SkJpegGainmapEncoder.cpp File Reference

#include "include/private/SkJpegGainmapEncoder.h"
#include "include/core/SkBitmap.h"
#include "include/core/SkPixmap.h"
#include "include/core/SkStream.h"
#include "include/encode/SkEncoder.h"
#include "include/encode/SkJpegEncoder.h"
#include "include/private/SkGainmapInfo.h"
#include "src/codec/SkCodecPriv.h"
#include "src/codec/SkJpegConstants.h"
#include "src/codec/SkJpegMultiPicture.h"
#include "src/codec/SkJpegPriv.h"
#include "src/codec/SkJpegSegmentScan.h"
#include <vector>

Go to the source code of this file.

Functions
static bool	is_single_channel (SkColor4f c)
sk_sp< SkData >	get_hdrgm_xmp_data (const SkGainmapInfo &gainmapInfo)
static sk_sp< SkData >	get_gcontainer_xmp_data (size_t gainmapItemLength)
std::vector< sk_sp< SkData > >	get_hdrgm_image_segments (sk_sp< SkData > image, size_t segmentMaxDataSize)
static sk_sp< SkData >	encode_to_data (const SkPixmap &pm, const SkJpegEncoder::Options &options, SkData *xmpMetadata)
static sk_sp< SkData >	get_mpf_segment (const SkJpegMultiPictureParameters &mpParams)

Function Documentation

encode_to_data()

static sk_sp< SkData > encode_to_data ( const SkPixmap &  pm, const SkJpegEncoder::Options &  options, SkData *  xmpMetadata  )

static

Definition at line 222 of file SkJpegGainmapEncoder.cpp.

                                                         {
    SkJpegEncoder::Options optionsWithXmp = options;
    optionsWithXmp.xmpMetadata = xmpMetadata;
    SkDynamicMemoryWStream encodeStream;
    auto encoder = SkJpegEncoder::Make(&encodeStream, pm, optionsWithXmp);
    if (!encoder || !encoder->encodeRows(pm.height())) {
        return nullptr;
    }
    return encodeStream.detachAsData();
}

get_gcontainer_xmp_data()

static sk_sp< SkData > get_gcontainer_xmp_data ( size_t  gainmapItemLength )

static

Definition at line 125 of file SkJpegGainmapEncoder.cpp.

                                                                       {
    SkDynamicMemoryWStream s;
    s.writeText(
            "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\" x:xmptk=\"Adobe XMP Core 5.1.2\">\n"
            "  <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">\n"
            "    <rdf:Description\n"
            "        xmlns:Container=\"http://ns.google.com/photos/1.0/container/\"\n"
            "        xmlns:Item=\"http://ns.google.com/photos/1.0/container/item/\"\n"
            "        xmlns:hdrgm=\"http://ns.adobe.com/hdr-gain-map/1.0/\"\n"
            "        hdrgm:Version=\"1.0\">\n"
            "      <Container:Directory>\n"
            "        <rdf:Seq>\n"
            "          <rdf:li rdf:parseType=\"Resource\">\n"
            "            <Container:Item\n"
            "             Item:Semantic=\"Primary\"\n"
            "             Item:Mime=\"image/jpeg\"/>\n"
            "          </rdf:li>\n"
            "          <rdf:li rdf:parseType=\"Resource\">\n"
            "            <Container:Item\n"
            "             Item:Semantic=\"GainMap\"\n"
            "             Item:Mime=\"image/jpeg\"\n"
            "             Item:Length=\"");
    s.writeDecAsText(gainmapItemLength);
    s.writeText(
            "\"/>\n"
            "          </rdf:li>\n"
            "        </rdf:Seq>\n"
            "      </Container:Directory>\n"
            "    </rdf:Description>\n"
            "  </rdf:RDF>\n"
            "</x:xmpmeta>\n");
    return s.detachAsData();
}

get_hdrgm_image_segments()

std::vector< sk_sp< SkData > > get_hdrgm_image_segments	(	sk_sp< SkData >	image,
		size_t	segmentMaxDataSize
	)

Definition at line 160 of file SkJpegGainmapEncoder.cpp.

