SkJpegEncoderMgr Class Reference

Inheritance diagram for SkJpegEncoderMgr:

Public Member Functions
bool	setParams (const SkImageInfo &srcInfo, const SkJpegEncoder::Options &options)
bool	setParams (const SkYUVAPixmapInfo &srcInfo, const SkJpegEncoder::Options &options)
jpeg_compress_struct *	cinfo ()
skjpeg_error_mgr *	errorMgr ()
transform_scanline_proc	proc () const
	~SkJpegEncoderMgr ()

Static Public Member Functions
static std::unique_ptr< SkJpegEncoderMgr >	Make (SkWStream *stream)

Detailed Description

Definition at line 47 of file SkJpegEncoderImpl.cpp.

Constructor & Destructor Documentation

~SkJpegEncoderMgr()

SkJpegEncoderMgr::~SkJpegEncoderMgr ( )

inline

Definition at line 66 of file SkJpegEncoderImpl.cpp.

{ jpeg_destroy_compress(&fCInfo); }

Member Function Documentation

cinfo()

jpeg_compress_struct * SkJpegEncoderMgr::cinfo ( )

inline

Definition at line 60 of file SkJpegEncoderImpl.cpp.

{ return &fCInfo; }

errorMgr()

skjpeg_error_mgr * SkJpegEncoderMgr::errorMgr ( )

inline

Definition at line 62 of file SkJpegEncoderImpl.cpp.

{ return &fErrMgr; }

Make()

static std::unique_ptr< SkJpegEncoderMgr > SkJpegEncoderMgr::Make ( SkWStream *  stream )

inlinestatic

Definition at line 53 of file SkJpegEncoderImpl.cpp.

                                                                   {
        return std::unique_ptr<SkJpegEncoderMgr>(new SkJpegEncoderMgr(stream));
    }

proc()

transform_scanline_proc SkJpegEncoderMgr::proc ( ) const

inline

Definition at line 64 of file SkJpegEncoderImpl.cpp.

{ return fProc; }

setParams() [1/2]

bool SkJpegEncoderMgr::setParams	(	const SkImageInfo &	srcInfo,
		const SkJpegEncoder::Options &	options
	)

Definition at line 82 of file SkJpegEncoderImpl.cpp.

                                                                      {
    auto chooseProc8888 = [&]() {
        if (kUnpremul_SkAlphaType == srcInfo.alphaType() &&
            options.fAlphaOption == SkJpegEncoder::AlphaOption::kBlendOnBlack) {
            return transform_scanline_to_premul_legacy;
        }
        return (transform_scanline_proc) nullptr;
    };
 
    J_COLOR_SPACE jpegColorType = JCS_EXT_RGBA;
    int numComponents = 0;
    switch (srcInfo.colorType()) {
        case kRGBA_8888_SkColorType:
            fProc = chooseProc8888();
            jpegColorType = JCS_EXT_RGBA;
            numComponents = 4;
            break;
        case kBGRA_8888_SkColorType:
            fProc = chooseProc8888();
            jpegColorType = JCS_EXT_BGRA;
            numComponents = 4;
            break;
        case kRGB_565_SkColorType:
            fProc = transform_scanline_565;
            jpegColorType = JCS_RGB;
            numComponents = 3;
            break;
        case kARGB_4444_SkColorType:
            if (SkJpegEncoder::AlphaOption::kBlendOnBlack == options.fAlphaOption) {
                return false;
            }
 
            fProc = transform_scanline_444;
            jpegColorType = JCS_RGB;
            numComponents = 3;
            break;
        case kGray_8_SkColorType:
        case kAlpha_8_SkColorType:
        case kR8_unorm_SkColorType:
            jpegColorType = JCS_GRAYSCALE;
            numComponents = 1;
            break;
        case kRGBA_F16_SkColorType:
            if (kUnpremul_SkAlphaType == srcInfo.alphaType() &&
                options.fAlphaOption == SkJpegEncoder::AlphaOption::kBlendOnBlack) {
                fProc = transform_scanline_F16_to_premul_8888;
            } else {
                fProc = transform_scanline_F16_to_8888;
            }
            jpegColorType = JCS_EXT_RGBA;
            numComponents = 4;
            break;
        default:
            return false;
    }
 
    fCInfo.image_width = srcInfo.width();
    fCInfo.image_height = srcInfo.height();
    fCInfo.in_color_space = jpegColorType;
    fCInfo.input_components = numComponents;
    jpeg_set_defaults(&fCInfo);
 
    if (numComponents != 1) {
        switch (options.fDownsample) {
            case SkJpegEncoder::Downsample::k420:
                SkASSERT(2 == fCInfo.comp_info[0].h_samp_factor);
                SkASSERT(2 == fCInfo.comp_info[0].v_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[1].h_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[1].v_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[2].h_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[2].v_samp_factor);
                break;
            case SkJpegEncoder::Downsample::k422:
                fCInfo.comp_info[0].h_samp_factor = 2;
                fCInfo.comp_info[0].v_samp_factor = 1;
                SkASSERT(1 == fCInfo.comp_info[1].h_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[1].v_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[2].h_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[2].v_samp_factor);
                break;
            case SkJpegEncoder::Downsample::k444:
                fCInfo.comp_info[0].h_samp_factor = 1;
                fCInfo.comp_info[0].v_samp_factor = 1;
                SkASSERT(1 == fCInfo.comp_info[1].h_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[1].v_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[2].h_samp_factor);
                SkASSERT(1 == fCInfo.comp_info[2].v_samp_factor);
                break;
        }
    }
 
    // Tells libjpeg-turbo to compute optimal Huffman coding tables
    // for the image.  This improves compression at the cost of
    // slower encode performance.
    fCInfo.optimize_coding = TRUE;
    return true;
}

setParams() [2/2]

bool SkJpegEncoderMgr::setParams	(	const SkYUVAPixmapInfo &	srcInfo,
		const SkJpegEncoder::Options &	options
	)

Definition at line 218 of file SkJpegEncoderImpl.cpp.

                                                                      {
    fCInfo.image_width = srcInfo.yuvaInfo().width();
    fCInfo.image_height = srcInfo.yuvaInfo().height();
    fCInfo.in_color_space = JCS_YCbCr;
    fCInfo.input_components = 3;
    jpeg_set_defaults(&fCInfo);
 
    // Support no color space conversion.
    if (srcInfo.yuvColorSpace() != kJPEG_Full_SkYUVColorSpace) {
        return false;
    }
 
    // Support only 8-bit data.
    switch (srcInfo.dataType()) {
        case SkYUVAPixmapInfo::DataType::kUnorm8:
            break;
        default:
            return false;
    }
 
    // Support only Y,U,V and Y,UV configurations (they are the only ones supported by
    // yuva_copy_row).
    switch (srcInfo.yuvaInfo().planeConfig()) {
        case SkYUVAInfo::PlaneConfig::kY_U_V:
        case SkYUVAInfo::PlaneConfig::kY_UV:
            break;
        default:
            return false;
    }
 
    // Specify to the encoder to use the same subsampling as the input image. The U and V planes
    // always have a sampling factor of 1.
    auto [ssHoriz, ssVert] = SkYUVAInfo::SubsamplingFactors(srcInfo.yuvaInfo().subsampling());
    fCInfo.comp_info[0].h_samp_factor = ssHoriz;
    fCInfo.comp_info[0].v_samp_factor = ssVert;
 
    fCInfo.optimize_coding = TRUE;
    return true;
}

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The documentation for this class was generated from the following file:

• third_party/skia/src/encode/SkJpegEncoderImpl.cpp