I have already stripped a .xpm file to just a list of hex colour codes with grep -oP 'c #K[0-9A-Fa-f]{6}' $1. So perhaps we can start from there, if easier. Seeking how to populate the colours in config.def.h (for whatever) in sequence from a list of hex colours (or from a .xpm image file [~ that format chosen since can read the colours in plain text, and stored as hex]).