d1227a7417
This was an approach we considered for implementing Android's BitmapRegionDecoder. It was useful for testing and comparison, but now is no longer worth maintaining and testing. The approach to subset/scaled decodes (clipped decode, then scale) may be worth reconsidering at some point. BUG=skia:5307 GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1990543002 Review-Url: https://codereview.chromium.org/1990543002
90 lines
3.1 KiB
C++
90 lines
3.1 KiB
C++
/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkBitmapRegionDecoder_DEFINED
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#define SkBitmapRegionDecoder_DEFINED
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#include "SkBitmap.h"
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#include "SkBRDAllocator.h"
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#include "SkEncodedFormat.h"
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#include "SkStream.h"
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/*
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* This class aims to provide an interface to test multiple implementations of
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* SkBitmapRegionDecoder.
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*/
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class SkBitmapRegionDecoder {
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public:
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enum Strategy {
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kAndroidCodec_Strategy, // Uses SkAndroidCodec for scaling and subsetting
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};
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/*
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* @param data Refs the data while this object exists, unrefs on destruction
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* @param strategy Strategy used for scaling and subsetting
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* @return Tries to create an SkBitmapRegionDecoder, returns NULL on failure
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*/
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static SkBitmapRegionDecoder* Create(
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SkData* data, Strategy strategy);
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/*
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* @param stream Takes ownership of the stream
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* @param strategy Strategy used for scaling and subsetting
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* @return Tries to create an SkBitmapRegionDecoder, returns NULL on failure
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*/
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static SkBitmapRegionDecoder* Create(
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SkStreamRewindable* stream, Strategy strategy);
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/*
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* Decode a scaled region of the encoded image stream
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*
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* @param bitmap Container for decoded pixels. It is assumed that the pixels
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* are initially unallocated and will be allocated by this function.
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* @param allocator Allocator for the pixels. If this is NULL, the default
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* allocator (HeapAllocator) will be used.
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* @param desiredSubset Subset of the original image to decode.
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* @param sampleSize An integer downscaling factor for the decode.
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* @param colorType Preferred output colorType.
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* New implementations should return NULL if they do not support
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* decoding to this color type.
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* The old kOriginal_Strategy will decode to a default color type
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* if this color type is unsupported.
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* @param requireUnpremul If the image is not opaque, we will use this to determine the
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* alpha type to use.
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*
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*/
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virtual bool decodeRegion(SkBitmap* bitmap, SkBRDAllocator* allocator,
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const SkIRect& desiredSubset, int sampleSize,
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SkColorType colorType, bool requireUnpremul) = 0;
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/*
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* @param Requested destination color type
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* @return true if we support the requested color type and false otherwise
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*/
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virtual bool conversionSupported(SkColorType colorType) = 0;
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virtual SkEncodedFormat getEncodedFormat() = 0;
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int width() const { return fWidth; }
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int height() const { return fHeight; }
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virtual ~SkBitmapRegionDecoder() {}
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protected:
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SkBitmapRegionDecoder(int width, int height)
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: fWidth(width)
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, fHeight(height)
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{}
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private:
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const int fWidth;
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const int fHeight;
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};
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#endif
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