npm package discovery and stats viewer.

Discover Tips

  • General search

    [free text search, go nuts!]

  • Package details

    pkg:[package-name]

  • User packages

    @[username]

Sponsor

Optimize Toolset

I’ve always been into building performant and accessible sites, but lately I’ve been taking it extremely seriously. So much so that I’ve been building a tool to help me optimize and monitor the sites that I build to make sure that I’m making an attempt to offer the best experience to those who visit them. If you’re into performant, accessible and SEO friendly sites, you might like it too! You can check it out at Optimize Toolset.

About

Hi, 👋, I’m Ryan Hefner  and I built this site for me, and you! The goal of this site was to provide an easy way for me to check the stats on my npm packages, both for prioritizing issues and updates, and to give me a little kick in the pants to keep up on stuff.

As I was building it, I realized that I was actually using the tool to build the tool, and figured I might as well put this out there and hopefully others will find it to be a fast and useful way to search and browse npm packages as I have.

If you’re interested in other things I’m working on, follow me on Twitter or check out the open source projects I’ve been publishing on GitHub.

I am also working on a Twitter bot for this site to tweet the most popular, newest, random packages from npm. Please follow that account now and it will start sending out packages soon–ish.

Open Software & Tools

This site wouldn’t be possible without the immense generosity and tireless efforts from the people who make contributions to the world and share their work via open source initiatives. Thank you 🙏

© 2024 – Pkg Stats / Ryan Hefner

@logisticinfotech/react-native-openalpr

v1.0.0

Published

Open ALRP component for React Native

Downloads

42

Readme

react-native-openalpr

OpenALPR integration for React Native. Provides a camera component that recognizes license plates in real-time. Supports both iOS and Android.

Requirements

  • iOS 9+
  • Android 5.0+
  • RN 0.60+

Installation

Installation with React Native

Start by adding the package and linking it.

yarn add @logisticinfotech/react-native-openalpr

iOS Specific Setup

Install react-native-permissions

It is a good practice to check and request CAMERA permission. Check full implementation in example folder.

yarn add react-native-permissions

Add camera permission into your podfile.

pod 'Permission-Camera', :path => "../node_modules/react-native-permissions/ios/Camera.podspec"

Install pods

cd ios && pod install && cd ...

Camera Permissions

  • Add an entry for NSCameraUsageDescription in your info.plist explaining why your app will use the camera. If you forget to add this, your app will crash!
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
  ...
  <key>NSCameraUsageDescription</key>
  <string>We use your camera for license plate recognition to make it easier for you to add your vehicle.</string>
</dict>

Bitcode

Because the OpenCV binary framework release is compiled without bitcode, the other frameworks built by this script are also built without it, which ultimately means your Xcode project also cannot be built with bitcode enabled. Per this message, it sounds like we want this feature disabled for OpenCV anyway.

To disable bitcode in your project:

  • In Build SettingsBuild Options, search for Enable Bitcode and set it to No.

Android-specific Setup

Camera Permissions

  • Add permissions for CAMERA and FLASHLIGHT and the related features (below) to AndroidManifest.xml. If you forget to add these permissions, your app will crash!
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
  <!-- Camera Permissions -->
  <uses-permission android:name="android.permission.CAMERA" />

  <uses-feature
      android:name="android.hardware.camera"
      android:required="false" />
  <uses-feature
      android:name="android.hardware.camera.autofocus"
      android:required="false" />

  <uses-permission android:name="android.permission.FLASHLIGHT" />

Add to Gradle

Your android/settings.gradle file should have following lines

rootProject.name = 'RNOpenALPRExample'
apply from: file("../node_modules/@react-native-community/cli-platform-android/native_modules.gradle"); applyNativeModulesSettingsGradle(settings)
include ':app'

# Add these lines
include ':openalpr'
project(':openalpr').projectDir = new File(rootProject.projectDir, '../node_modules/@logisticinfotech/react-native-openalpr/android/libraries/openalpr')
include ':opencv'
project(':opencv').projectDir = new File(rootProject.projectDir, '../node_modules/@logisticinfotech/react-native-openalpr/android/libraries/opencv')

Linking

The library is linked automatically with leptonica, opencv, tesseract, and openalpr (openalpr). To make it work, copy and paste the directory with the runtime needed data to your project at path android/app/src/main/assets/runtime_data.