                                                                               {
    // Compute the total size of the header to a gainmap image segment (not including the 2 bytes
    // for the segment size, which the encoder is responsible for writing).
    constexpr size_t kGainmapHeaderSize = sizeof(kGainmapSig) + 2 * kGainmapMarkerIndexSize;
 
    // Compute the payload size for each segment.
    const size_t kGainmapPayloadSize = segmentMaxDataSize - kGainmapHeaderSize;
 
    // Compute the number of segments we'll need.
    const size_t segmentCount = (image->size() + kGainmapPayloadSize - 1) / kGainmapPayloadSize;
    std::vector<sk_sp<SkData>> result;
    result.reserve(segmentCount);
 
    // Move |imageData| through |image| until it hits |imageDataEnd|.
    const uint8_t* imageData = image->bytes();
    const uint8_t* imageDataEnd = image->bytes() + image->size();
    while (imageData < imageDataEnd) {
        SkDynamicMemoryWStream segmentStream;
 
        // Write the signature.
        segmentStream.write(kGainmapSig, sizeof(kGainmapSig));
 
        // Write the segment index as big-endian.
        size_t segmentIndex = result.size() + 1;
        uint8_t segmentIndexBytes[2] = {
                static_cast<uint8_t>(segmentIndex / 256u),
                static_cast<uint8_t>(segmentIndex % 256u),
        };
        segmentStream.write(segmentIndexBytes, sizeof(segmentIndexBytes));
 
        // Write the segment count as big-endian.
        uint8_t segmentCountBytes[2] = {
                static_cast<uint8_t>(segmentCount / 256u),
                static_cast<uint8_t>(segmentCount % 256u),
        };
        segmentStream.write(segmentCountBytes, sizeof(segmentCountBytes));
 
        // Verify that our header size math is correct.
        SkASSERT(segmentStream.bytesWritten() == kGainmapHeaderSize);
 
        // Write the rest of the segment.
        size_t bytesToWrite =
                std::min(imageDataEnd - imageData, static_cast<intptr_t>(kGainmapPayloadSize));
        segmentStream.write(imageData, bytesToWrite);
        imageData += bytesToWrite;
 
        // Verify that our data size math is correct.
        if (segmentIndex == segmentCount) {
            SkASSERT(segmentStream.bytesWritten() <= segmentMaxDataSize);
        } else {
            SkASSERT(segmentStream.bytesWritten() == segmentMaxDataSize);
        }
        result.push_back(segmentStream.detachAsData());
    }
 
    // Verify that our segment count math was correct.
    SkASSERT(imageData == imageDataEnd);
    SkASSERT(result.size() == segmentCount);
    return result;
}

get_hdrgm_xmp_data()

sk_sp< SkData > get_hdrgm_xmp_data

(

const SkGainmapInfo &

gainmapInfo

)

Definition at line 30 of file SkJpegGainmapEncoder.cpp.

                                                                   {
    SkDynamicMemoryWStream s;
    const float kLog2 = std::log(2.f);
    const SkColor4f gainMapMin = {std::log(gainmapInfo.fGainmapRatioMin.fR) / kLog2,
                                  std::log(gainmapInfo.fGainmapRatioMin.fG) / kLog2,
                                  std::log(gainmapInfo.fGainmapRatioMin.fB) / kLog2,
                                  1.f};
    const SkColor4f gainMapMax = {std::log(gainmapInfo.fGainmapRatioMax.fR) / kLog2,
                                  std::log(gainmapInfo.fGainmapRatioMax.fG) / kLog2,
                                  std::log(gainmapInfo.fGainmapRatioMax.fB) / kLog2,
                                  1.f};
    const SkColor4f gamma = {1.f / gainmapInfo.fGainmapGamma.fR,
                             1.f / gainmapInfo.fGainmapGamma.fG,
                             1.f / gainmapInfo.fGainmapGamma.fB,
                             1.f};
    // Write a scalar attribute.
    auto write_scalar_attr = [&s](const char* attrib, SkScalar value) {
        s.writeText("        ");
        s.writeText(attrib);
        s.writeText("=\"");
        s.writeScalarAsText(value);
        s.writeText("\"\n");
    };
 
    // Write a scalar attribute only if all channels of |value| are equal (otherwise, write
    // nothing).
    auto maybe_write_scalar_attr = [&write_scalar_attr](const char* attrib, SkColor4f value) {
        if (!is_single_channel(value)) {
            return;
        }
        write_scalar_attr(attrib, value.fR);
    };
 
