FUNPRINT 🖨️

A tiny local CLI photo booth for 80mm / 58mm ESC/POS thermal receipt printers. Drag a picture into your terminal, see a preview of exactly what will print, and hit P.

Works on macOS, Linux, and Windows, with any thermal printer installed as a system print queue (MUNBYN, Epson TM clones, Rongta, etc.).

How it works

• Renders your image to 1-bit ESC/POS raster (GS v 0): center-crop (or full image), resize to the printable width, and Floyd–Steinberg dithering (toggle to hard threshold).
• Sends raw bytes straight to the OS print queue — no QZ Tray, no server, no driver tricks:
  • macOS / Linux: CUPS lp -o raw
  • Windows: winspool RAW via a bundled PowerShell helper
• Previews in the terminal with truecolor half-block ANSI (works in any terminal).
• Reports honest status: queued → printed, or warns if the printer is offline.

Setup

Requires Node.js 18+ (and git). Then:

git clone https://github.com/KevinGallaccio/funprint.git
cd funprint
npm install
npm link        # puts `funprint` on your PATH (all platforms)

Now run funprint from anywhere.

Prefer not to npm link?

• Any OS: npm start (or node src/cli.mjs) from the project folder.
• macOS/Linux alias: alias funprint='node /full/path/to/funprint/src/cli.mjs' in your shell rc.

Controls

Key	Action
drag + Enter	load an image (png/jpg/webp/gif/tiff/bmp/avif/heic…)
P / Enter	print it
S	paper format: 58mm ↔ 80mm (↔ custom FUNPRINT_WIDTH)
F	square crop ↔ full image (whole picture, no crop)
W	blank write-space below: off → 40mm → 80mm (polaroid style)
←/→ or ↑/↓	reframe — slide the square crop along a non-square image
D	dither ↔ hard threshold
R	rotate 90°
N / Q	new image / quit

The header shows the resolved printer and a live ● dot: green = connected, red = offline, dim = unknown (some platforms can't probe USB cheaply). On print, status goes queued → printed; if the printer is unplugged you're told the job is queued and will print once reconnected.

Testing without paper

funprint --dry-run     # writes the ESC/POS job to a file instead of printing

Configuration

• FUNPRINT_PRINTER — print queue name. Unset = your OS default printer.
• FUNPRINT_WIDTH — custom printable dot-width (default 576 = 80mm). Becomes a selectable paper option. Rounded down to a multiple of 8.

Platform notes

• macOS — fully tested. Connection dot reads the USB device via ioreg.
• Linux — uses the same CUPS path; the connection dot reports offline from CUPS but shows unknown otherwise (no cheap USB probe without root).
• Windows — raw printing goes through scripts/raw-print.ps1 (winspool). Tested less than macOS — issues/PRs welcome.

License

MIT © Kevin Gallaccio