| /* |
| * 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 SkCodec_DEFINED |
| #define SkCodec_DEFINED |
| |
| #include "../private/SkTemplates.h" |
| #include "SkCodecAnimation.h" |
| #include "SkColor.h" |
| #include "SkColorSpaceXform.h" |
| #include "SkEncodedImageFormat.h" |
| #include "SkEncodedInfo.h" |
| #include "SkImageInfo.h" |
| #include "SkSize.h" |
| #include "SkStream.h" |
| #include "SkTypes.h" |
| #include "SkYUVSizeInfo.h" |
| |
| #include <vector> |
| |
| class SkColorSpace; |
| class SkData; |
| class SkFrameHolder; |
| class SkPngChunkReader; |
| class SkSampler; |
| |
| namespace DM { |
| class CodecSrc; |
| class ColorCodecSrc; |
| } |
| class ColorCodecBench; |
| |
| /** |
| * Abstraction layer directly on top of an image codec. |
| */ |
| class SK_API SkCodec : SkNoncopyable { |
| public: |
| /** |
| * Minimum number of bytes that must be buffered in SkStream input. |
| * |
| * An SkStream passed to NewFromStream must be able to use this many |
| * bytes to determine the image type. Then the same SkStream must be |
| * passed to the correct decoder to read from the beginning. |
| * |
| * This can be accomplished by implementing peek() to support peeking |
| * this many bytes, or by implementing rewind() to be able to rewind() |
| * after reading this many bytes. |
| */ |
| static size_t MinBufferedBytesNeeded(); |
| |
| /** |
| * Error codes for various SkCodec methods. |
| */ |
| enum Result { |
| /** |
| * General return value for success. |
| */ |
| kSuccess, |
| /** |
| * The input is incomplete. A partial image was generated. |
| */ |
| kIncompleteInput, |
| /** |
| * Like kIncompleteInput, except the input had an error. |
| * |
| * If returned from an incremental decode, decoding cannot continue, |
| * even with more data. |
| */ |
| kErrorInInput, |
| /** |
| * The generator cannot convert to match the request, ignoring |
| * dimensions. |
| */ |
| kInvalidConversion, |
| /** |
| * The generator cannot scale to requested size. |
| */ |
| kInvalidScale, |
| /** |
| * Parameters (besides info) are invalid. e.g. NULL pixels, rowBytes |
| * too small, etc. |
| */ |
| kInvalidParameters, |
| /** |
| * The input did not contain a valid image. |
| */ |
| kInvalidInput, |
| /** |
| * Fulfilling this request requires rewinding the input, which is not |
| * supported for this input. |
| */ |
| kCouldNotRewind, |
| /** |
| * An internal error, such as OOM. |
| */ |
| kInternalError, |
| /** |
| * This method is not implemented by this codec. |
| * FIXME: Perhaps this should be kUnsupported? |
| */ |
| kUnimplemented, |
| }; |
| |
| /** |
| * If this stream represents an encoded image that we know how to decode, |
| * return an SkCodec that can decode it. Otherwise return NULL. |
| * |
| * As stated above, this call must be able to peek or read |
| * MinBufferedBytesNeeded to determine the correct format, and then start |
| * reading from the beginning. First it will attempt to peek, and it |
| * assumes that if less than MinBufferedBytesNeeded bytes (but more than |
| * zero) are returned, this is because the stream is shorter than this, |
| * so falling back to reading would not provide more data. If peek() |
| * returns zero bytes, this call will instead attempt to read(). This |
| * will require that the stream can be rewind()ed. |
| * |
| * If Result is not NULL, it will be set to either kSuccess if an SkCodec |
| * is returned or a reason for the failure if NULL is returned. |
| * |
| * If SkPngChunkReader is not NULL, take a ref and pass it to libpng if |
| * the image is a png. |
| * |
| * If the SkPngChunkReader is not NULL then: |
| * If the image is not a PNG, the SkPngChunkReader will be ignored. |
| * If the image is a PNG, the SkPngChunkReader will be reffed. |
| * If the PNG has unknown chunks, the SkPngChunkReader will be used |
| * to handle these chunks. SkPngChunkReader will be called to read |
| * any unknown chunk at any point during the creation of the codec |
| * or the decode. Note that if SkPngChunkReader fails to read a |
| * chunk, this could result in a failure to create the codec or a |
| * failure to decode the image. |
| * If the PNG does not contain unknown chunks, the SkPngChunkReader |
| * will not be used or modified. |
| * |
| * If NULL is returned, the stream is deleted immediately. Otherwise, the |
| * SkCodec takes ownership of it, and will delete it when done with it. |
| */ |
| static SkCodec* NewFromStream(SkStream*, Result* = nullptr, |
| SkPngChunkReader* = nullptr); |
| |
| /** |
| * If this data represents an encoded image that we know how to decode, |
| * return an SkCodec that can decode it. Otherwise return NULL. |
| * |
| * If the SkPngChunkReader is not NULL then: |
| * If the image is not a PNG, the SkPngChunkReader will be ignored. |
| * If the image is a PNG, the SkPngChunkReader will be reffed. |
| * If the PNG has unknown chunks, the SkPngChunkReader will be used |
| * to handle these chunks. SkPngChunkReader will be called to read |
| * any unknown chunk at any point during the creation of the codec |
| * or the decode. Note that if SkPngChunkReader fails to read a |
| * chunk, this could result in a failure to create the codec or a |
| * failure to decode the image. |
| * If the PNG does not contain unknown chunks, the SkPngChunkReader |
| * will not be used or modified. |
| */ |
| static SkCodec* NewFromData(sk_sp<SkData>, SkPngChunkReader* = NULL); |
| static SkCodec* NewFromData(SkData* data, SkPngChunkReader* reader) { |
| return NewFromData(sk_ref_sp(data), reader); |
| } |
| |
| virtual ~SkCodec(); |
| |
| /** |
| * Return the ImageInfo associated with this codec. |
| */ |
| const SkImageInfo& getInfo() const { return fSrcInfo; } |
| |
| const SkEncodedInfo& getEncodedInfo() const { return fEncodedInfo; } |
| |
| enum Origin { |
| kTopLeft_Origin = 1, // Default |
| kTopRight_Origin = 2, // Reflected across y-axis |
| kBottomRight_Origin = 3, // Rotated 180 |
| kBottomLeft_Origin = 4, // Reflected across x-axis |
| kLeftTop_Origin = 5, // Reflected across x-axis, Rotated 90 CCW |
| kRightTop_Origin = 6, // Rotated 90 CW |
| kRightBottom_Origin = 7, // Reflected across x-axis, Rotated 90 CW |
| kLeftBottom_Origin = 8, // Rotated 90 CCW |
| kDefault_Origin = kTopLeft_Origin, |
| kLast_Origin = kLeftBottom_Origin, |
| }; |
| |
| /** |
| * Returns the image orientation stored in the EXIF data. |
| * If there is no EXIF data, or if we cannot read the EXIF data, returns kTopLeft. |
| */ |
| Origin getOrigin() const { return fOrigin; } |
| |
| /** |
| * Return a size that approximately supports the desired scale factor. |
| * The codec may not be able to scale efficiently to the exact scale |
| * factor requested, so return a size that approximates that scale. |
| * The returned value is the codec's suggestion for the closest valid |
| * scale that it can natively support |
| */ |
| SkISize getScaledDimensions(float desiredScale) const { |
| // Negative and zero scales are errors. |
| SkASSERT(desiredScale > 0.0f); |
| if (desiredScale <= 0.0f) { |
| return SkISize::Make(0, 0); |
| } |
| |
| // Upscaling is not supported. Return the original size if the client |
| // requests an upscale. |
| if (desiredScale >= 1.0f) { |
| return this->getInfo().dimensions(); |
| } |
| return this->onGetScaledDimensions(desiredScale); |
| } |
| |
| /** |
| * Return (via desiredSubset) a subset which can decoded from this codec, |
| * or false if this codec cannot decode subsets or anything similar to |
| * desiredSubset. |
| * |
| * @param desiredSubset In/out parameter. As input, a desired subset of |
| * the original bounds (as specified by getInfo). If true is returned, |
| * desiredSubset may have been modified to a subset which is |
| * supported. Although a particular change may have been made to |
| * desiredSubset to create something supported, it is possible other |
| * changes could result in a valid subset. |
| * If false is returned, desiredSubset's value is undefined. |
| * @return true if this codec supports decoding desiredSubset (as |
| * returned, potentially modified) |
| */ |
| bool getValidSubset(SkIRect* desiredSubset) const { |
| return this->onGetValidSubset(desiredSubset); |
| } |
| |
| /** |
| * Format of the encoded data. |
| */ |
| SkEncodedImageFormat getEncodedFormat() const { return this->onGetEncodedFormat(); } |
| |
| /** |
| * Whether or not the memory passed to getPixels is zero initialized. |
| */ |
| enum ZeroInitialized { |
| /** |
| * The memory passed to getPixels is zero initialized. The SkCodec |
| * may take advantage of this by skipping writing zeroes. |
| */ |
| kYes_ZeroInitialized, |
| /** |
| * The memory passed to getPixels has not been initialized to zero, |
| * so the SkCodec must write all zeroes to memory. |
| * |
| * This is the default. It will be used if no Options struct is used. |
| */ |
| kNo_ZeroInitialized, |
| }; |
| |
| /** |
| * Additional options to pass to getPixels. |
| */ |
| struct Options { |
| Options() |
| : fZeroInitialized(kNo_ZeroInitialized) |
| , fSubset(nullptr) |
| , fFrameIndex(0) |
| , fPriorFrame(kNone) |
| , fPremulBehavior(SkTransferFunctionBehavior::kRespect) |
| {} |
| |
| ZeroInitialized fZeroInitialized; |
| /** |
| * If not NULL, represents a subset of the original image to decode. |
| * Must be within the bounds returned by getInfo(). |
| * If the EncodedFormat is SkEncodedImageFormat::kWEBP (the only one which |
| * currently supports subsets), the top and left values must be even. |
| * |
| * 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 |
| * to get and which rows to skip. During scanline decodes, we will |
| * require that the subset top be zero and the subset height be equal |
| * to the full height. We will, however, use the values of |
| * subset left and subset width to decode partial scanlines on calls |
| * to getScanlines(). |
| */ |
| const SkIRect* fSubset; |
| |
| /** |
| * The frame to decode. |
| * |
| * Only meaningful for multi-frame images. |
| */ |
| int fFrameIndex; |
| |
| /** |
| * If not kNone, the dst already contains the prior frame at this index. |
| * |
| * Only meaningful for multi-frame images. |
| * |
| * If fFrameIndex needs to be blended with a prior frame (as reported by |
| * getFrameInfo[fFrameIndex].fRequiredFrame), the client can set this to |
| * any non-kRestorePrevious frame in [fRequiredFrame, fFrameIndex) to |
| * indicate that that frame is already in the dst. Options.fZeroInitialized |
| * is ignored in this case. |
| * |
| * If set to kNone, the codec will decode any necessary required frame(s) first. |
| */ |
| int fPriorFrame; |
| |
| /** |
| * Indicates whether we should do a linear premultiply or a legacy premultiply. |
| * |
| * In the case where the dst SkColorSpace is nullptr, this flag is ignored and |
| * we will always do a legacy premultiply. |
| */ |
| SkTransferFunctionBehavior fPremulBehavior; |
| }; |
| |
| /** |
| * Decode into the given pixels, a block of memory of size at |
| * least (info.fHeight - 1) * rowBytes + (info.fWidth * |
| * bytesPerPixel) |
| * |
| * Repeated calls to this function should give the same results, |
| * allowing the PixelRef to be immutable. |
| * |
| * @param info A description of the format (config, size) |
| * expected by the caller. This can simply be identical |
| * to the info returned by getInfo(). |
| * |
| * This contract also allows the caller to specify |
| * different output-configs, which the implementation can |
| * decide to support or not. |
| * |
| * A size that does not match getInfo() implies a request |
| * to scale. If the generator cannot perform this scale, |
| * it will return kInvalidScale. |
| * |
| * If the info contains a non-null SkColorSpace, the codec |
| * will perform the appropriate color space transformation. |
| * If the caller passes in the same color space that was |
| * reported by the codec, the color space transformation is |
| * a no-op. |
| * |
| * If a scanline decode is in progress, scanline mode will end, requiring the client to call |
| * startScanlineDecode() in order to return to decoding scanlines. |
| * |
| * @return Result kSuccess, or another value explaining the type of failure. |
| */ |
| Result getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes, const Options*); |
| |
| /** |
| * Simplified version of getPixels() that uses the default Options. |
| */ |
| Result getPixels(const SkImageInfo& info, void* pixels, size_t rowBytes) { |
| return this->getPixels(info, pixels, rowBytes, nullptr); |
| } |
| |
| /** |
| * If decoding to YUV is supported, this returns true. Otherwise, this |
| * returns false and does not modify any of the parameters. |
| * |
| * @param sizeInfo Output parameter indicating the sizes and required |
| * allocation widths of the Y, U, and V planes. |
| * @param colorSpace Output parameter. If non-NULL this is set to kJPEG, |
| * otherwise this is ignored. |
| */ |
| bool queryYUV8(SkYUVSizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const { |
| if (nullptr == sizeInfo) { |
| return false; |
| } |
| |
| return this->onQueryYUV8(sizeInfo, colorSpace); |
| } |
| |
| /** |
| * Returns kSuccess, or another value explaining the type of failure. |
| * This always attempts to perform a full decode. If the client only |
| * wants size, it should call queryYUV8(). |
| * |
| * @param sizeInfo Needs to exactly match the values returned by the |
| * query, except the WidthBytes may be larger than the |
| * recommendation (but not smaller). |
| * @param planes Memory for each of the Y, U, and V planes. |
| */ |
| Result getYUV8Planes(const SkYUVSizeInfo& sizeInfo, void* planes[3]) { |
| if (nullptr == planes || nullptr == planes[0] || nullptr == planes[1] || |
| nullptr == planes[2]) { |
| return kInvalidInput; |
| } |
| |
| if (!this->rewindIfNeeded()) { |
| return kCouldNotRewind; |
| } |
| |
| return this->onGetYUV8Planes(sizeInfo, planes); |
| } |
| |
| /** |
| * 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. |
| * @return Enum representing success or reason for failure. |
| */ |
| Result startIncrementalDecode(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, |
| const Options*); |
| |
| Result startIncrementalDecode(const SkImageInfo& dstInfo, void* dst, size_t rowBytes) { |
| return this->startIncrementalDecode(dstInfo, dst, rowBytes, 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. |
| */ |
| |
| /** |
| * Prepare for a scanline decode with the specified options. |
| * |
| * After this call, this class will be ready to decode the first scanline. |
| * |
| * This must be called in order to call getScanlines or skipScanlines. |
| * |
| * This may require rewinding the stream. |
| * |
| * Not all SkCodecs support this. |
| * |
| * @param dstInfo Info of the destination. If the dimensions do not match |
| * those of getInfo, this implies a scale. |
| * @param options Contains decoding options, including if memory is zero |
| * initialized. |
| * @return Enum representing success or reason for failure. |
| */ |
| Result startScanlineDecode(const SkImageInfo& dstInfo, const Options* options); |
| |
| /** |
| * Simplified version of startScanlineDecode() that uses the default Options. |
| */ |
| Result startScanlineDecode(const SkImageInfo& dstInfo) { |
| return this->startScanlineDecode(dstInfo, nullptr); |
| } |
| |
| /** |
| * Write the next countLines scanlines into dst. |
| * |
| * Not valid to call before calling startScanlineDecode(). |
| * |
| * @param dst Must be non-null, and large enough to hold countLines |
| * scanlines of size rowBytes. |
| * @param countLines Number of lines to write. |
| * @param rowBytes Number of bytes per row. Must be large enough to hold |
| * a scanline based on the SkImageInfo used to create this object. |
| * @return the number of lines successfully decoded. If this value is |
| * less than countLines, this will fill the remaining lines with a |
| * default value. |
| */ |
| int getScanlines(void* dst, int countLines, size_t rowBytes); |
| |
| /** |
| * Skip count scanlines. |
| * |
| * Not valid to call before calling startScanlineDecode(). |
| * |
| * The default version just calls onGetScanlines and discards the dst. |
| * NOTE: If skipped lines are the only lines with alpha, this default |
| * will make reallyHasAlpha return true, when it could have returned |
| * false. |
| * |
| * @return true if the scanlines were successfully skipped |
| * false on failure, possible reasons for failure include: |
| * An incomplete input image stream. |
| * Calling this function before calling startScanlineDecode(). |
| * If countLines is less than zero or so large that it moves |
| * the current scanline past the end of the image. |
| */ |
| bool skipScanlines(int countLines); |
| |
| /** |
| * The order in which rows are output from the scanline decoder is not the |
| * same for all variations of all image types. This explains the possible |
| * output row orderings. |
| */ |
| enum SkScanlineOrder { |
| /* |
| * By far the most common, this indicates that the image can be decoded |
| * reliably using the scanline decoder, and that rows will be output in |
| * the logical order. |
| */ |
| kTopDown_SkScanlineOrder, |
| |
| /* |
| * This indicates that the scanline decoder reliably outputs rows, but |
| * they will be returned in reverse order. If the scanline format is |
| * kBottomUp, the nextScanline() API can be used to determine the actual |
| * y-coordinate of the next output row, but the client is not forced |
| * to take advantage of this, given that it's not too tough to keep |
| * track independently. |
| * |
| * For full image decodes, it is safe to get all of the scanlines at |
| * once, since the decoder will handle inverting the rows as it |
| * decodes. |
| * |
| * For subset decodes and sampling, it is simplest to get and skip |
| * scanlines one at a time, using the nextScanline() API. It is |
| * possible to ask for larger chunks at a time, but this should be used |
| * with caution. As with full image decodes, the decoder will handle |
| * inverting the requested rows, but rows will still be delivered |
| * starting from the bottom of the image. |
| * |
| * Upside down bmps are an example. |
| */ |
| kBottomUp_SkScanlineOrder, |
| }; |
| |
| /** |
| * An enum representing the order in which scanlines will be returned by |
| * the scanline decoder. |
| * |
| * This is undefined before startScanlineDecode() is called. |
| */ |
| SkScanlineOrder getScanlineOrder() const { return this->onGetScanlineOrder(); } |
| |
| /** |
| * Returns the y-coordinate of the next row to be returned by the scanline |
| * decoder. |
| * |
| * This will equal fCurrScanline, except in the case of strangely |
| * encoded image types (bottom-up bmps). |
| * |
| * Results are undefined when not in scanline decoding mode. |
