mimaki/webui

HPGL Plotter Web UI

Flask web interface for uploading HPGL files, previewing and transforming them (flip, rotate, scale, center), and sending to the plotter. Intended to run on a Raspberry Pi connected to the plotter via USB.

Setup (Raspberry Pi)

1. From the project root (mimaki/), install dependencies:

   If you get externally-managed-environment (Python 3.11+ / PEP 668) and don’t want a venv, use:

   pip install --break-system-packages -r webui/requirements.txt
   

   Otherwise:

   pip install -r webui/requirements.txt
   

   Optional – use a venv to avoid touching system Python:

   python3 -m venv venv
   source venv/bin/activate
   pip install -r webui/requirements.txt
   

2. Config: Copy config.example.ini to config.ini and adjust (port, baudrate, web UI host/port, etc.). config.ini is gitignored.

   cp config.example.ini config.ini
   

   Edit config.ini to set the plotter port (e.g. /dev/ttyUSB0) and optionally web UI port/host.

Run

From the project root (mimaki/):

python webui/app.py

Then open http://<raspi-ip>:5000 in a browser (e.g. http://192.168.1.10:5000).

• Host: 0.0.0.0 so other devices on the network can connect.
• Port: 5000 (override with PORT=8080 python webui/app.py if needed).

For production, run behind gunicorn and optionally a reverse proxy:

pip install --break-system-packages gunicorn   # or omit if not using system Python
gunicorn -w 1 -b 0.0.0.0:5000 "webui.app:app"

Usage

1. Upload – Choose an .hpgl or .plt file. It is validated and stored in webui/uploads/.
2. Preview – The drawing is converted to SVG and shown in the browser.
3. Transform – Flip, Rotate 90° / 180°, Scale + / −, Center. Each action updates the stored program and the preview.
4. Print – Sends the current (transformed) program to the plotter: scale to fit, center, then write HPGL to serial.

API

• POST /api/upload – Upload HPGL file (form field file).
• GET /api/svg – Get current program as SVG (query: width, height).
• POST /api/transform – Body: {"action": "flip"|"rotate"|"scale"|"centralize", "angle": 90, "factor": 1.25}.
• POST /api/print – Send current program to plotter.
• GET /api/status – has_file, filename, plotter_ready.

Session is used to keep the current file path; no database.