[GSOC WIP] PNG Metadata Reading Writing Improvements #27503
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sturkmen72
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modules/imgcodecs/src/grfmt_png.cpp
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| @@ -994,11 +997,61 @@ bool PngEncoder::write( const Mat& img, const std::vector<int>& params ) | |||
| if (!m_metadata.empty()) { | |||
| std::vector<uchar>& exif = m_metadata[IMAGE_METADATA_EXIF]; | |||
| if (!exif.empty()) { | |||
| writeChunk(f, "eXIf", exif.data(), (uint32_t)exif.size()); | |||
| png_set_eXIf_1(png_ptr, info_ptr, static_cast<png_uint_32>(exif.size()), exif.data()); | |||
| } | |||
| // [TODO] add xmp and icc. They need special handling, | |||
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Please remove XMP from todo. It's added by the PR.
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| while (ptr < end) { | ||
| // Find null terminator for key | ||
| const uchar* key_end = std::find(ptr, end, 0); |
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The idea of zero separator should be documented somewhere. It's not obvious from OpenCV API how to use the key-value approach.
| @@ -334,6 +334,51 @@ TEST(Imgcodecs_Png, ReadWriteWithExif) | |||
| remove(outputname.c_str()); | |||
| } | |||
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| TEST(Imgcodecs_Png, ReadWriteWithText) | |||
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Are there images with Text and XML in PNG test suite? It'll be great to test not only with self-generated files/
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@sturkmen72, following @asmorkalov request, I suggest you do add or modify one of png files in opencv test data, e.g. as described here: https://stackoverflow.com/questions/19154596/exiftool-to-create-osx-visible-xmp-metadata-in-png-images. I tried it and it works fine. exiftool can be installed from exiftool.org.
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Patch to opencv_extra has the same branch name.