mint

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Generate a random favicon (PNG). One bash script, seedable, no AI.

You’re starting a project. You need a favicon. You don’t want to design one and you don’t want to pull in a logo generator. mint rolls a tiny SVG composition from a curated palette + shape pool, hands it to rsvg-convert, and drops a square PNG on disk.

Install

curl -fsSL https://raw.githubusercontent.com/pbshgthm/stash/main/install | bash -s mint

Drops mint into ~/.local/bin/. The first run installs librsvg via Homebrew if it isn’t already (mint shells out to rsvg-convert for SVG → PNG). Make sure ~/.local/bin is on your PATH.

Usage

mint [destination] [options]

Bare mint prints help; pass at least one flag or a destination to actually generate. With no destination, writes ./favicon.png. Each run is different by default — pass --seed for reproducibility.

Destination

Same shape as pluck’s positional destination:

Argument	Result
omitted	`./favicon.png`
ends with `/` or points at an existing directory	`<dir>/favicon.png`
anything else	`<arg>` (`.png` appended if missing)

mint --seed hi                # → ./favicon.png           (omitted destination)
mint ~/Desktop/               # → ~/Desktop/favicon.png   (trailing slash = parent)
mint ~/Desktop                # → ~/Desktop/favicon.png   IF ~/Desktop exists
                              # → ~/Desktop.png otherwise
mint ~/icons/logo             # → ~/icons/logo.png
mint ~/icons/logo.png         # → ~/icons/logo.png        (already has extension)

If the target file already exists, mint refuses to clobber it. Pass -f / --force to overwrite.

Options

Flag	What it does
`--seed <str>`	Reproducible seed. Same seed + same flags = same output. Default is random.
`--size <px>`	PNG render size, square (default `512`).
`--padding <pct>`	Inset the artwork, as a percentage of the canvas (default `0`). Useful when something downstream adds its own padding.
`--transparent`	Force a transparent background on every roll. By default ~70% of rolls are transparent already; pass this when you specifically want one. mint switches to a 1–2 ink palette tuned for both dark and light surfaces.
`-f, --force`	Overwrite the destination if it already exists.
`--preview`	Also write `preview.png` (6×6 grid of fresh rolls) and `preview-small.png` (10 true-16px renders, scaled up) next to the main output. Handy for checking how the icon survives at favicon size.
`-h, --help`	Help.

How it works

Each run is a seeded pipeline:

Seed → RNG. --seed (or date +%s%N$$ if unset) becomes an integer via cksum and is loaded into bash’s $RANDOM. Subsequent rolls — colours, shapes, layout — all derive from that one stream, so the same seed gives the same icon byte-for-byte.
Colour mode. Each roll picks one of four modes: transparent (~70%, 1–2 inks tuned to survive on both light and dark surfaces), mono (single ink, 4.5+ contrast against a tuned bg), duo (two inks on a tuned bg), or palette (one of 30 hand-built 3-colour combos). --transparent forces the transparent mode every roll.
Shape and composition. mint picks one of 28 weighted styles. Single big shapes are weighted 4× — they read better at 16px than busy compositions. The pool covers single primitives (circle, ring, rounded square, diamond, hex, octagon, 4/5/8-pt stars, droplet, heart, lightning, chevron, capsule, plus), repetition layouts (pairs, triads, 2×2 and 3×3 grids, diagonals), and compositional styles (diagonal split, two arcs, quadrants, ring-with-dot, masked cuts, sunburst, pie slice, bars, arch, half disc).
Frame. Bg-coloured rolls get an iOS-style rounded-square frame: bg + content are clipped to a rx=22% rounded rect so inner shapes that hit the canvas edges (quadrants, bars, diagonal splits) follow the corner curve. Transparent rolls stay sharp — clipping a triangle or quadrant composition to a rounded rect would clip its inherent silhouette.
SVG → PNG. mint emits a 100×100 viewBox SVG to a tmp file, then rsvg-convert -w $SIZE -h $SIZE rasterises it to your destination.

Everything that needs floating-point math goes through awk — bash 3.2 only has integer arithmetic. The RNG is a Numerical Recipes LCG with state in a temp file, because bash 3.2 reseeds $RANDOM per subshell and the script’s helpers all run via $(...). WCAG contrast ratios use the standard relative-luminance formula so the colour picker can reject low-contrast combinations.

What’s deliberately not in the pool

Religious-coded primitives are omitted: no crescents, no big crosses, no 6-point stars (would read as Star of David). The 8-point star is in. If you want one of these specifically, you’re past what a random generator should be doing for you.

Examples

# Reproducible — pin the seed in your project README
mint --seed acmecorp-2026

# 1024px for retina, 10% inset
mint --size 1024 --padding 10

# Transparent background — for placing on top of a coloured surface
mint --transparent ~/Desktop/

# Browse 36 fresh rolls + see how they look at true 16px
mint --preview /tmp/scratch
ls /tmp/scratch
# favicon.png  preview.png  preview-small.png

A workflow that often beats one-shot rolls: mint --preview into a scratch dir, scroll through the grid, copy the seed of the one you like (printed alongside the ok line), then mint --seed <that> into your real destination.

Limitations

PNG output only. SVG-on-disk used to be supported and was removed — if you need vector, look at the SVG mint generates internally and lift the relevant style function.
macOS-first. Works on any Unix with awk + rsvg-convert, but the auto-install path assumes Homebrew.
One square PNG per run. mint doesn’t generate .ico bundles, multi-resolution sets, or apple-touch sizes — pipe the PNG through sips/magick if you need that.
No alpha tuning. The transparent mode is a simple flag, not a full alpha pass — fine for flat icons, not for soft-edged artwork.