Upstream Android modifications to the image encoders/decoders.

include/images/SkBitmapRegionDecoder.h

+/*
+ * Copyright 2011 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 SkBitmapRegionDecoder_DEFINED
+#define SkBitmapRegionDecoder_DEFINED
+
+#include "SkBitmap.h"
+#include "SkImageDecoder.h"
+#include "SkStream.h"
+
+class SkIRect;
+
+/**
+ * SkBitmapRegionDecoder can be used to decode a specified rect from an image.
+ * This is particularly useful when the original image is large and you only
+ * need parts of the image.
+ *
+ * However, not all image codecs on all platforms support this feature so be
+ * prepared to fallback to standard decoding if decodeRegion(...) returns false.
+ */
+class SkBitmapRegionDecoder {
+public:
+    SkBitmapRegionDecoder(SkImageDecoder* decoder, SkStream* stream,
+                          int width, int height) {
+        fDecoder = decoder;
+        fStream = stream;
+        fWidth = width;
+        fHeight = height;
+    }
+    ~SkBitmapRegionDecoder() {
+        SkDELETE(fDecoder);
+        SkSafeUnref(fStream);
+    }
+
+    bool decodeRegion(SkBitmap* bitmap, const SkIRect& rect,
+                      SkBitmap::Config pref, int sampleSize);
+
+    SkImageDecoder* getDecoder() const { return fDecoder; }
+    int getWidth() const { return fWidth; }
+    int getHeight() const { return fHeight; }
+
+private:
+    SkImageDecoder* fDecoder;
+    SkStream* fStream;
+    int fWidth;
+    int fHeight;
+};
+
+#endif