1*c8dee2aaSAndroid Build Coastguard Worker /* 2*c8dee2aaSAndroid Build Coastguard Worker * Copyright 2015 Google Inc. 3*c8dee2aaSAndroid Build Coastguard Worker * 4*c8dee2aaSAndroid Build Coastguard Worker * Use of this source code is governed by a BSD-style license that can be 5*c8dee2aaSAndroid Build Coastguard Worker * found in the LICENSE file. 6*c8dee2aaSAndroid Build Coastguard Worker */ 7*c8dee2aaSAndroid Build Coastguard Worker 8*c8dee2aaSAndroid Build Coastguard Worker #ifndef SkPngChunkReader_DEFINED 9*c8dee2aaSAndroid Build Coastguard Worker #define SkPngChunkReader_DEFINED 10*c8dee2aaSAndroid Build Coastguard Worker 11*c8dee2aaSAndroid Build Coastguard Worker #include "include/core/SkRefCnt.h" 12*c8dee2aaSAndroid Build Coastguard Worker #include "include/core/SkTypes.h" 13*c8dee2aaSAndroid Build Coastguard Worker 14*c8dee2aaSAndroid Build Coastguard Worker /** 15*c8dee2aaSAndroid Build Coastguard Worker * SkPngChunkReader 16*c8dee2aaSAndroid Build Coastguard Worker * 17*c8dee2aaSAndroid Build Coastguard Worker * Base class for optional callbacks to retrieve meta/chunk data out of a PNG 18*c8dee2aaSAndroid Build Coastguard Worker * encoded image as it is being decoded. 19*c8dee2aaSAndroid Build Coastguard Worker * Used by SkCodec. 20*c8dee2aaSAndroid Build Coastguard Worker */ 21*c8dee2aaSAndroid Build Coastguard Worker class SkPngChunkReader : public SkRefCnt { 22*c8dee2aaSAndroid Build Coastguard Worker public: 23*c8dee2aaSAndroid Build Coastguard Worker /** 24*c8dee2aaSAndroid Build Coastguard Worker * This will be called by the decoder when it sees an unknown chunk. 25*c8dee2aaSAndroid Build Coastguard Worker * 26*c8dee2aaSAndroid Build Coastguard Worker * Use by SkCodec: 27*c8dee2aaSAndroid Build Coastguard Worker * Depending on the location of the unknown chunks, this callback may be 28*c8dee2aaSAndroid Build Coastguard Worker * called by 29*c8dee2aaSAndroid Build Coastguard Worker * - the factory (NewFromStream/NewFromData) 30*c8dee2aaSAndroid Build Coastguard Worker * - getPixels 31*c8dee2aaSAndroid Build Coastguard Worker * - startScanlineDecode 32*c8dee2aaSAndroid Build Coastguard Worker * - the first call to getScanlines/skipScanlines 33*c8dee2aaSAndroid Build Coastguard Worker * The callback may be called from a different thread (e.g. if the SkCodec 34*c8dee2aaSAndroid Build Coastguard Worker * is passed to another thread), and it may be called multiple times, if 35*c8dee2aaSAndroid Build Coastguard Worker * the SkCodec is used multiple times. 36*c8dee2aaSAndroid Build Coastguard Worker * 37*c8dee2aaSAndroid Build Coastguard Worker * @param tag Name for this type of chunk. 38*c8dee2aaSAndroid Build Coastguard Worker * @param data Data to be interpreted by the subclass. 39*c8dee2aaSAndroid Build Coastguard Worker * @param length Number of bytes of data in the chunk. 40*c8dee2aaSAndroid Build Coastguard Worker * @return true to continue decoding, or false to indicate an error, which 41*c8dee2aaSAndroid Build Coastguard Worker * will cause the decoder to not return the image. 42*c8dee2aaSAndroid Build Coastguard Worker */ 43*c8dee2aaSAndroid Build Coastguard Worker virtual bool readChunk(const char tag[], const void* data, size_t length) = 0; 44*c8dee2aaSAndroid Build Coastguard Worker }; 45*c8dee2aaSAndroid Build Coastguard Worker #endif // SkPngChunkReader_DEFINED 46