Integrating SkSurface with SkDeferredCanvas

src/image/SkSurface_Gpu.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"
 #include "SkGpuDevice.h"
 
 class SkSurface_Gpu : public SkSurface_Base {
 public:
     SK_DECLARE_INST_COUNT(SkSurface_Gpu)
 
     SkSurface_Gpu(GrContext*, const SkImage::Info&, int sampleCount);
     SkSurface_Gpu(GrContext*, GrRenderTarget*);
     virtual ~SkSurface_Gpu();
 
     virtual SkCanvas* onNewCanvas() SK_OVERRIDE;
     virtual SkSurface* onNewSurface(const SkImage::Info&) SK_OVERRIDE;
     virtual SkImage* onNewImageShapshot() SK_OVERRIDE;
     virtual void onDraw(SkCanvas*, SkScalar x, SkScalar y,
                         const SkPaint*) SK_OVERRIDE;
-    virtual void onCopyOnWrite(SkImage*, SkCanvas*) SK_OVERRIDE;
+    virtual void onCopyOnWrite(SkImage*, SkCanvas*, bool canDiscardContents) SK_OVERRIDE;
 
 private:
     SkGpuDevice* fDevice;
 
     typedef SkSurface_Base INHERITED;
 };
 
 SK_DEFINE_INST_COUNT(SkSurface_Gpu)
 
 ///////////////////////////////////////////////////////////////////////////////
@@ skipping 39 matching lines @@
     GrRenderTarget* rt = (GrRenderTarget*) fDevice->accessRenderTarget();
 
     return SkImage::NewTexture(rt->asTexture());
 }
 
 void SkSurface_Gpu::onDraw(SkCanvas* canvas, SkScalar x, SkScalar y,
                               const SkPaint* paint) {
     canvas->drawBitmap(fDevice->accessBitmap(false), x, y, paint);
 }
 
-// Copy the contents of the SkGpuDevice into a new texture and give that
-// texture to the SkImage. Note that this flushes the SkGpuDevice but
+// Create a new SkGpuDevice and, if necessary, copy the contents of the old
+// device into it. Note that this flushes the SkGpuDevice but
 // doesn't force an OpenGL flush.
-void SkSurface_Gpu::onCopyOnWrite(SkImage* image, SkCanvas*) {
+void SkSurface_Gpu::onCopyOnWrite(SkImage* image, SkCanvas* canvas, bool canDiscardContents) {
     GrRenderTarget* rt = (GrRenderTarget*) fDevice->accessRenderTarget();
 
     // are we sharing our render target with the image?
     if (rt->asTexture() == SkTextureImageGetTexture(image)) {
-        GrTextureDesc desc;
-        // copyTexture requires a render target as the destination
-        desc.fFlags = kRenderTarget_GrTextureFlagBit;
-        desc.fWidth = fDevice->width();
-        desc.fHeight = fDevice->height();
-        desc.fConfig = SkBitmapConfig2GrPixelConfig(fDevice->config());
-        desc.fSampleCnt = 0;
-
-        SkAutoTUnref<GrTexture> tex(fDevice->context()->createUncachedTexture(desc, NULL, 0));
-        if (NULL == tex) {
-            SkTextureImageSetTexture(image, NULL);
-            return;
+        SkGpuDevice* newDevice = static_cast<SkGpuDevice*>(
+            fDevice->createCompatibleDevice(fDevice->config(), fDevice->width(),
+            fDevice->height(), fDevice->isOpaque()));
+        SkAutoTUnref<SkGpuDevice> aurd(newDevice);
+        if (!canDiscardContents) {
+            fDevice->context()->copyTexture(rt->asTexture(),
+                (GrRenderTarget*)newDevice->accessRenderTarget());
         }
-
-        fDevice->context()->copyTexture(rt->asTexture(), tex->asRenderTarget());
-
-        SkTextureImageSetTexture(image, tex);
+        SkASSERT(NULL != canvas);
+        SkASSERT(canvas->getDevice() == fDevice);
+        canvas->setDevice(newDevice);
+        SkRefCnt_SafeAssign(fDevice, newDevice);
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkSurface* SkSurface::NewRenderTargetDirect(GrContext* ctx,
                                             GrRenderTarget* target) {
     if (NULL == ctx || NULL == target) {
         return NULL;
     }
@@ skipping 16 matching lines @@
     desc.fConfig = SkBitmapConfig2GrPixelConfig(config);
     desc.fSampleCnt = sampleCount;
 
     SkAutoTUnref<GrTexture> tex(ctx->createUncachedTexture(desc, NULL, 0));
     if (NULL == tex) {
         return NULL;
     }
 
     return SkNEW_ARGS(SkSurface_Gpu, (ctx, tex->asRenderTarget()));
 }