Self-contained, plain Go implementation of calendar heatmap inspired by Github contribution activity.

Colorscales

Without month separator

Without labels

Without labels, without separator

Example:

countByDayOfYear := map[int]int{
    1: 10,
    22: 15,
    150: 22,
    366: 55,
}

img := charts.NewHeatmap(charts.HeatmapConfig{
    Year:               2020,
    CountByDay:         countByDay,
    ColorScale:         colorscales.PuBu9,
    DrawMonthSeparator: true,
    DrawLabels:         true,
    ...
})

You can run it in your Go code or as standalone script. Check full example at examples/main.go and input.txt for more details. Generate examples above with ./generate_examples.sh.