Integrating SkSurface with SkDeferredCanvas

src/image/SkSurface.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkSurface_Base.h"
 #include "SkImagePriv.h"
 #include "SkCanvas.h"
@@ skipping 41 matching lines @@
 }
 
 SkImage* SkSurface_Base::getCachedImage() {
     if (NULL == fCachedImage) {
         fCachedImage = this->onNewImageShapshot();
         this->installIntoCanvasForDirtyNotification();
     }
     return fCachedImage;
 }
 
-void SkSurface_Base::aboutToDraw(SkCanvas* canvas) {
+void SkSurface_Base::aboutToDraw(SkCanvas* canvas, bool canDiscardContents) {
     this->dirtyGenerationID();
 
-    if (canvas) {
-        SkASSERT(canvas == fCachedCanvas);
-        SkASSERT(canvas->getSurfaceBase() == this);
-        canvas->setSurfaceBase(NULL);
-    }
+    SkASSERT(canvas == fCachedCanvas);
+    SkASSERT(canvas->getSurfaceBase() == this || NULL == fCachedImage);

[reed1, 2013/03/27 15:31:43]

Why this || clause?

I presume it is because the passed canvas is the deferred canvas, not the one
built-into the surface?

+    canvas->setSurfaceBase(NULL);
 
     if (fCachedImage) {
-        // the surface may need to fork its backend, if its sharing it with
+        // the surface may need to fork its backend, if it's sharing it with
         // the cached image. Note: we only call if there is an outstanding owner
         // on the image (besides us).
         if (fCachedImage->getRefCnt() > 1) {
-            this->onCopyOnWrite(fCachedImage, canvas);
+            this->onCopyOnWrite(fCachedImage, canvas, canDiscardContents);
         }
 
         // regardless of copy-on-write, we must drop our cached image now, so
         // that the next request will get our new contents.
         fCachedImage->unref();
         fCachedImage = NULL;
     }
 }
 
 uint32_t SkSurface_Base::newGenerationID() {
@@ skipping 15 matching lines @@
     fGenerationID = 0;
 }
 
 uint32_t SkSurface::generationID() {
     if (0 == fGenerationID) {
         fGenerationID = asSB(this)->newGenerationID();
     }
     return fGenerationID;
 }
 
-void SkSurface::notifyContentChanged() {
-    asSB(this)->aboutToDraw(NULL);
+void SkSurface::notifyContentChanged(bool canDiscardContents) {
+    asSB(this)->aboutToDraw(this->getCanvas(), canDiscardContents);
 }
 
 SkCanvas* SkSurface::getCanvas() {
     return asSB(this)->getCachedCanvas();
 }
 
 SkImage* SkSurface::newImageShapshot() {
     SkImage* image = asSB(this)->getCachedImage();
     SkSafeRef(image);   // the caller will call unref() to balance this
     return image;
 }
 
 SkSurface* SkSurface::newSurface(const SkImage::Info& info) {
     return asSB(this)->onNewSurface(info);
 }
 
 void SkSurface::draw(SkCanvas* canvas, SkScalar x, SkScalar y,
                      const SkPaint* paint) {
     return asSB(this)->onDraw(canvas, x, y, paint);
 }