dither.py is a simple library I wrote to implement various dithering algorithms as a learning exercise. The following algorithms are currently implemented:
- Threshold - basic per-pixel quantization
- Ordered Dithering - quantization based on matrix templates
- Bayer 4x4
- Bayer 8x8
- Cluster 4x4
- Cluster 8x8
- Error Diffusion - adaptive forward quantization
- Floyd-Steinberg
- JaJuNi
- Fan
- Stucki
- Burkes
- Sierra
- Sierra-2
- Sierra Lite
- Atkinson
- Randomized - randomized quantization
- Per-pixel random
- Block random
Several palettes are also available:
- Grayscale
- 1-bit (black and white) through 7-bit (128 level)
- Gamma-corrected Commodore 64 (without the color limitation of either HiRes or MultiColor modes)
- CGA (using the RGBI monitor brown color)
- Mode 4, low intensity
- Palette 1
- Palette 2
- Mode 4, high intensity
- Palette 1
- Palette 2
- Mode 5, low intensity
- Mode 5, high intensity
- Mode 4, low intensity
- EGA
- Websafe (most common 6-bit variant)
Use dither.py to dither an input image with a given palette:
python dither.py -m floyd_steinberg -p ega images/parrot.jpg
or use the -a flag to create a collage with all combinations of methods and palettes:
