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Angular Sample To Generate QR Code Using @techiediaries/ngx-qrcode


In this article, we are going to explore and implement a QR Code generator in the angular application using @techiediaries/ngx-qrcode library.

QR Code:

The quick response, or QR, Code is a two-dimensional version of the BarCode able to convey a wide variety of information almost instantly with the scan of a mobile device.

An Overview On @techiediaries/ngrx-qrcode And It's Configurations:

The @techiediaries/ngrx-qrcode is the angular library to generate a QR Code in an angular application.
The 'NgxQRCodeModule' is QR Code angular module, that will be imported from the '@tehiediaries/ngrx-qrcode'. Using this library we can set up the QRCode generator angular component with basic configuration values. All the configurations are accepted as 'Input()' directive values of the QR Code component. Configuration input parameters are as follows:
  • elementType - this input parameter is used to define the rendering type of QR Code whether like an Image or Canvas.
  • cssClass - this input parameter to add custom CSS class.
  • alt - this input parameter to render string value in case of failed render code.
  • value - this input parameter accepts our secret data or value which will be encrypted and render in QR Code. This is the QR Scanner going to get on scanning our QR Code.
  • version - this represents the version number.
  • errorCorrectionLevel - this input parameter is to define the level of damage to the QR Code. Based on this level QL code image will be generated, by any reason image got damaged or defaced then also QR code scanner can able to scan it.
  • margin - this input parameter defines the margin around the QR Code around it.
  • scale - this input parameter to resize or scale the lines in the QR Code.
  • width- this input parameter to define the size to render the QR Code image.
  • colorDark - this input parameter to define the color of the lines of the QR Code.
  • colorLight - this input parameter to define the background color of the QR Code.

Create An Angular Sample Application:

To implement a QR Code generator let's begin by creating an angular sample application.
Command To Install Angular CLI:(If not installed on your system previously)

npm install -g @angular/cli
Angular CLI Command To Create Angular App:

ng new your_project_name
Command To Run App:

ng serve

Install QR Code NPM Package:

To integrate the QR Code generator we need to install '@techiediaries/ngx-qrcode' third-party library.
Command To Install QR Code:

npm install @techiediaries/ngx-qrcode --save
After running the command check for its presence in the 'dependencies' property in package.json as below.

Add NgxQRCodeModule Into AppModule:

Now import NgxQRCodeModule into AppModule to make QR Code features available at the time of application starts.
src/app.module.ts:
import { NgxQRCodeModule } from '@techiediaries/ngx-qrcode';
// code hidden for display purpose

@NgModule({
  imports: [NgxQRCodeModule]
})
export class AppModule {}

Declare QR Code Component:

Let's add the QR Code component HTML tab in the app.component.html file as below.
src/app.component.html:
<ngx-qrcode [value]='value'></ngx-qrcode>
'[value]' input property it accepts that secret data stored by QR Code. This data will be the heart of the QR Code. The QR Code scanner will fetch this data on scanning.
src/app.component.ts:
export class AppComponent {
  value = 'This is my barcode secret data';
}
'value' variable that contains the data for our bar code.

Now run the application and the QR Code appears as below.

And use the scanner on your mobile, we can download free scanners also to use. After scanning you can observe the output as below.

elementType Input Property:

elementType Input property of QR Code component to define whether to render the QR Code as Image or Canvas. The '@techiediaries/ngx-code' provides enum with 3 different values like:
  • NgxQrCodeElementTypes.URL,
  • NgxQrCodeElementTypes.IMG,
  • NgxQrCodeElementTypes.CANVAS
Enum types 'URL', 'IMG' both render image tag with src value as base64 image(Note: don't know why they provided 2 types of enum type for same type rendering). By default QR Code component render with of elementType value with 'URL'.

