QRCode Overview

Getting Started with QRcode Web Component

Smart UI for Web Components is distributed as smart-webcomponents NPM package. You can also get the full download from our website with all demos from the Download page.

Setup the QRcode

Smart UI for Web Components is distributed as smart-webcomponents NPM package

  1. Download and install the package.

    npm install smart-webcomponents

  2. Once installed, import the QRcode module in your application.

    <script type="module" src="node_modules/smart-webcomponents/source/modules/smart.qrcode.js"></script>

  3. Adding CSS reference

    The smart.default.css CSS file should be referenced using following code.

    <link rel="stylesheet" type="text/css" href="node_modules/smart-webcomponents/source/styles/smart.default.css" />

  4. Add the QRcode tag to your Web Page

    <smart-qrcode id="qrcode"></smart-qrcode>

  5. Create the QRcode Component

    The following code adds a simple QR Code to the page.

    <!DOCTYPE html>
    <html lang="en">
    <head>
     <link rel="stylesheet" href="../../source/styles/smart.base.css" type="text/css" />
     <script type="text/javascript" src="../../source/smart.element.js"></script>
     <script type="text/javascript" src="../../source/smart.barcode.js"></script>
     <script type="text/javascript" src="../../source/smart.qrcode.js"></script>
    </head>
    <body>
     <smart-qrcode value="HTMLELEMENTS.COM"></smart-qrcode>
    </body>
    </html>

    Demo

    The qrcode element supports all officialy adopted encoding modes as per ISO 2015:

    • Numeric
    • Alphanumeric
    • Byte / Binary
    • Kanji

    <!DOCTYPE html>
        <html lang="en">
        <head>
            <link rel="stylesheet" href="../../source/styles/smart.base.css" type="text/css" />
            <script type="text/javascript" src="../../source/smart.element.js"></script>
            <script type="text/javascript" src="../../source/smart.barcode.js"></script>
            <script type="text/javascript" src="../../source/smart.qrcode.js"></script>
        </head>
        <body>
            <smart-qrcode value="こんにちは世界" display-label="true"></smart-qrcode>
        </body>
        </html>

    Demo

    The QR Code supports four different Error Correction Levels - L, M, Q, H.
    As per the ISO standard, the Error Correction Level L is the lowest and the H the highest.
    The higher the Error Correction Level, the higher is the amount of data that can be retrieved if part of the QR Code is damaged or hidden.

                        <smart-qrcode value="HTMLELEMENTS.COM" error-correction-level="H"></smart-qrcode>
                        <smart-qrcode value="HTMLELEMENTS.COM" error-correction-level="L"></smart-qrcode>
                    

    Demo

    When the Error Correction Level is sufficiently big, it is possible to embed an Image inside the QR Code.
    The maximum size of the image depends on the Error Correction Level and the QR Code value.

                        <smart-qrcode value="HTMLELEMENTS.COM" error-level="H" square-width="13" 
                        embed-image="https://www.htmlelements.com/favicon-32x32.png" image-width="50" image-height="50">
                        </smart-qrcode>
                    

    Demo

    Appearance

    The rendering mode is set using the renderAs property - svg(default) and canvas are supported.
    The recommended rendering mode is svg as the image quality remains the same as the QR Code is zoomed in.

    <!DOCTYPE html>
        <html lang="en">
        <head>
            <link rel="stylesheet" href="../../source/styles/smart.base.css" type="text/css" />
            <script type="text/javascript" src="../../source/smart.element.js"></script>
            <script type="text/javascript" src="../../source/smart.barcode.js"></script>
            <script type="text/javascript" src="../../source/smart.qrcode.js"></script>
        </head>
        <body>
            <smart-qrcode render-as="svg" value="12345"></smart-qrcode>
            <smart-qrcode render-as="canvas" value="12345"></smart-qrcode>
        </body>
        </html>

    Demo

    The QR Code's color, background color and square dimensions can be customized by their respective properties:

    <smart-qrcode value="HTMLELEMENTS.COM" value="HTMLELEMENTS.COM" line-color="green" background-color="#D3D3D3" square-width="10"></smart-qrcode>

    Demo

    The label of the QR Code can be set to visible or hidden with displayLabel. Its color, font, size, margins and position can be customized by their respective properties. When the qrcode is rendered as svg, the label can also be customized with CSS.

    <smart-qrcode value="HTMLELEMENTS.COM" line-color="orange" display-label="true" label-position="top" label-font-size="20" label-color="orange"></smart-qrcode>

    Behavior

    Every valid qrcode can be exported to a downloadable file. The export method supports the following formats:

    • svg
    • png
    • jpg
    <script>
        function exportQRCode(){
            let qrcode1 = document.getElementById('export-qrcode');
            qrcode1.export('png', 'my-qrcode');
        }
    </script>
    <smart-qrcode id="export-qrcode" value="A2402B" label-position="top" label-font-size="30" label-color="orange" label-font="arial" line-color="orange"></smart-qrcode>
    <button onclick="exportQRCode()">Download</button>

    Demo

    Smart.QRcode contains a built-in validator, which depends on the qrcode type.
    In the case of a invalid value, the isValid method will return false and the invalid event will be triggered.

    The invalid event.detail contains multiple values that can indicate the validity of the qrcode:

    • invalidCharacters - An array indicating the invalid characters.
    • patternValidity - A boolean indicating the validity of the qrcode pattern.
    • lengthValidity - A boolean indicating the validity of the qrcode length.

    The demo below will output the illegal charcters of the qrcode:

    <!DOCTYPE html>
    <html lang="en">
    <head>
     <link rel="stylesheet" href="../../source/styles/smart.base.css" type="text/css" />
     <script type="text/javascript" src="../../source/smart.element.js"></script>
     <script type="text/javascript" src="../../source/smart.barcode.js"></script>
     <script type="text/javascript" src="../../source/smart.qrcode.js"></script>
     <script>
     window.onload = function(){
        var qrcode2 = document.getElementById('invalid-qrcode');
        const OnInvalid = (event) => {
                let invalidChars = event.detail.invalidCharacters;
                document.getElementById("invalid-box").textContent+= invalidChars.join(' and ')
            };
    
        qrcode2.addEventListener("invalid", OnInvalid);
    }
     function changeValue(){
        qrcode2 = document.getElementById('invalid-qrcode');
        qrcode2.value = "AB1230ШЪ"
    }
     </script>
    </head>
    <body>
     <smart-qrcode id="invalid-qrcode" value="AB1230"></smart-qrcode>
     <button onclick="changeValue()">Change Value</button>   
     <h3 id="invalid-box">Invalid symbols:</h3>
    </body>
    </html>

    Demo


Another option is to create the QRcode is by using the traditional Javascript way:
	const qrcode = document.createElement('smart-qrcode');

	qrcode.disabled = true;
	document.body.appendChild(qrcode);
		

Smart framework provides a way to dynamically create a web component on demand from a DIV tag which is used as a host. The following imports the web component's module and creates it on demand, when the document is ready. The #qrcode is the ID of a DIV tag.

	import "../../source/modules/smart.qrcode.js";

	document.readyState === 'complete' ? init() : window.onload = init;

	function init() { 
		const qrcode = new Smart.QRcode('#qrcode', [object Object]);
	}
	

  • Open the page in your web server.
  • Create, Append, Remove, Get/Set Property, Invoke Method, Bind to Event


    Create a new element:
    	const qrcode = document.createElement('smart-qrcode');
    	

    Append it to the DOM:
    	document.body.appendChild(qrcode);
    	

    Remove it from the DOM:
    	qrcode.parentNode.removeChild(qrcode);
    	

    Set a property:
    	qrcode.propertyName = propertyValue;
    	

