Brow

brow -- Browser Rendering CLI

Goal

Produce PNG images from web pages or Excalidraw files using headless Chrome.

Workflow

1. Ensure browser is installed

Before any rendering command, install Chrome for Testing (safe to re-run; no-ops if already cached):

brow browser install

Skip this step if the user provides a --browser <path> to an existing Chrome/Chromium binary.

2. Screenshot a web page (default mode)

brow \
  -u <URL> \
  -o <output.png>

Required flags:

• -u, --url -- URL to capture
• -o, --output -- output PNG file path

Optional flags:

• --width -- viewport width in pixels (default: 1280)
• --height -- viewport height in pixels (default: 800)
• -s, --scale -- device scale factor; use 2 for retina/2x (default: 1)
• --full-page -- capture full scrollable page (default: true; use --no-full-page for viewport only)

Output resolution is width * scale by height * scale pixels.

3. Render an Excalidraw file

brow \
  -m excalidraw \
  -i <drawing.excalidraw> \
  -o <output.png>

Required flags:

• -i, --input -- path to .excalidraw file
• -o, --output -- output PNG file path

Optional flags:

• -t, --theme -- light or dark (default: light)
• -s, --scale -- scale multiplier (default: 1; use 2 or 3 for higher resolution)
• --width -- explicit output width in pixels (overrides natural dimensions)
• --height -- explicit output height in pixels (overrides natural dimensions)

By default output matches the drawing's natural size times scale. Use --width/--height together for exact pixel dimensions.

4. Verify output

Confirm the output file was created:

ls -la <output.png>

Output Format

All output is PNG. The file is written to the path given by -o, --output. On success the tool prints the output path to stdout. On failure it prints an error to stderr and exits with code 1.

Constraints

• Browser required. Always run browser install first or pass --browser <path>. The tool errors if no browser is found.
• -o is mandatory on every render command.
• Web mode requires -u (URL). Excalidraw mode requires -i (input file path).
• PNG only. No other output formats are supported.
• Network access required. Web mode fetches the target page. Excalidraw mode loads renderer libraries from unpkg.com at runtime.
• -m web is the default. You can omit -m web when taking screenshots.