Method Encode

src/core/codecs/webp/WebpCodec.cpp:148–213

}

std::shared_ptr<Data> WebpCodec::Encode(const Pixmap& pixmap, int quality) {
  const uint8_t* srcPixels = static_cast<uint8_t*>(const_cast<void*>(pixmap.pixels()));
  auto srcInfo = pixmap.info();
  Buffer tempBuffer = {};
  if (pixmap.alphaType() == AlphaType::Premultiplied ||
      (pixmap.colorType() != ColorType::RGBA_8888 && pixmap.colorType() != ColorType::BGRA_8888)) {
    auto alphaType =
        pixmap.alphaType() == AlphaType::Opaque ? AlphaType::Opaque : AlphaType::Unpremultiplied;
    srcInfo = ImageInfo::Make(pixmap.width(), pixmap.height(), ColorType::RGBA_8888, alphaType);
    tempBuffer.alloc(srcInfo.byteSize());
    srcPixels = tempBuffer.bytes();
    if (!pixmap.readPixels(srcInfo, tempBuffer.data())) {
      return nullptr;
    }
  }
  WebPConfig webp_config;
  bool isLossless = false;
  if (quality == 100) {
    quality = 75;
    isLossless = true;
  }
  if (!WebPConfigPreset(&webp_config, WEBP_PRESET_DEFAULT, static_cast<float>(quality))) {
    return nullptr;
  }
  WebPPicture pic;
  WebPPictureInit(&pic);
  pic.width = srcInfo.width();
  pic.height = srcInfo.height();
  pic.writer = webp_reader_write_data;
  if (isLossless) {
    webp_config.lossless = 1;
    webp_config.method = 1;
    pic.use_argb = 1;
  } else {
    webp_config.lossless = 0;
    webp_config.method = 3;
    pic.use_argb = 0;
  }

  WebpWriter webpWriter;
  pic.custom_ptr = &webpWriter;
  auto importProc = WebPPictureImportRGBX;
  if (ColorType::RGBA_8888 == srcInfo.colorType()) {
    if (AlphaType::Opaque == srcInfo.alphaType()) {
      importProc = WebPPictureImportRGBX;
    } else {
      importProc = WebPPictureImportRGBA;
    }
  } else if (ColorType::BGRA_8888 == srcInfo.colorType()) {
    if (AlphaType::Opaque == srcInfo.alphaType()) {
      importProc = WebPPictureImportBGRX;
    } else {
      importProc = WebPPictureImportBGRA;
    }
  }
  auto rowBytes = static_cast<int>(srcInfo.rowBytes());
  if (!importProc(&pic, srcPixels, rowBytes) || !WebPEncode(&webp_config, &pic)) {
    WebPPictureFree(&pic);