108 lines
3.2 KiB
Markdown
108 lines
3.2 KiB
Markdown
# path2d-polyfill
|
|
|
|
[](https://github.com/nilzona/path2d-polyfill/actions/workflows/validate.yaml)
|
|
|
|
Polyfills `Path2D` api and `roundRect` for CanvasRenderingContext2D
|
|
|
|
## Usage
|
|
|
|
Add this script tag to your page to enable the feature.
|
|
|
|
```html
|
|
<script lang="javascript" src="https://cdn.jsdelivr.net/npm/path2d-polyfill/dist/path2d-polyfill.min.js"></script>
|
|
```
|
|
|
|
or install from npm
|
|
|
|
```shell
|
|
npm install --save path2d-polyfill
|
|
```
|
|
|
|
and import with module bundler e.g. webpack _before_ using the feature
|
|
|
|
```javascript
|
|
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
|
|
|
|
```javascript
|
|
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 methods
|
|
- `polyfillPath2D` - function that adds Path2D to a "window like" object and polyfills CanvasRenderingContext2D to use Path2D
|
|
- `polyfillRoundRect` - 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:
|
|
|
|
```js
|
|
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](https://github.com/Automattic/node-canvas) use the following pattern:
|
|
|
|
```js
|
|
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](https://gist.github.com/nilzona/e611c99336d8ea1f645bd391a459c24f)
|
|
|
|
## 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
|
|
|
|
```shell
|
|
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.
|