| */ |
| int nextScanline() const { return this->outputScanline(fCurrScanline); } |
| |
| /** |
| * Returns the output y-coordinate of the row that corresponds to an input |
| * y-coordinate. The input y-coordinate represents where the scanline |
| * is located in the encoded data. |
| * |
| * This will equal inputScanline, except in the case of strangely |
| * encoded image types (bottom-up bmps, interlaced gifs). |
| */ |
| int outputScanline(int inputScanline) const; |
| |
| /** |
| * Return the number of frames in the image. |
| * |
| * May require reading through the stream. |
| */ |
| int getFrameCount() { |
| return this->onGetFrameCount(); |
| } |
| |
| // The required frame for an independent frame is marked as |
| // kNone. |
| static constexpr int kNone = -1; |
| |
| /** |
| * Information about individual frames in a multi-framed image. |
| */ |
| struct FrameInfo { |
| /** |
| * The frame that this frame needs to be blended with, or |
| * kNone if this frame is independent. |
| * |
| * Note that this is the *earliest* frame that can be used |
| * for blending. Any frame from [fRequiredFrame, i) can be |
| * used, unless its fDisposalMethod is kRestorePrevious. |
| */ |
| int fRequiredFrame; |
| |
| /** |
| * Number of milliseconds to show this frame. |
| */ |
| int fDuration; |
| |
| /** |
| * Whether the end marker for this frame is contained in the stream. |
| * |
| * Note: this does not guarantee that an attempt to decode will be complete. |
| * There could be an error in the stream. |
| */ |
| bool fFullyReceived; |
| |
| /** |
| * This is conservative; it will still return non-opaque if e.g. a |
| * color index-based frame has a color with alpha but does not use it. |
| */ |
| SkAlphaType fAlphaType; |
| |
| /** |
| * How this frame should be modified before decoding the next one. |
| */ |
| SkCodecAnimation::DisposalMethod fDisposalMethod; |
| }; |
| |
| /** |
| * Return info about a single frame. |
| * |
| * Only supported by multi-frame images. Does not read through the stream, |
| * so it should be called after getFrameCount() to parse any frames that |
| * have not already been parsed. |
| */ |
| bool getFrameInfo(int index, FrameInfo* info) const { |
| if (index < 0) { |
| return false; |
| } |
| return this->onGetFrameInfo(index, info); |
| } |
| |
| /** |
| * Return info about all the frames in the image. |
| * |
| * May require reading through the stream to determine info about the |
| * frames (including the count). |
| * |
| * As such, future decoding calls may require a rewind. |
| * |
| * For single-frame images, this will return an empty vector. |
| */ |
| std::vector<FrameInfo> getFrameInfo(); |
| |
| static constexpr int kRepetitionCountInfinite = -1; |
| |
| /** |
| * Return the number of times to repeat, if this image is animated. |
| * |
| * May require reading the stream to find the repetition count. |
| * |
| * As such, future decoding calls may require a rewind. |
| * |
| * For single-frame images, this will return 0. |
| */ |
| int getRepetitionCount() { |
| return this->onGetRepetitionCount(); |
| } |
| |
| protected: |
| using XformFormat = SkColorSpaceXform::ColorFormat; |
| |
| /** |
| * Takes ownership of SkStream* |
| */ |
| SkCodec(int width, |
| int height, |
| const SkEncodedInfo&, |
| XformFormat srcFormat, |
| SkStream*, |
| sk_sp<SkColorSpace>, |
| Origin = kTopLeft_Origin); |
| |
| /** |
| * Takes ownership of SkStream* |
| * Allows the subclass to set the recommended SkImageInfo |
| */ |
| SkCodec(const SkEncodedInfo&, |
| const SkImageInfo&, |
| XformFormat srcFormat, |
| SkStream*, |
| Origin = kTopLeft_Origin); |
| |
| virtual SkISize onGetScaledDimensions(float /*desiredScale*/) const { |
| // By default, scaling is not supported. |
| return this->getInfo().dimensions(); |
| } |
| |
| // FIXME: What to do about subsets?? |
| /** |
| * Subclasses should override if they support dimensions other than the |
| * srcInfo's. |
| */ |
| virtual bool onDimensionsSupported(const SkISize&) { |
| return false; |
| } |
| |
| virtual SkEncodedImageFormat onGetEncodedFormat() const = 0; |
| |
| /** |
| * @param rowsDecoded When the encoded image stream is incomplete, this function |
| * will return kIncompleteInput and rowsDecoded will be set to |
| * the number of scanlines that were successfully decoded. |
| * This will allow getPixels() to fill the uninitialized memory. |
| */ |
| virtual Result onGetPixels(const SkImageInfo& info, |
| void* pixels, size_t rowBytes, const Options&, |
| int* rowsDecoded) = 0; |
| |
| virtual bool onQueryYUV8(SkYUVSizeInfo*, SkYUVColorSpace*) const { |
| return false; |
| } |
| |
| virtual Result onGetYUV8Planes(const SkYUVSizeInfo&, void*[3] /*planes*/) { |
| return kUnimplemented; |
| } |
| |
| virtual bool onGetValidSubset(SkIRect* /*desiredSubset*/) const { |
| // By default, subsets are not supported. |
| return false; |
| } |
| |
| /** |
| * If the stream was previously read, attempt to rewind. |
| * |
| * If the stream needed to be rewound, call onRewind. |
| * @returns true if the codec is at the right position and can be used. |
| * false if there was a failure to rewind. |
| * |
| * This is called by getPixels() and start(). Subclasses may call if they |
| * need to rewind at another time. |
| */ |
| bool SK_WARN_UNUSED_RESULT rewindIfNeeded(); |
| |
| /** |
| * Called by rewindIfNeeded, if the stream needed to be rewound. |
| * |
| * Subclasses should do any set up needed after a rewind. |
| */ |
| virtual bool onRewind() { |
| return true; |
| } |
| |
| /** |
| * On an incomplete input, getPixels() and getScanlines() will fill any uninitialized |
| * scanlines. This allows the subclass to indicate what value to fill with. |
| * |
| * @param dstInfo Describes the destination. |
| * @return The value with which to fill uninitialized pixels. |
| * |
| * Note that we can interpret the return value as a 64-bit Float16 color, a SkPMColor, |
| * a 16-bit 565 color, an 8-bit gray color, or an 8-bit index into a color table, |
| * depending on the color type. |
| */ |
| uint64_t getFillValue(const SkImageInfo& dstInfo) const { |
| return this->onGetFillValue(dstInfo); |
| } |
| |
| /** |
| * Some subclasses will override this function, but this is a useful default for the color |
| * types that we support. Note that for color types that do not use the full 64-bits, |
| * we will simply take the low bits of the fill value. |
| * |
| * The defaults are: |
| * kRGBA_F16_SkColorType: Transparent or Black, depending on the src alpha type |
| * kN32_SkColorType: Transparent or Black, depending on the src alpha type |
| * kRGB_565_SkColorType: Black |
| * kGray_8_SkColorType: Black |
| */ |
| virtual uint64_t onGetFillValue(const SkImageInfo& dstInfo) const; |
| |
| /** |
| * Get method for the input stream |
| */ |
| SkStream* stream() { |
| return fStream.get(); |
| } |
| |
| /** |
| * The remaining functions revolve around decoding scanlines. |
| */ |
| |
| /** |
| * Most images types will be kTopDown and will not need to override this function. |
| */ |
| virtual SkScanlineOrder onGetScanlineOrder() const { return kTopDown_SkScanlineOrder; } |
| |
| const SkImageInfo& dstInfo() const { return fDstInfo; } |
| |
| const Options& options() const { return fOptions; } |
| |
| /** |
| * Returns the number of scanlines that have been decoded so far. |
| * This is unaffected by the SkScanlineOrder. |
| * |
| * Returns -1 if we have not started a scanline decode. |
| */ |
| int currScanline() const { return fCurrScanline; } |
