Fixing SkPicture command pattern optimizations to make them work correctly with bounding box hierar…

src/core/SkPictureStateTree.h

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkPictureStateTree_DEFINED
 #define SkPictureStateTree_DEFINED
@@ skipping 45 matching lines @@
      */
     Iterator getIterator(const SkTDArray<void*>& draws, SkCanvas* canvas);
 
     void appendSave();
     void appendSaveLayer(uint32_t offset);
     void appendRestore();
     void appendTransform(const SkMatrix& trans);
     void appendClip(uint32_t offset);
 
     /**
+     * Call this immediately after an appendRestore call that is associated
+     * a save or saveLayer that was removed from the command stream
+     * due to a command pattern optimization in SkPicture.
+     */
+    void saveCollapsed();
+
+    /**
      * Playback helper
      */
     class Iterator {
     public:
         /** Returns the next offset into the picture stream, or kDrawComplete if complete. */
         uint32_t draw();
         static const uint32_t kDrawComplete = SK_MaxU32;
         Iterator() : fPlaybackMatrix(), fValid(false) { }
         bool isValid() const { return fValid; }
     private:
@@ skipping 25 matching lines @@
         bool fValid;
 
         friend class SkPictureStateTree;
     };
 
 private:
 
     void appendNode(uint32_t offset);
 
     SkChunkAlloc fAlloc;
     Node* fRoot;

[robertphillips, 2013/03/14 18:55:44]

Do we want a comment like: // ideally the state tree would be doubly linked so
we could XXX but for right now we allow one level patches
I'm thinking about the case where we apply the peephole optimizations
iteratively and we can get consecutive collapses.

[Justin Novosad, 2013/03/14 20:04:14]

Done.

+    Node* fLastRestoredNode;
 
     // The currently active state
     Draw fCurrentState;
     // A stack of states for tracking save/restores
     SkDeque fStateStack;
 
     // Represents a notable piece of state that requires an offset into the command buffer,
     // corresponding to a clip/saveLayer/etc call, to apply.
     struct Node {
         Node* fParent;
         uint32_t fOffset;
         uint16_t fLevel;
         uint16_t fFlags;
         SkMatrix* fMatrix;
         enum Flags {
             kSave_Flag      = 0x1,
             kSaveLayer_Flag = 0x2
         };
     };
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif