🖨️ Thermal Printer API

Go API for BLE thermal printers. Print text, images, barcodes, receipts, and more.

✨ Features

• Text: auto-wrap, alignment (left/center/right), bold, custom font size
• Emoji: full Unicode emoji support (auto-downloaded from Google Noto)
• Images: Floyd-Steinberg dithering, ASCII art mode, invert colors
• Barcodes: Code128, Code39, EAN-13, QR codes
• Templates: receipts, tables, calendar day views
• GitHub PR: print PR details as a receipt
• Multiple copies: ?times=N on all endpoints
• API key auth: optional ?key= authentication
• CLI + HTTP API: use from terminal or as a service

🖨️ Compatible Printers

Tested with cat-style BLE thermal printers:

• X6h-8BA5 (default)
• Other 384px-wide BLE printers using the same protocol

📦 Install

make build

Or download binaries from Releases.

🚀 Usage

CLI

./bin/print "Hello World"
./bin/print --align center "Centered text"
./bin/print --image photo.jpg

HTTP Server

./bin/server --port 8080
./bin/server --port 8080 --api-key mysecret  # with auth

📡 API Endpoints

Endpoint	Method	Description
/	GET	Health check
/print	POST	Mixed content (text + images)
/print/text	POST	Plain text
/print/image	POST	Image from URL
/print/barcode	POST	Barcode/QR code
/print/receipt	POST	Receipt template
/print/table	POST	Table template
/print/calendar	POST	Calendar day view
/print/pr	POST	GitHub PR receipt
/feed	POST	Feed paper

Query Parameters

All print endpoints support:

• ?times=N - print N copies (1-10)
• ?key=XXX - API key (if auth enabled)

Quick Examples

# Text
curl -X POST "localhost:8080/print/text?text=Hello"

# Image with ASCII art mode
curl -X POST "localhost:8080/print/image?url=https://example.com/img.png&mode=ascii"

# Image inverted (white on black)
curl -X POST "localhost:8080/print/image?url=https://example.com/logo.png&invert=true"

# QR Code
curl -X POST "localhost:8080/print/barcode?data=https://example.com&type=qr"

# Receipt (2 copies)
curl -X POST "localhost:8080/print/receipt?times=2" \
  -H "Content-Type: application/json" \
  -d '{"header":"STORE","items":[{"name":"Item","quantity":1,"price":9.99}],"total":9.99}'

# GitHub PR
curl -X POST "localhost:8080/print/pr?url=https://github.com/owner/repo/pull/1"

See EXAMPLES.md for full documentation and more examples

⚙️ Configuration

Edit internal/config/config.go:

PrinterConfig{
    DeviceName:   "X6h-8BA5",  // BLE device name
    Speed:        15,          // 10-90, lower = better quality
    Energy:       14000,       // higher = darker
    PaperWidth:   384,
    CommandDelay: 20,          // ms between commands
    DPI:          50,
}

🤝 Contributing

1. Fork the repo
2. Create a feature branch
3. Submit a PR

⚠️ Vibe Code Alert

This project was vibe coded with zero prior Go knowledge. Built entirely through AI-assisted development. If you see something cursed, that's why. PRs welcome.

📄 License

MIT