react-native-drawing-canvas v1.1.0

react-native-signature-canvas

React Native Signature Component based Canvas for Android && IOS && expo

• Supports Android and iOS and Expo
• Pure JavaScript implementation with no native dependencies
• Tested with RN 0.50
• Core use signature_pad.js
• Only depend on react and react native
• Generates a base64 encoded png image of the signature Note: Expo support for React Native Signature Canvas v1.5.0 started with Expo SDK v33.0.0.

Installation(for React Native V0.60.0 or Expo SDK v35.0.0)

npm install --save react-native-signature-canvas

Installation(for React Native V0.5x.x or Expo SDK < v33)

npm install --save react-native-signature-canvas@1.4.2

Usage

import Signature from 'react-native-signature-canvas';

Properties

Methods

You need to use ref like:

import SignatureScreen from 'react-native-signature-canvas';

const Sign = ({text, onOK}) => {
  const ref = useRef();

  const handleSignature = signature => {
    console.log(signature);
    onOK(signature);
  };

  const handleEmpty = () => {
    console.log('Empty');
  }

  const handleClear = () => {
    console.log('clear success!');
  }

  const handleEnd = () => {
      ref.current.readSignature();
  }

  return (
    <SignatureScreen
        ref={ref}
        onEnd={handleEnd}
        onOK={handleSignature} 
        onEmpty={handleEmpty}
        onClear={handleClear}
        autoClear={true} 
        descriptionText={text}
    />
  );
}

export default Sign;

Save Base64 Image as File

If you use expo, you can use expo-file-system for save base64 image as local file, if you use react-native-cli, use react-native-fs.

import * as FileSystem from 'expo-file-system';

const handleSignature = signature => {
    const path = FileSystem.cacheDirectory + 'sign.png';
    FileSystem.writeAsStringAsync(path, signature.replace('data:image/png;base64,', ''), {encoding: FileSystem.EncodingType.Base64}).then(res => {
      console.log(res);
      FileSystem.getInfoAsync(path, {size: true, md5: true}).then(file => {
        console.log(file);
      })
    }).catch(err => {
      console.log("err", err);
    })
};

Basic parameters

<Signature
  // handle when you click save button
  onOK={(img) => console.log(img)}
  onEmpty={() => console.log("empty")}
  // description text for signature
  descriptionText="Sign"
  // clear button text
  clearText="Clear"
  // save button text
  confirmText="Save"
  // String, webview style for overwrite default style, all style: https://github.com/YanYuanFE/react-native-signature-canvas/blob/master/h5/css/signature-pad.css
  webStyle={`.m-signature-pad--footer
    .button {
      background-color: red;
      color: #FFF;
    }`
  }
  autoClear={true}
  imageType={"image/svg+xml"}
/>

If you create your own triggers for the readSignature and/or clearSignature you can hide the built in Clear and Save buttons with css styles passed into the webStyle property.

const webStyle = `.m-signature-pad--footer
	.save {
		display: none;
	}
	.clear {
		display: none;
	}
`;
...
  <Signature
    webStyle={webStyle}
    onOK={handleOK}
    onEmpt={handleEmpty}
    onEnd={handleEnd}
  />

Example

• Android

• iOS

import React from 'react';
import { StyleSheet, Text, View, Image } from 'react-native';
import Signature from 'react-native-signature-canvas';

export const SignatureScreen = () => {
  const [signature, setSign] = useState(null);

  const handleSignature = signature => {
    console.log(signature);
    setSign(signature);
  };

  const handleEmpty = () => {
    console.log('Empty');
  }

  const style = `.m-signature-pad--footer
    .button {
      background-color: red;
      color: #FFF;
    }`;
  return (
    <View style={{ flex: 1 }}>
      <View style={styles.preview}>
        {this.state.signature ? (
          <Image
            resizeMode={"contain"}
            style={{ width: 335, height: 114 }}
            source={{ uri: this.state.signature }}
          />
        ) : null}
      </View>
      <Signature
        onOK={this.handleSignature}
        onEmpty={this.handleEmpty}
        descriptionText="Sign"
        clearText="Clear"
        confirmText="Save"
        webStyle={style}
      />
    </View>
  );
}

const styles = StyleSheet.create({
  preview: {
    width: 335,
    height: 114,
    backgroundColor: "#F8F8F8",
    justifyContent: "center",
    alignItems: "center",
    marginTop: 15
  },
  previewText: {
    color: "#FFF",
    fontSize: 14,
    height: 40,
    lineHeight: 40,
    paddingLeft: 10,
    paddingRight: 10,
    backgroundColor: "#69B2FF",
    width: 120,
    textAlign: "center",
    marginTop: 10
  }
});