Mathias Panzenböck
Just for fun I'm writing an #ILBM impl. for #Qt (QImageIOPlugin). I'm having trouble with the PCHG chunk. Any #Amiga dev/hobbyist here who might have a clue what's wrong? My code:
parsing: https://github.com/panzi/qilbm/blob/4222c4bdf5b81ab67fc68b3647ca231d1685d53a/src/ILBM.cpp#L865-L1097
rendering: https://github.com/panzi/qilbm/blob/4222c4bdf5b81ab67fc68b3647ca231d1685d53a/src/ILBM.cpp#L1297-L1346
sample file: https://sembiance.com/fileFormatSamples/image/iffILBM/pchgcmp.iff
Other impl. I've looked at and can't finde the difference to:
https://aminet.net/package/dev/misc/PCHGLib14 (includes 2 images that *do* work)
https://fossies.org/linux/netpbm/converter/ppm/ilbmtoppm.c line 1596 and onward, which is used by #ImageMagick. #RetroComputing
qilbm/src/ILBM.cpp at 4222c4bdf5b81ab67fc68b3647ca231d1685d53a · panzi/qilbm

QImageIO Plugin to read and display ILBM files. Contribute to panzi/qilbm development by creating an account on GitHub.

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Apr 13, 2025 at 5:28pmWeb
Show threadMathias PanzenböckApr 13, 2025
I don't know if my bug is in the Huffman decompression of the color palettes or the rendering. I don't think it is in the parsing/decompression of the BODY chunk, since that works for all other ILBM files that I've found.
Show threadMathias PanzenböckApr 13, 2025
Just to have posted it somewhere, sources for ILBM files that I've found are:
https://sembiance.com/fileFormatSamples/image/iffILBM
https://www.randelshofer.ch/animations/index.html (especially: https://www.randelshofer.ch/animations/anims_ibm/mark_j_ferrari/thu_mark_j_ferrari.html)
https://cd.textfiles.com/fishandmore/More/Graphics/Pictures/Sham
https://samples.mplayerhq.hu/image-samples/atarist/iff/
https://taws.ch/
Index of /fileFormatSamples/image/iffILBM/