    Get a property value:
    	const propertyValue = qrcode.propertyName;
    	

    Invoke a method:
    	qrcode.methodName(argument1, argument2);
    	

    Add Event Listener:
    	const eventHandler = (event) => {
    	   // your code here.
    	};
    
    	qrcode.addEventListener(eventName, eventHandler);
    	

    Remove Event Listener:
    	qrcode.removeEventListener(eventName, eventHandler, true);
    	

    Using with Typescript

    Smart Web Components package includes TypeScript definitions which enables strongly-typed access to the Smart UI Components and their configuration.

    Inside the download package, the typescript directory contains .d.ts file for each web component and a smart.elements.d.ts typescript definitions file for all web components. Copy the typescript definitions file to your project and in your TypeScript file add a reference to smart.elements.d.ts

    Read more about using Smart UI with Typescript.

    Getting Started with Angular QRcode Component

    Setup Angular Environment

    Angular provides the easiest way to set angular CLI projects using Angular CLI tool.

    Install the CLI application globally to your machine.

    npm install -g @angular/cli

    Create a new Application

    ng new smart-angular-qrcode

    Navigate to the created project folder

    cd smart-angular-qrcode

    Setup the QRcode

    Smart UI for Angular is distributed as smart-webcomponents-angular NPM package

    1. Download and install the package.
      npm install smart-webcomponents-angular
    2. Once installed, import the QRcodeModule in your application root or feature module.

      app.module.ts

      import { NgModule } from '@angular/core';
      import { BrowserModule } from '@angular/platform-browser';
      import { ButtonModule } from 'smart-webcomponents-angular/button';
      import { QRcodeModule } from 'smart-webcomponents-angular/qrcode';
      
      import { AppComponent } from './app.component';
      
      @NgModule({
          declarations: [ AppComponent ],
          imports: [ BrowserModule, QRcodeModule, ButtonModule ],
          bootstrap: [ AppComponent ],
      	entryComponents: [ AppComponent ]
      })
      
      export class AppModule { }
      	

    3. Adding CSS reference

      The following CSS file is available in ../node_modules/smart-webcomponents-angular/ package folder. This can be referenced in [src/styles.css] using following code.

      	@import 'smart-webcomponents-angular/source/styles/smart.default.css';

      Another way to achieve the same is to edit the angular.json file and in the styles add the style.

      	"styles": [
      		"node_modules/smart-webcomponents-angular/source/styles/smart.default.css"
      	]
      	
    4. Example


      app.component.html

       
      <div class="container">
          <h3>QR Code is a two-dimensional version of the barcode. It typically contains data that points to a website or application.</h3>
          <smart-qrcode #qrcode value="HTMLELEMENTS.COM"></smart-qrcode>
      </div>
      		

      app.component.ts

       
      import { Component, ViewChild, OnInit, AfterViewInit } from '@angular/core';
      import { QRcodeComponent } from 'smart-webcomponents-angular/qrcode';
      
      
      @Component({
          selector: 'app-root',
          templateUrl: './app.component.html',
      	styleUrls: ['./app.component.css']
      })
      
      export class AppComponent implements AfterViewInit, OnInit {	
      	@ViewChild('qrcode', { read: QRcodeComponent, static: false }) qrcode: QRcodeComponent;
      	
       
      	ngOnInit(): void {
      		// onInit code.
      	}
      
      	ngAfterViewInit(): void {
      		// afterViewInit code.
      		this.init();
          }
      		
      	init(): void {
      		// init code.
      	    
