3.2 KiB
path2d-polyfill
Polyfills Path2D api and roundRect for CanvasRenderingContext2D
Usage
Add this script tag to your page to enable the feature.
<script lang="javascript" src="https://cdn.jsdelivr.net/npm/path2d-polyfill/dist/path2d-polyfill.min.js"></script>
or install from npm
npm install --save path2d-polyfill
and import with module bundler e.g. webpack before using the feature
import "path2d-polyfill";
This will polyfill the browser's window object with Path2D features and it will also polyfill roundRect if they are missing in both CanvasRenderingContexst and Path2D.
Example of usage
ctx.fill(new Path2D("M 80 80 A 45 45 0 0 0 125 125 L 125 80 Z"));
ctx.stroke(new Path2D("M 80 80 A 45 45 0 0 0 125 125 L 125 80 Z"));
Usage in a node environment
It is possible to use this library in a node environment as well. The package exports a few functions that can be used:
Path2D- class to create Path2D objects used by the polyfill methodspolyfillPath2D- function that adds Path2D to a "window like" object and polyfills CanvasRenderingContext2D to use Path2DpolyfillRoundRect- polyfills roundRect function on Path2D and CanvasRenderingContext2D (missing in firefox)parsePath- function for parsing an SVG path string into canvas commands
use any of these functions like:
const { polyfillRoundRect } = require "path2d-polyfill";
const windowlike = { CanvasRenderingContext2D, Path2D };
polyfillRoundRect(windowLike);
// roundRect functions has now been added if they were missing
usage with node-canvas
To get Path2D features with the node-canvas library use the following pattern:
const { createCanvas, CanvasRenderingContext2D } = require("canvas");
const { polyfillPath2D } = require("path2d-polyfill/path2d");
global.CanvasRenderingContext2D = CanvasRenderingContext2D;
polyfillPath2D(global);
// Path2D has now been added to global object
const canvas = createCanvas(200, 200);
const ctx = canvas.getContext("2d");
const p = new Path2D("M10 10 l 20 0 l 0 20 Z");
ctx.fillStyle = "green";
ctx.fill(p);
A working example of a node express server that serves an image drawn with canvas can be seen here
Support table
| Method | Supported |
|---|---|
| constructor(SVGPath) | Yes |
| addPath() | Yes |
| closePath() | Yes |
| moveTo() | Yes |
| lineTo() | Yes |
| bezierCurveTo() | Yes |
| quadraticCurveTo() | Yes |
| arc() | Yes |
| ellipse() | Yes |
| rect() | Yes |
| roundRect() | Yes |
See it in action
Clone this repo and run the following
yarn
yarn start
open http://localhost:10001 to see the example page.
Contributing
Recommended to use vscode with the prettier extension to keep formatting intact.