Let's generate the Canvas image for QR Code.
src/app.component.ts:
import { NgxQrcodeElementTypes } from '@techiediaries/ngx-qrcode';
// some code hidden for display purpos
export class AppComponent {
  value = 'This is my barcode secret data';
  elementType = NgxQrcodeElementTypes.CANVAS;
}
  • (Line: 1) imported 'NgxQrCodeElementTypes' enum from '@techiediaries/ngx-qrcode' library.
  • (Line: 5) for 'elementType' variable assigns the value of 'CANVAS'.
src/app.component.html:
<ngx-qrcode 
[value]='value' 
[elementType]='elementType'
></ngx-qrcode>
  • (Linet: 3) '[elementType]' input directive declared.
Now run the application and open chrome browser developer's tools to check rendered HTML output.

errorCorrectionLevel Input Propery:

QR Codes in the physical environment is their ability to sustain "damage" and continue to function even when the part of the QR Code image is obscured, defaced, or removed. So we can determine or set the QR Code image to work with a range of parameters using the 'error correction level'.

There are 4 error correction levels used for QR codes, with each one adding different amounts of "backup" data depending on how much damage the QR code is expected to suffer in its intended environment, and hence how much error correction may be required.
  • Level L- up to 7% damage.
  • Level M - up to 15% damage.
  • Level Q - up to 25% damage.
  • Level H - up to 30% damage.
The '@techiediaries/ngx-qrcode' library provides enum like 'NgxQrcodeErrorCorrectionLevels' with 4  values like:
  • NgxQrcodeErrorCorrectionLevels.LOW
  • NgxQrcodeErrorCorrectionLevels.MEDIUM
  • NgxQrcodeErrorCorrectionLevels.QUARTILE
  • NgxQrcodeErrorCorrectionLevels.HIGH
Default value used by QR Code component for 'errorCorrectionLevel' property is 'NgxQrcodeErrorCorrectionLevels.MEDIUM'. To change the default value do as below.
src/app.component.ts:
import { NgxQrcodeErrorCorrectionLevels } from '@techiediaries/ngx-qrcode';

export class AppComponent {
  value = 'This is my barcode secret data';
  errorCorrectionLevel = NgxQrcodeErrorCorrectionLevels.HIGH
}
src/app.component.html:
<ngx-qrcode 
[value]='value' 
[errorCorrectionLevel] = 'errorCorrectionLevel'

></ngx-qrcode>

From the above image, we can observe an increase in damage level the change in the scales of the QR Code.

margin Input Property:

'margin' input property applies the margin for QR Code image rendering. The default value set for 'margin' property is '4'.
src/app.component.ts:
export class AppComponent {
  value = 'This is my barcode secret data';
  margin = 80;
}
src/app.component.html:
<ngx-qrcode 
[value]='value' 
[margin] = 'margin'
></ngx-qrcode>

scale Input Property:

'scale' input property helps to increase or reduce the lines or stripes or scales of the QR Code. The default 'scale' was set to '4'.
src/app.component.ts:
export class AppComponent {
  value = 'This is my barcode secret data';
  scale = 15
}
src/app.component.html:
<ngx-qrcode 
[value]='value' 
[scale]='scale'

></ngx-qrcode>

colorDark Input Property:

'colorDark' input property to change scales or lines of the QRCode. The default 'colorDark' set to 'black' color.
src/app.component.ts:
export class AppComponent {
  value = 'This is my barcode secret data';
  redColor = '#FF0000'
}
src/app.component.html:
<ngx-qrcode 
[value]='value' 
[colorDark]='redColor'

></ngx-qrcode>

colorLight Input Property:

'colorLight' input property is used to change the background color of the QR Code. The default background color is white.
src/app.component.ts:
export class AppComponent {
  value = 'This is my barcode secret data';
  backgroundColor = '#33BBFF'
}
src/app.component.html:
<ngx-qrcode 
[value]='value' 
[colorLight]='backgroundColor'

></ngx-qrcode>

Wrapping Up:

Hopefully, I think this article delivered some useful information on creating a QR Code generator in Angular application. I love to have your feedback, suggestions, and better techniques in the comment section below.

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