b227e37eae
Enabling JPEG YUV Decoding in Skia BUG=skia:3005, skia:1674, skia:3029 Committed: https://skia.googlesource.com/skia/+/8e6c3b93a39e19111662a760ede97df55e51d39f Review URL: https://codereview.chromium.org/399683007
507 lines
19 KiB
C++
507 lines
19 KiB
C++
/*
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* Copyright 2006 The Android Open Source Project
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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 SkImageDecoder_DEFINED
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#define SkImageDecoder_DEFINED
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#include "SkBitmap.h"
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#include "SkImage.h"
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#include "SkRect.h"
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#include "SkRefCnt.h"
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#include "SkTRegistry.h"
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#include "SkTypes.h"
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class SkStream;
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class SkStreamRewindable;
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/** \class SkImageDecoder
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Base class for decoding compressed images into a SkBitmap
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*/
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class SkImageDecoder : SkNoncopyable {
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public:
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virtual ~SkImageDecoder();
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enum Format {
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kUnknown_Format,
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kBMP_Format,
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kGIF_Format,
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kICO_Format,
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kJPEG_Format,
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kPNG_Format,
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kWBMP_Format,
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kWEBP_Format,
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kPKM_Format,
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kKTX_Format,
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kASTC_Format,
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kLastKnownFormat = kKTX_Format,
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};
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/** Return the format of image this decoder can decode. If this decoder can decode multiple
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formats, kUnknown_Format will be returned.
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*/
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virtual Format getFormat() const;
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/** If planes or rowBytes is NULL, decodes the header and computes componentSizes
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for memory allocation.
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Otherwise, decodes the YUV planes into the provided image planes and
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updates componentSizes to the final image size.
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Returns whether the decoding was successful.
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*/
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bool decodeYUV8Planes(SkStream* stream, SkISize componentSizes[3], void* planes[3],
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size_t rowBytes[3], SkYUVColorSpace*);
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/** Return the format of the SkStreamRewindable or kUnknown_Format if it cannot be determined.
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Rewinds the stream before returning.
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*/
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static Format GetStreamFormat(SkStreamRewindable*);
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/** Return a readable string of the Format provided.
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*/
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static const char* GetFormatName(Format);
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/** Return a readable string of the value returned by getFormat().
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*/
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const char* getFormatName() const;
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/** Whether the decoder should skip writing zeroes to output if possible.
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*/
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bool getSkipWritingZeroes() const { return fSkipWritingZeroes; }
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/** Set to true if the decoder should skip writing any zeroes when
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creating the output image.
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This is a hint that may not be respected by the decoder.
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It should only be used if it is known that the memory to write
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to has already been set to 0; otherwise the resulting image will
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have garbage.
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This is ideal for images that contain a lot of completely transparent
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pixels, but may be a performance hit for an image that has only a
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few transparent pixels.
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The default is false.
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*/
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void setSkipWritingZeroes(bool skip) { fSkipWritingZeroes = skip; }
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/** Returns true if the decoder should try to dither the resulting image.
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The default setting is true.
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*/
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bool getDitherImage() const { return fDitherImage; }
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/** Set to true if the the decoder should try to dither the resulting image.
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The default setting is true.
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*/
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void setDitherImage(bool dither) { fDitherImage = dither; }
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/** Returns true if the decoder should try to decode the
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resulting image to a higher quality even at the expense of
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the decoding speed.
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*/
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bool getPreferQualityOverSpeed() const { return fPreferQualityOverSpeed; }
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/** Set to true if the the decoder should try to decode the
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resulting image to a higher quality even at the expense of
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the decoding speed.
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*/
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void setPreferQualityOverSpeed(bool qualityOverSpeed) {
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fPreferQualityOverSpeed = qualityOverSpeed;
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}
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/** Set to true to require the decoder to return a bitmap with unpremultiplied
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colors. The default is false, meaning the resulting bitmap will have its
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colors premultiplied.
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NOTE: Passing true to this function may result in a bitmap which cannot
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be properly used by Skia.
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*/
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void setRequireUnpremultipliedColors(bool request) {
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fRequireUnpremultipliedColors = request;
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}
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/** Returns true if the decoder will only return bitmaps with unpremultiplied
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colors.
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*/
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bool getRequireUnpremultipliedColors() const { return fRequireUnpremultipliedColors; }
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/** \class Peeker
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Base class for optional callbacks to retrieve meta/chunk data out of
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an image as it is being decoded.
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*/
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class Peeker : public SkRefCnt {
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public:
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SK_DECLARE_INST_COUNT(Peeker)
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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 peek(const char tag[], const void* data, size_t length) = 0;
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private:
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typedef SkRefCnt INHERITED;
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};
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Peeker* getPeeker() const { return fPeeker; }
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Peeker* setPeeker(Peeker*);
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#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
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/** \class Chooser
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Base class for optional callbacks to choose an image from a format that
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contains multiple images.
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*/
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class Chooser : public SkRefCnt {
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public:
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SK_DECLARE_INST_COUNT(Chooser)
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virtual void begin(int count) {}
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virtual void inspect(int index, SkBitmap::Config config, int width, int height) {}
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/** Return the index of the subimage you want, or -1 to choose none of them.
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*/
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virtual int choose() = 0;
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private:
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typedef SkRefCnt INHERITED;
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};
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Chooser* getChooser() const { return fChooser; }
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Chooser* setChooser(Chooser*);
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#endif
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/**
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* By default, the codec will try to comply with the "pref" colortype
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* that is passed to decode() or decodeSubset(). However, this can be called
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* to override that, causing the codec to try to match the src depth instead
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* (as shown below).
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*
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* src_8Index -> kIndex_8_SkColorType
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* src_8Gray -> kN32_SkColorType
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* src_8bpc -> kN32_SkColorType
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*/
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void setPreserveSrcDepth(bool preserve) {
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fPreserveSrcDepth = preserve;
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}
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SkBitmap::Allocator* getAllocator() const { return fAllocator; }
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SkBitmap::Allocator* setAllocator(SkBitmap::Allocator*);
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// sample-size, if set to > 1, tells the decoder to return a smaller than
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// original bitmap, sampling 1 pixel for every size pixels. e.g. if sample
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// size is set to 3, then the returned bitmap will be 1/3 as wide and high,
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// and will contain 1/9 as many pixels as the original.
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// Note: this is a hint, and the codec may choose to ignore this, or only
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// approximate the sample size.
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int getSampleSize() const { return fSampleSize; }
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void setSampleSize(int size);
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/** Reset the sampleSize to its default of 1
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*/
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void resetSampleSize() { this->setSampleSize(1); }
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/** Decoding is synchronous, but for long decodes, a different thread can
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call this method safely. This sets a state that the decoders will
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periodically check, and if they see it changed to cancel, they will
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cancel. This will result in decode() returning false. However, there is
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no guarantee that the decoder will see the state change in time, so
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it is possible that cancelDecode() will be called, but will be ignored
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and decode() will return true (assuming no other problems were
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encountered).
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This state is automatically reset at the beginning of decode().
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*/
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void cancelDecode() {
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// now the subclass must query shouldCancelDecode() to be informed
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// of the request
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fShouldCancelDecode = true;
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}
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/** Passed to the decode method. If kDecodeBounds_Mode is passed, then
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only the bitmap's info need be set. If kDecodePixels_Mode
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is passed, then the bitmap must have pixels or a pixelRef.
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*/
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enum Mode {
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kDecodeBounds_Mode, //!< only return info in bitmap
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kDecodePixels_Mode //!< return entire bitmap (including pixels)
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};
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/** Given a stream, decode it into the specified bitmap.
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If the decoder can decompress the image, it calls bitmap.setInfo(),
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and then if the Mode is kDecodePixels_Mode, call allocPixelRef(),
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which will allocated a pixelRef. To access the pixel memory, the codec
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needs to call lockPixels/unlockPixels on the
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bitmap. It can then set the pixels with the decompressed image.
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* If the image cannot be decompressed, return false. After the
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* decoding, the function converts the decoded colortype in bitmap
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* to pref if possible. Whether a conversion is feasible is
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* tested by Bitmap::canCopyTo(pref).
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If an SkBitmap::Allocator is installed via setAllocator, it will be
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used to allocate the pixel memory. A clever allocator can be used
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to allocate the memory from a cache, volatile memory, or even from
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an existing bitmap's memory.
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If a Peeker is installed via setPeeker, it may be used to peek into
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meta data during the decode.
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*/
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bool decode(SkStream*, SkBitmap* bitmap, SkColorType pref, Mode);
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bool decode(SkStream* stream, SkBitmap* bitmap, Mode mode) {
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return this->decode(stream, bitmap, kUnknown_SkColorType, mode);
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}
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/**
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* Given a stream, build an index for doing tile-based decode.
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* The built index will be saved in the decoder, and the image size will
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* be returned in width and height.
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*
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* Return true for success or false on failure.
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*/
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bool buildTileIndex(SkStreamRewindable*, int *width, int *height);
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/**
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* Decode a rectangle subset in the image.
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* The method can only be called after buildTileIndex().
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*
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* Return true for success.
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* Return false if the index is never built or failing in decoding.
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*/
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bool decodeSubset(SkBitmap* bm, const SkIRect& subset, SkColorType pref);
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/** Given a stream, this will try to find an appropriate decoder object.
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If none is found, the method returns NULL.
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*/
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static SkImageDecoder* Factory(SkStreamRewindable*);
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/** Decode the image stored in the specified file, and store the result
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in bitmap. Return true for success or false on failure.
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@param pref If the PrefConfigTable is not set, prefer this colortype.
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See NOTE ABOUT PREFERRED CONFIGS.
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@param format On success, if format is non-null, it is set to the format
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of the decoded file. On failure it is ignored.
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*/
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static bool DecodeFile(const char file[], SkBitmap* bitmap, SkColorType pref, Mode,
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Format* format = NULL);
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static bool DecodeFile(const char file[], SkBitmap* bitmap) {
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return DecodeFile(file, bitmap, kUnknown_SkColorType, kDecodePixels_Mode, NULL);
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}
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/** Decode the image stored in the specified memory buffer, and store the
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result in bitmap. Return true for success or false on failure.
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@param pref If the PrefConfigTable is not set, prefer this colortype.
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See NOTE ABOUT PREFERRED CONFIGS.
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@param format On success, if format is non-null, it is set to the format
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of the decoded buffer. On failure it is ignored.
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*/
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static bool DecodeMemory(const void* buffer, size_t size, SkBitmap* bitmap, SkColorType pref,
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Mode, Format* format = NULL);
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static bool DecodeMemory(const void* buffer, size_t size, SkBitmap* bitmap){
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return DecodeMemory(buffer, size, bitmap, kUnknown_SkColorType, kDecodePixels_Mode, NULL);
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}
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/**
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* Struct containing information about a pixel destination.
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*/
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struct Target {
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/**
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* Pre-allocated memory.
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*/
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void* fAddr;
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/**
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* Rowbytes of the allocated memory.
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*/
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size_t fRowBytes;
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};
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/** Decode the image stored in the specified SkStreamRewindable, and store the result
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in bitmap. Return true for success or false on failure.
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@param pref If the PrefConfigTable is not set, prefer this colortype.
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See NOTE ABOUT PREFERRED CONFIGS.
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@param format On success, if format is non-null, it is set to the format
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of the decoded stream. On failure it is ignored.
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*/
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static bool DecodeStream(SkStreamRewindable* stream, SkBitmap* bitmap, SkColorType pref, Mode,
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Format* format = NULL);
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static bool DecodeStream(SkStreamRewindable* stream, SkBitmap* bitmap) {
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return DecodeStream(stream, bitmap, kUnknown_SkColorType, kDecodePixels_Mode, NULL);
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}
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protected:
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// must be overridden in subclasses. This guy is called by decode(...)
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virtual bool onDecode(SkStream*, SkBitmap* bitmap, Mode) = 0;
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// If the decoder wants to support tiled based decoding,
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// this method must be overridden. This guy is called by buildTileIndex(...)
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virtual bool onBuildTileIndex(SkStreamRewindable*, int *width, int *height) {
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return false;
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}
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// If the decoder wants to support tiled based decoding,
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// this method must be overridden. This guy is called by decodeRegion(...)
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virtual bool onDecodeSubset(SkBitmap* bitmap, const SkIRect& rect) {
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return false;
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}
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/** If planes or rowBytes is NULL, decodes the header and computes componentSizes
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for memory allocation.
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Otherwise, decodes the YUV planes into the provided image planes and
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updates componentSizes to the final image size.
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Returns whether the decoding was successful.
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*/
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virtual bool onDecodeYUV8Planes(SkStream* stream, SkISize componentSizes[3], void* planes[3],
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size_t rowBytes[3], SkYUVColorSpace*) {
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return false;
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}
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/*
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* Crop a rectangle from the src Bitmap to the dest Bitmap. src and dst are
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* both sampled by sampleSize from an original Bitmap.
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*
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* @param dst the destination bitmap.
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* @param src the source bitmap that is sampled by sampleSize from the
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* original bitmap.
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* @param sampleSize the sample size that src is sampled from the original bitmap.
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* @param (dstX, dstY) the upper-left point of the dest bitmap in terms of
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* the coordinate in the original bitmap.
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* @param (width, height) the width and height of the unsampled dst.
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* @param (srcX, srcY) the upper-left point of the src bitmap in terms of
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* the coordinate in the original bitmap.
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* @return bool Whether or not it succeeded.
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*/
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bool cropBitmap(SkBitmap *dst, SkBitmap *src, int sampleSize,
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int dstX, int dstY, int width, int height,
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int srcX, int srcY);
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/**
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* Copy all fields on this decoder to the other decoder. Used by subclasses
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* to decode a subimage using a different decoder, but with the same settings.
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*/
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void copyFieldsToOther(SkImageDecoder* other);
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/** Can be queried from within onDecode, to see if the user (possibly in
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a different thread) has requested the decode to cancel. If this returns
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true, your onDecode() should stop and return false.
