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  1. Qt
  2. QTBUG-134738

QImageIOHandler - PNG Exif transformations not supported

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Details

    • Bug
    • Resolution: Unresolved
    • P3: Somewhat important
    • None
    • 6.8.2
    • Image formats
    • None
    • All

    Description

      PNG Spec 1.5 supports Exif data. 
      https://ftp-osl.osuosl.org/pub/libpng/documents/pngext-1.5.0.html#C.eXIf

      macOS preview and GIMP support this metadata.

      It would be nice if QImageIOHandler would support PNG Exif.

      //Load the image
      QImageReader imageReader(fileName);
      
      //This return false for PNG but true for jpeg
      qDebug() << "Transfrom supported:"  << imageReader.supportsOption(QImageIOHandler::ImageTransformation);
      
      imageReader.setAutoTransform(true); //This doesn't automatically rotate png images with Exif 

      You can create a rotated PNG image with this:

       

      exiftool -Orientation="Rotate 90 CW" my_test.png

       

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            vgt Eirik Aavitsland
            vpicaver Philip Schuchardt
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            Dates

              Created:
              Updated:

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