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- /*
- * Copyright 2017 Google Inc.
- *
- * Use of this source code is governed by a BSD-style license that can be
- * found in the LICENSE file.
- */
- #ifndef SkJpegEncoder_DEFINED
- #define SkJpegEncoder_DEFINED
- #include "include/encode/SkEncoder.h"
- class SkJpegEncoderMgr;
- class SkWStream;
- class SK_API SkJpegEncoder : public SkEncoder {
- public:
- enum class AlphaOption {
- kIgnore,
- kBlendOnBlack,
- };
- enum class Downsample {
- /**
- * Reduction by a factor of two in both the horizontal and vertical directions.
- */
- k420,
- /**
- * Reduction by a factor of two in the horizontal direction.
- */
- k422,
- /**
- * No downsampling.
- */
- k444,
- };
- struct Options {
- /**
- * |fQuality| must be in [0, 100] where 0 corresponds to the lowest quality.
- */
- int fQuality = 100;
- /**
- * Choose the downsampling factor for the U and V components. This is only
- * meaningful if the |src| is not kGray, since kGray will not be encoded as YUV.
- *
- * Our default value matches the libjpeg-turbo default.
- */
- Downsample fDownsample = Downsample::k420;
- /**
- * Jpegs must be opaque. This instructs the encoder on how to handle input
- * images with alpha.
- *
- * The default is to ignore the alpha channel and treat the image as opaque.
- * Another option is to blend the pixels onto a black background before encoding.
- * In the second case, the encoder supports linear or legacy blending.
- */
- AlphaOption fAlphaOption = AlphaOption::kIgnore;
- };
- /**
- * Encode the |src| pixels to the |dst| stream.
- * |options| may be used to control the encoding behavior.
- *
- * Returns true on success. Returns false on an invalid or unsupported |src|.
- */
- static bool Encode(SkWStream* dst, const SkPixmap& src, const Options& options);
- /**
- * Create a jpeg encoder that will encode the |src| pixels to the |dst| stream.
- * |options| may be used to control the encoding behavior.
- *
- * |dst| is unowned but must remain valid for the lifetime of the object.
- *
- * This returns nullptr on an invalid or unsupported |src|.
- */
- static std::unique_ptr<SkEncoder> Make(SkWStream* dst, const SkPixmap& src,
- const Options& options);
- ~SkJpegEncoder() override;
- protected:
- bool onEncodeRows(int numRows) override;
- private:
- SkJpegEncoder(std::unique_ptr<SkJpegEncoderMgr>, const SkPixmap& src);
- std::unique_ptr<SkJpegEncoderMgr> fEncoderMgr;
- typedef SkEncoder INHERITED;
- };
- #endif
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