Move SkBitmapRegionDecoder to include/android and src/android

This will expose the BitmapRegionDecoder API as a public include
and move the implementation to src.

This makes this code more naturally exposed in Android and easier
to test in DM and nanobench.

BUG=skia:

Review URL: https://codereview.chromium.org/1438873002

2 files changed, 119 insertions, 0 deletions

diff --git a/include/android/SkBRDAllocator.h b/include/android/SkBRDAllocator.h
new file mode 100644
index 0000000000..3ca30c9b41
--- /dev/null
+++ b/include/android/SkBRDAllocator.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkBRDAllocator_DEFINED
+#define SkBRDAllocator_DEFINED
+
+#include "SkBitmap.h"
+#include "SkCodec.h"
+
+/**
+ *  Abstract subclass of SkBitmap's allocator.
+ *  Allows the allocator to indicate if the memory it allocates
+ *  is zero initialized.
+ */
+class SkBRDAllocator : public SkBitmap::Allocator {
+public:
+
+    /**
+     *  Indicates if the memory allocated by this allocator is
+     *  zero initialized.
+     */
+    virtual SkCodec::ZeroInitialized zeroInit() const = 0;
+};
+
+#endif // SkBRDAllocator_DEFINED
diff --git a/include/android/SkBitmapRegionDecoder.h b/include/android/SkBitmapRegionDecoder.h
new file mode 100644
index 0000000000..575ad9dc01
--- /dev/null
+++ b/include/android/SkBitmapRegionDecoder.h
@@ -0,0 +1,90 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * 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 "SkBRDAllocator.h"
+#include "SkEncodedFormat.h"
+#include "SkStream.h"
+
+/*
+ * This class aims to provide an interface to test multiple implementations of
+ * SkBitmapRegionDecoder.
+ */
+class SkBitmapRegionDecoder {
+public:
+
+    enum Strategy {
+        kCanvas_Strategy,       // Draw to the canvas, uses SkCodec
+        kAndroidCodec_Strategy, // Uses SkAndroidCodec for scaling and subsetting
+    };
+
+    /*
+     * @param data     Refs the data while this object exists, unrefs on destruction
+     * @param strategy Strategy used for scaling and subsetting
+     * @return         Tries to create an SkBitmapRegionDecoder, returns NULL on failure
+     */
+    static SkBitmapRegionDecoder* Create(
+            SkData* data, Strategy strategy);
+
+    /*
+     * @param stream   Takes ownership of the stream
+     * @param strategy Strategy used for scaling and subsetting
+     * @return         Tries to create an SkBitmapRegionDecoder, returns NULL on failure
+     */
+    static SkBitmapRegionDecoder* Create(
+            SkStreamRewindable* stream, Strategy strategy);
+
+    /*
+     * Decode a scaled region of the encoded image stream
+     *
+     * @param bitmap          Container for decoded pixels.  It is assumed that the pixels
+     *                        are initially unallocated and will be allocated by this function.
+     * @param allocator       Allocator for the pixels.  If this is NULL, the default
+     *                        allocator (HeapAllocator) will be used.
+     * @param desiredSubset   Subset of the original image to decode.
+     * @param sampleSize      An integer downscaling factor for the decode.
+     * @param colorType       Preferred output colorType.
+     *                        New implementations should return NULL if they do not support
+     *                        decoding to this color type.
+     *                        The old kOriginal_Strategy will decode to a default color type
+     *                        if this color type is unsupported.
+     * @param requireUnpremul If the image is not opaque, we will use this to determine the
+     *                        alpha type to use.
+     *
+     */
+    virtual bool decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocator,
+                              const SkIRect& desiredSubset, int sampleSize,
+                              SkColorType colorType, bool requireUnpremul) = 0;
+    /*
+     * @param  Requested destination color type
+     * @return true if we support the requested color type and false otherwise
+     */
+    virtual bool conversionSupported(SkColorType colorType) = 0;
+
+    virtual SkEncodedFormat getEncodedFormat() = 0;
+
+    int width() const { return fWidth; }
+    int height() const { return fHeight; }
+
+    virtual ~SkBitmapRegionDecoder() {}
+
+protected:
+
+    SkBitmapRegionDecoder(int width, int height)
+        : fWidth(width)
+        , fHeight(height)
+    {}
+
+private:
+    const int fWidth;
+    const int fHeight;
+};
+
+#endif