128 lines
3.7 KiB
C++
128 lines
3.7 KiB
C++
/*
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* Copyright 2017 Google LLC
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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 SkJpegEncoder_DEFINED
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#define SkJpegEncoder_DEFINED
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#include "include/codec/SkEncodedOrigin.h"
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#include "include/core/SkRefCnt.h"
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#include "include/private/base/SkAPI.h"
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#include <memory>
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#include <optional>
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class SkColorSpace;
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class SkData;
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class SkEncoder;
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class SkPixmap;
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class SkWStream;
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class SkImage;
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class GrDirectContext;
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class SkYUVAPixmaps;
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struct skcms_ICCProfile;
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namespace SkJpegEncoder {
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enum class AlphaOption {
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kIgnore,
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kBlendOnBlack,
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};
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enum class Downsample {
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/**
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* Reduction by a factor of two in both the horizontal and vertical directions.
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*/
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k420,
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/**
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* Reduction by a factor of two in the horizontal direction.
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*/
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k422,
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/**
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* No downsampling.
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*/
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k444,
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};
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struct Options {
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/**
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* |fQuality| must be in [0, 100] where 0 corresponds to the lowest quality.
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*/
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int fQuality = 100;
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/**
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* Choose the downsampling factor for the U and V components. This is only
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* meaningful if the |src| is not kGray, since kGray will not be encoded as YUV.
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* This is ignored in favor of |src|'s subsampling when |src| is an SkYUVAPixmaps.
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*
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* Our default value matches the libjpeg-turbo default.
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*/
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Downsample fDownsample = Downsample::k420;
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/**
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* Jpegs must be opaque. This instructs the encoder on how to handle input
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* images with alpha.
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*
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* The default is to ignore the alpha channel and treat the image as opaque.
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* Another option is to blend the pixels onto a black background before encoding.
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* In the second case, the encoder supports linear or legacy blending.
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*/
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AlphaOption fAlphaOption = AlphaOption::kIgnore;
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/**
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* Optional XMP metadata.
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*/
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const SkData* xmpMetadata = nullptr;
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std::optional<SkEncodedOrigin> fOrigin;
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};
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/**
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* Encode the |src| pixels to the |dst| stream.
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* |options| may be used to control the encoding behavior.
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*
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* Returns true on success. Returns false on an invalid or unsupported |src|.
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*/
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SK_API bool Encode(SkWStream* dst, const SkPixmap& src, const Options& options);
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SK_API bool Encode(SkWStream* dst,
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const SkYUVAPixmaps& src,
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const SkColorSpace* srcColorSpace,
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const Options& options);
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/**
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* Returns the encoded data for the pixmap, or nullptr on failure.
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*/
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SK_API sk_sp<SkData> Encode(const SkPixmap& src, const Options& options);
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/**
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* Encode the provided image and return the resulting bytes. If the image was created as
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* a texture-backed image on a GPU context, that |ctx| must be provided so the pixels
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* can be read before being encoded. For raster-backed images, |ctx| can be nullptr.
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* |options| may be used to control the encoding behavior.
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*
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* Returns nullptr if the pixels could not be read or encoding otherwise fails.
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*/
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SK_API sk_sp<SkData> Encode(GrDirectContext* ctx, const SkImage* img, const Options& options);
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/**
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* Create a jpeg encoder that will encode the |src| pixels to the |dst| stream.
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* |options| may be used to control the encoding behavior.
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*
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* |dst| is unowned but must remain valid for the lifetime of the object.
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*
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* This returns nullptr on an invalid or unsupported |src|.
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*/
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SK_API std::unique_ptr<SkEncoder> Make(SkWStream* dst, const SkPixmap& src, const Options& options);
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SK_API std::unique_ptr<SkEncoder> Make(SkWStream* dst,
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const SkYUVAPixmaps& src,
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const SkColorSpace* srcColorSpace,
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const Options& options);
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} // namespace SkJpegEncoder
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#endif
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