 @@ public:
        sprite, frame,
        pixelFormat,
        dithering,
-       rgbMapAlgorithm,
        toGray,
        newBlend]() { // Copy the matrix
         run(sprite, frame,
             pixelFormat,
             dithering,
-            rgbMapAlgorithm,
             toGray,
             newBlend);
       })
@@ -114,7 +112,6 @@ private:
            const doc::frame_t frame,
            const doc::PixelFormat pixelFormat,
            const render::Dithering& dithering,
-           const doc::RgbMapAlgorithm rgbMapAlgorithm,
            const gen::ToGrayAlgorithm toGray,
            const bool newBlend) {
     doc::ImageRef tmp(
@@ -136,9 +133,7 @@ private:
       m_image.get(),
       pixelFormat,
       dithering,
-      sprite->rgbMap(frame,
-                     sprite->rgbMapForSprite(),
-                     rgbMapAlgorithm),
+      sprite->rgbMap(frame),
       sprite->palette(frame),
       (sprite->backgroundLayer() != nullptr),
       0,
@@ -193,6 +188,7 @@ public:
     , m_selectedItem(nullptr)
     , m_ditheringSelector(nullptr)
     , m_mapAlgorithmSelector(nullptr)
+    , m_bestFitCriteriaSelector(nullptr)
     , m_imageJustCreated(true)
   {
     const auto& pref = Preferences::instance();
@@ -219,6 +215,9 @@ public:
       m_mapAlgorithmSelector = new RgbMapAlgorithmSelector;
       m_mapAlgorithmSelector->setExpansive(true);
 
+      m_bestFitCriteriaSelector = new BestFitCriteriaSelector;
+      m_bestFitCriteriaSelector->setExpansive(true);
+
       // Select default dithering method
       {
         int index = m_ditheringSelector->findItemIndex(
@@ -230,8 +229,12 @@ public:
       // Select default RgbMap algorithm
       m_mapAlgorithmSelector->algorithm(pref.quantization.rgbmapAlgorithm());
 
+      // Select default best fit criteria
+      m_bestFitCriteriaSelector->criteria(pref.quantization.fitCriteria());
+
       ditheringPlaceholder()->addChild(m_ditheringSelector);
       rgbmapAlgorithmPlaceholder()->addChild(m_mapAlgorithmSelector);
+      bestFitCriteriaPlaceholder()->addChild(m_bestFitCriteriaSelector);
 
       const bool adv = pref.quantization.advanced();
       advancedCheck()->setSelected(adv);
@@ -240,6 +243,7 @@ public:
       // Signals
       m_ditheringSelector->Change.connect([this]{ onIndexParamChange(); });
       m_mapAlgorithmSelector->Change.connect([this]{ onIndexParamChange(); });
+      m_bestFitCriteriaSelector->Change.connect([this]{ onIndexParamChange(); });
       factor()->Change.connect([this]{ onIndexParamChange(); });
 
       advancedCheck()->Click.connect(
@@ -301,6 +305,13 @@ public:
       return doc::RgbMapAlgorithm::DEFAULT;
   }
 
+  doc::FitCriteria fitCriteria() const {
+    if (m_bestFitCriteriaSelector)
+      return m_bestFitCriteriaSelector->criteria();
+    else
+      return doc::FitCriteria::DEFAULT;
+  }
+
   gen::ToGrayAlgorithm toGray() const {
     static_assert(
       int(gen::ToGrayAlgorithm::LUMA) == 0 &&
@@ -331,7 +342,7 @@ public:
       }
     }
 
-    if (m_mapAlgorithmSelector)
+    if (m_mapAlgorithmSelector || m_bestFitCriteriaSelector)
       pref.quantization.advanced(advancedCheck()->isSelected());
   }
 
@@ -396,6 +407,12 @@ private:
       visibleBounds.origin(),
       doc::BlendMode::SRC);
 
+    m_editor->sprite()->rgbMap(
+      0,
+      m_editor->sprite()->rgbMapForSprite(),
+      rgbMapAlgorithm(),
+      fitCriteria());
+
     m_editor->invalidate();
     progress()->setValue(0);
     progress()->setVisible(false);
@@ -408,7 +425,6 @@ private:
         m_editor->frame(),
         dstPixelFormat,
         dithering(),
-        rgbMapAlgorithm(),
         toGray(),
         visibleBounds.origin(),
         Preferences::instance().experimental.newBlend()));
@@ -463,6 +479,7 @@ private:
   ConversionItem* m_selectedItem;
   DitheringSelector* m_ditheringSelector;
   RgbMapAlgorithmSelector* m_mapAlgorithmSelector;
+  BestFitCriteriaSelector* m_bestFitCriteriaSelector;
   bool m_imageJustCreated;
 };
 
@@ -485,6 +502,7 @@ private:
   doc::PixelFormat m_format;
   render::Dithering m_dithering;
   doc::RgbMapAlgorithm m_rgbmap;
+  doc::FitCriteria m_fitCriteria = FitCriteria::DEFAULT;
   gen::ToGrayAlgorithm m_toGray;
 };
 
@@ -624,7 +642,10 @@ void ChangePixelFormatCommand::onExecute(Context* context)
 {
   bool flatten = false;
 
-  if (context->isUIAvailable() && m_showDlg) {
+  if (!context->isUIAvailable()) {
+    // do nothing
+  }
+  else if (m_showDlg) {
     ColorModeWindow window(Editor::activeEditor());
 
     window.remapWindow();
@@ -640,11 +661,17 @@ void ChangePixelFormatCommand::onExecute(Context* context)
     m_format = window.pixelFormat();
     m_dithering = window.dithering();
     m_rgbmap = window.rgbMapAlgorithm();
+    m_fitCriteria = window.fitCriteria();
     m_toGray = window.toGray();
     flatten = window.flattenEnabled();
 
     window.saveOptions();
   }
+  else {
+    // TO DO: in a first approach a simple conversion to indexed color mode
+    // it's just via the old fit criteria (Euclidean color distance).
+    m_fitCriteria = FitCriteria::DEFAULT;
+  }
 
   // No conversion needed
   Doc* doc = context->activeDocument();
@@ -679,7 +706,8 @@ void ChangePixelFormatCommand::onExecute(Context* context)
             m_dithering,
             m_rgbmap,
             get_gray_func(m_toGray),
-            &job));             // SpriteJob is a render::TaskDelegate
+            &job,
+            m_fitCriteria));             // SpriteJob is a render::TaskDelegate
       });
     job.waitJob();
   }
diff --git a/src/app/commands/cmd_options.cpp b/src/app/commands/cmd_options.cpp
index 90d07121e..4814ae5dd 100644
--- a/src/app/commands/cmd_options.cpp
+++ b/src/app/commands/cmd_options.cpp
@@ -26,6 +26,7 @@
 #include "app/recent_files.h"
 #include "app/resource_finder.h"
 #include "app/tx.h"
+#include "app/ui/best_fit_criteria_selector.h"
 #include "app/ui/color_button.h"
 #include "app/ui/main_window.h"
 #include "app/ui/pref_widget.h"
@@ -478,6 +479,10 @@ public:
     m_rgbmapAlgorithmSelector.setExpansive(true);
     m_rgbmapAlgorithmSelector.algorithm(m_pref.quantization.rgbmapAlgorithm());
 
+    bestFitCriteriaPlaceholder()->addChild(&m_bestFitCriteriaSelector);
+    m_bestFitCriteriaSelector.setExpansive(true);
+    m_bestFitCriteriaSelector.criteria(m_pref.quantization.fitCriteria());
+
     if (m_pref.editor.showScrollbars())
       showScrollbars()->setSelected(true);
 
@@ -828,6 +833,7 @@ public:
     m_pref.experimental.flashLayer(flashLayer()->isSelected());
     m_pref.experimental.nonactiveLayersOpacity(nonactiveLayersOpacity()->getValue());
     m_pref.quantization.rgbmapAlgorithm(m_rgbmapAlgorithmSelector.algorithm());
+    m_pref.quantization.fitCriteria(m_bestFitCriteriaSelector.criteria());
 
