NativeScript DrawingPad

NativeScript plugin to provide a way to capture any drawing (signatures are a common use case) from the device. You can use this component to capture really anything you want that can be drawn on the screen.

Installation

From your command prompt/termial go to your app’s root folder and execute:

NativeScript 7+:

ns plugin add @nativescript-community/drawingpad

NativeScript < 7:

tns plugin add nativescript-drawingpad

Samples

Android	iOS

Native Libraries:

Video Tutorial

Egghead lesson - https://egghead.io/lessons/javascript-capture-drawings-and-signatures-in-a-nativescript-app

Written Tutorial

Blog post using Angular - http://tylerablake.com/nativescript/2019/05/02/capturing-signatures.html

Usage

XML:

<Page xmlns="http://schemas.nativescript.org/tns.xsd" xmlns:DrawingPad="@nativescript-community/drawingpad" loaded="pageLoaded">
    <ActionBar title="NativeScript-DrawingPad" ></ActionBar>
    <ScrollView>
        <StackLayout>
            <DrawingPad:DrawingPad
            height="400"
            id="drawingPad"
            penColor="{{ penColor }}" penWidth="{{ penWidth }}" ></DrawingPad:DrawingPad>
        </StackLayout>
    </ScrollView>
</Page>

TS:

import { Frame, ImageSource } from '@nativescript/core';
import { DrawingPad } from '@nativescript-community/drawingpad';
// To get the drawing...
public getMyDrawing() {
    const drawingPad = Frame.topmost().getViewById('myDrawingPad');
    drawingPad.getDrawing().then((res) => {
        console.log(res);
        // At this point you have a native image (Bitmap on Android or UIImage on iOS)
        // so lets convert to a NS Image using the ImageSource
        const img = new ImageSource(res); // this can be set as the `src` of an `Image` inside your NSapplication now.
        // now you might want a base64 version of the image
        const base64imageString = image.toBase64String('jpg'); // if you need it as base64
    });
}
// If you want to clear the signature/drawing...
public clearMyDrawing() {
    const drawingPad = Frame.topmost().getViewById('myDrawingPad');
    drawingPad.clearDrawing();
}

Angular:

import { Component, ElementRef, ViewChild } from '@angular/core';
import { registerElement } from '@nativescript/angular';
import { ImageSource } from '@nativescript/core';
import { DrawingPad } from '@nativescript-community/drawingpad';
registerElement('DrawingPad', () => DrawingPad);
@Component({
  selector: 'drawing-pad-example',
  template: `
    <ScrollView>
      <StackLayout>
        <DrawingPad
          #DrawingPad
          height="400"
          id="drawingPad"
          penColor="#ff4081"
          penWidth="3"
        >
        </DrawingPad>
        <StackLayout orientation="horizontal">
          <Button text="Get Drawing" (tap)="getMyDrawing()"></Button>
          <Button text="Clear Drawing" (tap)="clearMyDrawing()"></Button>
        </StackLayout>
      </StackLayout>
    </ScrollView>
  `
})
export class DrawingPadExample {
  @ViewChild('DrawingPad') DrawingPad: ElementRef;
  getMyDrawing(args) {
    // get reference to the drawing pad
    const pad = this.DrawingPad.nativeElement;
    // then get the drawing (Bitmap on Android) of the drawingpad
    let drawingImage;
    pad.getDrawing().then((data) => {
        console.log(data);
        // At this point you have a native image (Bitmap on Android or UIImage on iOS)
        // so lets convert to a NS Image using the ImageSource
        const image = new ImageSource(data); // this can be set as the `src` of an `Image` inside your NS
        drawingImage = image; // to set the src of an Image if needed.
        // now you might want a base64 version of the image
        const base64imageString = image.toBase64String('jpg'); // if you need it as base64
        console.log('::IMG_BASE64::', base64imageString);
      },
      (err) => {
        console.log(err);
      }
    );
  }
  clearMyDrawing(args) {
    const pad = this.DrawingPad.nativeElement;
    pad.clearDrawing();
  }
}

Properties

penColor - (Color) - optional
Property to specify the pen (stroke) color to use.

penWidth - (int) - optional
Property to specify the pen (stroke) width to use.

clearOnLongPress - (boolean = true) - optional iOS Only
Gets/sets whether a long press will clear the view.

Methods

getDrawing() - Promise (returns image if successful)

getDrawingAsBase64(format?: “png” | “jpg” | “jpeg”) - Promise (returns image as base64 string if successful)

clearDrawing() - clears the drawing from the DrawingPad view.

getDrawingSvg() - Promise (returns a Scalable Vector Graphics document)

Android Only

• getTransparentDrawing() - Promise (returns a bitmap with a transparent background)