React Native Skia

High-performance 2d Graphics for React Native using Skia

Checkout the full documentation here.

React Native Skia brings the Skia Graphics Library to React Native. Skia serves as the graphics engine for Google Chrome and Chrome OS, Android, Flutter, Mozilla Firefox and Firefox OS, and many other products.

This is an alpha release. Use with caution.

Installation

React Native Skia brings the Skia Graphics Library to React Native. Skia serves as the graphics engine for Google Chrome and Chrome OS, Android, Flutter, Mozilla Firefox and Firefox OS, and many other products.

yarn add @shopify/react-native-skia

Or using npm:

npm install @shopify/react-native-skia

iOS

Run pod install on the ios/ directory.

Android

Version compatibility: react-native@>=0.66 is required.

Currently, you will need Android NDK to be installed. If you have Android Studio installed, make sure $ANDROID_NDK is available. ANDROID_NDK=/Users/username/Library/Android/sdk/ndk-bundle for instance.

If the NDK is not installed, you can install it via Android Studio by going to the menu File > Project Structure

And then the SDK Location section. It will show you the NDK path, or the option to Download it if you don't have it installed.

And them the Modules section. click on shopify_react-native-skia and select NDK version with dropdown, and click on apply.

TroubleShooting

For error CMake 'X.X.X' was not found in SDK, PATH, or by cmake.dir property.

open Tools > SDK Manager, switch to the SDK Tools tab. Find CMake and click Show Package Details and download compatiable version 'X.X.X', and apply to install.

Playground

We have an example project you can play with here.

$ yarn
$ cd package && yarn && cd ..
$ cd example && yarn && yarn start

To run the example project on iOS, you will need to run pod install and on Android you will also need Android NDK to be installed (see here).

Hello World

React Native Skia has two APIs: a declarative API available as a React Native Renderer and an imperative API backed by JSI. The recommended way to use this library is via the declarative API. Library developers may take advantage of the imperative API to provide custom features.

Declarative API

Example

import { Canvas, Circle, Group } from "@shopify/react-native-skia";

export const HelloWorld = () => {
  const width = 256;
  const height = 256;
  const r = 215;
  return (
    <Canvas style={{ flex: 1 }}>
      <Group blendMode="multiply">
        <Circle cx={r} cy={r} r={r} color="cyan" />
        <Circle cx={width - r} cy={r} r={r} color="magenta" />
        <Circle cx={width / 2} cy={height - r} r={r} color="yellow" />
      </Group>
    </Canvas>
  );
};

Imperative API

Example

import {
  Skia,
  BlendMode,
  SkiaView,
  useDrawCallback,
} from "@shopify/react-native-skia";

const paint = Skia.Paint();
paint.setAntiAlias(true);
paint.setBlendMode(BlendMode.Multiply);

export const HelloWorld = () => {
  const width = 256;
  const height = 256;
  const r = 215;
  const onDraw = useDrawCallback((canvas) => {
    // Cyan Circle
    const cyan = paint.copy();
    cyan.setColor(Skia.Color("cyan"));
    canvas.drawCircle(r, r, r, cyan);
    // Magenta Circle
    const magenta = paint.copy();
    magenta.setColor(Skia.Color("magenta"));
    canvas.drawCircle(width - r, r, r, magenta);
    // Yellow Circle
    const yellow = paint.copy();
    yellow.setColor(Skia.Color("yellow"));
    canvas.drawCircle(width / 2, height - r, r, yellow);
  });
  return <SkiaView style={{ flex: 1 }} onDraw={onDraw} />;
};

Library Development

To develop react-native-skia, you need to build the skia libraries on your computer.

Make sure to check out the sub modules:

git submodule update --init --recursive

You also need to install some tools for the build scripts to work. Run yarn in the root of the project to install them.

Make sure you have all the tools required for building the skia libraries (XCode, Ninja, CMake, Android NDK / build tools)

On MacOS you can install Ninja via homebrew:

brew install ninja

If you have Android Studio installed, make sure $ANDROID_NDK is available. ANDROID_NDK=/Users/username/Library/Android/sdk/ndk-bundle for instance.

If the NDK is not installed, you can install it via Android Studio by going to the menu File > Project Structure

And then the SDK Location section. It will show you the NDK path, or the option to Download it if you don't have it installed.

Building

• Install dependencies in the root project yarn
• Install dependencies in the root project cd package && yarn && cd ..
• Install dependencies in the example cd example && yarn && cd ..
• Build the Skia libraries with yarn build-skia (this can take a while)
• Copy Skia headers yarn copy-skia-headers
• Run pod install in the example project

Upgrading

If a new version of Skia is included in an upgrade of this library, you need to perform a few extra steps before continuing:

1. Update submodules: git submodule update --recursive
2. Copy Skia Headers: yarn copy-skia-headers
3. Clean Skia: yarn clean-skia
4. Build Skia: yarn build-skia
5. Run pod install in the example project

Publishing

• Run the commands in the Building section
• Build the Android binaries with yarn build-android
• Build the NPM package with yarn build-npm;

Publish the NPM package manually. The output is found in the dist folder.

• Install Cocoapods in the example/ios folder cd example/ios && pod install && cd ..