 #ifdef LAF_WINDOWS
     {
@@ -1842,6 +1848,7 @@ private:
   std::vector<os::ColorSpaceRef> m_colorSpaces;
   std::string m_templateTextForDisplayCS;
   RgbMapAlgorithmSelector m_rgbmapAlgorithmSelector;
+  BestFitCriteriaSelector m_bestFitCriteriaSelector;
   ButtonSet* m_themeVars = nullptr;
   SamplingSelector* m_samplingSelector = nullptr;
 };
diff --git a/src/app/script/values.cpp b/src/app/script/values.cpp
index 70c91d7e5..4151c106d 100644
--- a/src/app/script/values.cpp
+++ b/src/app/script/values.cpp
@@ -342,6 +342,7 @@ FOR_ENUM(app::tools::RotationAlgorithm)
 FOR_ENUM(doc::AniDir)
 FOR_ENUM(doc::BrushPattern)
 FOR_ENUM(doc::ColorMode)
+FOR_ENUM(doc::FitCriteria)
 FOR_ENUM(doc::RgbMapAlgorithm)
 FOR_ENUM(filters::HueSaturationFilter::Mode)
 FOR_ENUM(filters::TiledMode)
diff --git a/src/app/ui/best_fit_criteria_selector.cpp b/src/app/ui/best_fit_criteria_selector.cpp
new file mode 100644
index 000000000..a6823d417
--- /dev/null
+++ b/src/app/ui/best_fit_criteria_selector.cpp
@@ -0,0 +1,46 @@
+// Aseprite
+// Copyright (C) 2024  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "app/ui/best_fit_criteria_selector.h"
+
+#include "app/i18n/strings.h"
+
+namespace app {
+
+BestFitCriteriaSelector::BestFitCriteriaSelector()
+{
+  // addItem() must match the FitCriteria enum
+  static_assert(int(doc::FitCriteria::DEFAULT) == 0 &&
+                int(doc::FitCriteria::RGB) == 1 &&
+                int(doc::FitCriteria::linearizedRGB) == 2 &&
+                int(doc::FitCriteria::CIEXYZ) == 3 &&
+                int(doc::FitCriteria::CIELAB) == 4,
+                "Unexpected doc::FitCriteria values");
+
+  addItem(Strings::best_fit_criteria_selector_default());
+  addItem(Strings::best_fit_criteria_selector_rgb());
+  addItem(Strings::best_fit_criteria_selector_linearized_rgb());
+  addItem(Strings::best_fit_criteria_selector_cie_xyz());
+  addItem(Strings::best_fit_criteria_selector_cie_lab());
+
+  criteria(doc::FitCriteria::DEFAULT);
+}
+
+doc::FitCriteria BestFitCriteriaSelector::criteria()
+{
+  return (doc::FitCriteria)getSelectedItemIndex();
+}
+
+void BestFitCriteriaSelector::criteria(const doc::FitCriteria criteria)
+{
+  setSelectedItemIndex((int)criteria);
+}
+
+} // namespace app
diff --git a/src/app/ui/best_fit_criteria_selector.h b/src/app/ui/best_fit_criteria_selector.h
new file mode 100644
index 000000000..712c28c83
--- /dev/null
+++ b/src/app/ui/best_fit_criteria_selector.h
@@ -0,0 +1,27 @@
+// Aseprite
+// Copyright (C) 2024  Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#ifndef APP_UI_BEST_FIT_CRITERIA_SELECTOR_H_INCLUDED
+#define APP_UI_BEST_FIT_CRITERIA_SELECTOR_H_INCLUDED
+#pragma once
+
+#include "doc/fit_criteria.h"
+#include "doc/palette.h"
+#include "ui/combobox.h"
+
+namespace app {
+
+  class BestFitCriteriaSelector : public ui::ComboBox {
+  public:
+    BestFitCriteriaSelector();
+
+    doc::FitCriteria criteria();
+    void criteria(doc::FitCriteria criteria);
+  };
+
+} // namespace app
+
+#endif
diff --git a/src/doc/CMakeLists.txt b/src/doc/CMakeLists.txt
index 621dfc7db..308fe7c77 100644
--- a/src/doc/CMakeLists.txt
+++ b/src/doc/CMakeLists.txt
@@ -61,6 +61,7 @@ add_library(doc-lib
   primitives.cpp
   remap.cpp
   render_plan.cpp
+  rgbmap_base.cpp
   rgbmap_rgb5a3.cpp
   selected_frames.cpp
   selected_layers.cpp
diff --git a/src/doc/fit_criteria.h b/src/doc/fit_criteria.h
new file mode 100644
index 000000000..7704b14d3
--- /dev/null
+++ b/src/doc/fit_criteria.h
@@ -0,0 +1,23 @@
+// Aseprite Document Library
+// Copyright (C) 2024  Igara Studio S.A.
+//
+// This file is released under the terms of the MIT license.
+// Read LICENSE.txt for more information.
+
+#ifndef DOC_FIT_CRITERIA_H_INCLUDED
+#define DOC_FIT_CRITERIA_H_INCLUDED
+#pragma once
+
+namespace doc {
+
+  enum class FitCriteria {
+    DEFAULT = 0,
+    RGB = 1,
+    linearizedRGB = 2,
+    CIEXYZ = 3,
+    CIELAB = 4
+  };
+
+} // namespace doc
+
+#endif
diff --git a/src/doc/octree_map.cpp b/src/doc/octree_map.cpp
index b4304bb2f..d76949f83 100644
--- a/src/doc/octree_map.cpp
+++ b/src/doc/octree_map.cpp
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (c) 2020-2023 Igara Studio S.A.
+// Copyright (c) 2020-2024 Igara Studio S.A.
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -35,19 +35,21 @@ void OctreeNode::addColor(color_t c, int level, OctreeNode* parent,
   (*m_children)[index].addColor(c, level + 1, this, paletteIndex, levelDeep);
 }
 
-int OctreeNode::mapColor(int  r, int g, int b, int a, int mask_index, const Palette* palette, int level) const
+int OctreeNode::mapColor(int  r, int g, int b, int a, int mask_index,
+                         const Palette* palette, int level,
+                         const OctreeMap* octree) const
 {
   // New behavior: if mapColor do not have an exact rgba match, it must calculate which
   // color of the current palette is the bestfit and memorize the index in a octree leaf.
   if (level >= 8) {
     if (m_paletteIndex == -1)
-      m_paletteIndex = palette->findBestfit(r, g, b, a, mask_index);
+      m_paletteIndex = octree->findBestfit(r, g, b, a, mask_index);
     return m_paletteIndex;
   }
   int index = getHextet(r, g, b, a, level);
   if (!m_children)
     m_children.reset(new std::array<OctreeNode, 16>());
-  return (*m_children)[index].mapColor(r, g, b, a, mask_index, palette, level + 1);
+  return (*m_children)[index].mapColor(r, g, b, a, mask_index, palette, level + 1, octree);
 }
 
 void OctreeNode::collectLeafNodes(OctreeNodes& leavesVector, int& paletteIndex)
@@ -268,10 +270,13 @@ int OctreeMap::mapColor(color_t rgba) const
                          rgba_getb(rgba),
                          rgba_geta(rgba),
                          m_maskIndex,
-                         m_palette, 0);
+                         m_palette, 0,
+                         this);
 }
 
-void OctreeMap::regenerateMap(const Palette* palette, const int maskIndex)
+void OctreeMap::regenerateMap(const Palette* palette,
+                              const int maskIndex,
+                              const FitCriteria fitCriteria)
 {
   ASSERT(palette);
   if (!palette)
@@ -280,9 +285,12 @@ void OctreeMap::regenerateMap(const Palette* palette, const int maskIndex)
   // Skip useless regenerations
   if (m_palette == palette &&
       m_modifications == palette->getModifications() &&
-      m_maskIndex == maskIndex)
+      m_maskIndex == maskIndex &&
+      m_fitCriteria == fitCriteria)
     return;
 
