Merge pull request #448 from Tom94/fix-srgb-png

Fix explicitly srgb-tagged PNGs

Author: Tom94

src/imageio/PngImageLoader.cpp

@@ -543,7 +543,7 @@ Task<vector<ImageData>> PngImageLoader::load(istream& iStream, const fs::path&,
             resultData.nativeMetadata.chroma = rec709Chroma(); // default to Rec.709 primaries unless cHRM chunk says otherwise
 
             int srgbIntent = 0;
-            const bool hasChunkSrgb = png_get_sRGB(pngPtr, infoPtr, &srgbIntent) == PNG_INFO_iCCP;
+            const bool hasChunkSrgb = png_get_sRGB(pngPtr, infoPtr, &srgbIntent) == PNG_INFO_sRGB;
 
             double invGamma64 = 1.0 / 2.2;
             const bool hasChunkGama = png_get_gAMA(pngPtr, infoPtr, &invGamma64) == PNG_INFO_gAMA;

src/imageio/PngImageSaver.cpp

@@ -78,6 +78,8 @@ Task<void> PngImageSaver::save(ostream& oStream, const fs::path&, span<const uin
         png, info, imageSize.x(), imageSize.y(), 8, colorType, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT
     );
 
+    png_set_sRGB(png, info, 3 /* absolute colorimetric */);
+
     png_write_info(png, info);
 
     const auto stride = (size_t)imageSize.x() * nChannels;