retrographics

A command-line program that reduces the number of colors in an image and adds attribute clash to it for a retro effect. Requires Python and the Pillow module.

Some of the example images are from Doom and Commander Keen: Secret of the Oracle by id Software. The license of this project doesn't apply to them.

Table of contents:

• Command line arguments
• Examples

Command line arguments

options inputFile outputFile

options (all optional):

• --cellwidth N: width of attribute cells in pixels; N is 8 to 64; default = 8
• --cellheight N: height of attribute cells in pixels; N is 1 to 64; default = 8
• --cellcolors N: maximum number of colors in each attribute cell; N is 0 to 16; 0 = unlimited; default = 2
• --masterpal P: which master palette to use; P is one of:
  • rgb3: 3-bit RGB (1 bit/channel, 8 colors); the default
  • rgb6: 6-bit RGB (2 bits/channel, 64 colors)
  • cga: IBM CGA master palette (RGBI, 1 bit/channel, 16 colors)

inputFile: Required. The image file to read. Width must be a multiple of --cellwidth. Height must be a multiple of --cellheight.

outputFile: Required. The PNG file to write. Same width and height as inputFile.

Examples

Doom title screen – original, 3-bit RGB palette without attribute clash, 3-bit RGB palette with no more than 2 colors in each 8×8-pixel cell: