React Native Document Scanner and Cropper (iOS only)

Live document detection library. Returns either a URI or a base64 encoded string of the captured image, allowing you to easily store it or use it as you wish !

Features :

• Live detection
• Perspective correction and crop of the image
• Live camera filters (brightness, saturation, contrast)
• Flash
• Easy to use base64 image
• Native Cropper

Getting started

This is a forked version of https://github.com/Michaelvilleneuve/react-native-document-scanner, our versions diverged by the embed native cropper I added. I'm planning to add android scanner-cropper soon (https://github.com/Diastorm/rn-doc-scanner-android).

Use version >=1.4.1 if you are using react-native 0.48+

npm install git+https://github.com/Pompette/react-native-document-scanner.git

$ react-native link react-native-document-scanner

Edit the info.plist file in XCode and add the following permission : NSCameraUsageDescription

Remember, this library uses your device camera, you can't run it on a simulator.

With Cocoapods

If you want to use Cocoapods insteads of react-native link, add the following to your Podfile

  pod 'RNPdfScanner', :path => '../node_modules/react-native-document-scanner/ios'

Usage

import React,{ Component } from 'react';
import { View, Image } from 'react-native';

import DocumentScanner from 'react-native-document-scanner';

class YourComponent extends Component {
  render() {
    return (
      <View>
        <DocumentScanner
          useBase64
          saveInAppDocument={false}
          onCrop={(data) => {
            console.log('Cropped data : ', data);
          }}
          onCancelCrop={() => {
            console.log('Cancel crop');
          }}
          cropperOpts={{
            base64: true, // false by default
            // doneButtonTitle: "Valider",
            // cancelButtonTitle: "Annuler"
            // saveFile: false, // true by default
            // directory: '/my/super/path',
            // fileName: 'test'
          }}
          onPictureTaken={data => this.setState({
            image: data.croppedImage,
            initialImage: data.initialImage,
            rectangleCoordinates: data.rectangleCoordinates,
          })}
          overlayColor="rgba(255,130,0, 0.7)"
          enableTorch={false}
          brightness={0.3}
          saturation={1}
          contrast={1.1}
          quality={0.5}
          onRectangleDetect={({ stableCounter, lastDetectionType }) => this.setState({ stableCounter, lastDetectionType })}
          detectionCountBeforeCapture={5}
          detectionRefreshRateInMS={50}
        />
        <Image source={{ uri: `data:image/jpeg;base64,${this.state.image}`}} resizeMode="contain" />
      </View>
    );
  }
}

Properties

Prop	Default	Type	Description
overlayColor	none	string	Color of the detected rectangle : rgba recommended
detectionCountBeforeCapture	5	integer	Number of correct rectangle to detect before capture
detectionRefreshRateInMS	50	integer	Time between two rectangle detection attempt
enableTorch	false	bool	Allows to active or deactivate flash during document detection
useFrontCam	false	bool	Allows you to switch between front and back camera
brightness	0	float	Increase or decrease camera brightness. Normal as default.
saturation	1	float	Increase or decrease camera saturation. Set 0 for black & white
contrast	1	float	Increase or decrease camera contrast. Normal as default
quality	0.8	float	Image compression. Reduces both image size and quality
useBase64	false	bool	If base64 representation should be passed instead of image uri's
saveInAppDocument	false	bool	If should save in app document in case of not using base 64
captureMultiple	false	bool	Keeps the scanner on after a successful capture
cropperOpts	{}	object	Options for the cropper

Cropper

In order to use the cropper, you must specify onCrop function.

Props	Params	Type	Description
onCrop	(data)	function	Function called when you press the done button of the cropper
onCancelCrop	()	function	Function called when you press the cancel button of the cropper

CropperOpts

Prop	Default	Type	Description
base64	false	bool	If should return base 64 on crop
doneButtonTitle	done	string	Title of done button
cancelButtonTitle	cancel	string	Title of cancel button
saveFile	true	bool	If should save file or not
directory	none	string	Set a subdirectory where to store cropped file, if saveInAppDocument is enabled it will create it in document directory, otherwise it will create it in temp directory
fileName	none	string	Custom fileName, by default it will be called to_cropped_img_TIMESTAMP

Manual capture

• First get component ref

<DocumentScanner ref={(ref) => this.scanner = ref} />

• Then call :

this.scanner.capture();

Handle play/pause on camera

• First get component ref

<DocumentScanner ref={(ref) => this.scanner = ref} />

• Then call :

this.scanner.startCamera(true); // If true will start, if false will stop

Each rectangle detection

Props	Params	Type	Description
onRectangleDetect	{ stableCounter, lastDetectionType }	object	See below

The returned object includes the following keys :

• stableCounter

Number of correctly formated rectangle found (this number triggers capture once it goes above detectionCountBeforeCapture)

• lastDetectionType

Enum (0, 1 or 2) corresponding to the type of rectangle found 0. Correctly formated rectangle

1. Wrong perspective, bad angle
2. Too far

Returned image

Prop	Params	Type	Description
onPictureTaken	data	object	Returns the captured image in an object { croppedImage: ('URI or BASE64 string'), initialImage: 'URI or BASE64 string', rectangleCoordinates: 'object of coordinates' }

Save in app document

If you want to use saveInAppDocument options, then don't forget to add those raws in .plist :

<key>LSSupportsOpeningDocumentsInPlace</key>
<true/>

If you prefer manual installation

1. In XCode, in the project navigator, right click Libraries ➜ Add Files to [your project's name]
2. Go to node_modules ➜ react-native-pdf-scanner and add RNPdfScanner.xcodeproj
3. In XCode, in the project navigator, select your project. Add libRNPdfScanner.a to your project's Build Phases ➜ Link Binary With Libraries
4. Run your project (Cmd+R)<