add SkBitmap::installPixelRef()

include/core/SkBitmap.h

 /*
  * Copyright 2006 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 SkBitmap_DEFINED
 #define SkBitmap_DEFINED
 
@@ skipping 250 matching lines @@
         this if you are handling ownership/lifetime of the pixel memory.
 
         If the bitmap retains a reference to the colortable (assuming it is
         not null) it will take care of incrementing the reference count.
 
         @param pixels   Address for the pixels, managed by the caller.
         @param ctable   ColorTable (or null) that matches the specified pixels
     */
     void setPixels(void* p, SkColorTable* ctable = NULL);
 
+    /**
+     *  Install the specified pixelref into the bitmap, with an optional rect
+     *  for referencing a subset of the pixels in the pixelref. This sets the
+     *  config/width/height/alphatype of the bitmap to match the pixelref.
+     *
+     *  The subset rect, if not null, is intersected with the bounds of the
+     *  pixelref (taken from its SkImageInfo).
+     */
+    SkPixelRef* installPixelRef(SkPixelRef*, const SkIRect* subset = NULL);
+
     /** Copies the bitmap's pixels to the location pointed at by dst and returns
         true if possible, returns false otherwise.
 
         In the case when the dstRowBytes matches the bitmap's rowBytes, the copy
         may be made faster by copying over the dst's per-row padding (for all
         rows but the last). By setting preserveDstPad to true the caller can
         disable this optimization and ensure that pixels in the padding are not
         overwritten.
 
         Always returns false for RLE formats.
@@ skipping 547 matching lines @@
 
 inline SkPMColor SkBitmap::getIndex8Color(int x, int y) const {
     SkASSERT(fPixels);
     SkASSERT(fConfig == kIndex8_Config);
     SkASSERT((unsigned)x < fWidth && (unsigned)y < fHeight);
     SkASSERT(fColorTable);
     return (*fColorTable)[*((const uint8_t*)fPixels + y * fRowBytes + x)];
 }
 
 #endif