| /* |
| * 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 SkJpegCodec_DEFINED |
| #define SkJpegCodec_DEFINED |
| |
| #include "SkCodec.h" |
| #include "SkImageInfo.h" |
| #include "SkJpegDecoderMgr.h" |
| #include "SkJpegUtility_codec.h" |
| #include "SkStream.h" |
| |
| extern "C" { |
| #include "jpeglib.h" |
| } |
| |
| /* |
| * |
| * This class implements the decoding for jpeg images |
| * |
| */ |
| class SkJpegCodec : public SkCodec { |
| public: |
| |
| /* |
| * Checks the start of the stream to see if the image is a jpeg |
| * Does not take ownership of the stream |
| */ |
| static bool IsJpeg(SkStream*); |
| |
| /* |
| * Assumes IsJpeg was called and returned true |
| * Creates a jpeg decoder |
| * Takes ownership of the stream |
| */ |
| static SkCodec* NewFromStream(SkStream*); |
| |
| protected: |
| |
| /* |
| * Recommend a set of destination dimensions given a requested scale |
| */ |
| SkISize onGetScaledDimensions(float desiredScale) const override; |
| |
| /* |
| * Initiates the jpeg decode |
| */ |
| Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&, |
| SkPMColor*, int*) override; |
| |
| SkEncodedFormat onGetEncodedFormat() const override { |
| return kJPEG_SkEncodedFormat; |
| } |
| |
| SkScanlineDecoder* onGetScanlineDecoder(const SkImageInfo& dstInfo, const Options& options, |
| SkPMColor ctable[], int* ctableCount) override; |
| |
| private: |
| |
| /* |
| * Read enough of the stream to initialize the SkJpegCodec. |
| * Returns a bool representing success or failure. |
| * |
| * @param codecOut |
| * If this returns true, and codecOut was not NULL, |
| * codecOut will be set to a new SkJpegCodec. |
| * |
| * @param decoderMgrOut |
| * If this returns true, and codecOut was NULL, |
| * decoderMgrOut must be non-NULL and decoderMgrOut will be set to a new |
| * JpegDecoderMgr pointer. |
| * |
| * @param stream |
| * Deleted on failure. |
| * codecOut will take ownership of it in the case where we created a codec. |
| * Ownership is unchanged when we set decoderMgrOut. |
| * |
| */ |
| static bool ReadHeader(SkStream* stream, SkCodec** codecOut, |
| JpegDecoderMgr** decoderMgrOut); |
| |
| /* |
| * Creates an instance of the decoder |
| * Called only by NewFromStream |
| * |
| * @param srcInfo contains the source width and height |
| * @param stream the encoded image data |
| * @param decoderMgr holds decompress struct, src manager, and error manager |
| * takes ownership |
| */ |
| SkJpegCodec(const SkImageInfo& srcInfo, SkStream* stream, JpegDecoderMgr* decoderMgr); |
| |
| /* |
| * Handles rewinding the input stream if it is necessary |
| */ |
| bool handleRewind(); |
| |
| /* |
| * Checks if we can scale to the requested dimensions and scales the dimensions |
| * if possible |
| */ |
| bool scaleToDimensions(uint32_t width, uint32_t height); |
| |
| /* |
| * Create the swizzler based on the encoded format |
| */ |
| void initializeSwizzler(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, |
| const Options& options); |
| |
| SkAutoTDelete<JpegDecoderMgr> fDecoderMgr; |
| SkAutoTDelete<SkSwizzler> fSwizzler; |
| size_t fSrcRowBytes; |
| |
| friend class SkJpegScanlineDecoder; |
| |
| typedef SkCodec INHERITED; |
| }; |
| |
| #endif |