resvg-js

resvg-js is a high-performance SVG renderer and toolkit, powered by Rust based resvg, with Node.js backend using napi-rs, also a pure WebAssembly backend.

Please use all lowercase resvg-js when referencing project names.

Playground

https://resvg-js.vercel.app

Features

Fast, safe and zero dependencies, with correct output.
Convert SVG to PNG, includes cropping, scaling and setting the background color.
Support system fonts and custom fonts in SVG text.
v2: Gets the width and height of the SVG and the generated PNG.
v2: Support for outputting simplified SVG strings, such as converting shapes(rect, circle, etc) to <path>.
v2: Support WebAssembly.
v2: Support to get SVG bounding box and crop according to bounding box.
v2: Support for loading images of external links in <image>.
No need for node-gyp and postinstall, the .node file has been compiled for you.
Cross-platform support, including Apple M Chips.
Support for running as native addons in Deno.

Installation

Node.js

npm i @resvg/resvg-js

Browser(Wasm)

<script src="https://unpkg.com/@resvg/resvg-wasm"></script>

Docs

Node.js see index.d.ts
Wasm see wasm/index.d.ts

Example

Node.js Example

This example will load Source Han Serif, and then render the SVG to PNG.

node example/index.js

Loaded 1 font faces in 0ms.
Font './example/SourceHanSerifCN-Light-subset.ttf':0 found in 0.006ms.
✨ Done in 55.65491008758545 ms

Deno Example

deno run --unstable --allow-read --allow-write --allow-ffi example/index-deno.js

[2022-11-16T15:03:29Z DEBUG resvg_js::fonts] Loaded 1 font faces in 0.067ms.
[2022-11-16T15:03:29Z DEBUG resvg_js::fonts] Font './example/SourceHanSerifCN-Light-subset.ttf':0 found in 0.001ms.
Original SVG Size: 1324 x 687
Output PNG Size  : 1200 x 623
✨ Done in 66 ms

SVG	PNG

Usage

Node.js

const { promises } = require('fs')
const { join } = require('path')
const { Resvg } = require('@resvg/resvg-js')

async function main() {
  const svg = await promises.readFile(join(__dirname, './text.svg'))
  const opts = {
    background: 'rgba(238, 235, 230, .9)',
    fitTo: {
      mode: 'width',
      value: 1200,
    },
    font: {
      fontFiles: ['./example/SourceHanSerifCN-Light-subset.ttf'], // Load custom fonts.
      loadSystemFonts: false, // It will be faster to disable loading system fonts.
      // defaultFontFamily: 'Source Han Serif CN Light', // You can omit this.
    },
  }
  const resvg = new Resvg(svg, opts)
  const pngData = resvg.render()
  const pngBuffer = pngData.asPng()

  console.info('Original SVG Size:', `${resvg.width} x ${resvg.height}`)
  console.info('Output PNG Size  :', `${pngData.width} x ${pngData.height}`)

  await promises.writeFile(join(__dirname, './text-out.png'), pngBuffer)
}

main()

Bun

Starting with Bun 0.8.1, resvg-js can be run directly in Bun without any modification to the JS files, and is fully compatible with the syntax in Node.js.

bun example/index.js

Deno

Starting with Deno 1.26.1, there is support for running Native Addons directly from Node.js. This allows for performance that is close to that found in Node.js.

deno run --unstable --allow-read --allow-write --allow-ffi example/index-deno.js

import * as path from 'https://deno.land/std@0.159.0/path/mod.ts'
import { Resvg } from 'npm:@resvg/resvg-js'
const __dirname = path.dirname(path.fromFileUrl(import.meta.url))

const svg = await Deno.readFile(path.join(__dirname, './text.svg'))
const opts = {
  fitTo: {
    mode: 'width',
    value: 1200,
  },
}

const t = performance.now()
const resvg = new Resvg(svg, opts)
const pngData = resvg.render()
const pngBuffer = pngData.asPng()
console.info('Original SVG Size:', `${resvg.width} x ${resvg.height}`)
console.info('Output PNG Size  :', `${pngData.width} x ${pngData.height}`)
console.info('✨ Done in', performance.now() - t, 'ms')

await Deno.writeFile(path.join(__dirname, './text-out-deno.png'), pngBuffer)

WebAssembly

This package also ships a pure WebAssembly artifact built with wasm-bindgen to run in browsers.

Browser

<script src="https://unpkg.com/@resvg/resvg-wasm"></script>
<script>
  ;(async function () {
    // The Wasm must be initialized first
    await resvg.initWasm(fetch('https://unpkg.com/@resvg/resvg-wasm/index_bg.wasm'))

    const font = await fetch('./fonts/Pacifico-Regular.woff2')
    if (!font.ok) return

    const fontData = await font.arrayBuffer()
    const buffer = new Uint8Array(fontData)

    const opts = {
      fitTo: {
        mode: 'width', // If you need to change the size
        value: 800,
      },
      font: {
        fontBuffers: [buffer], // New in 2.5.0, loading custom fonts
      },
    }

    const svg = '<svg> ... </svg>' // Input SVG, String or Uint8Array
    const resvgJS = new resvg.Resvg(svg, opts)
    const pngData = resvgJS.render(svg, opts) // Output PNG data, Uint8Array
    const pngBuffer = pngData.asPng()
    const svgURL = URL.createObjectURL(new Blob([pngData], { type: 'image/png' }))
    document.getElementById('output').src = svgURL
  })()
</script>

See playground, it is also possible to call Wasm in Node.js, but it is slower.

