Defer saves() until they're needed

include/core/SkCanvas.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkCanvas_DEFINED
 #define SkCanvas_DEFINED
 
@@ skipping 1247 matching lines @@
 
     SkClipStack fClipStack;
     SkDeque     fMCStack;
     // points to top of stack
     MCRec*      fMCRec;
     // the first N recs that can fit here mean we won't call malloc
     uint32_t    fMCRecStorage[32];
 
     const SkSurfaceProps fProps;
 
+    int         fSaveCount;         // value returned by getSaveCount()
     int         fSaveLayerCount;    // number of successful saveLayer calls
     int         fCullCount;         // number of active culls
 
     SkMetaData* fMetaData;
 
     SkSurface_Base*  fSurfaceBase;
     SkSurface_Base* getSurfaceBase() const { return fSurfaceBase; }
     void setSurfaceBase(SkSurface_Base* sb) {
         fSurfaceBase = sb;
     }
     friend class SkSurface_Base;
     friend class SkSurface_Gpu;
 
     bool fDeviceCMDirty;            // cleared by updateDeviceCMCache()
     void updateDeviceCMCache();
 
+    void doSave();
+    void checkForDeferredSave();
+
     friend class SkDrawIter;        // needs setupDrawForLayerDevice()
     friend class AutoDrawLooper;
     friend class SkLua;             // needs top layer size and offset
     friend class SkDebugCanvas;     // needs experimental fAllowSimplifyClip
     friend class SkDeferredDevice;  // needs getTopDevice()
     friend class SkSurface_Raster;  // needs getDevice()
     friend class SkRecorder;        // InitFlags
     friend class SkNoSaveLayerCanvas;   // InitFlags
     friend class SkPictureImageFilter;  // SkCanvas(SkBaseDevice*, SkSurfaceProps*, InitFlags)
 
@@ skipping 33 matching lines @@
 
     // internal methods are not virtual, so they can safely be called by other
     // canvas apis, without confusing subclasses (like SkPictureRecording)
     void internalDrawBitmap(const SkBitmap&, const SkMatrix& m, const SkPaint* paint);
     void internalDrawBitmapRect(const SkBitmap& bitmap, const SkRect* src,
                                 const SkRect& dst, const SkPaint* paint,
                                 DrawBitmapRectFlags flags);
     void internalDrawBitmapNine(const SkBitmap& bitmap, const SkIRect& center,
                                 const SkRect& dst, const SkPaint* paint);
     void internalDrawPaint(const SkPaint& paint);
-    int internalSaveLayer(const SkRect* bounds, const SkPaint* paint,
-                          SaveFlags, bool justForImageFilter, SaveLayerStrategy strategy);
+    void internalSaveLayer(const SkRect* bounds, const SkPaint* paint,
+                           SaveFlags, bool justForImageFilter, SaveLayerStrategy strategy);
     void internalDrawDevice(SkBaseDevice*, int x, int y, const SkPaint*);
 
     // shared by save() and saveLayer()
-    int internalSave();
+    void internalSave();
     void internalRestore();
     static void DrawRect(const SkDraw& draw, const SkPaint& paint,
                          const SkRect& r, SkScalar textSize);
     static void DrawTextDecorations(const SkDraw& draw, const SkPaint& paint,
                                     const char text[], size_t byteLength,
                                     SkScalar x, SkScalar y);
 
     // only for canvasutils
     const SkRegion& internal_private_getTotalClip() const;
 
@@ skipping 154 matching lines @@
 
 class SkCanvasClipVisitor {
 public:
     virtual ~SkCanvasClipVisitor();
     virtual void clipRect(const SkRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipRRect(const SkRRect&, SkRegion::Op, bool antialias) = 0;
     virtual void clipPath(const SkPath&, SkRegion::Op, bool antialias) = 0;
 };
 
 #endif