support direct writing to top layer

include/core/SkDevice.h

 
 /*
  * Copyright 2010 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 SkDevice_DEFINED
@@ skipping 120 matching lines @@
      *  If the bitmap has config kARGB_8888_Config then the config8888 param
      *  will determines how the pixel valuess are intepreted. If the bitmap is
      *  not kARGB_8888_Config then this parameter is ignored.
      */
     virtual void writePixels(const SkBitmap& bitmap, int x, int y,
                              SkCanvas::Config8888 config8888 = SkCanvas::kNative_Premul_Config8888);
 #endif
 
     bool writePixelsDirect(const SkImageInfo&, const void*, size_t rowBytes, int x, int y);
 
+    void* accessPixels(SkImageInfo* info, size_t* rowBytes);
+
     /**
      * Return the device's associated gpu render target, or NULL.
      */
     virtual GrRenderTarget* accessRenderTarget() = 0;
 
 
     /**
      *  Return the device's origin: its offset in device coordinates from
      *  the default origin in its canvas' matrix/clip
      */
@@ skipping 242 matching lines @@
 
     /**
      *  The caller is responsible for "pre-clipping" the src. The impl can assume that the src
      *  image at the specified x,y offset will fit within the device's bounds.
      *
      *  This is explicitly asserted in writePixelsDirect(), the public way to call this.
      */
     virtual bool onWritePixels(const SkImageInfo&, const void*, size_t, int x, int y);
 
     /**
+     *  Default impl returns NULL.
+     */
+    virtual void* onAccessPixels(SkImageInfo* info, size_t* rowBytes);
+
+    /**
      *  Leaky properties are those which the device should be applying but it isn't.
      *  These properties will be applied by the draw, when and as it can.
      *  If the device does handle a property, that property should be set to the identity value
      *  for that property, effectively making it non-leaky.
      */
     SkDeviceProperties fLeakyProperties;
 
 private:
     friend class SkCanvas;
     friend struct DeviceCM; //for setMatrixClip
     friend class SkDraw;
     friend class SkDrawIter;
     friend class SkDeviceFilteredPaint;
     friend class SkDeviceImageFilterProxy;
-    friend class DeferredDevice;    // for newSurface
+    friend class SkDeferredDevice;    // for newSurface
 
     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.
     // TODO: move to SkBitmapDevice
     virtual void replaceBitmapBackendForRasterSurface(const SkBitmap&) = 0;
 
     // just called by SkCanvas when built as a layer
@@ skipping 25 matching lines @@
     SkMetaData* fMetaData;
 
 #ifdef SK_DEBUG
     bool        fAttachedToCanvas;
 #endif
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif