add callbacks to Images that wrap client-provided content

include/core/SkImage.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 SkImage_DEFINED
 #define SkImage_DEFINED
 
@@ skipping 26 matching lines @@
  *
  *  SkImage always has a non-zero dimensions. If there is a request to create a new image, either
  *  directly or via SkSurface, and either of the requested dimensions are zero, then NULL will be
  *  returned.
  */
 class SK_API SkImage : public SkRefCnt {
 public:
     SK_DECLARE_INST_COUNT(SkImage)
 
     typedef SkImageInfo Info;
+    typedef void* ReleaseContext;
 
     static SkImage* NewRasterCopy(const Info&, const void* pixels, size_t rowBytes);
     static SkImage* NewRasterData(const Info&, SkData* pixels, size_t rowBytes);
 
+    typedef void (*RasterReleaseProc)(const void* pixels, ReleaseContext);
+
+    /**
+     *  Return a new Image referencing the specified pixels. These must remain valid and unchanged
+     *  until the specified release-proc is called, indicating that Skia no longer has a reference
+     *  to the pixels.
+     *
+     *  Returns NULL if the requested Info is unsupported.
+     */
+    static SkImage* NewFromRaster(const Info&, const void* pixels, size_t rowBytes,
+                                  RasterReleaseProc, ReleaseContext);
+
     /**
      *  Construct a new SkImage based on the given ImageGenerator.
      *  This function will always take ownership of the passed
      *  ImageGenerator.  Returns NULL on error.
      */
     static SkImage* NewFromGenerator(SkImageGenerator*);
 
     /**
      *  Construct a new SkImage based on the specified encoded data. Returns NULL on failure,
      *  which can mean that the format of the encoded data was not recognized/supported.
      *
      *  Regardless of success or failure, the caller is responsible for managing their ownership
      *  of the data.
      */
     static SkImage* NewFromData(SkData* data);
 
     /**
      *  Create a new image from the specified descriptor. Note - the caller is responsible for
      *  managing the lifetime of the underlying platform texture.
      *
      *  Will return NULL if the specified descriptor is unsupported.
      */
-    static SkImage* NewFromTexture(GrContext*, const GrBackendTextureDesc&,
-                                   SkAlphaType = kPremul_SkAlphaType);
+    static SkImage* NewFromTexture(GrContext* ctx, const GrBackendTextureDesc& desc) {
+        return NewFromTexture(ctx, desc, kPremul_SkAlphaType, NULL, NULL);
+    }
+
+    static SkImage* NewFromTexture(GrContext* ctx, const GrBackendTextureDesc& de, SkAlphaType at) {
+        return NewFromTexture(ctx, de, at, NULL, NULL);
+    }
+
+    typedef void (*TextureReleaseProc)(ReleaseContext);
+
+    /**
+     *  Create a new image from the specified descriptor. The underlying platform texture must stay
+     *  valid and unaltered until the specified release-proc is invoked, indicating that Skia
+     *  nolonger is holding a reference to it.
+     *
+     *  Will return NULL if the specified descriptor is unsupported.
+     */
+    static SkImage* NewFromTexture(GrContext*, const GrBackendTextureDesc&, SkAlphaType,
+                                   TextureReleaseProc, ReleaseContext);
 
     /**
      *  Create a new image from the specified descriptor. Note - Skia will delete or recycle the
      *  texture when the image is released.
      *
      *  Will return NULL if the specified descriptor is unsupported.
      */
     static SkImage* NewFromAdoptedTexture(GrContext*, const GrBackendTextureDesc&,
                                           SkAlphaType = kPremul_SkAlphaType);
 
@@ skipping 128 matching lines @@
     const int       fWidth;
     const int       fHeight;
     const uint32_t  fUniqueID;
 
     static uint32_t NextUniqueID();
 
     typedef SkRefCnt INHERITED;
 };
 
 #endif