Read and write pixel offset when serializing bitmaps.

src/core/SkOrderedReadBuffer.cpp

 
 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmap.h"
 #include "SkErrorInternals.h"
@@ skipping 174 matching lines @@
             // fall through to use a place holder bitmap.
             SkErrorInternals::SetError(kParseError_SkError, "SkOrderedWriteBuffer::writeBitmap "
                                        "stored the SkBitmap in an SkBitmapHeap, but "
                                        "SkOrderedReadBuffer has no SkBitmapHeapReader to "
                                        "retrieve the SkBitmap.");
         }
     } else {
         // The writer stored false, meaning the SkBitmap was not stored in an SkBitmapHeap.
         const size_t length = this->readUInt();
         if (length > 0) {
-            // A non-zero size means the SkBitmap was encoded.
+            // A non-zero size means the SkBitmap was encoded. Read the data and pixel
+            // offset.
             const void* data = this->skip(length);
+            const int32_t xOffset = fReader.readS32();
+            const int32_t yOffset = fReader.readS32();
             if (fBitmapDecoder != NULL && fBitmapDecoder(data, length, bitmap)) {
                 if (bitmap->width() == width && bitmap->height() == height) {
+                    // If the width and height match, there should be no offset.
+                    SkASSERT(0 == xOffset && 0 == yOffset);
                     return;
                 }
 
                 // This case can only be reached if extractSubset was called, so
                 // the recorded width and height must be smaller than (or equal to
                 // the encoded width and height.
                 SkASSERT(width <= bitmap->width() && height <= bitmap->height());
 
-                // FIXME: Once the writer is changed to record the (x,y) offset,
-                // they will be used to store the correct portion of the picture.
                 SkBitmap subsetBm;
-#ifdef BUMP_PICTURE_VERSION
-                int32_t x = fReader.readS32();
-                int32_t y = fReader.readS32();
-                SkIRect subset = SkIRect::MakeXYWH(x, y, width, height);
-#else
-                SkIRect subset = SkIRect::MakeWH(width, height);
-#endif
+                SkIRect subset = SkIRect::MakeXYWH(xOffset, yOffset, width, height);
                 if (bitmap->extractSubset(&subsetBm, subset)) {
                     bitmap->swap(subsetBm);
                     return;
                 }
             }
             // This bitmap was encoded when written, but we are unable to decode, possibly due to
             // not having a decoder.
             SkErrorInternals::SetError(kParseError_SkError,
                                        "Could not decode bitmap. Resulting bitmap will be red.");
         } else {
@@ skipping 59 matching lines @@
         if (sizeRecorded != sizeRead) {
             // we could try to fix up the offset...
             sk_throw();
         }
     } else {
         // we must skip the remaining data
         fReader.skip(sizeRecorded);
     }
     return obj;
 }