skr canvas

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Google Skia binding to Node.js via Node-API, 0 System dependencies!

⚠️ This project is in pre-release stage. And there may be some bugs.<br/> For details on planned features and future direction please refer to the Roadmap.

中文文档

Install

yarn add @napi-rs/canvas
npm install @napi-rs/canvas

Support matrix

System requirement

arm64

cortex-a57 or newer CPU architecture on Linux.

All Apple M chips on macOS.

armv7

cortex-a7 or newer CPU architecture.

glibc

Since Skia relies on the glibc 2.18 API, you need to have at least glibc version >= 2.18 on your system.

AWS Lambda usage

To use this library on Lambda you will need to use a Lambda layer.

You can simply attach a lambda layer by getting an ARN from Canvas-Lambda-Layer

Make sure to exclude @napi-rs/canvas while bundling your Lambda.

Usage

const { promises } = require('node:fs')
const { join } = require('node:path')
const { createCanvas, loadImage } = require('@napi-rs/canvas')

const canvas = createCanvas(300, 320)
const ctx = canvas.getContext('2d')

ctx.lineWidth = 10
ctx.strokeStyle = '#03a9f4'
ctx.fillStyle = '#03a9f4'

// Wall
ctx.strokeRect(75, 140, 150, 110)

// Door
ctx.fillRect(130, 190, 40, 60)

// Roof
ctx.beginPath()
ctx.moveTo(50, 140)
ctx.lineTo(150, 60)
ctx.lineTo(250, 140)
ctx.closePath()
ctx.stroke()

async function main() {
  // load images from disk or from a URL
  const catImage = await loadImage('path/to/cat.png')
  const dogImage = await loadImage('https://example.com/path/to/dog.jpg')

  ctx.drawImage(catImage, 0, 0, catImage.width, catImage.height)

  ctx.drawImage(dogImage, canvas.width / 2, canvas.height / 2, dogImage.width, dogImage.height)

  // export canvas as image
  const pngData = await canvas.encode('png') // JPEG, AVIF and WebP are also supported
  // encoding in libuv thread pool, non-blocking
  await promises.writeFile(join(__dirname, 'simple.png'), pngData)
}

main()

Emoji text

const { writeFileSync } = require('fs')
const { join } = require('path')

const { createCanvas, GlobalFonts } = require('@napi-rs/canvas')

GlobalFonts.registerFromPath(join(__dirname, '..', 'fonts', 'AppleColorEmoji@2x.ttf'), 'Apple Emoji')
GlobalFonts.registerFromPath(join(__dirname, '..', '__test__', 'fonts', 'COLRv1.ttf'), 'COLRv1')

console.info(GlobalFonts.families)

const canvas = createCanvas(760, 360)
const ctx = canvas.getContext('2d')

ctx.font = '50px Apple Emoji'
ctx.strokeText('😀😃😄😁😆😅😂🤣☺️😊😊😇', 50, 150)

ctx.font = '100px COLRv1'
ctx.fillText('abc', 50, 300)

const b = canvas.toBuffer('image/png')

writeFileSync(join(__dirname, 'draw-emoji.png'), b)

Performance

See benchmark for benchmark code.

Hardware info:

                  ,MMMM.           Host        -  xxxxxxxxxxxxxxxxxxxxxxx
                .MMMMMM            Machine     -  Mac15,9
                MMMMM,             Kernel      -  24.0.0
      .;MMMMM:' MMMMMMMMMM;.       OS          -  macOS 15.0.1 Sequoia
    MMMMMMMMMMMMNWMMMMMMMMMMM:     DE          -  Aqua
  .MMMMMMMMMMMMMMMMMMMMMMMMWM.     WM          -  Quartz Compositor
  MMMMMMMMMMMMMMMMMMMMMMMMM.       Packages    -  194 (Homebrew), 32 (cargo)
 ;MMMMMMMMMMMMMMMMMMMMMMMM:        Shell       -  zsh
 :MMMMMMMMMMMMMMMMMMMMMMMM:        Terminal    -  warpterminal (Version v0.2024.10.23.14.49.stable_00)
 .MMMMMMMMMMMMMMMMMMMMMMMMM.       Resolution  -  5120x2880@160fps (as 2560x1440)
  MMMMMMMMMMMMMMMMMMMMMMMMMMM.                    2992x1934@120fps (as 1496x967)
   .MMMMMMMMMMMMMMMMMMMMMMMMMM.                   2232x1512@60fps (as 1116x756)
     MMMMMMMMMMMMMMMMMMMMMMMM      Uptime      -  1d 2h 32m
      ;MMMMMMMMMMMMMMMMMMMM.       CPU         -  Apple M3 Max (16)
        .MMMM,.    .MMMM,.         CPU Load    -  16%
                                   Memory      -  50.1 GB / 134.2 GB
                                   Battery     -  78% & Discharging
                                   Disk Space  -  624.0 GB / 994.7 GB