    // Write a float3 attribute as a list ony if not all channels of |value| are equal (otherwise,
    // write nothing).
    auto maybe_write_float3_attr = [&s](const char* attrib, SkColor4f value) {
        if (is_single_channel(value)) {
            return;
        }
        s.writeText("      <");
        s.writeText(attrib);
        s.writeText(">\n");
        s.writeText("        <rdf:Seq>\n");
        s.writeText("          <rdf:li>");
        s.writeScalarAsText(value.fR);
        s.writeText("</rdf:li>\n");
        s.writeText("          <rdf:li>");
        s.writeScalarAsText(value.fG);
        s.writeText("</rdf:li>\n");
        s.writeText("          <rdf:li>");
        s.writeScalarAsText(value.fB);
        s.writeText("</rdf:li>\n");
        s.writeText("        </rdf:Seq>\n");
        s.writeText("      </");
        s.writeText(attrib);
        s.writeText(">\n");
    };
 
    s.writeText(
            "<x:xmpmeta xmlns:x=\"adobe:ns:meta/\" x:xmptk=\"XMP Core 5.5.0\">\n"
            "  <rdf:RDF xmlns:rdf=\"http://www.w3.org/1999/02/22-rdf-syntax-ns#\">\n"
            "    <rdf:Description rdf:about=\"\"\n"
            "        xmlns:hdrgm=\"http://ns.adobe.com/hdr-gain-map/1.0/\"\n"
            "        hdrgm:Version=\"1.0\"\n");
    maybe_write_scalar_attr("hdrgm:GainMapMin", gainMapMin);
    maybe_write_scalar_attr("hdrgm:GainMapMax", gainMapMax);
    maybe_write_scalar_attr("hdrgm:Gamma", gamma);
    maybe_write_scalar_attr("hdrgm:OffsetSDR", gainmapInfo.fEpsilonSdr);
    maybe_write_scalar_attr("hdrgm:OffsetHDR", gainmapInfo.fEpsilonHdr);
    write_scalar_attr("hdrgm:HDRCapacityMin", std::log(gainmapInfo.fDisplayRatioSdr) / kLog2);
    write_scalar_attr("hdrgm:HDRCapacityMax", std::log(gainmapInfo.fDisplayRatioHdr) / kLog2);
    switch (gainmapInfo.fBaseImageType) {
        case SkGainmapInfo::BaseImageType::kSDR:
            s.writeText("        hdrgm:BaseRenditionIsHDR=\"False\">\n");
            break;
        case SkGainmapInfo::BaseImageType::kHDR:
            s.writeText("        hdrgm:BaseRenditionIsHDR=\"True\">\n");
            break;
    }
 
    // Write any of the vector parameters that cannot be represented as scalars (and thus cannot
    // be written inline as above).
    maybe_write_float3_attr("hdrgm:GainMapMin", gainMapMin);
    maybe_write_float3_attr("hdrgm:GainMapMax", gainMapMax);
    maybe_write_float3_attr("hdrgm:Gamma", gamma);
    maybe_write_float3_attr("hdrgm:OffsetSDR", gainmapInfo.fEpsilonSdr);
    maybe_write_float3_attr("hdrgm:OffsetHDR", gainmapInfo.fEpsilonHdr);
    s.writeText(
            "    </rdf:Description>\n"
            "  </rdf:RDF>\n"
            "</x:xmpmeta>");
    return s.detachAsData();
}

get_mpf_segment()

static sk_sp< SkData > get_mpf_segment ( const SkJpegMultiPictureParameters &  mpParams )

static

Definition at line 235 of file SkJpegGainmapEncoder.cpp.

                                                                                   {
    SkDynamicMemoryWStream s;
    auto segmentParameters = mpParams.serialize();
    const size_t mpParameterLength = kJpegSegmentParameterLengthSize + segmentParameters->size();
    s.write8(0xFF);
    s.write8(kMpfMarker);
    s.write8(mpParameterLength / 256);
    s.write8(mpParameterLength % 256);
    s.write(segmentParameters->data(), segmentParameters->size());
    return s.detachAsData();
}

is_single_channel()

static bool is_single_channel ( SkColor4f  c )

static

Definition at line 24 of file SkJpegGainmapEncoder.cpp.

{ return c.fR == c.fG && c.fG == c.fB; };