RLE8-BMP-Decompressor
What is this?
This is a Python program that convert RLE8 compressed BMPs to paletted PNGs.
How to use this program
Use py main.py to convert RLE8 BMPs that are in the Input folder to paletted PNGs that will be put in the Output folder.
Any files that aren't RLE8 BMPs will be skipped, so if your BMP isn't being converted then it isn't RLE8 compressed.
In the Tests folder you'll find BMPs that can be moved to the Input folder to verify whether the program still works on a bunch of edge cases.
Limitations
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If there are offset "Delta" bytes in the RLE8 BMP, this program is currently hardcoded to fill the empty space with palette index 0 values.
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This program won't work for BMPs with palettes that don't have an alpha layer, or that don't have exactly 256 palette colors.
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This program won't decompress RLE4 BMPs, but it should be pretty easy to add this feature. I'd be happy to merge any pull request for it!
I recommend reading the MS Documentation on bitmaps to learn how RLE8 (and RLE4) compression exactly works.