Add wrapBackendTextureAsRenderTarget API

include/core/SkSurface.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkSurface_DEFINED
 #define SkSurface_DEFINED
 
@@ skipping 90 matching lines @@
      *  SkSurface.
      */
     static SkSurface* NewFromBackendTexture(GrContext*, const GrBackendTextureDesc&,
                                             const SkSurfaceProps*);
     // Legacy alias
     static SkSurface* NewWrappedRenderTarget(GrContext* ctx, const GrBackendTextureDesc& desc,
                                              const SkSurfaceProps* props) {
         return NewFromBackendTexture(ctx, desc, props);
     }
 
-
     /**
      *  Used to wrap a pre-existing 3D API rendering target as a SkSurface. Skia will not assume
      *  ownership of the render target and the client must ensure the render target is valid for the
      *  lifetime of the SkSurface.
      */
     static SkSurface* NewFromBackendRenderTarget(GrContext*, const GrBackendRenderTargetDesc&,
                                                  const SkSurfaceProps*);
 
     /**
+     *  Used to wrap a pre-existing 3D API texture as a SkSurface. Skia will treat the texture as
+     *  a rendering target only, but unlike NewFromBackendRenderTarget, Skia will manage and own
+     *  the associated render target objects (but not the provided texture). The kRenderTarget flag
+     *  must be set on GrBackendTextureDesc for this to succeed. Skia will not assume ownership
+     *  of the texture and the client must ensure the texture is valid for the lifetime of the
+     *  SkSurface.
+     */
+    static SkSurface* NewFromBackendTextureAsRenderTarget(
+            GrContext*, const GrBackendTextureDesc&, const SkSurfaceProps*);
+
+    /**
      *  Return a new surface whose contents will be drawn to an offscreen
      *  render target, allocated by the surface.
      *
      *  The GrTextureStorageAllocator will be reused if SkImage snapshots create
      *  additional textures.
      */
     static SkSurface* NewRenderTarget(
             GrContext*, Budgeted, const SkImageInfo&, int sampleCount, const SkSurfaceProps* = NULL,
             GrTextureStorageAllocator = GrTextureStorageAllocator());
 
@@ skipping 142 matching lines @@
      *
      *  This call can fail, returning false, for several reasons:
      *  - If srcR does not intersect the surface bounds.
      *  - If the requested colortype/alphatype cannot be converted from the surface's types.
      */
     bool readPixels(const SkImageInfo& dstInfo, void* dstPixels, size_t dstRowBytes,
                     int srcX, int srcY);
 
     const SkSurfaceProps& props() const { return fProps; }
 
+    /**
+     * Issue any pending surface IO to the current backend 3D API and resolve any surface MSAA.
+     */
+    void prepareForExternalIO();
+
 protected:
     SkSurface(int width, int height, const SkSurfaceProps*);
     SkSurface(const SkImageInfo&, const SkSurfaceProps*);
 
     // called by subclass if their contents have changed
     void dirtyGenerationID() {
         fGenerationID = 0;
     }
 
 private:
     const SkSurfaceProps fProps;
     const int            fWidth;
     const int            fHeight;
     uint32_t             fGenerationID;
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif