diff options
Diffstat (limited to 'include/codec/SkCodec.h')
| -rw-r--r-- | include/codec/SkCodec.h | 99 |
1 files changed, 79 insertions, 20 deletions
diff --git a/include/codec/SkCodec.h b/include/codec/SkCodec.h index b0647edc6f..363347dd72 100644 --- a/include/codec/SkCodec.h +++ b/include/codec/SkCodec.h @@ -24,11 +24,11 @@ class SkPngChunkReader; class SkSampler; namespace DM { +class CodecSrc; class ColorCodecSrc; } class ColorCodecBench; - /** * Abstraction layer directly on top of an image codec. */ @@ -253,8 +253,8 @@ public: * If the EncodedFormat is kWEBP_SkEncodedFormat (the only one which * currently supports subsets), the top and left values must be even. * - * In getPixels, we will attempt to decode the exact rectangular - * subset specified by fSubset. + * In getPixels and incremental decode, we will attempt to decode the + * exact rectangular subset specified by fSubset. * * In a scanline decode, it does not make sense to specify a subset * top or subset height, since the client already controls which rows @@ -355,6 +355,67 @@ public: } /** + * Prepare for an incremental decode with the specified options. + * + * This may require a rewind. + * + * @param dstInfo Info of the destination. If the dimensions do not match + * those of getInfo, this implies a scale. + * @param dst Memory to write to. Needs to be large enough to hold the subset, + * if present, or the full image as described in dstInfo. + * @param options Contains decoding options, including if memory is zero + * initialized and whether to decode a subset. + * @param ctable A pointer to a color table. When dstInfo.colorType() is + * kIndex8, this should be non-NULL and have enough storage for 256 + * colors. The color table will be populated after decoding the palette. + * @param ctableCount A pointer to the size of the color table. When + * dstInfo.colorType() is kIndex8, this should be non-NULL. It will + * be modified to the true size of the color table (<= 256) after + * decoding the palette. + * @return Enum representing success or reason for failure. + */ + Result startIncrementalDecode(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, + const SkCodec::Options*, SkPMColor* ctable, int* ctableCount); + + Result startIncrementalDecode(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, + const SkCodec::Options* options) { + return this->startIncrementalDecode(dstInfo, dst, rowBytes, options, nullptr, nullptr); + } + + Result startIncrementalDecode(const SkImageInfo& dstInfo, void* dst, size_t rowBytes) { + return this->startIncrementalDecode(dstInfo, dst, rowBytes, nullptr, nullptr, nullptr); + } + + /** + * Start/continue the incremental decode. + * + * Not valid to call before calling startIncrementalDecode(). + * + * After the first call, should only be called again if more data has been + * provided to the source SkStream. + * + * Unlike getPixels and getScanlines, this does not do any filling. This is + * left up to the caller, since they may be skipping lines or continuing the + * decode later. In the latter case, they may choose to initialize all lines + * first, or only initialize the remaining lines after the first call. + * + * @param rowsDecoded Optional output variable returning the total number of + * lines initialized. Only meaningful if this method returns kIncompleteInput. + * Otherwise the implementation may not set it. + * Note that some implementations may have initialized this many rows, but + * not necessarily finished those rows (e.g. interlaced PNG). This may be + * useful for determining what rows the client needs to initialize. + * @return kSuccess if all lines requested in startIncrementalDecode have + * been completely decoded. kIncompleteInput otherwise. + */ + Result incrementalDecode(int* rowsDecoded = nullptr) { + if (!fStartedIncrementalDecode) { + return kInvalidParameters; + } + return this->onIncrementalDecode(rowsDecoded); + } + + /** * The remaining functions revolve around decoding scanlines. */ @@ -474,17 +535,6 @@ public: * Interlaced gifs are an example. */ kOutOfOrder_SkScanlineOrder, - - /* - * Indicates that the entire image must be decoded in order to output - * any amount of scanlines. In this case, it is a REALLY BAD IDEA to - * request scanlines 1-by-1 or in small chunks. The client should - * determine which scanlines are needed and ask for all of them in - * a single call to getScanlines(). - * - * Interlaced pngs are an example. - */ - kNone_SkScanlineOrder, }; /** @@ -642,11 +692,6 @@ protected: */ virtual SkScanlineOrder onGetScanlineOrder() const { return kTopDown_SkScanlineOrder; } - /** - * Update the current scanline. Used by interlaced png. - */ - void updateCurrScanline(int newY) { fCurrScanline = newY; } - const SkImageInfo& dstInfo() const { return fDstInfo; } const SkCodec::Options& options() const { return fOptions; } @@ -673,11 +718,14 @@ private: bool fNeedsRewind; const Origin fOrigin; - // These fields are only meaningful during scanline decodes. SkImageInfo fDstInfo; SkCodec::Options fOptions; + + // Only meaningful during scanline decodes. int fCurrScanline; + bool fStartedIncrementalDecode; + /** * Return whether these dimensions are supported as a scale. * @@ -697,6 +745,16 @@ private: return kUnimplemented; } + virtual Result onStartIncrementalDecode(const SkImageInfo& /*dstInfo*/, void*, size_t, + const SkCodec::Options&, SkPMColor*, int*) { + return kUnimplemented; + } + + virtual Result onIncrementalDecode(int*) { + return kUnimplemented; + } + + virtual bool onSkipScanlines(int /*countLines*/) { return false; } virtual int onGetScanlines(void* /*dst*/, int /*countLines*/, size_t /*rowBytes*/) { return 0; } @@ -733,6 +791,7 @@ private: friend class DM::ColorCodecSrc; friend class ColorCodecBench; + friend class DM::CodecSrc; // for fillIncompleteImage friend class SkSampledCodec; friend class SkIcoCodec; }; |