+  m_palette = palette;
+  m_fitCriteria = fitCriteria;
   m_root = OctreeNode();
   m_leavesVector.clear();
   m_maskIndex = maskIndex;
@@ -293,10 +301,10 @@ void OctreeMap::regenerateMap(const Palette* palette, const int maskIndex)
   }
   else {
     m_maskColor = palette->getEntry(maskIndex);
-    maskColorBestFitIndex = palette->findBestfit(rgba_getr(m_maskColor),
-                                                 rgba_getg(m_maskColor),
-                                                 rgba_getb(m_maskColor),
-                                                 rgba_geta(m_maskColor), maskIndex);
+    maskColorBestFitIndex = findBestfit(rgba_getr(m_maskColor),
+                                        rgba_getg(m_maskColor),
+                                        rgba_getb(m_maskColor),
+                                        rgba_geta(m_maskColor), maskIndex);
   }
 
   for (int i=0; i<palette->size(); i++) {
@@ -307,7 +315,6 @@ void OctreeMap::regenerateMap(const Palette* palette, const int maskIndex)
     m_root.addColor(palette->entry(i), 0, &m_root, i, 8);
   }
 
-  m_palette = palette;
   m_modifications = palette->getModifications();
 }
 
diff --git a/src/doc/octree_map.h b/src/doc/octree_map.h
index a4a9a0244..b50f3c6cd 100644
--- a/src/doc/octree_map.h
+++ b/src/doc/octree_map.h
@@ -1,5 +1,5 @@
 // Aseprite
-// Copyright (c) 2020-2022 Igara Studio S.A.
+// Copyright (c) 2020-2024 Igara Studio S.A.
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -11,7 +11,7 @@
 #include "doc/color.h"
 #include "doc/image_impl.h"
 #include "doc/palette.h"
-#include "doc/rgbmap.h"
+#include "doc/rgbmap_base.h"
 
 #include <array>
 #include <memory>
@@ -26,6 +26,8 @@
 namespace doc {
 
 class OctreeNode;
+class OctreeMap;
+
 using OctreeNodes = std::vector<OctreeNode*>;
 
 class OctreeNode {
@@ -93,7 +95,9 @@ public:
   void addColor(color_t c, int level, OctreeNode* parent,
                 int paletteIndex = 0, int levelDeep = 7);
 
-  int mapColor(int  r, int g, int b, int a, int mask_index, const Palette* palette, int level) const;
+  int mapColor(int  r, int g, int b, int a, int mask_index,
+               const Palette* palette, int level,
+               const OctreeMap* octree) const;
 
   void collectLeafNodes(OctreeNodes& leavesVector, int& paletteIndex);
 
@@ -117,7 +121,7 @@ private:
   OctreeNode* m_parent = nullptr;
 };
 
-class OctreeMap : public RgbMap {
+class OctreeMap : public RgbMapBase {
 public:
   void addColor(color_t color, int levelDeep = 7) {
     m_root.addColor(color, 0, &m_root, 0, levelDeep);
@@ -135,27 +139,23 @@ public:
                      const int levelDeep = 7);
 
   // RgbMap impl
-  void regenerateMap(const Palette* palette, const int maskIndex) override;
-  int mapColor(color_t rgba) const override;
-  int maskIndex() const override { return m_maskIndex; }
-  int mapColor(const int r, const int g,
-               const int b, const int a) const
-  {
-    ASSERT(r >= 0 && r < 256);
-    ASSERT(g >= 0 && g < 256);
-    ASSERT(b >= 0 && b < 256);
-    ASSERT(a >= 0 && a < 256);
-    return mapColor(rgba(r, g, b, a));
+  void regenerateMap(const Palette* palette,
+                     const int maskIndex,
+                     const FitCriteria fitCriteria) override;
+  void regenerateMap(const Palette* palette,
+                     const int maskIndex) override {
+    regenerateMap(palette, maskIndex, m_fitCriteria);
   }
 
-  int moodifications() const { return m_modifications; };
+  int mapColor(color_t rgba) const override;
+
+  RgbMapAlgorithm rgbmapAlgorithm() const override {
+    return RgbMapAlgorithm::OCTREE;
+  }
 
 private:
   OctreeNode m_root;
   OctreeNodes m_leavesVector;
-  const Palette* m_palette = nullptr;
-  int m_modifications = 0;
-  int m_maskIndex = 0;
   color_t m_maskColor = 0;
 };
 
diff --git a/src/doc/palette.cpp b/src/doc/palette.cpp
index 681c3e432..753d91adb 100644
--- a/src/doc/palette.cpp
+++ b/src/doc/palette.cpp
@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2020-2023 Igara Studio S.A.
+// Copyright (c) 2020-2024 Igara Studio S.A.
 // Copyright (c) 2001-2017 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -26,14 +26,6 @@ namespace doc {
 
 using namespace gfx;
 
-enum class FitCriteria {
-  OLD,
-  RGB,
-  linearizedRGB,
-  CIEXYZ,
-  CIELAB
-};
-
 Palette::Palette()
   : Palette(0, 256)
 {
@@ -346,154 +338,46 @@ void Palette::initBestfit()
   }
 }
 
