Add a timer to MovingPixelsState to avoid RotSprite on each mouse move

We can use the fast algorithm for fast feedback, and use a timer to
draw with RotSprite when the mouse doesn't move after 50ms.

src/app/doc.cpp

@@ -255,6 +255,12 @@ void Doc::setFormatOptions(const FormatOptionsPtr& format_options)
 //////////////////////////////////////////////////////////////////////
 // Boundaries
 
+void Doc::destroyMaskBoundaries()
+{
+  m_maskBoundaries.reset();
+  notifySelectionBoundariesChanged();
+}
+
 void Doc::generateMaskBoundaries(const Mask* mask)
 {
   m_maskBoundaries.reset();

src/app/doc.h

@@ -135,6 +135,7 @@ namespace app {
     //////////////////////////////////////////////////////////////////////
     // Boundaries
 
+    void destroyMaskBoundaries();
     void generateMaskBoundaries(const Mask* mask = nullptr);
 
     const MaskBoundaries* getMaskBoundaries() const {

src/app/ui/editor/moving_pixels_state.cpp

@@ -58,6 +58,7 @@ MovingPixelsState::MovingPixelsState(Editor* editor, MouseMessage* msg, PixelsMo
   , m_editor(editor)
   , m_observingEditor(false)
   , m_discarded(false)
+  , m_renderTimer(50)
 {
   // MovingPixelsState needs a selection tool to avoid problems
   // sharing the extra cel between the drawing cursor preview and the
@@ -80,6 +81,8 @@ MovingPixelsState::MovingPixelsState(Editor* editor, MouseMessage* msg, PixelsMo
   }
   onTransparentColorChange();
 
+  m_renderTimer.Tick.connect([this]{ onRenderTimer(); });
+
   // Hook BeforeCommandExecution signal so we know if the user wants
   // to execute other command, so we can drop pixels.
   m_ctxConn =
@@ -114,6 +117,7 @@ MovingPixelsState::~MovingPixelsState()
 
   removePixelsMovement();
   removeAsEditorObserver();
+  m_renderTimer.stop();
 
   m_editor->manager()->removeMessageFilter(kKeyDownMessage, m_editor);
   m_editor->manager()->removeMessageFilter(kKeyUpMessage, m_editor);
@@ -164,6 +168,8 @@ EditorState::LeaveAction MovingPixelsState::onLeaveState(Editor* editor, EditorS
   ASSERT(m_pixelsMovement);
   ASSERT(editor == m_editor);
 
+  onRenderTimer();
+
   // If we are changing to another state, we've to drop the image.
   if (m_pixelsMovement->isDragging())
     m_pixelsMovement->dropImageTemporarily();
@@ -341,6 +347,9 @@ bool MovingPixelsState::onMouseMove(Editor* editor, MouseMessage* msg)
 
   // If there is a button pressed
   if (m_pixelsMovement->isDragging()) {
+    m_renderTimer.start();
+    m_pixelsMovement->setFastMode(true);
+
     // Auto-scroll
     gfx::Point mousePos = editor->autoScroll(msg, AutoScroll::MouseDir);
 
@@ -657,6 +666,12 @@ void MovingPixelsState::onTransparentColorChange()
       Preferences::instance().selection.transparentColor());
 }
 
+void MovingPixelsState::onRenderTimer()
+{
+  m_pixelsMovement->setFastMode(false);
+  m_renderTimer.stop();
+}
+
 void MovingPixelsState::onDropPixels(ContextBarObserver::DropAction action)
 {
   if (!isActiveEditor())

src/app/ui/editor/moving_pixels_state.h

@@ -16,6 +16,7 @@
 #include "app/ui/editor/standby_state.h"
 #include "app/ui/status_bar.h"
 #include "obs/connection.h"
+#include "ui/timer.h"
 
 namespace doc {
   class Image;
@@ -68,6 +69,7 @@ namespace app {
 
   private:
     void onTransparentColorChange();
+    void onRenderTimer();
 
     // ContextObserver
     void onBeforeCommandExecution(CommandExecutionEvent& ev);
@@ -90,6 +92,8 @@ namespace app {
     // used to remove the dragged image).
     bool m_discarded;
 
