Merge bd2ae1eb61 into 80fa065bd5

With #5230, now that we can show the IME dialog on Windows, when we
are selecting a specific word/composition in the IME dialog, if we
press Enter we'll receive that Enter onKeyUp(). It's better if we
process the Enter key onKeyDown() (as the IME enter key is not
received in that case).

data/pref.xml

@@ -329,6 +329,7 @@
     <section id="quantization">
       <option id="with_alpha" type="bool" default="true" />
       <option id="dithering_algorithm" type="std::string" />
+      <option id="zig_zag" type="bool" default="true" />
       <option id="dithering_factor" type="int" default="100" />
       <option id="to_gray" type="ToGrayAlgorithm" default="ToGrayAlgorithm::DEFAULT" />
       <option id="advanced" type="bool" default="false" />

data/strings/en.ini

@@ -235,8 +235,14 @@ ChangePixelFormat_Grayscale = Grayscale
 ChangePixelFormat_Indexed = Indexed
 ChangePixelFormat_Indexed_OrderedDithering = Indexed with Ordered Dithering
 ChangePixelFormat_Indexed_OldDithering = Indexed with Old Dithering
-ChangePixelFormat_Indexed_ErrorDiffusion = Indexed with Floyd-Steinberg Error Diffusion Dithering
+ChangePixelFormat_Indexed_FloydSteinberg = Indexed with Floyd-Steinberg Error Diffusion Dithering
+ChangePixelFormat_Indexed_JarvisJudiceNinke = Indexed with Jarvis-Judice-Ninke Error Diffusion Dithering
+ChangePixelFormat_Indexed_Stucki = Indexed with Stucki Error Diffusion Dithering
+ChangePixelFormat_Indexed_Atkinson = Indexed with Atkinson Error Diffusion Dithering
+ChangePixelFormat_Indexed_Burkes = Indexed with Burkes Error Diffusion Dithering
+ChangePixelFormat_Indexed_Sierra = Indexed with Sierra Error Diffusion Dithering
 ChangePixelFormat_MoreOptions = More Options
+ChangePixelFormat_ZigZag = Zig Zag
 Clear = Clear
 ClearCel = Clear Cel
 ClearRecentFiles = Clear Recent Files
@@ -516,6 +522,11 @@ no_dithering = No Dithering
 old_dithering = Old Dithering +\s
 ordered_dithering = Ordered Dithering +\s
 floyd_steinberg = Floyd-Steinberg Error Diffusion Dithering
+jarvis_judice_ninke = Jarvis Judice Ninke Error Diffusion Dithering
+stucki = Stucki Error Diffusion Dithering
+atkinson = Atkinson Error Diffusion Dithering
+burkes = Burkes Error Diffusion Dithering
+sierra = Sierra Error Diffusion Dithering
 
 [canvas_size]
 title = Canvas Size

laf

@@ -1 +1 @@
-Subproject commit a2bb9ec7fb98354279a2c49870a4a47a67a8e86e
+Subproject commit 8ec4b553f1618f7a4b47cdcf4cfc2663266111ac

src/app/cli/cli_processor.cpp

@@ -447,19 +447,13 @@ int CliProcessor::process(Context* ctx)
         }
         // --dithering-algorithm <algorithm>
         else if (opt == &m_options.ditheringAlgorithm()) {
-          if (value.value() == "none")
-            ditheringAlgorithm = render::DitheringAlgorithm::None;
-          else if (value.value() == "ordered")
-            ditheringAlgorithm = render::DitheringAlgorithm::Ordered;
-          else if (value.value() == "old")
-            ditheringAlgorithm = render::DitheringAlgorithm::Old;
-          else if (value.value() == "error-diffusion")
-            ditheringAlgorithm = render::DitheringAlgorithm::ErrorDiffusion;
-          else
+          ditheringAlgorithm = render::DitheringAlgorithmFromString(value.value());
+          if (ditheringAlgorithm == render::DitheringAlgorithm::Unknown) {
             throw std::runtime_error(
               "--dithering-algorithm needs a valid algorithm name\n"
               "Usage: --dithering-algorithm <algorithm>\n"
-              "Where <algorithm> can be none, ordered, old, or error-diffusion");
+              "Where <algorithm> can be: none, ordered, old, floyd-steinberg, jarvis-judice-ninke, stucki, atkinson, burkes or sierra.");
+          }
         }
         // --dithering-matrix <id>
         else if (opt == &m_options.ditheringMatrix()) {
@@ -477,15 +471,7 @@ int CliProcessor::process(Context* ctx)
           }
           else if (value.value() == "indexed") {
             params.set("format", "indexed");
-            switch (ditheringAlgorithm) {
-              case render::DitheringAlgorithm::None:    params.set("dithering", "none"); break;
-              case render::DitheringAlgorithm::Ordered: params.set("dithering", "ordered"); break;
-              case render::DitheringAlgorithm::Old:     params.set("dithering", "old"); break;
-              case render::DitheringAlgorithm::ErrorDiffusion:
-                params.set("dithering", "error-diffusion");
-                break;
-            }
-
+            params.set("dithering", DitheringAlgorithmToString(ditheringAlgorithm).c_str());
             if (ditheringAlgorithm != render::DitheringAlgorithm::None &&
                 !ditheringMatrix.empty()) {
               params.set("dithering-matrix", ditheringMatrix.c_str());

src/app/commands/cmd_change_pixel_format.cpp

@@ -41,6 +41,7 @@
 #include "render/quantization.h"
 #include "render/render.h"
 #include "render/task_delegate.h"
+#include "ui/button.h"
 #include "ui/listitem.h"
 #include "ui/paint_event.h"
 #include "ui/size_hint_event.h"
@@ -177,6 +178,7 @@ public:
     , m_imageBuffer(new doc::ImageBuffer)
     , m_selectedItem(nullptr)
     , m_ditheringSelector(nullptr)
+    , m_zigZagCheck(nullptr)
     , m_mapAlgorithmSelector(nullptr)
     , m_bestFitCriteriaSelector(nullptr)
     , m_imageJustCreated(true)
@@ -204,6 +206,8 @@ public:
       m_ditheringSelector = new DitheringSelector(DitheringSelector::SelectBoth);
       m_ditheringSelector->setExpansive(true);
 
