46 lines
1.5 KiB
C
46 lines
1.5 KiB
C
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/*
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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 SkPngChunkReader_DEFINED
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#define SkPngChunkReader_DEFINED
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#include "SkTypes.h"
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#include "SkRefCnt.h"
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/**
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* SkPngChunkReader
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*
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* Base class for optional callbacks to retrieve meta/chunk data out of a PNG
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* encoded image as it is being decoded.
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* Used by SkImageDecoder and SkCodec.
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*/
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class SkPngChunkReader : public SkRefCnt {
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public:
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/**
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* This will be called by the decoder when it sees an unknown chunk.
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*
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* Use by SkCodec:
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* Depending on the location of the unknown chunks, this callback may be
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* called by
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* - the factory (NewFromStream/NewFromData)
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* - getPixels
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* - startScanlineDecode
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* - the first call to getScanlines/skipScanlines
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* The callback may be called from a different thread (e.g. if the SkCodec
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* is passed to another thread), and it may be called multiple times, if
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* the SkCodec is used multiple times.
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*
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* @param tag Name for this type of chunk.
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* @param data Data to be interpreted by the subclass.
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* @param length Number of bytes of data in the chunk.
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* @return true to continue decoding, or false to indicate an error, which
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* will cause the decoder to not return the image.
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*/
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virtual bool readChunk(const char tag[], const void* data, size_t length) = 0;
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};
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#endif // SkPngChunkReader_DEFINED
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