-// Auxiliary function for rgbToOtherSpace()
-static double f(double t)
-{
-  if (t > 0.00885645171)
-    return std::pow(t, 0.3333333333333333);
-  else
-    return (t / 0.12841855 + 0.137931034);
-}
-
-// Auxiliary function for findBestfit()
-static void rgbToOtherSpace(double& r, double& g, double& b, FitCriteria fc)
-{
-  if (fc == FitCriteria::RGB)
-    return;
-  double Rl, Gl, Bl;
-  // Linearization:
-  r = r / 255.0;
-  g = g / 255.0;
-  b = b / 255.0;
-  if (r <= 0.04045)
-    Rl = r / 12.92;
-  else
-    Rl = std::pow((r + 0.055) / 1.055, 2.4);
-  if (g <= 0.04045)
-    Gl = g / 12.92;
-  else
-    Gl = std::pow((g + 0.055) / 1.055, 2.4);
-  if (b <= 0.04045)
-    Bl = b / 12.92;
-  else
-    Bl = std::pow((b + 0.055) / 1.055, 2.4);
-  if (fc == FitCriteria::linearizedRGB) {
-    r = Rl;
-    g = Gl;
-    b = Bl;
-    return;
-  }
-  // Conversion lineal RGB to CIE XYZ
-  r = 41.24564*Rl + 35.75761 * Gl + 18.04375 * Bl;
-  g = 21.26729*Rl + 71.51522 * Gl + 7.2175   * Bl;
-  b = 1.93339*Rl  + 11.91920 * Gl + 95.03041 * Bl;
-  switch (fc) {
-
-    case FitCriteria::CIEXYZ:
-      return;
-
-    case FitCriteria::CIELAB: {
-      // Converting CIEXYZ to CIELAB:
-      // For Standard Illuminant D65:
-      //  const double xn = 95.0489;
-      //  const double yn = 100.0;
-      //  const double zn = 108.884;
-      double xxn = r / 95.0489;
-      double yyn = g / 100.0;
-      double zzn = b / 108.884;
-      double fyyn = f(yyn);
-
-      double Lstar = 116.0 * fyyn - 16.0;
-      double aStar = 500.0 * (f(xxn) - fyyn);
-      double bStar = 200.0 * (fyyn - f(zzn));
-
-      r = Lstar;
-      g = aStar;
-      b = bStar;
-      return;
-    }
-  }
-}
-
 int Palette::findBestfit(int r, int g, int b, int a, int mask_index) const
 {
   ASSERT(r >= 0 && r <= 255);
   ASSERT(g >= 0 && g <= 255);
   ASSERT(b >= 0 && b <= 255);
   ASSERT(a >= 0 && a <= 255);
+  ASSERT(!col_diff.empty());
 
-  FitCriteria fc = FitCriteria::OLD;
-
-  if (fc == FitCriteria::OLD) {
-    ASSERT(!col_diff.empty());
-
-    r >>= 3;
-    g >>= 3;
-    b >>= 3;
-    a >>= 3;
-
-    // Mask index is like alpha = 0, so we can use it as transparent color.
-    if (a == 0 && mask_index >= 0)
-      return mask_index;
-
-    int bestfit = 0;
-    int lowest = std::numeric_limits<int>::max();
-    int size = std::min(256, int(m_colors.size()));
-
-    for (int i=0; i<size; ++i) {
-      color_t rgb = m_colors[i];
-
-      int coldiff = col_diff_g[((rgba_getg(rgb)>>3) - g) & 127];
-      if (coldiff < lowest) {
-        coldiff += col_diff_r[(((rgba_getr(rgb)>>3) - r) & 127)];
-        if (coldiff < lowest) {
-          coldiff += col_diff_b[(((rgba_getb(rgb)>>3) - b) & 127)];
-          if (coldiff < lowest) {
-            coldiff += col_diff_a[(((rgba_geta(rgb)>>3) - a) & 127)];
-            if (coldiff < lowest && i != mask_index) {
-              if (coldiff == 0)
-                return i;
-
-              bestfit = i;
-              lowest = coldiff;
-            }
-          }
-        }
-      }
-    }
-
-    return bestfit;
-  }
+  r >>= 3;
+  g >>= 3;
+  b >>= 3;
+  a >>= 3;
 
+  // Mask index is like alpha = 0, so we can use it as transparent color.
   if (a == 0 && mask_index >= 0)
     return mask_index;
 
   int bestfit = 0;
-  double lowest = std::numeric_limits<double>::max();
-  int size = m_colors.size();
-  // Linearice:
-  double x = double(r);
-  double y = double(g);
-  double z = double(b);
-
-  rgbToOtherSpace(x, y, z, fc);
+  int lowest = std::numeric_limits<int>::max();
+  int size = std::min(256, int(m_colors.size()));
 
   for (int i=0; i<size; ++i) {
     color_t rgb = m_colors[i];
-    double Xpal = double(rgba_getr(rgb));
-    double Ypal = double(rgba_getg(rgb));
-    double Zpal = double(rgba_getb(rgb));
-    // Palette color conversion RGB-->XYZ and r,g,b is assumed CIE XYZ
-    rgbToOtherSpace(Xpal, Ypal, Zpal, fc);
-    double xDiff = x - Xpal;
-    double yDiff = y - Ypal;
-    double zDiff = z - Zpal;
-    double aDiff = double(a - rgba_geta(rgb)) / 128.0;
 
-    double diff = xDiff * xDiff + yDiff * yDiff + zDiff * zDiff + aDiff * aDiff;
-    if (diff < lowest) {
-      lowest = diff;
-      bestfit = i;
+    int coldiff = col_diff_g[((rgba_getg(rgb)>>3) - g) & 127];
+    if (coldiff < lowest) {
+      coldiff += col_diff_r[(((rgba_getr(rgb)>>3) - r) & 127)];
+      if (coldiff < lowest) {
+        coldiff += col_diff_b[(((rgba_getb(rgb)>>3) - b) & 127)];
+        if (coldiff < lowest) {
+          coldiff += col_diff_a[(((rgba_geta(rgb)>>3) - a) & 127)];
+          if (coldiff < lowest && i != mask_index) {
+            if (coldiff == 0)
+              return i;
+
+            bestfit = i;
+            lowest = coldiff;
+          }
+        }
+      }
     }
   }
   return bestfit;
diff --git a/src/doc/rgbmap.h b/src/doc/rgbmap.h
index ac1bf9fd0..faec5a38c 100644
--- a/src/doc/rgbmap.h
+++ b/src/doc/rgbmap.h
@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2020-2022 Igara Studio S.A.
+// Copyright (c) 2020-2024 Igara Studio S.A.
 //
 // This file is released under the terms of the MIT license.
 // Read LICENSE.txt for more information.
@@ -10,6 +10,8 @@
 
 #include "base/debug.h"
 #include "doc/color.h"
+#include "doc/fit_criteria.h"
+#include "doc/rgbmap_algorithm.h"
 
 namespace doc {
 
@@ -20,13 +22,26 @@ namespace doc {
   public:
     virtual ~RgbMap() { }
 
-    virtual void regenerateMap(const Palette* palette, const int maskIndex) = 0;
+    virtual void regenerateMap(const Palette* palette,
+                               const int maskIndex,
+                               const FitCriteria fitCriteria) = 0;
+
+    virtual void regenerateMap(const Palette* palette,
+                               const int maskIndex) = 0;
 
     // Should return the best index in a palette that matches the given RGBA values.
     virtual int mapColor(const color_t rgba) const = 0;
 
     virtual int maskIndex() const = 0;
 
+    virtual RgbMapAlgorithm rgbmapAlgorithm() const = 0;
+
+    virtual int modifications() const = 0;
+
+    // Color Best Fit Criteria used to generate the rgbmap
+    virtual FitCriteria fitCriteria() const = 0;
+    virtual void fitCriteria(const FitCriteria fitCriteria) = 0;
+
     int mapColor(const int r,
                  const int g,
                  const int b,
diff --git a/src/doc/rgbmap_base.cpp b/src/doc/rgbmap_base.cpp
new file mode 100644
index 000000000..53d97256d
--- /dev/null
+++ b/src/doc/rgbmap_base.cpp
@@ -0,0 +1,131 @@
+// Aseprite Document Library
+// Copyright (c) 2024 Igara Studio S.A.
+//
+// This file is released under the terms of the MIT license.
+// Read LICENSE.txt for more information.
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "doc/rgbmap_base.h"
+
+#include <cmath>
+
+namespace doc {
+
+// Auxiliary function for rgbToOtherSpace()
+double f(double t)
+{
+  if (t > 0.00885645171)
+    return std::pow(t, 0.3333333333333333);
+  else
+    return (t / 0.12841855 + 0.137931034);
+}
+
+// Auxiliary function for findBestfit()
+void RgbMapBase::rgbToOtherSpace(double& r, double& g, double& b) const
+{
+  if (m_fitCriteria == FitCriteria::RGB)
+    return;
+  double Rl, Gl, Bl;
+  // Linearization:
+  r = r / 255.0;
+  g = g / 255.0;
+  b = b / 255.0;
+  if (r <= 0.04045)
+    Rl = r / 12.92;
+  else
+    Rl = std::pow((r + 0.055) / 1.055, 2.4);
+  if (g <= 0.04045)
+    Gl = g / 12.92;
+  else
+    Gl = std::pow((g + 0.055) / 1.055, 2.4);
+  if (b <= 0.04045)
+    Bl = b / 12.92;
+  else
+    Bl = std::pow((b + 0.055) / 1.055, 2.4);
+  if (m_fitCriteria == FitCriteria::linearizedRGB) {
+    r = Rl;
+    g = Gl;
+    b = Bl;
+    return;
+  }
+  // Conversion lineal RGB to CIE XYZ
+  r = 41.24564*Rl + 35.75761 * Gl + 18.04375 * Bl;
+  g = 21.26729*Rl + 71.51522 * Gl + 7.2175   * Bl;
+  b = 1.93339*Rl  + 11.91920 * Gl + 95.03041 * Bl;
+  switch (m_fitCriteria) {
+
+    case FitCriteria::CIEXYZ:
+      return;
+
+    case FitCriteria::CIELAB: {
+      // Converting CIEXYZ to CIELAB:
+      // For Standard Illuminant D65:
+      //  const double xn = 95.0489;
+      //  const double yn = 100.0;
+      //  const double zn = 108.884;
+      double xxn = r / 95.0489;
+      double yyn = g / 100.0;
+      double zzn = b / 108.884;
+      double fyyn = f(yyn);
+
+      double Lstar = 116.0 * fyyn - 16.0;
+      double aStar = 500.0 * (f(xxn) - fyyn);
+      double bStar = 200.0 * (fyyn - f(zzn));
+
+      r = Lstar;
+      g = aStar;
+      b = bStar;
+      return;
+    }
+  }
+}
+
+int RgbMapBase::findBestfit(int r, int g, int b, int a,
+                            int mask_index) const
+{
+  ASSERT(r >= 0 && r <= 255);
+  ASSERT(g >= 0 && g <= 255);
+  ASSERT(b >= 0 && b <= 255);
+  ASSERT(a >= 0 && a <= 255);
+
+  if (m_fitCriteria == FitCriteria::DEFAULT)
+    return m_palette->findBestfit(r, g, b, a, mask_index);
+
+  if (a == 0 && mask_index >= 0)
+    return mask_index;
+
+  int bestfit = 0;
+  double lowest = std::numeric_limits<double>::max();
+  const int size = m_palette->size();
+  // Linearice:
+  double x = double(r);
+  double y = double(g);
+  double z = double(b);
+
+  rgbToOtherSpace(x, y, z);
+
+  for (int i=0; i<size; ++i) {
+    color_t rgb = m_palette->getEntry(i);
+    double Xpal = double(rgba_getr(rgb));
+    double Ypal = double(rgba_getg(rgb));
+    double Zpal = double(rgba_getb(rgb));
+    // Palette color conversion RGB-->XYZ and r,g,b is assumed CIE XYZ
+    rgbToOtherSpace(Xpal, Ypal, Zpal);
+    const double xDiff = x - Xpal;
+    const double yDiff = y - Ypal;
+    const double zDiff = z - Zpal;
+    const double aDiff = double(a - rgba_geta(rgb)) / 128.0;
+
+    double diff = xDiff * xDiff + yDiff * yDiff + zDiff * zDiff + aDiff * aDiff;
+    if (diff < lowest) {
+      lowest = diff;
+      bestfit = i;
+    }
+  }
+  return bestfit;
+}
+
+} // namespace doc
diff --git a/src/doc/rgbmap_base.h b/src/doc/rgbmap_base.h
new file mode 100644
index 000000000..3004adc7d
--- /dev/null
+++ b/src/doc/rgbmap_base.h
@@ -0,0 +1,42 @@
+// Aseprite Document Library
+// Copyright (c) 2024 Igara Studio S.A.
+//
+// This file is released under the terms of the MIT license.
+// Read LICENSE.txt for more information.
+
+#ifndef DOC_RGBMAP_BASE_H_INCLUDED
+#define DOC_RGBMAP_BASE_H_INCLUDED
+#pragma once
+
+#include "doc/fit_criteria.h"
+#include "doc/palette.h"
+#include "doc/rgbmap.h"
+
+namespace doc {
+
+class RgbMapBase : public RgbMap {
+public:
+  int findBestfit(int r, int g, int b, int a,
+                  int mask_index) const;
+
+  // RgbMap impl
+  int modifications() const override { return m_modifications; }
+  int maskIndex() const override { return m_maskIndex; }
+  FitCriteria fitCriteria() const override { return m_fitCriteria; }
+  void fitCriteria(const FitCriteria fitCriteria) override {
+    m_fitCriteria = fitCriteria;
+  }
+
+private:
+  void rgbToOtherSpace(double& r, double& g, double& b) const;
+
+protected:
+  FitCriteria m_fitCriteria;
+  const Palette* m_palette = nullptr;
+  int m_modifications = 0;
+  int m_maskIndex = 0;
+};
+
+} // namespace doc
+
+#endif
diff --git a/src/doc/rgbmap_rgb5a3.cpp b/src/doc/rgbmap_rgb5a3.cpp
index 5f0ec2653..89482f1b5 100644
--- a/src/doc/rgbmap_rgb5a3.cpp
+++ b/src/doc/rgbmap_rgb5a3.cpp
@@ -1,5 +1,5 @@
 // Aseprite Document Library
-// Copyright (c) 2020 Igara Studio S.A.
+// Copyright (c) 2020-2024 Igara Studio S.A.
 // Copyright (c) 2001-2015 David Capello
 //
 // This file is released under the terms of the MIT license.
@@ -22,23 +22,21 @@ namespace doc {
 #define ASIZE   8
 #define MAPSIZE (RSIZE*GSIZE*BSIZE*ASIZE)
 