+      m_zigZagCheck = new CheckBox(Strings::commands_ChangePixelFormat_ZigZag());
+
       m_mapAlgorithmSelector = new RgbMapAlgorithmSelector;
       m_mapAlgorithmSelector->setExpansive(true);
 
@@ -217,6 +221,9 @@ public:
           m_ditheringSelector->setSelectedItemIndex(index);
       }
 
+      // Select default zig zag
+      m_zigZagCheck->setSelected(pref.quantization.zigZag());
+
       // Select default RgbMap algorithm
       m_mapAlgorithmSelector->algorithm(pref.quantization.rgbmapAlgorithm());
 
@@ -224,6 +231,7 @@ public:
       m_bestFitCriteriaSelector->criteria(pref.quantization.fitCriteria());
 
       ditheringPlaceholder()->addChild(m_ditheringSelector);
+      ditheringPlaceholder()->addChild(m_zigZagCheck);
       rgbmapAlgorithmPlaceholder()->addChild(m_mapAlgorithmSelector);
       bestFitCriteriaPlaceholder()->addChild(m_bestFitCriteriaSelector);
 
@@ -233,6 +241,7 @@ public:
 
       // Signals
       m_ditheringSelector->Change.connect([this] { onIndexParamChange(); });
+      m_zigZagCheck->Click.connect([this] { onIndexParamChange(); });
       m_mapAlgorithmSelector->Change.connect([this] { onIndexParamChange(); });
       m_bestFitCriteriaSelector->Change.connect([this] { onIndexParamChange(); });
       factor()->Change.connect([this] { onIndexParamChange(); });
@@ -281,6 +290,7 @@ public:
     if (m_ditheringSelector) {
       d.algorithm(m_ditheringSelector->ditheringAlgorithm());
       d.matrix(m_ditheringSelector->ditheringMatrix());
+      d.zigzag(m_zigZagCheck->isSelected());
     }
     d.factor(double(factor()->getValue()) / 100.0);
     return d;
@@ -317,16 +327,16 @@ public:
   {
     auto& pref = Preferences::instance();
 
-    // Save the dithering method used for the future
+    // Save the dithering method and zig-zag setting used for the future
     if (m_ditheringSelector) {
       if (auto item = m_ditheringSelector->getSelectedItem()) {
         pref.quantization.ditheringAlgorithm(item->text());
 
-        if (m_ditheringSelector->ditheringAlgorithm() ==
-            render::DitheringAlgorithm::ErrorDiffusion) {
+        if (DitheringAlgorithmIsDiffusion(m_ditheringSelector->ditheringAlgorithm()))
           pref.quantization.ditheringFactor(factor()->getValue());
-        }
       }
+
+      pref.quantization.zigZag(m_zigZagCheck->isEnabled());
     }
 
     if (m_mapAlgorithmSelector || m_bestFitCriteriaSelector)
@@ -364,9 +374,10 @@ private:
     if (m_ditheringSelector) {
       const bool toIndexed = (dstColorMode == doc::ColorMode::INDEXED);
       m_ditheringSelector->setVisible(toIndexed);
+      m_zigZagCheck->setVisible(toIndexed);
 
-      const bool errorDiff = (m_ditheringSelector->ditheringAlgorithm() ==
-                              render::DitheringAlgorithm::ErrorDiffusion);
+      const bool errorDiff =
+        (render::DitheringAlgorithmIsDiffusion(m_ditheringSelector->ditheringAlgorithm()));
       amount()->setVisible(toIndexed && errorDiff);
     }
 
@@ -460,6 +471,7 @@ private:
   std::unique_ptr<ConvertThread> m_bgThread;
   ConversionItem* m_selectedItem;
   DitheringSelector* m_ditheringSelector;
+  CheckBox* m_zigZagCheck;
   RgbMapAlgorithmSelector* m_mapAlgorithmSelector;
   BestFitCriteriaSelector* m_bestFitCriteriaSelector;
   bool m_imageJustCreated;
@@ -487,6 +499,11 @@ struct ChangePixelFormatParams : public NewParams {
     1.0,
     { "ditheringFactor", "dithering-factor" }
   };
+  Param<bool> zigZag{
+    this,
+    true,
+    { "zigZag", "zig-zag" }
+  };
   Param<doc::RgbMapAlgorithm> rgbmap{ this, RgbMapAlgorithm::DEFAULT, "rgbmap" };
   Param<gen::ToGrayAlgorithm> toGray{ this, gen::ToGrayAlgorithm::DEFAULT, "toGray" };
   Param<doc::FitCriteria> fitCriteria{ this, doc::FitCriteria::DEFAULT, "fitCriteria" };
@@ -568,10 +585,13 @@ void ChangePixelFormatCommand::onExecute(Context* ctx)
     if (window.closer() != window.ok())
       return;
 
+    const auto d = window.dithering();
+
     params().colorMode(window.selectedColorMode());
-    params().dithering(window.dithering().algorithm());
-    matrix = window.dithering().matrix();
-    params().factor(window.dithering().factor());
+    params().dithering(d.algorithm());
+    matrix = d.matrix();
+    params().factor(d.factor());
+    params().zigZag(d.zigzag());
     params().rgbmap(window.rgbMapAlgorithm());
     params().fitCriteria(window.fitCriteria());
     params().toGray(window.toGray());
@@ -615,13 +635,14 @@ void ChangePixelFormatCommand::onExecute(Context* ctx)
     }
 
     job.startJobWithCallback([this, &job, sprite, &matrix](Tx& tx) {
-      tx(new cmd::SetPixelFormat(sprite,
-                                 (PixelFormat)params().colorMode(),
-                                 render::Dithering(params().dithering(), matrix, params().factor()),
-                                 params().rgbmap(),
-                                 get_gray_func(params().toGray()),
-                                 &job, // SpriteJob is a render::TaskDelegate
-                                 params().fitCriteria()));
+      tx(new cmd::SetPixelFormat(
+        sprite,
+        (PixelFormat)params().colorMode(),
+        render::Dithering(params().dithering(), matrix, params().zigZag(), params().factor()),
+        params().rgbmap(),
+        get_gray_func(params().toGray()),
+        &job, // SpriteJob is a render::TaskDelegate
+        params().fitCriteria()));
     });
     job.waitJob();
   }
@@ -651,8 +672,23 @@ std::string ChangePixelFormatCommand::onGetFriendlyName() const
           case render::DitheringAlgorithm::Old:
             conversion = Strings::commands_ChangePixelFormat_Indexed_OldDithering();
             break;
-          case render::DitheringAlgorithm::ErrorDiffusion:
-            conversion = Strings::commands_ChangePixelFormat_Indexed_ErrorDiffusion();
+          case render::DitheringAlgorithm::FloydSteinberg:
+            conversion = Strings::commands_ChangePixelFormat_Indexed_FloydSteinberg();
+            break;
+          case render::DitheringAlgorithm::JarvisJudiceNinke:
+            conversion = Strings::commands_ChangePixelFormat_Indexed_JarvisJudiceNinke();
+            break;
+          case render::DitheringAlgorithm::Stucki:
+            conversion = Strings::commands_ChangePixelFormat_Indexed_Stucki();
+            break;
+          case render::DitheringAlgorithm::Atkinson:
+            conversion = Strings::commands_ChangePixelFormat_Indexed_Atkinson();
+            break;
+          case render::DitheringAlgorithm::Burkes:
+            conversion = Strings::commands_ChangePixelFormat_Indexed_Burkes();
+            break;
+          case render::DitheringAlgorithm::Sierra:
+            conversion = Strings::commands_ChangePixelFormat_Indexed_Sierra();
             break;
         }
         break;

src/app/commands/new_params.cpp

@@ -275,14 +275,10 @@ void Param<doc::FitCriteria>::fromString(const std::string& value)
 template<>
 void Param<render::DitheringAlgorithm>::fromString(const std::string& value)
 {
-  if (base::utf8_icmp(value, "ordered") == 0)
-    setValue(render::DitheringAlgorithm::Ordered);
-  else if (base::utf8_icmp(value, "old") == 0)
-    setValue(render::DitheringAlgorithm::Old);
-  else if (base::utf8_icmp(value, "error-diffusion") == 0)
-    setValue(render::DitheringAlgorithm::ErrorDiffusion);
-  else
-    setValue(render::DitheringAlgorithm::None);
+  auto algo = render::DitheringAlgorithmFromString(value);
+  if (algo == render::DitheringAlgorithm::Unknown)
+    algo = render::DitheringAlgorithm::None;
+  setValue(algo);
 }
 
 template<>

src/app/script/site_class.cpp

@@ -13,6 +13,8 @@
 #include "app/console.h"
 #include "app/context.h"
 #include "app/context_observer.h"
+#include "app/doc.h"
+#include "app/doc_undo.h"
 #include "app/script/docobj.h"
 #include "app/script/engine.h"
 #include "app/script/luacpp.h"

src/app/script/sprite_class.cpp

@@ -64,6 +64,7 @@
 #include "doc/tag.h"
 #include "doc/tileset.h"
 #include "doc/tilesets.h"
+#include "undo/undo_state.h"
 
 #include <algorithm>
 
@@ -1029,6 +1030,42 @@ int Sprite_set_useLayerUuids(lua_State* L)
   return 0;
 }
 
+int Sprite_get_undoHistory(lua_State* L)
+{
+  const auto* sprite = get_docobj<Sprite>(L, 1);
+  const auto* doc = static_cast<Doc*>(sprite->document());
+  const auto* history = doc->undoHistory();
+
+  if (!history) {
+    lua_pushnil(L);
+    return 1;
+  }
+
+  const undo::UndoState* currentState = history->currentState();
+  const undo::UndoState* s = history->firstState();
+  const bool canRedo = history->canRedo();
+  bool pastCurrent = !currentState && canRedo;
+
+  int undoSteps = 0;
+  int redoSteps = 0;
+  while (s) {
+    if (pastCurrent && canRedo)
+      redoSteps++;
+    else if (currentState || !canRedo)
+      undoSteps++;
+
+    if (s == currentState || !currentState)
+      pastCurrent = true;
+
+    s = s->next();
+  }
+
+  lua_newtable(L);
+  setfield_integer(L, "undoSteps", undoSteps);
+  setfield_integer(L, "redoSteps", redoSteps);
+  return 1;
+}
+
 const luaL_Reg Sprite_methods[] = {
   { "__eq",              Sprite_eq                },
   { "resize",            Sprite_resize            },
@@ -1094,6 +1131,7 @@ const Property Sprite_properties[] = {
   { "events",               Sprite_get_events,               nullptr                         },
   { "tileManagementPlugin", Sprite_get_tileManagementPlugin, Sprite_set_tileManagementPlugin },
   { "useLayerUuids",        Sprite_get_useLayerUuids,        Sprite_set_useLayerUuids        },
+  { "undoHistory",          Sprite_get_undoHistory,          nullptr                         },
   { nullptr,                nullptr,                         nullptr                         }
 };
 

src/app/ui/context_bar.cpp

@@ -2577,8 +2577,26 @@ render::DitheringAlgorithmBase* ContextBar::ditheringAlgorithm()
     case render::DitheringAlgorithm::None:    s_dither.reset(nullptr); break;
     case render::DitheringAlgorithm::Ordered: s_dither.reset(new render::OrderedDither2(-1)); break;
     case render::DitheringAlgorithm::Old:     s_dither.reset(new render::OrderedDither(-1)); break;
-    case render::DitheringAlgorithm::ErrorDiffusion:
-      s_dither.reset(new render::ErrorDiffusionDither(-1));
+    case render::DitheringAlgorithm::FloydSteinberg:
+      s_dither.reset(
+        new render::ErrorDiffusionDither(render::ErrorDiffusionType::FloydSteinberg, -1));
+      break;
+    case render::DitheringAlgorithm::JarvisJudiceNinke:
+      s_dither.reset(
+        new render::ErrorDiffusionDither(render::ErrorDiffusionType::JarvisJudiceNinke, -1));
+      break;
+    case render::DitheringAlgorithm::Stucki:
+      s_dither.reset(new render::ErrorDiffusionDither(render::ErrorDiffusionType::Stucki, -1));
+      break;
+    case render::DitheringAlgorithm::Atkinson:
+      s_dither.reset(new render::ErrorDiffusionDither(render::ErrorDiffusionType::Atkinson, -1));
+      break;
+    case render::DitheringAlgorithm::Burkes:
+      s_dither.reset(new render::ErrorDiffusionDither(render::ErrorDiffusionType::Burkes, -1));
+      break;
+    case render::DitheringAlgorithm::Sierra:
+      s_dither.reset(new render::ErrorDiffusionDither(render::ErrorDiffusionType::Sierra, -1));
+      break;
       break;
   }
 

src/app/ui/dithering_selector.cpp

@@ -231,9 +231,24 @@ void DitheringSelector::regenerate(int selectedItemIndex)
           Console::showException(e);
         }
       }
-      addItem(new DitherItem(render::DitheringAlgorithm::ErrorDiffusion,
+      addItem(new DitherItem(render::DitheringAlgorithm::FloydSteinberg,
                              render::DitheringMatrix(),
                              Strings::dithering_selector_floyd_steinberg()));
+      addItem(new DitherItem(render::DitheringAlgorithm::JarvisJudiceNinke,
+                             render::DitheringMatrix(),
+                             Strings::dithering_selector_jarvis_judice_ninke()));
+      addItem(new DitherItem(render::DitheringAlgorithm::Stucki,
+                             render::DitheringMatrix(),
+                             Strings::dithering_selector_stucki()));
+      addItem(new DitherItem(render::DitheringAlgorithm::Atkinson,
+                             render::DitheringMatrix(),
+                             Strings::dithering_selector_atkinson()));
+      addItem(new DitherItem(render::DitheringAlgorithm::Burkes,
+                             render::DitheringMatrix(),
+                             Strings::dithering_selector_burkes()));
+      addItem(new DitherItem(render::DitheringAlgorithm::Sierra,
+                             render::DitheringMatrix(),
+                             Strings::dithering_selector_sierra()));
       break;
     case SelectMatrix:
       addItem(

src/app/ui/editor/writing_text_state.cpp

@@ -443,12 +443,7 @@ bool WritingTextState::onSetCursor(Editor* editor, const gfx::Point& mouseScreen
   return true;
 }
 
-bool WritingTextState::onKeyDown(Editor*, KeyMessage*)
-{
-  return false;
-}
-
-bool WritingTextState::onKeyUp(Editor*, KeyMessage* msg)
+bool WritingTextState::onKeyDown(Editor*, KeyMessage* msg)
 {
   // Cancel loop pressing Esc key
   if (msg->scancode() == ui::kKeyEsc) {
@@ -457,7 +452,17 @@ bool WritingTextState::onKeyUp(Editor*, KeyMessage* msg)
   // Drop text pressing Enter key
   else if (msg->scancode() == ui::kKeyEnter) {
     drop();
+    return true;
   }
+  return false;
+}
+
+bool WritingTextState::onKeyUp(Editor*, KeyMessage* msg)
+{
+  // Note: We cannot process kKeyEnter key here to drop the text as it
+  // could be received after the Enter key is pressed in the IME
+  // dialog to accept the composition (not to accept the text). So we
+  // process kKeyEnter in onKeyDown().
   return true;
 }
 

src/render/CMakeLists.txt

@@ -3,6 +3,7 @@
 # Copyright (C) 2001-2018 David Capello
 
 add_library(render-lib
+  dithering_algorithm.cpp
   error_diffusion.cpp
   get_sprite_pixel.cpp
   gradient.cpp

src/render/dithering.h

@@ -18,24 +18,29 @@ class Dithering {
 public:
   Dithering(DitheringAlgorithm algorithm = DitheringAlgorithm::None,
             const DitheringMatrix& matrix = DitheringMatrix(),
+            bool zigzag = true,
             double factor = 1.0)
     : m_algorithm(algorithm)
     , m_matrix(matrix)
+    , m_zigzag(zigzag)
     , m_factor(factor)
   {
   }
 
   DitheringAlgorithm algorithm() const { return m_algorithm; }
   DitheringMatrix matrix() const { return m_matrix; }
+  bool zigzag() const { return m_zigzag; }
   double factor() const { return m_factor; }
 
   void algorithm(const DitheringAlgorithm algorithm) { m_algorithm = algorithm; }
   void matrix(const DitheringMatrix& matrix) { m_matrix = matrix; }
+  void zigzag(bool zigzag) { m_zigzag = zigzag; }
   void factor(const double factor) { m_factor = factor; }
 
 private:
   DitheringAlgorithm m_algorithm;
   DitheringMatrix m_matrix;
+  bool m_zigzag;
   double m_factor;
 };
 