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Each subclass needs to decide how often it can query this, to balance
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responsiveness with performance.
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Calling this outside of onDecode() may return undefined values.
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*/
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public:
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bool shouldCancelDecode() const { return fShouldCancelDecode; }
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protected:
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SkImageDecoder();
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/**
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* Return the default preference being used by the current or latest call to decode.
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*/
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SkColorType getDefaultPref() { return fDefaultPref; }
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#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
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// helper function for decoders to handle the (common) case where there is only
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// once choice available in the image file.
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bool chooseFromOneChoice(SkColorType, int width, int height) const;
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#endif
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/* Helper for subclasses. Call this to allocate the pixel memory given the bitmap's info.
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Returns true on success. This method handles checking for an optional Allocator.
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*/
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bool allocPixelRef(SkBitmap*, SkColorTable*) const;
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/**
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* The raw data of the src image.
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*/
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enum SrcDepth {
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// Color-indexed.
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kIndex_SrcDepth,
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// Grayscale in 8 bits.
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k8BitGray_SrcDepth,
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// 8 bits per component. Used for 24 bit if there is no alpha.
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k32Bit_SrcDepth,
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};
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/** The subclass, inside onDecode(), calls this to determine the colorType of
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the returned bitmap. SrcDepth and hasAlpha reflect the raw data of the
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src image. This routine returns the caller's preference given
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srcDepth and hasAlpha, or kUnknown_SkColorType if there is no preference.
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*/
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SkColorType getPrefColorType(SrcDepth, bool hasAlpha) const;
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private:
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Peeker* fPeeker;
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#ifdef SK_SUPPORT_LEGACY_IMAGEDECODER_CHOOSER
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Chooser* fChooser;
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#endif
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SkBitmap::Allocator* fAllocator;
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int fSampleSize;
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SkColorType fDefaultPref; // use if fUsePrefTable is false
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bool fPreserveSrcDepth;
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bool fDitherImage;
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bool fSkipWritingZeroes;
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mutable bool fShouldCancelDecode;
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bool fPreferQualityOverSpeed;
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bool fRequireUnpremultipliedColors;
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};
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/** Calling newDecoder with a stream returns a new matching imagedecoder
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instance, or NULL if none can be found. The caller must manage its ownership
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of the stream as usual, calling unref() when it is done, as the returned
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decoder may have called ref() (and if so, the decoder is responsible for
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balancing its ownership when it is destroyed).
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*/
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class SkImageDecoderFactory : public SkRefCnt {
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public:
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SK_DECLARE_INST_COUNT(SkImageDecoderFactory)
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virtual SkImageDecoder* newDecoder(SkStreamRewindable*) = 0;
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private:
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typedef SkRefCnt INHERITED;
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};
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class SkDefaultImageDecoderFactory : SkImageDecoderFactory {
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public:
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// calls SkImageDecoder::Factory(stream)
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virtual SkImageDecoder* newDecoder(SkStreamRewindable* stream) {
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return SkImageDecoder::Factory(stream);
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}
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};
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// This macro declares a global (i.e., non-class owned) creation entry point
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// for each decoder (e.g., CreateJPEGImageDecoder)
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#define DECLARE_DECODER_CREATOR(codec) \
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SkImageDecoder *Create ## codec ();
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// This macro defines the global creation entry point for each decoder. Each
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// decoder implementation that registers with the decoder factory must call it.
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#define DEFINE_DECODER_CREATOR(codec) \
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SkImageDecoder *Create ## codec () { \
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return SkNEW( Sk ## codec ); \
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}
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// All the decoders known by Skia. Note that, depending on the compiler settings,
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// not all of these will be available
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DECLARE_DECODER_CREATOR(BMPImageDecoder);
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DECLARE_DECODER_CREATOR(GIFImageDecoder);
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DECLARE_DECODER_CREATOR(ICOImageDecoder);
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DECLARE_DECODER_CREATOR(JPEGImageDecoder);
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DECLARE_DECODER_CREATOR(PNGImageDecoder);
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DECLARE_DECODER_CREATOR(WBMPImageDecoder);
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DECLARE_DECODER_CREATOR(WEBPImageDecoder);
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DECLARE_DECODER_CREATOR(PKMImageDecoder);
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DECLARE_DECODER_CREATOR(KTXImageDecoder);
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DECLARE_DECODER_CREATOR(ASTCImageDecoder);
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// Typedefs to make registering decoder and formatter callbacks easier.
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// These have to be defined outside SkImageDecoder. :(
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typedef SkTRegistry<SkImageDecoder*(*)(SkStreamRewindable*)> SkImageDecoder_DecodeReg;
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typedef SkTRegistry<SkImageDecoder::Format(*)(SkStreamRewindable*)> SkImageDecoder_FormatReg;
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#endif
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