README.md

ESM Potrace Wasm

A modern ESM build of the Potrace library for use in the browser.

Installation

npm install --save esm-potrace-wasm

Usage

import { potrace, init } from 'esm-potrace-wasm';

(async () => {
  // Initialize the module once.
  await init();

  /**
   * The `imageBitmapSource` parameter is an `ImageBitmapSource`, that is any of:
   * - `HTMLImageElement`
   * - `SVGImageElement`
   * - `HTMLVideoElement`
   * - `HTMLCanvasElement`
   * - `ImageData`
   * - `ImageBitmap`
   * - `Blob`
   */
  const svg = await potrace(
    imageBitmapSource,
    (options = {
      turdsize: 2,
      turnpolicy: 4,
      alphamax: 1,
      opticurve: 1,
      opttolerance: 0.2,
      pathonly: false,
      extractcolors: true,
      posterizelevel: 2, // [1, 255]
      posterizationalgorithm: 0, // 0: simple, 1: interpolation
    })
  );
})();

Developing

Modify src/potrace/ and run npm run build to update the ESM build in dist/. The emscripten build file is located at ./build.sh (or build.ps1 for Win32) respectively. A simple demo that imports dist/index.js is available in demo/ and can be started by running npm start.

Apps using this

This library is used in SVGcode.

License

⚠️ GPL-v2.0, due to the original Potrace license.

Acknowledgements

Based on @nturley's fork of @IguteChung's initial potrace-wasm. Unfortunately, the original author did not react on my Pull Request, so I forked.