src/render/dithering_algorithm.cpp

@@ -0,0 +1,53 @@
+// Aseprite
+// Copyright (C) 2025 Igara Studio S.A.
+//
+// This program is distributed under the terms of
+// the End-User License Agreement for Aseprite.
+
+#include <algorithm>
+#include <string>
+#include <unordered_map>
+
+#include "base/string.h"
+#include "render/dithering_algorithm.h"
+
+namespace render {
+
+static const std::unordered_map<DitheringAlgorithm, std::string> names = {
+  { DitheringAlgorithm::None,              "none"                },
+  { DitheringAlgorithm::Ordered,           "ordered"             },
+  { DitheringAlgorithm::Old,               "old"                 },
+  { DitheringAlgorithm::FloydSteinberg,    "floyd-steinberg"     },
+  { DitheringAlgorithm::FloydSteinberg,    "error-diffusion"     }, // alias
+  { DitheringAlgorithm::JarvisJudiceNinke, "jarvis-judice-ninke" },
+  { DitheringAlgorithm::Stucki,            "stucki"              },
+  { DitheringAlgorithm::Atkinson,          "atkinson"            },
+  { DitheringAlgorithm::Burkes,            "burkes"              },
+  { DitheringAlgorithm::Sierra,            "sierra"              },
+};
+
+bool DitheringAlgorithmIsDiffusion(DitheringAlgorithm algo)
+{
+  switch (algo) {
+    case DitheringAlgorithm::None:
+    case DitheringAlgorithm::Ordered:
+    case DitheringAlgorithm::Old:     return false;
+    default:                          return true;
+  }
+}
+
+std::string DitheringAlgorithmToString(DitheringAlgorithm algo)
+{
+  auto it = names.find(algo);
+  return (it != names.end()) ? it->second : "unknown";
+}
+
+DitheringAlgorithm DitheringAlgorithmFromString(const std::string& name)
+{
+  auto it = std::find_if(names.begin(), names.end(), [name](const auto& pair) {
+    return base::utf8_icmp(pair.second, name) == 0;
+  });
+  return (it != names.end()) ? it->first : DitheringAlgorithm::Unknown;
+}
+
+} // namespace render

src/render/dithering_algorithm.h

@@ -9,6 +9,8 @@
 #define RENDER_DITHERING_METHOD_H_INCLUDED
 #pragma once
 
+#include <string>
+
 namespace render {
 
 // Dithering algorithms
@@ -16,9 +18,19 @@ enum class DitheringAlgorithm {
   None,
   Ordered,
   Old,
-  ErrorDiffusion,
+  FloydSteinberg,
+  JarvisJudiceNinke,
+  Stucki,
+  Atkinson,
+  Burkes,
+  Sierra,
+  Unknown
 };
 
+bool DitheringAlgorithmIsDiffusion(DitheringAlgorithm algo);
+std::string DitheringAlgorithmToString(DitheringAlgorithm algo);
+DitheringAlgorithm DitheringAlgorithmFromString(const std::string& name);
+
 } // namespace render
 
 #endif

src/render/error_diffusion.cpp

@@ -15,23 +15,139 @@
 #include "gfx/rgb.h"
 
 #include <algorithm>
+#include <vector>
 
 namespace render {
 
-ErrorDiffusionDither::ErrorDiffusionDither(int transparentIndex)
+// Predefined error diffusion algorithms
+class ErrorDiffusionMatrices {
+public:
+  static const ErrorDiffusionMatrix& getFloydSteinberg()
+  {
+    static const ErrorDiffusionMatrix matrix(3,
+                                             2,
+                                             1,
+                                             0,
+                                             {
+                                               { 0, 0, 7 },
+                                               { 3, 5, 1 }
+    },
+                                             16);
+    return matrix;
+  }
+
+  static const ErrorDiffusionMatrix& getJarvisJudiceNinke()
+  {
+    static const ErrorDiffusionMatrix matrix(5,
+                                             3,
+                                             2,
+                                             0,
+                                             {
+                                               { 0, 0, 0, 7, 5 },
+                                               { 3, 5, 7, 5, 3 },
+                                               { 1, 3, 5, 3, 1 }
+    },
+                                             48);
+    return matrix;
+  }
+
+  static const ErrorDiffusionMatrix& getStucki()
+  {
+    static const ErrorDiffusionMatrix matrix(5,
+                                             3,
+                                             2,
+                                             0,
+                                             {
+                                               { 0, 0, 0, 8, 4 },
+                                               { 2, 4, 8, 4, 2 },
+                                               { 1, 2, 4, 2, 1 }
+    },
+                                             42);
+    return matrix;
+  }
+
+  static const ErrorDiffusionMatrix& getAtkinson()
+  {
+    static const ErrorDiffusionMatrix matrix(4,
+                                             3,
+                                             1,
+                                             0,
+                                             {
+                                               { 0, 0, 1, 1 },
+                                               { 1, 1, 1, 0 },
+                                               { 0, 1, 0, 0 }
+    },
+                                             8);
+    return matrix;
+  }
+
+  static const ErrorDiffusionMatrix& getBurkes()
+  {
+    static const ErrorDiffusionMatrix matrix(5,
+                                             2,
+                                             2,
+                                             0,
+                                             {
+                                               { 0, 0, 0, 8, 4 },
+                                               { 2, 4, 8, 4, 2 }
+    },
+                                             32);
+    return matrix;
+  }
+
+  static const ErrorDiffusionMatrix& getSierra()
+  {
+    static const ErrorDiffusionMatrix matrix(5,
+                                             3,
+                                             2,
+                                             0,
+                                             {
+                                               { 0, 0, 0, 5, 3 },
+                                               { 2, 4, 5, 4, 2 },
+                                               { 0, 2, 3, 2, 0 }
+    },
+                                             32);
+    return matrix;
+  }
+};
+
+ErrorDiffusionDither::ErrorDiffusionDither(ErrorDiffusionType type, int transparentIndex)
   : m_transparentIndex(transparentIndex)
+  , m_diffusionType(type)
 {
 }
 
+const ErrorDiffusionMatrix& ErrorDiffusionDither::getCurrentMatrix() const
+{
+  switch (m_diffusionType) {
+    case ErrorDiffusionType::JarvisJudiceNinke:
+      return ErrorDiffusionMatrices::getJarvisJudiceNinke();
+    case ErrorDiffusionType::Stucki:         return ErrorDiffusionMatrices::getStucki();
+    case ErrorDiffusionType::Atkinson:       return ErrorDiffusionMatrices::getAtkinson();
+    case ErrorDiffusionType::Burkes:         return ErrorDiffusionMatrices::getBurkes();
+    case ErrorDiffusionType::Sierra:         return ErrorDiffusionMatrices::getSierra();
+    case ErrorDiffusionType::FloydSteinberg: return ErrorDiffusionMatrices::getFloydSteinberg();
+  }
+}
+
 void ErrorDiffusionDither::start(const doc::Image* srcImage,
                                  doc::Image* dstImage,
                                  const double factor)
 {
   m_srcImage = srcImage;
   m_width = 2 + srcImage->width();
+
+  // Get the current matrix to determine buffer size needed
+  const ErrorDiffusionMatrix& matrix = getCurrentMatrix();
+  const int bufferRows = matrix.height;
+
+  // Resize error buffers to accommodate the matrix height
+  const std::vector<int>::size_type bufferSize = m_width * bufferRows;
   for (int i = 0; i < kChannels; ++i)
-    m_err[i].resize(m_width * 2, 0);
+    m_err[i].resize(bufferSize, 0);
+
   m_lastY = -1;
+  m_currentRowOffset = 0;
   m_factor = int(factor * 100.0);
 }
 
@@ -42,30 +158,39 @@ void ErrorDiffusionDither::finish()
 doc::color_t ErrorDiffusionDither::ditherRgbToIndex2D(const int x,
                                                       const int y,
                                                       const doc::RgbMap* rgbmap,
-                                                      const doc::Palette* palette)
+                                                      const doc::Palette* palette,
+                                                      const int direction)
 {
+  const ErrorDiffusionMatrix& matrix = getCurrentMatrix();
+
   if (y != m_lastY) {
-    for (int i = 0; i < kChannels; ++i) {
-      int* row0 = &m_err[i][0];
-      int* row1 = row0 + m_width;
-      int* end1 = row1 + m_width;
-      std::copy(row1, end1, row0);
-      std::fill(row1, end1, 0);
+    // Instead of shifting all rows, just advance the circular buffer
+    // and clear the row that will be reused
+    m_currentRowOffset = (m_currentRowOffset + 1) % matrix.height;
+
+    // Clear only the row that will be used as the "last" row
+    const int clearRowIndex = (m_currentRowOffset + matrix.height - 1) % matrix.height;
+    for (int c = 0; c < kChannels; ++c) {
+      int* rowToClear = &m_err[c][m_width * clearRowIndex];
+      std::fill(rowToClear, rowToClear + m_width, 0);
     }
+
     m_lastY = y;
   }
 
   doc::color_t color = doc::get_pixel_fast<doc::RgbTraits>(m_srcImage, x, y);
 
-  // Get RGB values + quatization error
+  // Get RGB values + quantization error
   int v[kChannels] = { doc::rgba_getr(color),
                        doc::rgba_getg(color),
                        doc::rgba_getb(color),
                        doc::rgba_geta(color) };
-  for (int i = 0; i < kChannels; ++i) {
-    v[i] += m_err[i][x + 1];
-    v[i] = std::clamp(v[i], 0, 255);
-  }
+
+  // Add accumulated error (16-bit fixed point) and convert to 0..255
+  for (int c = 0; c < kChannels; ++c)
+    v[c] = std::clamp(((v[c] << 16) + m_err[c][m_width * m_currentRowOffset + x + 1] + 32767) >> 16,
+                      0,
+                      255);
 
   const doc::color_t index = (rgbmap ?
                                 rgbmap->mapColor(v[0], v[1], v[2], v[3]) :
@@ -82,26 +207,36 @@ doc::color_t ErrorDiffusionDither::ditherRgbToIndex2D(const int x,
                                       v[2] - doc::rgba_getb(palColor),
                                       v[3] - doc::rgba_geta(palColor) };
 
-  // TODO using Floyd-Steinberg matrix here but it should be configurable
-  for (int i = 0; i < kChannels; ++i) {
-    int* err = &m_err[i][x];
-    const int q = quantError[i] * m_factor / 100;
-    const int a = q * 7 / 16;
-    const int b = q * 3 / 16;
-    const int c = q * 5 / 16;
-    const int d = q * 1 / 16;
+  const int srcWidth = m_srcImage->width();
 
-    if (y & 1) {
-      err[0] += a;
-      err[m_width + 2] += b;
-      err[m_width + 1] += c;
-      err[m_width] += d;
-    }
-    else {
-      err[+2] += a;
-      err[m_width] += b;
-      err[m_width + 1] += c;
-      err[m_width + 2] += d;
+  // Distribute error using the configurable matrix
+  for (int c = 0; c < kChannels; ++c) {
+    const int qerr = quantError[c] * m_factor / 100;
+
+    for (int my = 0; my < matrix.height; ++my) {
+      // Use circular buffer indexing
+      const int bufferRow = (m_currentRowOffset + my) % matrix.height;
+      const int bufferRowIndex = bufferRow * m_width;
+
+      for (int mx = 0; mx < matrix.width; ++mx) {
+        const int coeff = direction > 0 ? matrix.coefficients[my][mx] :
+                                          matrix.coefficients[my][matrix.width - 1 - mx];
+        if (coeff == 0)
+          continue;
+
+        const int errorPixelX = x + mx - matrix.centerX;
+        const int errorPixelY = y + my - matrix.centerY;
+
+        // Check bounds
+        if (errorPixelX < 0 || errorPixelX >= srcWidth)
+          continue;
+        if (errorPixelY < y)
+          continue; // Don't go backwards
+
+        // Calculate error as 16-bit fixed point
+        const int errorValue = ((qerr * coeff) << 16) / matrix.divisor;
+        m_err[c][bufferRowIndex + errorPixelX + 1] += errorValue;
+      }
     }
   }
 

src/render/error_diffusion.h

@@ -16,22 +16,58 @@
 
 namespace render {
 
+enum class ErrorDiffusionType : uint8_t {
+  FloydSteinberg,
+  JarvisJudiceNinke,
+  Stucki,
+  Atkinson,
+  Burkes,
+  Sierra
+};
+
+// Error diffusion matrix structure
+struct ErrorDiffusionMatrix {
+  int width, height;
+  int centerX, centerY;
+  std::vector<std::vector<int>> coefficients;
+  int divisor;
+
+  ErrorDiffusionMatrix(int w,
+                       int h,
+                       int cx,
+                       int cy,
+                       const std::vector<std::vector<int>>& coeff,
+                       int div)
+    : width(w)
+    , height(h)
+    , centerX(cx)
+    , centerY(cy)
+    , coefficients(coeff)
+    , divisor(div)
+  {
+  }
+};
+
 class ErrorDiffusionDither : public DitheringAlgorithmBase {
 public:
-  ErrorDiffusionDither(int transparentIndex = -1);
+  ErrorDiffusionDither(ErrorDiffusionType type, int transparentIndex);
   int dimensions() const override { return 2; }
-  bool zigZag() const override { return true; }
   void start(const doc::Image* srcImage, doc::Image* dstImage, const double factor) override;
   void finish() override;
   doc::color_t ditherRgbToIndex2D(const int x,
                                   const int y,
                                   const doc::RgbMap* rgbmap,
-                                  const doc::Palette* palette) override;
+                                  const doc::Palette* palette,
+                                  const int direction) override;
 
 private:
+  const ErrorDiffusionMatrix& getCurrentMatrix() const;
+
   int m_transparentIndex;
+  ErrorDiffusionType m_diffusionType;
   const doc::Image* m_srcImage;
   int m_width, m_lastY;
+  int m_currentRowOffset;
   static const int kChannels = 4;
   std::vector<int> m_err[kChannels];
   int m_factor;

src/render/ordered_dither.cpp

@@ -240,47 +240,38 @@ void dither_rgb_image_to_indexed(DitheringAlgorithmBase& algorithm,
         ASSERT(srcIt != srcBits.end());
         ASSERT(dstIt != dstBits.end());
         *dstIt = algorithm.ditherRgbPixelToIndex(dithering.matrix(), *srcIt, x, y, rgbmap, palette);
-
-        if (delegate) {
-          if (!delegate->continueTask())
-            return;
-        }
       }
 
       if (delegate) {
+        if (!delegate->continueTask())
+          return;
         delegate->notifyTaskProgress(double(y + 1) / double(h));
       }
     }
   }
   else {
     auto dstIt = doc::get_pixel_address_fast<doc::IndexedTraits>(dstImage, 0, 0);
-    const bool zigZag = algorithm.zigZag();
+    auto zigZag = dithering.zigzag();
 
     for (int y = 0; y < h; ++y) {
       if (zigZag && (y & 1)) { // Odd row: go from right-to-left
         dstIt += w - 1;
         for (int x = w - 1; x >= 0; --x, --dstIt) {
           ASSERT(dstIt == doc::get_pixel_address_fast<doc::IndexedTraits>(dstImage, x, y));
-          *dstIt = algorithm.ditherRgbToIndex2D(x, y, rgbmap, palette);
-          if (delegate) {
-            if (!delegate->continueTask())
-              return;
-          }
+          *dstIt = algorithm.ditherRgbToIndex2D(x, y, rgbmap, palette, -1);
         }
         dstIt += w + 1;
       }
-      else { // Even row: go fromo left-to-right
+      else { // Even row: go from left-to-right
         for (int x = 0; x < w; ++x, ++dstIt) {
           ASSERT(dstIt == doc::get_pixel_address_fast<doc::IndexedTraits>(dstImage, x, y));
-          *dstIt = algorithm.ditherRgbToIndex2D(x, y, rgbmap, palette);
-
-          if (delegate) {
-            if (!delegate->continueTask())
-              return;
-          }
+          *dstIt = algorithm.ditherRgbToIndex2D(x, y, rgbmap, palette, +1);
         }
       }
+
       if (delegate) {
+        if (!delegate->continueTask())
+          return;
         delegate->notifyTaskProgress(double(y + 1) / double(h));
       }
     }

src/render/ordered_dither.h

@@ -27,7 +27,6 @@ public:
   virtual ~DitheringAlgorithmBase() {}
 
   virtual int dimensions() const { return 1; }
-  virtual bool zigZag() const { return false; }
 
   virtual void start(const doc::Image* srcImage, doc::Image* dstImage, const double factor) {}
 
@@ -46,7 +45,8 @@ public:
   virtual doc::color_t ditherRgbToIndex2D(const int x,
                                           const int y,
                                           const doc::RgbMap* rgbmap,
-                                          const doc::Palette* palette)
+                                          const doc::Palette* palette,
+                                          const int direction)
   {
     return 0;
   }