          // no code
      
      	}	
      }
      		

      app.module.ts

       
      import { NgModule } from '@angular/core';
      import { BrowserModule } from '@angular/platform-browser';
      import { ButtonModule } from 'smart-webcomponents-angular/button';
      import { QRcodeModule } from 'smart-webcomponents-angular/qrcode';
      
      import { AppComponent } from './app.component';
      
      @NgModule({
          declarations: [ AppComponent ],
          imports: [ BrowserModule, QRcodeModule, ButtonModule ],
          bootstrap: [ AppComponent ],
      	entryComponents: [ AppComponent ]
      })
      
      export class AppModule { }
      		


    Running the Angular application

    After completing the steps required to render a QRcode, run the following command to display the output in your web browser

    ng serve
    and open localhost:4200 in your favorite web browser.

    Read more about using Smart UI for Angular: https://www.htmlelements.com/docs/angular-cli/.

    Getting Started with React QRcode Component

    Setup React Environment

    The easiest way to start with React is to use create-react-app. To scaffold your project structure, follow the installation instructions.

    	npm install -g create-react-app
    	create-react-app my-app
    	cd my-app
    	npm start
    	

    Preparation

    Open src/App.js andsrc/App.css

    1. Remove everything inside the App div tag in src/App.js:
      <div className="App"> </div>
    2. Remove the logo.svg import
    3. Remove the contents of src/App.css
    4. Remove src/logo.svg

    Setup the QRcode

    Smart UI for React is distributed as smart-webcomponents-react NPM package

    1. Download and install the package.
      npm install smart-webcomponents-react
    2. Once installed, import the React QRcode Component and CSS files in your application and render it app.js

      import 'smart-webcomponents-react/source/styles/smart.default.css';
      import React from "react";
      import ReactDOM from "react-dom";
      import { QRcode } from 'smart-webcomponents-react/qrcode';
      
      class App extends React.Component {
      
      	componentDidMount() {
      	}
      
      	render() {
      		return (
      			<div class="container">
      					<h3>QR Code is a two-dimensional version of the barcode. It typically contains data that points to a website or application.</h3>
      					<QRcode value="HTMLELEMENTS.COM"></QRcode>
      			</div>
      		);
      	}
      }
      
      ReactDOM.render(<App />, document.querySelector("#root"));
      
      export default App;
      	

    Running the React application

    Start the app with
    npm start
    and open localhost:3000 in your favorite web browser to see the output.

    Read more about using Smart UI for React: https://www.htmlelements.com/docs/react/.

    Getting Started with Vue QRcode Component


    Setup Vue Environment

    We will use vue-cli to get started. Let's install vue-cli

    npm install -g @vue/cli

    Then we can start creating our Vue.js projects with:

    vue create my-project

    Setup the QRcode

    Open the "my-project" folder and run:

    npm install smart-webcomponents

    Setup with Vue 3.x

    • Make Vue ignore custom elements defined outside of Vue (e.g., using the Web Components APIs). Otherwise, it will throw a warning about an Unknown custom element, assuming that you forgot to register a global component or misspelled a component name.

      Open src/main.js in your favorite text editor and change its contents to the following:

      main.js

      import { createApp } from 'vue'
      import App from './App.vue'
      
      const app = createApp(App)
      
      app.config.isCustomElement = tag => tag.startsWith('smart-');
      app.mount('#app')
      		
    • Open src/App.vue in your favorite text editor and change its contents to the following:

      App.vue

      <template>
        <div class="vue-root">
          <div class="container">
              <h3>QR Code is a two-dimensional version of the barcode. It typically contains data that points to a website or application.</h3>
      		<smart-qrcode  value="HTMLELEMENTS.COM"></smart-qrcode>
          </div>
        </div>
      </template>
      
      <script>
      import { onMounted } from "vue";
      import "smart-webcomponents/source/styles/smart.default.css";
      import "smart-webcomponents/source/modules/smart.qrcode.js";
      
      export default {
        name: "app",
        setup() {
          onMounted(() => {});
        }
      };
      </script>
      		
      We can now use the smart-qrcode with Vue 3. Data binding and event handlers will just work right out of the box.

    Read more about using Smart UI for Vue: https://www.htmlelements.com/docs/vue/.