| |
| virtual int onOutputScanline(int inputScanline) const; |
| |
| bool initializeColorXform(const SkImageInfo& dstInfo, |
| SkTransferFunctionBehavior premulBehavior); |
| void applyColorXform(void* dst, const void* src, int count, SkAlphaType) const; |
| void applyColorXform(void* dst, const void* src, int count) const; |
| |
| SkColorSpaceXform* colorXform() const { return fColorXform.get(); } |
| bool xformOnDecode() const { return fXformOnDecode; } |
| |
| virtual int onGetFrameCount() { |
| return 1; |
| } |
| |
| virtual bool onGetFrameInfo(int, FrameInfo*) const { |
| return false; |
| } |
| |
| virtual int onGetRepetitionCount() { |
| return 0; |
| } |
| |
| private: |
| const SkEncodedInfo fEncodedInfo; |
| const SkImageInfo fSrcInfo; |
| const XformFormat fSrcXformFormat; |
| std::unique_ptr<SkStream> fStream; |
| bool fNeedsRewind; |
| const Origin fOrigin; |
| |
| SkImageInfo fDstInfo; |
| Options fOptions; |
| XformFormat fDstXformFormat; // Based on fDstInfo. |
| std::unique_ptr<SkColorSpaceXform> fColorXform; |
| bool fXformOnDecode; |
| |
| // Only meaningful during scanline decodes. |
| int fCurrScanline; |
| |
| bool fStartedIncrementalDecode; |
| |
| /** |
| * Return whether these dimensions are supported as a scale. |
| * |
| * The codec may choose to cache the information about scale and subset. |
| * Either way, the same information will be passed to onGetPixels/onStart |
| * on success. |
| * |
| * This must return true for a size returned from getScaledDimensions. |
| */ |
| bool dimensionsSupported(const SkISize& dim) { |
| return dim == fSrcInfo.dimensions() || this->onDimensionsSupported(dim); |
| } |
| |
| /** |
| * For multi-framed images, return the object with information about the frames. |
| */ |
| virtual const SkFrameHolder* getFrameHolder() const { |
| return nullptr; |
| } |
| |
| /** |
| * Check for a valid Options.fFrameIndex, and decode prior frames if necessary. |
| */ |
| Result handleFrameIndex(const SkImageInfo&, void* pixels, size_t rowBytes, const Options&); |
| |
| // Methods for scanline decoding. |
| virtual Result onStartScanlineDecode(const SkImageInfo& /*dstInfo*/, |
| const Options& /*options*/) { |
| return kUnimplemented; |
| } |
| |
| virtual Result onStartIncrementalDecode(const SkImageInfo& /*dstInfo*/, void*, size_t, |
| const Options&) { |
| 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; } |
| |
| /** |
| * On an incomplete decode, getPixels() and getScanlines() will call this function |
| * to fill any uinitialized memory. |
| * |
| * @param dstInfo Contains the destination color type |
| * Contains the destination alpha type |
| * Contains the destination width |
| * The height stored in this info is unused |
| * @param dst Pointer to the start of destination pixel memory |
| * @param rowBytes Stride length in destination pixel memory |
| * @param zeroInit Indicates if memory is zero initialized |
| * @param linesRequested Number of lines that the client requested |
| * @param linesDecoded Number of lines that were successfully decoded |
| */ |
| void fillIncompleteImage(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, |
| ZeroInitialized zeroInit, int linesRequested, int linesDecoded); |
| |
| /** |
| * Return an object which will allow forcing scanline decodes to sample in X. |
| * |
| * May create a sampler, if one is not currently being used. Otherwise, does |
| * not affect ownership. |
| * |
| * Only valid during scanline decoding or incremental decoding. |
| */ |
| virtual SkSampler* getSampler(bool /*createIfNecessary*/) { return nullptr; } |
| |
| friend class DM::CodecSrc; // for fillIncompleteImage |
| friend class SkSampledCodec; |
| friend class SkIcoCodec; |
| }; |
| #endif // SkCodec_DEFINED |