@systemic-games/vision-camera-rgb-averages

Vision Camera Frame Processor computing RGB averages

Find the latest published version on NPM.

Installation

npm install @systemic-games/vision-camera-rgb-averages

Add this to the project babel config file:

  plugins: [
    [
      // Reanimated plugin has to be listed last.
      "react-native-reanimated/plugin",
      {
        globals: ["__getImageRgbAverages"],
      },
    ],
  ],

Note: this package has a dependency on react-native-vision-camera.

Use version 2.13.0 for React Native < 0.66, see this issue.

Usage

import { useCallback, useRef, } from "react";
import { runOnJS } from "react-native-reanimated";
import {
  Camera,
  useCameraDevices,
  useFrameProcessor,
} from "react-native-vision-camera";
import {
  getImageRgbAverages,
  ImageRgbAverages,
} from "@systemic-games/vision-camera-rgb-averages";

function App() {
  const devices = useCameraDevices("wide-angle-camera");
  const cameraRef = useRef<Camera>(null);

  // Simply log the R, G, B values
  const processRgbAverages = useCallback((avg: ImageRgbAverages) => {
    console.log(
      `R=${s(avg.redAverage)} G=${s(avg.greenAverage)} B=${s(avg.blueAverage)}`
    );
  }, []);

  // Get the average R, G and B for each image captured by the camera
  const frameProcessor = useFrameProcessor(
    (frame) => {
      const result = getImageRgbAverages(frame);
      if (typeof result === "string") {
        console.error(
          `Error in frame processor "getImageRgbAverages": ${result}`
        );
      } else {
        runOnJS(processRgbAverages)(result);
      }
    },
    [processRgbAverages]
  );

  // Note: before rendering the camera component, ask for camera permissions
  //       and check that the camera device is valid.
  // See https://github.com/mrousavy/react-native-vision-camera for more info.
  return (
    <View style={{ flex: 1 }}>
      <Camera
        ref={cameraRef}
        device={devices.back}
        isActive
        frameProcessor={frameProcessor}
      />
    </View>
  );
}

Development workflow

To get started with the project, run yarn in the root directory to install the required dependencies for each package:

yarn

While it's possible to use npm, the tooling is built around yarn, so you'll have an easier time if you use yarn for development.

While developing, you can run the example app to test your changes. Any changes you make in your library's JavaScript code will be reflected in the example app without a rebuild. If you change any native code, then you'll need to rebuild the example app.

To start Metro:

yarn example start

To run the example app on Android:

yarn example android

To run the example app on iOS:

yarn example ios

Make sure your code passes TypeScript and ESLint. Run the following to verify:

yarn typescript
yarn lint

To fix formatting errors, run the following:

yarn lint --fix

Remember to add tests for your change if possible. Run the unit tests by:

yarn test

To edit the Objective-C files, open example/ios/VisionCameraRgbAveragesExample.xcworkspace in XCode and find the source files at Pods > Development Pods > vision-camera-rgb-averages.

To edit the Java files, open example/android in Android studio and find the source files at vision-camera-rgb-averages under Android.

Commit message convention

We follow the conventional commits specification for our commit messages:

• fix: bug fixes, e.g. fix crash due to deprecated method.
• feat: new features, e.g. add new method to the module.
• refactor: code refactor, e.g. migrate from class components to hooks.
• docs: changes into documentation, e.g. add usage example for the module..
• test: adding or updating tests, e.g. add integration tests using detox.
• chore: tooling changes, e.g. change CI config.

Our pre-commit hooks verify that your commit message matches this format when committing.

Publishing to npm

We use release-it to make it easier to publish new versions. It handles common tasks like bumping version based on semver, creating tags and releases etc.

To publish new versions, run the following:

yarn release

Scripts

The package.json file contains various scripts for common tasks:

• yarn bootstrap: setup project by installing all dependencies and pods.
• yarn typescript: type-check files with TypeScript.
• yarn lint: lint files with ESLint.
• yarn test: run unit tests with Jest.
• yarn example start: start the Metro server for the example app.
• yarn example android: run the example app on Android.
• yarn example ios: run the example app on iOS.

License

MIT

Made with create-react-native-library