Optimize ToolLoop with modified regions of pixels

Here we avoid copying and clearing pixels that will not be used
in the whole tool loop process.
Changes:
* Add several member functions in ToolLoop to validate/invalidate regions
  of source/destination images so we know what regions are safe to use
  by inks and can be shown in the editor
* Add new DocumentObserver::onExposeSpritePixels() member to validate
  pixels that will be displayed in the editor
* Add Ink::needs/createSpecialSourceArea() member functions to validate
  extra areas for inks like blur or jumble
* Add undoers::ModifiedRegion to save the undo information about the
  modified region
* Add ShowHideDrawingCursor class
* Change "blur" tool policy from overlap to accumulate

(This is a real fix for issue #239)

Author: dacap

data/gui.xml

@@ -696,7 +696,7 @@
             controller="freehand"
             pointshape="pixel"
             intertwine="as_lines"
-            tracepolicy="accumulative">
+            tracepolicy="accumulate">
         <tooltip>*
         Left-button: Replace/add to current selection.&#10;*
         Right-button: Remove from current selection.
@@ -723,7 +723,7 @@
             ink="selection"
             controller="one_point"
             pointshape="floodfill"
-            tracepolicy="accumulative">
+            tracepolicy="accumulate">
         <tooltip>*
         Left-button: Replace/add to current selection.&#10;*
         Right-button: Remove from current selection.
@@ -738,7 +738,7 @@
             controller="freehand"
             pointshape="brush"
             intertwine="as_lines"
-            tracepolicy="accumulative"
+            tracepolicy="accumulate"
             />
       <tool id="spray"
             text="Spray Tool"
@@ -757,7 +757,7 @@
             controller="freehand"
             pointshape="brush"
             intertwine="as_lines"
-            tracepolicy="accumulative"
+            tracepolicy="accumulate"
             default_brush_size="8">
         <tooltip>*
         Left-button: Erase with the background color in `Background' layer&#10;
@@ -810,7 +810,7 @@
             ink="paint"
             controller="one_point"
             pointshape="floodfill"
-            tracepolicy="accumulative"
+            tracepolicy="accumulate"
             />
     </group>
 
@@ -880,7 +880,7 @@
             controller="freehand"
             pointshape="brush"
             intertwine="as_lines"
-            tracepolicy="accumulative"
+            tracepolicy="accumulate"
             />
       <tool id="polygon"
             text="Polygon Tool"
@@ -900,7 +900,7 @@
             controller="freehand"
             pointshape="brush"
             intertwine="as_lines"
-            tracepolicy="overlap"
+            tracepolicy="accumulate"
             default_brush_size="16"
             />
       <tool id="jumble"

src/app/CMakeLists.txt

@@ -249,6 +249,7 @@ add_library(app-lib
   undoers/dirty_area.cpp
   undoers/flip_image.cpp
   undoers/image_area.cpp
+  undoers/modified_region.cpp
   undoers/move_layer.cpp
   undoers/open_group.cpp
   undoers/remap_palette.cpp

src/app/commands/cmd_export_sprite_sheet.cpp

@@ -337,7 +337,8 @@ void ExportSpriteSheetCommand::onExecute(Context* context)
     // destination clipping bounds in Sprite::render() function.
     tempImage->clear(0);
     sprite->render(tempImage, 0, 0, frame);
-    resultImage->copy(tempImage, column*sprite->width(), row*sprite->height());
+    resultImage->copy(tempImage, column*sprite->width(), row*sprite->height(),
+      0, 0, tempImage->width(), tempImage->height());
 
     if (++column >= columns) {
       column = 0;

src/app/commands/cmd_preview.cpp

@@ -192,8 +192,7 @@ class PreviewWindow : public Window {
 
       ImageBufferPtr buf = Editor::getRenderImageBuffer();
       m_render.reset(
-        renderEngine.renderSprite(
-          0, 0, m_sprite->width(), m_sprite->height(),
+        renderEngine.renderSprite(m_sprite->bounds(),
           m_editor->frame(), Zoom(1, 1), false, false, buf));
     }
 

src/app/document.cpp

@@ -108,6 +108,14 @@ void Document::notifySpritePixelsModified(Sprite* sprite, const gfx::Region& reg
   notifyObservers<doc::DocumentEvent&>(&doc::DocumentObserver::onSpritePixelsModified, ev);
 }
 
+void Document::notifyExposeSpritePixels(Sprite* sprite, const gfx::Region& region)
+{
+  doc::DocumentEvent ev(this);
+  ev.sprite(sprite);
+  ev.region(region);
+  notifyObservers<doc::DocumentEvent&>(&doc::DocumentObserver::onExposeSpritePixels, ev);
+}
+
 void Document::notifyLayerMergedDown(Layer* srcLayer, Layer* targetLayer)
 {
   doc::DocumentEvent ev(this);

src/app/document.h

@@ -91,6 +91,7 @@ namespace app {
 
     void notifyGeneralUpdate();
     void notifySpritePixelsModified(Sprite* sprite, const gfx::Region& region);
+    void notifyExposeSpritePixels(Sprite* sprite, const gfx::Region& region);
     void notifyLayerMergedDown(Layer* srcLayer, Layer* targetLayer);
     void notifyCelMoved(Layer* fromLayer, FrameNumber fromFrame, Layer* toLayer, FrameNumber toFrame);
     void notifyCelCopied(Layer* fromLayer, FrameNumber fromFrame, Layer* toLayer, FrameNumber toFrame);

src/app/document_api.cpp

@@ -1093,11 +1093,10 @@ void DocumentApi::flattenLayers(Sprite* sprite)
 