The runtime_data file can be found in /example/android/app/src/main/assets/ in this repo. Open runtime_data/openalpr.conf file and replace com.rnopenalprexample with your package name

[common]

; Specify the path to the runtime data directory
runtime_dir = /data/data/com.rnopenalprexample/runtime_data


ocr_img_size_percent = 1.33333333
state_id_img_size_percent = 2.0
...

Usage

OpenALPR exposes a camera component (based on react-native-camera) that is optimized to run OpenALPR image processing on a live camera stream. Among other parameters, the camera accepts a callback, onPlateRecognized, for when a plate is recognized.

import React, { Component } from 'react'
import { StyleSheet, Text, View } from 'react-native'

import Camera, {
  Aspect,
  CaptureQuality,
  TorchMode,
} from '@logisticinfotech/react-native-openalpr'

const styles = StyleSheet.create({
  container: {
    flex: 1,
  },
  textContainer: {
    position: 'absolute',
    top: 100,
    left: 50,
  },
  text: {
    textAlign: 'center',
    fontSize: 20,
  },
})

export default class PlateRecognizer extends React.Component {
  state = {
    plate: 'Scan a plate',
  }

  onPlateRecognized = ({ plate, confidence }) => {
    this.setState({
      plate,
    })
  }

  render() {
    return (
      <View style={styles.container}>
        <Camera
          style={styles.preview}
          aspect={Aspect.fill}
          captureQuality={CaptureQuality.medium}
          country="us"
          onPlateRecognized={this.onPlateRecognized}
          plateOutlineColor="#ff0000"
          showPlateOutline
          torchMode={TorchMode.off}
          touchToFocus
        />
        <View style={styles.textContainer}>
          <Text style={styles.text}>{this.state.plate}</Text>
        </View>
      </View>
    )
  }
}

Options

aspect

The aspect ratio of the camera. Can be one of:

  • Aspect.stretch
  • Aspect.fit
  • Aspect.fill

captureQuality

The resolution at which video frames are captured and analyzed. For completeness, several options are provided. However, it is strongly recommended that you stick with one of the following for the best frame rates and accuracy:

  • CaptureQuality.medium (480x360)
  • CaptureQuality.480p (640x480)

country

Specifies which OpenALPR config file to load, corresponding to the country whose plates you wish to recognize. Currently supported values are:

  • au
  • br
  • eu
  • fr
  • gb
  • kr
  • mx
  • sg
  • us
  • vn2

onPlateRecognized

This callback receives a hash with keys:

  • plate, representing the recognized license plate string
  • confidence, OpenALPR's confidence(%) in the result

plateOutlineColor

Hex string specifying the color of the border to draw around the recognized plate. Example: #ff0000 for red.

showPlateOutline

If true, this draws an outline over the recognized plate

torchMode

Turns the flashlight on or off. Can be one of:

  • TorchMode.on
  • TorchMode.off
  • TorchMode.auto

touchToFocus

If true, this focuses the camera where the user taps

Examples

Development

  • This project works with iOS and Android. It may have some bugs depending on how the underlying native components are updated

Running the Example project on Android While Developing

  1. Clone the repo and enter the example directory
git clone https://github.com/nileshkikani/react-native-openalpr.git
cd react-native-openalpr
cd example
  1. From the example directory, run yarn

  2. Copy the android folder from /@logisticinfotech/react-native-openalpr/android to /react-native-openalpr/example/node_modules/@logisticinfotech/react-native-openalpr/

  3. Open Android Studio and import the project react-native-openalpr/example/android and wait until Android Studio indexes and links.

  4. Run npm start from dir /react-native-openalpr/example/

  5. Open the path in your browser http://localhost:8081/index.android.bundle?platform=android&dev=true&hot=false&minify=false

  6. Create file the /react-native-openalpr/example/android/app/src/main/assets/index.android.bundle. Copy and paste the data from browser window to the file you just created and save.

  7. Return to Android Studio and run project on your development device.

Note: If you are getting errors, double check that you have completed all of the steps above. If you are having issues running npm start on Mac OSX and are using homebrew, this issue might help.

Credits