Sample Benchmark

npm i benny@3.x sharp@0.x @types/sharp svg2img@0.x
npm run bench

Running "resize width" suite...
  resvg-js(Rust):
    12 ops/s

  sharp:
    9 ops/s

  skr-canvas(Rust):
    7 ops/s

  svg2img(canvg and node-canvas):
    6 ops/s

Support matrix

	Node.js 12	Node.js 14	Node.js 16	Node.js 18	Node.js 20
Windows x64	✓	✓	✓	✓	✓
Windows x32	✓	✓	✓	✓	✓
Windows arm64	✓	✓	✓	✓	✓
macOS x64	✓	✓	✓	✓	✓
macOS arm64(M1)	✓	✓	✓	✓	✓
Linux x64 gnu	✓	✓	✓	✓	✓
Linux x64 musl	✓	✓	✓	✓	✓
Linux arm gnu	✓	✓	✓	✓	✓
Linux arm64 gnu	✓	✓	✓	✓	✓
Linux arm64 musl	✓	✓	✓	✓	✓
Android arm64	✓	✓	✓	✓	✓
Android armv7	✓	✓	✓	✓	✓

Test or Contributing

Install latest Rust
Install Node.js@10+ which fully supported Node-API
Install wasm-pack
```
curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh
```
Normally wasm-pack will install wasm-bindgen automatically, but if the installation fails due to network reasons, please try to install it manually.
```
cargo install wasm-bindgen-cli
```
On computers with Apple M chips, the following error message may appear:

Error: failed to download from https://github.com/WebAssembly/binaryen/releases/download/version_90/binaryen-version_90-x86_64-apple-darwin.tar.gz

Please install binaryen manually:
```
brew install binaryen
```

Build Node.js bindings

npm i
npm run build
npm test

Build WebAssembly bindings

npm i
npm run build:wasm
npm run test:wasm

Roadmap

I will consider implementing the following features, if you happen to be interested, please feel free to discuss with me or submit a PR.

Support async API
Upgrade to napi-rs v2
Support WebAssembly
Output usvg-simplified SVG string
Support for getting SVG Bounding box
Support for generating more lossless bitmap formats, e.g. avif, webp, JPEG XL

Release package

We use GitHub actions to automatically publish npm packages.

# 1.0.0 => 1.0.1
npm version patch

# or 1.0.0 => 1.1.0
npm version minor

License

Please use all lowercase resvg-js when referencing project names.

MPLv2.0

deno run --unstable --allow-read --allow-write --allow-ffi example/index-deno.js [2022-11-16T15:03:29Z DEBUG resvg_js::fonts] Loaded 1 font faces in 0.067ms. [2022-11-16T15:03:29Z DEBUG resvg_js::fonts] Font './example/SourceHanSerifCN-Light-subset.ttf':0 found in 0.001ms. Original SVG Size: 1324 x 687 Output PNG Size : 1200 x 623 ✨ Done in 66 ms

SVG

PNG

const { promises } = require('fs') const { join } = require('path') const { Resvg } = require('@resvg/resvg-js') async function main() { const svg = await promises.readFile(join(__dirname, './text.svg')) const opts = { background: 'rgba(238, 235, 230, .9)', fitTo: { mode: 'width', value: 1200, }, font: { fontFiles: ['./example/SourceHanSerifCN-Light-subset.ttf'], // Load custom fonts. loadSystemFonts: false, // It will be faster to disable loading system fonts. // defaultFontFamily: 'Source Han Serif CN Light', // You can omit this. }, } const resvg = new Resvg(svg, opts) const pngData = resvg.render() const pngBuffer = pngData.asPng() console.info('Original SVG Size:', `${resvg.width} x ${resvg.height}`) console.info('Output PNG Size :', `${pngData.width} x ${pngData.height}`) await promises.writeFile(join(__dirname, './text-out.png'), pngBuffer) } main()

import * as path from 'https://deno.land/std@0.159.0/path/mod.ts' import { Resvg } from 'npm:@resvg/resvg-js' const __dirname = path.dirname(path.fromFileUrl(import.meta.url)) const svg = await Deno.readFile(path.join(__dirname, './text.svg')) const opts = { fitTo: { mode: 'width', value: 1200, }, } const t = performance.now() const resvg = new Resvg(svg, opts) const pngData = resvg.render() const pngBuffer = pngData.asPng() console.info('Original SVG Size:', `${resvg.width} x ${resvg.height}`) console.info('Output PNG Size :', `${pngData.width} x ${pngData.height}`) console.info('✨ Done in', performance.now() - t, 'ms') await Deno.writeFile(path.join(__dirname, './text-out-deno.png'), pngBuffer)

Node.js 12

Node.js 14

Node.js 16

Node.js 18

Node.js 20

npm

Windows x64

✓

Windows x32

✓

Windows arm64

✓

macOS x64

✓

macOS arm64(M1)

✓

Linux x64 gnu

✓

Linux x64 musl

✓

Linux arm gnu

✓

Linux arm64 gnu

✓

Linux arm64 musl

✓

Android arm64

✓

Android armv7

✓