Add caching of the snapshot image form a surface

Notify the surface when the canvas draws into it, so it can invalidate the
cached image, and (if needed) perform a copy-on-write on the surface if it
was being shared with the image.
Review URL: https://codereview.appspot.com/6441115

git-svn-id: http://skia.googlecode.com/svn/trunk@5306 2bbb7eff-a529-9590-31e7-b0007b416f81

4 files changed, 29 insertions, 6 deletions

diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index 01e0c75a24..1f29e1c00a 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -26,6 +26,7 @@ class SkDevice;
 class SkDraw;
 class SkDrawFilter;
 class SkPicture;
+class SkSurface_Base;
 
 /** \class SkCanvas
 
@@ -950,6 +951,10 @@ protected:
     bool clipRectBounds(const SkRect* bounds, SaveFlags flags,
                         SkIRect* intersection);
 
+    // notify our surface (if we have one) that we are about to draw, so it
+    // can perform copy-on-write or invalidate any cached images
+    void predrawNotify();
+
 private:
     class MCRec;
 
@@ -964,6 +969,13 @@ private:
     SkDevice*   fLastDeviceToGainFocus;
     int         fSaveLayerCount;    // number of successful saveLayer calls
 
+    SkSurface_Base*  fSurfaceBase;
+    SkSurface_Base* getSurfaceBase() const { return fSurfaceBase; }
+    void setSurfaceBase(SkSurface_Base* sb) {
+        fSurfaceBase = sb;
+    }
+    friend class SkSurface_Base;
+
     void prepareForDeviceDraw(SkDevice*, const SkMatrix&, const SkRegion&);
 
     bool fDeviceCMDirty;            // cleared by updateDeviceCMCache()
diff --git a/include/core/SkDevice.h b/include/core/SkDevice.h
index 326115ca31..41e316c9cc 100644
--- a/include/core/SkDevice.h
+++ b/include/core/SkDevice.h
@@ -380,6 +380,12 @@ private:
     friend class SkDeviceFilteredPaint;
     friend class DeviceImageFilterProxy;
 
+    friend class SkSurface_Raster;
+    // used to change the backend's pixels (and possibly config/rowbytes)
+    // but cannot change the width/height, so there should be no change to
+    // any clip information.
+    void replaceBitmapBackendForRasterSurface(const SkBitmap&);
+
     // just called by SkCanvas when built as a layer
     void setOrigin(int x, int y) { fOrigin.set(x, y); }
     // just called by SkCanvas for saveLayer
diff --git a/include/core/SkImage.h b/include/core/SkImage.h
index 985a3bbbbb..b0071e28d8 100644
--- a/include/core/SkImage.h
+++ b/include/core/SkImage.h
@@ -37,7 +37,7 @@ class SkColorSpace;
  */
 class SkImage : public SkRefCnt {
 public:
-    SK_DECLARE_INST_COUNT(SkImage)
+//    SK_DECLARE_INST_COUNT(SkImage)
 
     enum ColorType {
         kAlpha_8_ColorType,
diff --git a/include/core/SkSurface.h b/include/core/SkSurface.h
index 8e407b92f6..9f8908a3bd 100644
--- a/include/core/SkSurface.h
+++ b/include/core/SkSurface.h
@@ -26,7 +26,7 @@ class GrRenderTarget;
  */
 class SkSurface : public SkRefCnt {
 public:
-    SK_DECLARE_INST_COUNT(SkSurface)
+//    SK_DECLARE_INST_COUNT(SkSurface)
 
     /**
      *  Create a new surface, using the specified pixels/rowbytes as its
@@ -78,7 +78,7 @@ public:
      *  If this surface is empty (i.e. has a zero-dimention), this will return
      *  0.
      */
-    uint32_t generationID() const;
+    uint32_t generationID();
 
     /**
      *  Call this if the contents have changed. This will (lazily) force a new
@@ -128,10 +128,15 @@ public:
 protected:
     SkSurface(int width, int height);
 
+    // called by subclass if their contents have changed
+    void dirtyGenerationID() {
+        fGenerationID = 0;
+    }
+
 private:
-    const int           fWidth;
-    const int           fHeight;
-    mutable uint32_t    fGenerationID;
+    const int   fWidth;
+    const int   fHeight;
+    uint32_t    fGenerationID;
 };
 
 #endif