       // We have to save the current state of `cel_image' in the undo.
       if (undoEnabled()) {
-        Dirty* dirty = new Dirty(cel_image, image, image->bounds());
-        dirty->saveImagePixels(cel_image);
+        Dirty dirty(cel_image, image, image->bounds());
+        dirty.saveImagePixels(cel_image);
         m_undoers->pushUndoer(new undoers::DirtyArea(
-            getObjects(), cel_image, dirty));
-        delete dirty;
+            getObjects(), cel_image, &dirty));
       }
     }
     else {
@@ -1296,10 +1295,9 @@ void DocumentApi::flipImageWithMask(Layer* layer, Image* image, const Mask* mask
 
   // Insert the undo operation.
   if (undoEnabled()) {
-    base::UniquePtr<Dirty> dirty((new Dirty(image, flippedImage, image->bounds())));
-    dirty->saveImagePixels(image);
-
-    m_undoers->pushUndoer(new undoers::DirtyArea(getObjects(), image, dirty));
+    Dirty dirty(image, flippedImage, image->bounds());
+    dirty.saveImagePixels(image);
+    m_undoers->pushUndoer(new undoers::DirtyArea(getObjects(), image, &dirty));
   }
 
   // Copy the flipped image into the image specified as argument.

src/app/settings/ui_settings_impl.cpp

@@ -1026,18 +1026,23 @@ class UIToolSettingsImpl
 
     tools::ToolBox* toolBox = App::instance()->getToolBox();
     for (int i=0; i<2; ++i) {
+      if (m_tool->getTracePolicy(i) != tools::TracePolicy::Accumulate &&
+          m_tool->getTracePolicy(i) != tools::TracePolicy::AccumulateUpdateLast) {
+        continue;
+      }
+
       switch (algorithm) {
         case kDefaultFreehandAlgorithm:
           m_tool->setIntertwine(i, toolBox->getIntertwinerById(tools::WellKnownIntertwiners::AsLines));
-          m_tool->setTracePolicy(i, tools::TracePolicyAccumulate);
+          m_tool->setTracePolicy(i, tools::TracePolicy::Accumulate);
           break;
         case kPixelPerfectFreehandAlgorithm:
           m_tool->setIntertwine(i, toolBox->getIntertwinerById(tools::WellKnownIntertwiners::AsPixelPerfect));
-          m_tool->setTracePolicy(i, tools::TracePolicyLast);
+          m_tool->setTracePolicy(i, tools::TracePolicy::AccumulateUpdateLast);
           break;
         case kDotsFreehandAlgorithm:
           m_tool->setIntertwine(i, toolBox->getIntertwinerById(tools::WellKnownIntertwiners::None));
-          m_tool->setTracePolicy(i, tools::TracePolicyAccumulate);
+          m_tool->setTracePolicy(i, tools::TracePolicy::Accumulate);
           break;
       }
     }

src/app/thumbnail_generator.cpp

@@ -85,8 +85,8 @@ class ThumbnailGenerator::Worker {
 
         doc::ImageBufferPtr thumbnail_buffer(new doc::ImageBuffer);
         base::UniquePtr<Image> image(renderEngine.renderSprite(
-            0, 0, sprite->width(), sprite->height(),
-            FrameNumber(0), Zoom(1, 1), true, false,
+            sprite->bounds(), FrameNumber(0),
+            Zoom(1, 1), true, false,
             thumbnail_buffer));
 
         // Calculate the thumbnail size

src/app/tools/ink.h

@@ -20,6 +20,10 @@
 #define APP_TOOLS_INK_H_INCLUDED
 #pragma once
 
+namespace gfx {
+  class Region;
+}
+
 namespace app {
   namespace tools {
 
@@ -64,6 +68,12 @@ namespace app {
       // Returns true if this ink is used to mark slices
       virtual bool isSlice() const { return false; }
 
+      // Returns true if this ink needs a special source area.  For
+      // example, blur tool needs one extra pixel to all sides of the
+      // modified area, so it can use a 3x3 convolution matrix.
+      virtual bool needsSpecialSourceArea() const { return false; }
+      virtual void createSpecialSourceArea(const gfx::Region& dirtyArea, gfx::Region& sourceArea) const { }
+
       // It is called when the tool-loop start (generally when the user
       // presses a mouse button over a sprite editor)
       virtual void prepareInk(ToolLoop* loop) { }