-RgbMapRGB5A3::RgbMapRGB5A3()
-  : m_map(MAPSIZE)
-  , m_palette(nullptr)
-  , m_modifications(0)
-  , m_maskIndex(0)
-{
-}
+RgbMapRGB5A3::RgbMapRGB5A3() : m_map(MAPSIZE) {}
 
-void RgbMapRGB5A3::regenerateMap(const Palette* palette, int maskIndex)
+void RgbMapRGB5A3::regenerateMap(const Palette* palette,
+                                 const int maskIndex,
+                                 const FitCriteria fitCriteria)
 {
   // Skip useless regenerations
   if (m_palette == palette &&
       m_modifications == palette->getModifications() &&
-      m_maskIndex == maskIndex)
+      m_maskIndex == maskIndex &&
+      m_fitCriteria == fitCriteria)
     return;
 
   m_palette = palette;
+  m_fitCriteria = fitCriteria;
   m_modifications = palette->getModifications();
   m_maskIndex = maskIndex;
 
@@ -50,7 +48,7 @@ void RgbMapRGB5A3::regenerateMap(const Palette* palette, int maskIndex)
 int RgbMapRGB5A3::generateEntry(int i, int r, int g, int b, int a) const
 {
   return m_map[i] =
-    m_palette->findBestfit(
+    findBestfit(
       scale_5bits_to_8bits(r>>3),
       scale_5bits_to_8bits(g>>3),
       scale_5bits_to_8bits(b>>3),
diff --git a/src/doc/rgbmap_rgb5a3.h b/src/doc/rgbmap_rgb5a3.h
index e17ab4ab3..0ff72e8bd 100644
--- a/src/doc/rgbmap_rgb5a3.h
+++ b/src/doc/rgbmap_rgb5a3.h
@@ -13,7 +13,8 @@
 #include "base/disable_copying.h"
 #include "base/ints.h"
 #include "doc/object.h"
-#include "doc/rgbmap.h"
+#include "doc/palette.h"
+#include "doc/rgbmap_base.h"
 
