Implement SkBaseDevice snapshot support

src/gpu/SkGpuDevice.h

 
 /*
  * Copyright 2010 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkGpuDevice_DEFINED
 #define SkGpuDevice_DEFINED
 
 #include "SkGr.h"
 #include "SkBitmap.h"
 #include "SkDevice.h"
 #include "SkPicture.h"
 #include "SkRegion.h"
 #include "SkSurface.h"
 #include "GrContext.h"
 #include "GrSurfacePriv.h"
 
 struct SkDrawProcs;
 struct GrSkDrawProcs;
 
 class GrAccelData;
 struct GrCachedLayer;
 class GrTextContext;
+class SkSurface_Gpu;
 
 /**
  *  Subclass of SkBaseDevice, which directs all drawing to the GrGpu owned by the
  *  canvas.
  */
 class SK_API SkGpuDevice : public SkBaseDevice {
 public:
     enum Flags {
         kNeedClear_Flag = 1 << 0,  //!< Surface requires an initial clear
     };
 
     /**
      * Creates an SkGpuDevice from a GrRenderTarget.
      */
     static SkGpuDevice* Create(GrRenderTarget* target, const SkSurfaceProps*, unsigned flags = 0);
 
     /**
      * New device that will create an offscreen renderTarget based on the ImageInfo and
      * sampleCount. The Budgeted param controls whether the device's backing store counts against
      * the resource cache budget. On failure, returns NULL.
      */
     static SkGpuDevice* Create(GrContext*, SkSurface::Budgeted, const SkImageInfo&,
                                int sampleCount, const SkSurfaceProps*, unsigned flags = 0);
 
     virtual ~SkGpuDevice();
 
+    void setSurface(SkSurface_Gpu* surface) {
+        fSurface = surface;
+    }
+
     SkGpuDevice* cloneDevice(const SkSurfaceProps& props) {
         SkBaseDevice* dev = this->onCreateDevice(CreateInfo(this->imageInfo(), kPossible_TileUsage,
                                                             props.pixelGeometry()),
                                                  NULL);
         return static_cast<SkGpuDevice*>(dev);
     }
 
     GrContext* context() const { return fContext; }
 
     // set all pixels to 0
     void clearAll();
 
-    void replaceRenderTarget(bool shouldRetainContent);
-
     GrRenderTarget* accessRenderTarget() SK_OVERRIDE;
 
     SkImageInfo imageInfo() const SK_OVERRIDE {
         return fRenderTarget ? fRenderTarget->surfacePriv().info() : SkImageInfo::MakeUnknown();
     }
 
     const SkSurfaceProps& surfaceProps() const { return fSurfaceProps; }
 
+    void discard() SK_OVERRIDE;
+    SkImage* newImageSnapshot() SK_OVERRIDE;
+    SkImage* newImageSnapshot(const SkSurfaceProps* props, SkSurface::Budgeted);
+    int getBackendSampleCnt() const { return fRenderTarget->numSamples(); }
+    bool isBackendBudgeted() const;
+
     void drawPaint(const SkDraw&, const SkPaint& paint) SK_OVERRIDE;
     virtual void drawPoints(const SkDraw&, SkCanvas::PointMode mode, size_t count,
                             const SkPoint[], const SkPaint& paint) SK_OVERRIDE;
     virtual void drawRect(const SkDraw&, const SkRect& r,
                           const SkPaint& paint) SK_OVERRIDE;
     virtual void drawRRect(const SkDraw&, const SkRRect& r,
                            const SkPaint& paint) SK_OVERRIDE;
     virtual void drawDRRect(const SkDraw& draw, const SkRRect& outer,
                             const SkRRect& inner, const SkPaint& paint) SK_OVERRIDE;
     virtual void drawOval(const SkDraw&, const SkRect& oval,
@@ skipping 54 matching lines @@
     GrSkDrawProcs*                  fDrawProcs;
     SkAutoTUnref<const SkClipStack> fClipStack;
     SkIPoint                        fClipOrigin;
     GrClip                          fClip;
     GrTextContext*                  fTextContext;
     SkSurfaceProps                  fSurfaceProps;
     GrRenderTarget*                 fRenderTarget;
     // remove when our clients don't rely on accessBitmap()
     SkBitmap                        fLegacyBitmap;
     bool                            fNeedClear;
+    SkSurface_Gpu*                  fSurface;
+    SkAutoTUnref<SkImage>           fSnapshot;
 
     SkGpuDevice(GrRenderTarget*, const SkSurfaceProps*, unsigned flags);
 
     SkBaseDevice* onCreateDevice(const CreateInfo&, const SkPaint*) SK_OVERRIDE;
 
     SkSurface* newSurface(const SkImageInfo&, const SkSurfaceProps&) SK_OVERRIDE;
 
     SkImageFilter::Cache* getImageFilterCache() SK_OVERRIDE;
 
     bool forceConservativeRasterClip() const SK_OVERRIDE { return true; }
 
-    // sets the render target and clip on context
-    void prepareDraw(const SkDraw&);
+    /* Prepares the device for modification and sets the clip on context.
+     * returns true if the draw can proceed. */
+    bool prepareDraw(const SkDraw&);
+
+    /* Prepares the device for modification.
+     * returns true if the draw can proceed. */
+    bool prepareWrite();
+
+    enum ModifyMode { kDrawContent_ModifyMode, kDiscard_ModifyMode };
+    /** Prepares the render target for modification.
+     * 1. Detaches the snapshot, if needed.
+     * 2. Creates new render target if snapshot refers to the current render target.
+     * 3. Does the deferred clear, if needed.
+     * returns true if the render target is functional and can be rendered to.
+     */
+    bool prepareBackendRenderTarget(ModifyMode);
 
     /**
      * Implementation for both drawBitmap and drawBitmapRect.
      */
     void drawBitmapCommon(const SkDraw&,
                           const SkBitmap& bitmap,
                           const SkRect* srcRectPtr,
                           const SkSize* dstSizePtr,      // ignored iff srcRectPtr == NULL
                           const SkPaint&,
                           SkCanvas::DrawBitmapRectFlags flags);
@@ skipping 41 matching lines @@
     static SkPicture::AccelData::Key ComputeAccelDataKey();
 
     static GrRenderTarget* CreateRenderTarget(GrContext*, SkSurface::Budgeted, const SkImageInfo&,
                                               int sampleCount);
 
     friend class GrTextContext;
     typedef SkBaseDevice INHERITED;
 };
 
 #endif