+    ui::Timer m_renderTimer;
+
     obs::connection m_ctxConn;
     obs::connection m_opaqueConn;
     obs::connection m_transparentConn;

src/app/ui/editor/pixels_movement.cpp

@@ -131,6 +131,8 @@ PixelsMovement::PixelsMovement(
   , m_opaque(false)
   , m_maskColor(m_site.sprite()->transparentColor())
   , m_canHandleFrameChange(false)
+  , m_fastMode(false)
+  , m_needsRotSpriteRedraw(false)
 {
   Transformation transform(mask->bounds());
   set_pivot_from_preferences(transform);
@@ -170,6 +172,17 @@ PixelsMovement::PixelsMovement(
   }
 }
 
+void PixelsMovement::setFastMode(const bool fastMode)
+{
+  bool redraw = (m_fastMode && !fastMode);
+  m_fastMode = fastMode;
+  if (m_needsRotSpriteRedraw && redraw) {
+    redrawExtraImage();
+    update_screen_for_document(m_document);
+    m_needsRotSpriteRedraw = false;
+  }
+}
+
 void PixelsMovement::flipImage(doc::algorithm::FlipType flipType)
 {
   m_innerCmds.push_back(InnerCmd::MakeFlip(flipType));
@@ -265,14 +278,7 @@ void PixelsMovement::cutMask()
 
 void PixelsMovement::copyMask()
 {
-  // Hide the mask (do not deselect it, it will be moved them using
-  // m_transaction.setMaskPosition)
-  Mask emptyMask;
-  {
-    ContextWriter writer(m_reader, 1000);
-    m_document->generateMaskBoundaries(&emptyMask);
-    update_screen_for_document(m_document);
-  }
+  hideDocumentMask();
 }
 
 void PixelsMovement::catchImage(const gfx::Point& pos, HandleType handle)
@@ -292,14 +298,7 @@ void PixelsMovement::catchImageAgain(const gfx::Point& pos, HandleType handle)
   m_catchPos = pos;
   m_handle = handle;
 
-  // Hide the mask (do not deselect it, it will be moved them using
-  // m_transaction.setMaskPosition)
-  Mask emptyMask;
-  {
-    ContextWriter writer(m_reader, 1000);
-    m_document->generateMaskBoundaries(&emptyMask);
-    update_screen_for_document(m_document);
-  }
+  hideDocumentMask();
 }
 
 void PixelsMovement::moveImage(const gfx::Point& pos, MoveModifier moveModifier)
@@ -862,6 +861,12 @@ void PixelsMovement::drawParallelogram(
     rotAlgo = tools::RotationAlgorithm::FAST;
   }
 
+  // Don't use RotSprite if we are in "fast mode"
+  if (rotAlgo == tools::RotationAlgorithm::ROTSPRITE && m_fastMode) {
+    m_needsRotSpriteRedraw = true;
+    rotAlgo = tools::RotationAlgorithm::FAST;
+  }
+
 retry:;      // In case that we don't have enough memory for RotSprite
              // we can try with the fast algorithm anyway.
 
@@ -931,6 +936,12 @@ void PixelsMovement::updateDocumentMask()
   m_document->generateMaskBoundaries(m_currentMask.get());
 }
 
+void PixelsMovement::hideDocumentMask()
+{
+  m_document->destroyMaskBoundaries();
+  update_screen_for_document(m_document);
+}
+
 void PixelsMovement::flipOriginalImage(const doc::algorithm::FlipType flipType)
 {
   // Flip the image.

src/app/ui/editor/pixels_movement.h

@@ -71,6 +71,8 @@ namespace app {
     HandleType handle() const { return m_handle; }
     bool canHandleFrameChange() const { return m_canHandleFrameChange; }
 
+    void setFastMode(const bool fastMode);
+
     void trim();
     void cutMask();
     void copyMask();
@@ -135,6 +137,7 @@ namespace app {
       const Transformation::Corners& corners,
       const gfx::Point& leftTop);
     void updateDocumentMask();
+    void hideDocumentMask();
 
     void flipOriginalImage(const doc::algorithm::FlipType flipType);
     void shiftOriginalImage(const int dx, const int dy,
@@ -166,6 +169,11 @@ namespace app {
     ExtraCelRef m_extraCel;
     bool m_canHandleFrameChange;
 
+    // Fast mode is used to give a faster feedback to the user
+    // avoiding RotSprite on each mouse movement.
+    bool m_fastMode;
+    bool m_needsRotSpriteRedraw;
+
     // Commands used in the interaction with the transformed pixels.
     // This is used to re-create the whole interaction on each
     // modified cel when we are modifying multiples cels at the same