 #include <vector>
 
@@ -22,7 +23,7 @@ namespace doc {
   class Palette;
 
   // It acts like a cache for Palette:findBestfit() calls.
-  class RgbMapRGB5A3 : public RgbMap {
+  class RgbMapRGB5A3 : public RgbMapBase {
     // Bit activated on m_map entries that aren't yet calculated.
     const uint16_t INVALID = 256;
 
@@ -30,7 +31,14 @@ namespace doc {
     RgbMapRGB5A3();
 
     // RgbMap impl
-    void regenerateMap(const Palette* palette, int maskIndex) override;
+    void regenerateMap(const Palette* palette,
+                       const int maskIndex,
+                       const FitCriteria fitCriteria) override;
+    void regenerateMap(const Palette* palette,
+                       const int maskIndex) override {
+      regenerateMap(palette, maskIndex, m_fitCriteria);
+    }
+
     int mapColor(const color_t rgba) const override {
       const uint8_t r = rgba_getr(rgba);
       const uint8_t g = rgba_getg(rgba);
@@ -42,15 +50,14 @@ namespace doc {
       return (v & INVALID) ? generateEntry(i, r, g, b, a): v;
     }
 
-    int maskIndex() const override { return m_maskIndex; }
+    RgbMapAlgorithm rgbmapAlgorithm() const override {
+      return RgbMapAlgorithm::RGB5A3;
+    }
 
   private:
     int generateEntry(int i, int r, int g, int b, int a) const;
 
     mutable std::vector<uint16_t> m_map;
-    const Palette* m_palette;
-    int m_modifications;
-    int m_maskIndex;
 
     DISABLE_COPYING(RgbMapRGB5A3);
   };
diff --git a/src/doc/sprite.cpp b/src/doc/sprite.cpp
index 81842e2ea..c555a8510 100644
--- a/src/doc/sprite.cpp
+++ b/src/doc/sprite.cpp
@@ -440,18 +440,24 @@ RgbMap* Sprite::rgbMap(const frame_t frame) const
 RgbMap* Sprite::rgbMap(const frame_t frame,
                        const RgbMapFor forLayer) const
 {
-  return rgbMap(frame,
-                forLayer,
-                g_rgbMapAlgorithm);
+  FitCriteria fc = FitCriteria::DEFAULT;
+  RgbMapAlgorithm algo = g_rgbMapAlgorithm;
+  if (m_rgbMap) {
+    fc = m_rgbMap->fitCriteria();
+    algo = m_rgbMap->rgbmapAlgorithm();
+  }
+  return rgbMap(frame, forLayer, algo, fc);
 }
 
 RgbMap* Sprite::rgbMap(const frame_t frame,
                        const RgbMapFor forLayer,
-                       RgbMapAlgorithm mapAlgo) const
+                       const RgbMapAlgorithm mapAlgo,
+                       const FitCriteria fitCriteria) const
 {
-  if (!m_rgbMap || m_rgbMapAlgorithm != mapAlgo) {
-    m_rgbMapAlgorithm = mapAlgo;
-    switch (m_rgbMapAlgorithm) {
+  if (!m_rgbMap ||
+      m_rgbMap->rgbmapAlgorithm() != mapAlgo ||
+      m_rgbMap->fitCriteria() != fitCriteria) {
+    switch (mapAlgo) {
       case RgbMapAlgorithm::RGB5A3: m_rgbMap.reset(new RgbMapRGB5A3); break;
       case RgbMapAlgorithm::DEFAULT:
       case RgbMapAlgorithm::OCTREE: m_rgbMap.reset(new OctreeMap); break;
@@ -460,6 +466,7 @@ RgbMap* Sprite::rgbMap(const frame_t frame,
         ASSERT(false);
         return nullptr;
     }
+    m_rgbMap->fitCriteria(fitCriteria);
   }
   int maskIndex;
   if (forLayer == RgbMapFor::OpaqueLayer)
@@ -469,7 +476,7 @@ RgbMap* Sprite::rgbMap(const frame_t frame,
     if (maskIndex == -1)
       maskIndex = 0;
   }
-  m_rgbMap->regenerateMap(palette(frame), maskIndex);
+  m_rgbMap->regenerateMap(palette(frame), maskIndex, fitCriteria);
   return m_rgbMap.get();
 }
 
diff --git a/src/doc/sprite.h b/src/doc/sprite.h
index 039cb833f..f0cf9731b 100644
--- a/src/doc/sprite.h
+++ b/src/doc/sprite.h
@@ -13,6 +13,7 @@
 #include "doc/cel_data.h"
 #include "doc/cel_list.h"
 #include "doc/color.h"
+#include "doc/fit_criteria.h"
 #include "doc/frame.h"
 #include "doc/image_buffer.h"
 #include "doc/image_ref.h"
@@ -167,7 +168,8 @@ namespace doc {
                    const RgbMapFor forLayer) const;
     RgbMap* rgbMap(const frame_t frame,
                    const RgbMapFor forLayer,
-                   RgbMapAlgorithm mapAlgo) const;
+                   const RgbMapAlgorithm mapAlgo,
+                   const FitCriteria fitCriteria = FitCriteria::DEFAULT) const;
 
     ////////////////////////////////////////
     // Frames
@@ -263,7 +265,6 @@ namespace doc {
     gfx::Rect m_gridBounds;                // grid settings
 
     // Current rgb map
-    mutable RgbMapAlgorithm m_rgbMapAlgorithm;
     mutable std::unique_ptr<RgbMap> m_rgbMap;
 
     Tags m_tags;