Made a tool that takes a list of tab-separated date-integer pairs on stdin and outputs a Github-like heatmap as a PNG on stdout.
Still needs some features, but it now produces the output I'd originally wanted.
https://codeberg.org/lykso/date-heatmap
3 months ago · 👍 alextheuxguy, totroptof
[1] https://codeberg.org/lykso/date-heatmap