❯ yarn bench
Draw a House and export to PNG
┌─────────┬─────────────────┬───────────────────────┬──────────────────────────┬────────────────────────────┬───────────────────────────┬─────────┐
│ (index) │ Task name       │ Latency average (ns)  │ Latency median (ns)      │ Throughput average (ops/s) │ Throughput median (ops/s) │ Samples │
├─────────┼─────────────────┼───────────────────────┼──────────────────────────┼────────────────────────────┼───────────────────────────┼─────────┤
│ 0       │ '@napi-rs/skia' │ '14676992.14 ± 0.68%' │ '14602333.00'            │ '68 ± 0.59%'               │ '68'                      │ 69      │
│ 1       │ 'skia-canvas'   │ '21167809.17 ± 2.05%' │ '20960021.00 ± 13646.00' │ '47 ± 1.31%'               │ '48'                      │ 64      │
│ 2       │ 'node-canvas'   │ '16552027.42 ± 0.70%' │ '16451291.50 ± 2208.50'  │ '60 ± 0.62%'               │ '61'                      │ 64      │
└─────────┴─────────────────┴───────────────────────┴──────────────────────────┴────────────────────────────┴───────────────────────────┴─────────┘
Draw Gradient and export to PNG
┌─────────┬─────────────────┬───────────────────────┬─────────────────────────┬────────────────────────────┬───────────────────────────┬─────────┐
│ (index) │ Task name       │ Latency average (ns)  │ Latency median (ns)     │ Throughput average (ops/s) │ Throughput median (ops/s) │ Samples │
├─────────┼─────────────────┼───────────────────────┼─────────────────────────┼────────────────────────────┼───────────────────────────┼─────────┤
│ 0       │ '@napi-rs/skia' │ '15228495.58 ± 0.53%' │ '15146312.50 ± 1187.50' │ '66 ± 0.48%'               │ '66'                      │ 66      │
│ 1       │ 'skia-canvas'   │ '21725564.41 ± 2.20%' │ '21412520.50 ± 2104.50' │ '46 ± 1.39%'               │ '47'                      │ 64      │
│ 2       │ 'node-canvas'   │ '17976022.14 ± 1.53%' │ '17563479.50 ± 5104.50' │ '56 ± 1.38%'               │ '57'                      │ 64      │
└─────────┴─────────────────┴───────────────────────┴─────────────────────────┴────────────────────────────┴───────────────────────────┴─────────┘

Features

Path2D

new Path2D()
new Path2D(path: Path2D)
// new Path2D('M108.956,403.826c0,0,0.178,3.344-1.276,3.311  c-1.455-0.033-30.507-84.917-66.752-80.957C40.928,326.18,72.326,313.197,108.956,403.826z')
new Path2D(path: string)

export interface DOMMatrix2DInit {
  a: number
  b: number
  c: number
  d: number
  e: number
  f: number
}

export class Path2D {
  constructor(path?: Path2D | string)

  addPath(path: Path2D, transform?: DOMMatrix2DInit): void
  arc(x: number, y: number, radius: number, startAngle: number, endAngle: number, anticlockwise?: boolean): void
  arcTo(x1: number, y1: number, x2: number, y2: number, radius: number): void
  bezierCurveTo(cp1x: number, cp1y: number, cp2x: number, cp2y: number, x: number, y: number): void
  closePath(): void
  ellipse(
    x: number,
    y: number,
    radiusX: number,
    radiusY: number,
    rotation: number,
    startAngle: number,
    endAngle: number,
    anticlockwise?: boolean,
  ): void
  lineTo(x: number, y: number): void
  moveTo(x: number, y: number): void
  quadraticCurveTo(cpx: number, cpy: number, x: number, y: number): void
  rect(x: number, y: number, w: number, h: number): void

  // PathKit methods
  op(path: Path2D, operation: PathOp): Path2D
  toSVGString(): string
  getFillType(): FillType
  getFillTypeString(): string
  setFillType(type: FillType): void
  simplify(): Path2D
  asWinding(): Path2D
  stroke(stroke?: StrokeOptions): Path2D
  transform(transform: DOMMatrix2DInit): Path2D
  getBounds(): [left: number, top: number, right: number, bottom: number]
  computeTightBounds(): [left: number, top: number, right: number, bottom: number]
  trim(start: number, end: number, isComplement?: boolean): Path2D
  round(radius: number): Path2D
  equals(path: Path2D): boolean
}

PathKit

PathKit is a toolset for manipulating Path in Skia, supporting quadratic beziers, cubic beziers and conics. The main features are.

Path Operation

.op(path, PathOp)

const pathOne = new Path2D(
  'M8 50H92C96.4183 50 100 53.5817 100 58V142C100 146.418 96.4183 150 92 150H8C3.58172 150 0 146.418 0 142V58C0 53.5817 3.58172 50 8 50Z',
)
const pathTwo = new Path2D(
  '"M58 0H142C146.418 0 150 3.58172 150 8V92C150 96.4183 146.418 100 142 100H58C53.5817 100 50 96.4183 50 92V8C50 3.58172 53.5817 0 58 0Z',
)

pathOne.op(pathTwo, PathOp.Intersect).toSVGString()
// => "M100 100L58 100C53.5817 100 50 96.4183 50 92L50 50L92 50C96.4183 50 100 53.5817 100 58L100 100Z"

• Union, subtract the op path from the first path
• Difference, intersect the two paths
• ReverseDifference, union (inclusive-or) the two paths
• Intersect, exclusive-or the two paths
• XOR, subtract the first path from the op path

Covert `FillT