React-CanvasKit

Experimental implementation of Skia CanvasKit using ReactJS.

This implementation allows you to use all familiar React concepts like hooks and contexts, in conjunction with JXS elements that closely match the existing Skia CanvasKit API. Everything is drawn to a hardware accelerated WebGL canvas.

Examples

Simple Paint

`typescript jsx const App: FunctionComponent = () => { return ( <ck-canvas clear={{ red: 255, green: 165, blue: 0 }}> <ck-text x={5} y={50} paint={{ color: '#00FFFF', antiAlias: true }} font={{ size: 24 }}> Hello React-CanvasKit! </ck-text> <ck-surface width={100} height={100} dx={100} dy={100}> <ck-canvas clear='#FF00FF' rotate={{ degree: 45 }}> <ck-text> React-CanvasKit.</ck-text> <ck-line x1={0} y1={10} x2={142} y2={10} paint={{ antiAlias: true, color: '#FFFFFF', strokeWidth: 10 }}/> </ck-canvas> </ck-surface> </ck-canvas> ) }

const htmlCanvasElement = document.createElement('canvas') const rootElement = document.getElementById('root') if (rootElement === null) { throw new Error('No root element defined.') } rootElement.appendChild(htmlCanvasElement) document.body.appendChild(htmlCanvasElement) htmlCanvasElement.width = 400 htmlCanvasElement.height = 300

init().then(() => render(<App/>, htmlCanvasElement))

#### Paragraph with dynamic font loading
![Alt text](/demos/paragraph-demo/paragraph-demo.gif?raw=true "Paragraph Demo")

```typescript jsx
import type { FunctionComponent } from 'react'
import React from 'react'
import { FontManagerProvider } from 'react-canvaskit'
import ParagraphDemo from './ParagraphDemo'

const robotoPromise = fetch('https://storage.googleapis.com/skia-cdn/google-web-fonts/Roboto-Regular.ttf')
  .then((resp) => resp.arrayBuffer())
const notoColorEmojiPromise = fetch('https://storage.googleapis.com/skia-cdn/misc/NotoColorEmoji.ttf')
  .then((resp) => resp.arrayBuffer())

const fontsPromise = Promise.all([robotoPromise, notoColorEmojiPromise])

export const App: FunctionComponent = () => {
  const [fonts, setFonts] = React.useState<ArrayBuffer[] | undefined>(undefined)
  fontsPromise.then(fetchedFonts => setFonts(fetchedFonts))

  return (
    <FontManagerProvider fontData={fonts}>
      <ParagraphDemo/>
    </FontManagerProvider>
  )
}

`typescript jsx import type { SkParagraph } from 'canvaskit-oc' import React from 'react' import type { SkObjectRef } from 'react-canvaskit' import { PaintStyle, TextAlignEnum, useFontManager } from 'react-canvaskit' import useAnimationFrame from './useAnimationFrame'

const fontPaint = { style: PaintStyle.Fill, antiAlias: true }

const X = 250 const Y = 250 const paragraphText = 'The quick brown fox 🦊 ate a zesty hamburgerfonts 🍔.\nThe 👩‍👩‍👧‍👧 laughed.'

export default () => { const skParagraphRef = React.useRef<SkObjectRef<SkParagraph>>(null) const fontManager = useFontManager()

const calcWrapTo = (time: number): number => 350 + 150 * Math.sin(time / 2000) const [wrapTo, setWrapTo] = React.useState(calcWrapTo(performance.now()))

useAnimationFrame(time => setWrapTo(calcWrapTo(time)))

return ( <ck-canvas clear='#FFFFFF'> <ck-paragraph fontManager={fontManager} ref={skParagraphRef} textStyle={{ color: '#000000', // Noto Mono is the default canvaskit font, we use it as a fallback fontFamilies: ['Noto Mono', 'Roboto', 'Noto Color Emoji'], fontSize: 50 }} textAlign={TextAlignEnum.Left} maxLines={7} ellipsis='...' layout={wrapTo} > {paragraphText} </ck-paragraph> <ck-line x1={wrapTo} y1={0} x2={wrapTo} y2={400} paint={fontPaint}/> <ck-text x={5} y={450} paint={fontPaint}>{At (${X.toFixed(2)}, ${Y.toFixed(2)}) glyph is '${glyph}'}</ck-text> </ck-canvas> ) } `