src/render/quantization.cpp

@@ -159,8 +159,29 @@ Image* convert_pixel_format(const Image* image,
       case DitheringAlgorithm::Old:
         dither.reset(new OrderedDither(is_background ? -1 : new_mask_color));
         break;
-      case DitheringAlgorithm::ErrorDiffusion:
-        dither.reset(new ErrorDiffusionDither(is_background ? -1 : new_mask_color));
+      case DitheringAlgorithm::FloydSteinberg:
+        dither.reset(new ErrorDiffusionDither(ErrorDiffusionType::FloydSteinberg,
+                                              is_background ? -1 : new_mask_color));
+        break;
+      case DitheringAlgorithm::JarvisJudiceNinke:
+        dither.reset(new ErrorDiffusionDither(ErrorDiffusionType::JarvisJudiceNinke,
+                                              is_background ? -1 : new_mask_color));
+        break;
+      case DitheringAlgorithm::Stucki:
+        dither.reset(new ErrorDiffusionDither(ErrorDiffusionType::Stucki,
+                                              is_background ? -1 : new_mask_color));
+        break;
+      case DitheringAlgorithm::Atkinson:
+        dither.reset(new ErrorDiffusionDither(ErrorDiffusionType::Atkinson,
+                                              is_background ? -1 : new_mask_color));
+        break;
+      case DitheringAlgorithm::Burkes:
+        dither.reset(new ErrorDiffusionDither(ErrorDiffusionType::Burkes,
+                                              is_background ? -1 : new_mask_color));
+        break;
+      case DitheringAlgorithm::Sierra:
+        dither.reset(new ErrorDiffusionDither(ErrorDiffusionType::Sierra,
+                                              is_background ? -1 : new_mask_color));
         break;
     }
     if (dither)

src/render/quantization.h

@@ -1,4 +1,4 @@
-// Aseprite Rener Library
+// Aseprite Render Library
 // Copyright (c) 2019-2021  Igara Studio S.A.
 // Copyright (c) 2001-2017  David Capello
 //

src/ui/entry.cpp

@@ -128,6 +128,15 @@ int Entry::lastCaretPos() const
   return int(m_boxes.size() - 1);
 }
 
+gfx::Point Entry::caretPosOnScreen() const
+{
+  const gfx::Point caretPos = getCharBoxBounds(m_caret).point2();
+  const os::Window* nativeWindow = display()->nativeWindow();
+  const gfx::Point pos = nativeWindow->pointToScreen(caretPos + bounds().origin());
+
+  return pos;
+}
+
 void Entry::setCaretPos(const int pos)
 {
   gfx::Size caretSize = theme()->getEntryCaretSize(this);
@@ -160,6 +169,8 @@ void Entry::setCaretPos(const int pos)
     startTimer();
   m_state = true;
 
+  os::System::instance()->setTextInput(true, caretPosOnScreen());
+
   invalidate();
 }
 
@@ -251,7 +262,7 @@ gfx::Rect Entry::getEntryTextBounds() const
   return onGetEntryTextBounds();
 }
 
-gfx::Rect Entry::getCharBoxBounds(const int i)
+gfx::Rect Entry::getCharBoxBounds(const int i) const
 {
   ASSERT(i >= 0 && i < int(m_boxes.size()));
   if (i >= 0 && i < int(m_boxes.size()))
@@ -288,8 +299,9 @@ bool Entry::onProcessMessage(Message* msg)
       }
 
       // Start processing dead keys
-      if (m_translate_dead_keys)
-        os::System::instance()->setTextInput(true);
+      if (m_translate_dead_keys) {
+        os::System::instance()->setTextInput(true, caretPosOnScreen());
+      }
       break;
 
     case kFocusLeaveMessage:

src/ui/entry.h

@@ -43,6 +43,7 @@ public:
 
   int caretPos() const { return m_caret; }
   int lastCaretPos() const;
+  gfx::Point caretPosOnScreen() const;
 
   void setCaretPos(int pos);
   void setCaretToEnd();
@@ -76,7 +77,7 @@ public:
   obs::signal<void()> Change;
 
 protected:
-  gfx::Rect getCharBoxBounds(int i);
+  gfx::Rect getCharBoxBounds(int i) const;
 
   // Events
   bool onProcessMessage(Message* msg) override;

tests/scripts/sprite.lua

@@ -228,3 +228,69 @@ do
   c = app.open(fn)
   assert(c.tileManagementPlugin == nil)
 end
+
+-- Undo History
+
+function test_undo_history()
+  local sprite = Sprite(1, 1)
+
+  assert(sprite.undoHistory.undoSteps == 0)
+  assert(sprite.undoHistory.redoSteps == 0)
+
+  sprite:resize(10, 10)
+
+  assert(sprite.undoHistory.undoSteps == 1)
+  assert(sprite.undoHistory.redoSteps == 0)
+
+  sprite:resize(10, 15)
+
+  assert(sprite.undoHistory.undoSteps == 2)
+  assert(sprite.undoHistory.redoSteps == 0)
+
+  sprite:resize(10, 30)
+
+  assert(sprite.undoHistory.undoSteps == 3)
+  assert(sprite.undoHistory.redoSteps == 0)
+
+  app.undo()
+  assert(sprite.undoHistory.undoSteps == 2)
+  assert(sprite.undoHistory.redoSteps == 1)
+
+  app.undo()
+  assert(sprite.undoHistory.undoSteps == 1)
+  assert(sprite.undoHistory.redoSteps == 2)
+
+  app.redo()
+  assert(sprite.undoHistory.undoSteps == 2)
+  assert(sprite.undoHistory.redoSteps == 1)
+
+  app.undo()
+  app.undo()
+
+  assert(sprite.undoHistory.undoSteps == 0)
+  assert(sprite.undoHistory.redoSteps == 3)
+
+  sprite:resize(10, 30)
+
+  if (app.preferences.undo.allow_nonlinear_history) then
+    assert(sprite.undoHistory.undoSteps == 4)
+    assert(sprite.undoHistory.redoSteps == 0)
+  else
+    assert(sprite.undoHistory.undoSteps == 1)
+    assert(sprite.undoHistory.redoSteps == 0)
+  end
+end
+
+do
+  local prevSetting = app.preferences.undo.allow_nonlinear_history
+  app.preferences.undo.allow_nonlinear_history = true
+  test_undo_history()
+  app.preferences.undo.allow_nonlinear_history = prevSetting
+end
+
+do
+  local prevSetting = app.preferences.undo.allow_nonlinear_history
+  app.preferences.undo.allow_nonlinear_history = false
+  test_undo_history()
+  app.preferences.undo.allow_nonlinear_history = prevSetting
+end