Function postProcessImage

YUViewLib/src/decoder/decoderTarga.cpp:561–605

}

void postProcessImage(dec::Targa::Image &image, const Header &header)
{
  // The post-processing is only for RGB images with possible invalid
  // alpha information.
  if (!header.isRgb() || !header.hasAlpha)
    return;

  bool transparentImage = true;
  bool blackImage       = true;

  for (unsigned y = 0; y < header.height; ++y)
  {
    for (unsigned x = 0; x < header.width; ++x)
    {
      auto idx = y * header.width * 4 + x * 4;
      auto r   = image.data.at(idx);
      auto g   = image.data.at(idx + 1);
      auto b   = image.data.at(idx + 2);
      auto a   = image.data.at(idx + 3);
      if (transparentImage && a != 0)
      {
        transparentImage = false;
      }
      if (blackImage && (r != 0 || g != 0 || b != 0))
      {
        blackImage = false;
      }
    }
  }

  // If the image is fully transparent (all pixels with alpha=0) and
  // there are pixels with RGB != 0 (!blackImage), we have to make the
  // image completely opaque (alpha=255).
  if (transparentImage && !blackImage)
  {
    for (unsigned y = 0; y < header.height; ++y)
    {
      for (unsigned x = 0; x < header.width; ++x)
      {
        auto idx               = y * header.width * 4 + x * 4;
        image.data.at(idx + 3) = 255;
      }
    }
  }
}

} // namespace