retsyo / libbpg-py

a pure python binding for BPG (Better Portable Graphics)

                Copyright (c) 2014 Lee June

#1. What

This is a pure python binding via CTYPES for BPG (Better Portable Graphics, http://bellard.org/bpg/, Fabrice Bellard) Image format.

#2. Where

https://github.com/retsyo/libbpg-py

#3. How

1. You should compile libbpg into dynamic library. To do so, a minor modified Makefile ( the original one is in libbpg-0.9.4.tar.gz from http://bellard.org/bpg/) is supplied here.

2. libbpg.py covers all in libbpg.h, which is the base of the python binding. bpgdec.py can only decode a BPG file into PPM, and there is no PNG output currently; however bpgdec.c can write both PPM and PNG. There is no bpgenc.py till now.

#4. Bugs or future plans

1. I only use Windows, and this binding uses 32-bit bpg.dll, which is compiled with MINGW. I don't know whether all python source files runs ok on Linux with your fresh dynamic library.

2. Maybe there needs more 'cast' in some functions in libbpg.py.

3. Maybe later, a PIL/Pillow plugin for I/O BPG

#5. Bug in BPG?

D:\tmp\libbpg-0.9.4\py>..\bpgenc.exe -o test.bpg -lossless test.png D:\tmp\libbpg-0.9.4\py>..\bpgdec.exe -o test_c_bpgdec.ppm test.bpg D:\tmp\libbpg-0.9.4\py>e:\msys\bin\diff.exe --binary test_c_bpgdec.ppm test_py_bpgdec.ppm However, the original test.bpg and the decoded ppm has different looks. The ppm file has some red color in it. Is this a BPG bug, or I misunderstood '-lossless' parameter?

#6. Licensing

BSD license