Implementing QR code generation in Vue3 requires the use of a third-party library to process the logic of generating QR codes. Commonly used libraries areqrcodeandvue-qrcode。
1. Basic usage implementation
The steps to generate QR code using the qrcode library in Vue3 are as follows:
- Install the qrcode library:
npm install qrcode
- Introduce the qrcode library into components that need to generate QR codes:
import qrcode from 'qrcode';
- Add a variable to the component's data
qrCodeDataUsed to store the generated QR code data:
data() {
return {
qrCodeData: ''
};
},
- Generate QR code data in the mounted hook function of the component:
mounted() {
const qrCodeData = 'your-data'; // Replace with the data you need to generate a QR code (qrCodeData, (err, url) => {
if (err) {
(err);
} else {
= url;
}
});
},
- Use the img tag in the template to display the generated QR code:
<template>
<div>
<img :src="qrCodeData" alt="QR Code">
</div>
</template>
The above code uses the () method to convert the generated QR code data into DataURL format and assigns the DataURL to the qrCodeData variable. Then use the img tag in the template to display the QR code.
You can also use the methods and parameters provided by other qrcode libraries to customize the size, color and other attributes of the QR code. For example, you can use the() method to render the QR code into the canvas element, use the margin parameter to set the margin of the QR code, etc.
2. toDataURL() method
The toDataURL() method is used to convert the generated QR code into a data URL. Data URL is a method of embedding file data into HTML documents in the form of a URL, which can directly display images in the browser.
The toDataURL() method accepts a configuration object as a parameter, which can contain the following properties:
- text: The text content to be encoded as a QR code (required).
- width: The width of the QR code (optional, default value is 256).
- height: The height of the QR code (optional, the default value is 256).
- correctLevel: Error correction level, optional values are "L", "M", "Q", and "H". The higher the level, the stronger the error correction ability, but the QR code size will also become larger (optional, the default value is "M").
Here is a sample code that uses Vue3 and qrcode libraries to generate a QR code and converts it into a data URL:
<template>
<div>
<img :src="qrcodeDataURL" alt="QR code" />
</div>
</template>
<script>
import QRCode from 'qrcode'
export default {
data() {
return {
qrcodeDataURL: ''
}
},
mounted() {
const text = 'Hello, Vue3!'
const width = 200
const height = 200
const correctLevel = 'M'
({
text,
width,
height,
correctLevel
}).then((url) => {
= url
}).catch((error) => {
(error)
})
}
}
</script>
In the example above, we first imported the qrcode library and called the toDataURL() method in the mounted lifecycle hook. We pass a configuration object that contains the text content of the QR code to be generated, the width and height of the QR code, and the error correction level. Finally, we assign the generated data URL to the component's qrcodeDataURL property and display it using the img tag in the template.
When the component is mounted on the page, the qrcode library generates a QR code and converts it into a data URL. This data URL will be assigned to the qrcodeDataURL property, and then displayed using the img tag in the template. In this way, we can see the generated QR code on the page.
3. toCanvas() method
The toCanvas() method is used to generate a QR code and render it on a canvas element.
The toCanvas() method has the following parameters:
- canvas: An HTMLCanvasElement object representing the canvas element to render the QR code.
- content: A string representing the content of the QR code to be generated.
- options: an optional object that represents the configuration option for generating QR codes.
The sample code is as follows:
import qrcode from 'qrcode';
export default {
mounted() {
const canvas = this.$; // Get a reference to the canvas element const content = ''; // Contents to generate QR code
// Generate QR code and render it on canvas (canvas, content, {
margin: 1,
color: {
dark: '#000000', // Black light: '#ffffffff' // White }
}, (error) => {
if (error) {
(error);
} else {
('QR code generation successfully');
}
});
},
};
In the example above, we first get a reference to a canvas element using this.$. Then, we call the() method and pass the canvas element, the QR code content to be generated and the configuration options to the method as parameters. Finally, we use the callback function to process the result of generating the QR code. If the generation is successful, the success information will be output, otherwise the error information will be output.
4. Create() method
The create() method is a method used to generate QR code images. It accepts a parameter object that configures the various properties of the generated QR code.
The following are the parameters and examples of the create() method:
Properties of parameter objects:
text: The text content to be encoded as a QR code image. For example: text: ‘’
options: The attribute object used to configure the QR code. It contains the following properties:
- width: The width of the QR code image (pixel). For example: width: 200
- height: The height (pixel) of the QR code image. For example: height: 200
- colorDark: The color value (CSS color) of the dark color (foreground color) of the QR code. For example: colorDark: ‘#000000’
- colorLight: The color value (CSS color) of the bright color (background color) of the QR code. For example: colorLight: ‘#ffffff’
- correctLevel: The error correction level of the QR code. Optional values are ‘L’ (low), ‘M’ (medium), ‘Q’ (high), ‘H’ (high). For example: correctLevel: ‘H’
Sample code:
import { create } from 'qrcode';
export default {
mounted() {
const qrcodeOptions = {
text: '',
options: {
width: 200,
height: 200,
colorDark: '#000000',
colorLight: '#ffffff',
correctLevel: 'H'
}
};
create(, , (canvas) => {
// Insert the generated QR code image into the page ('qrcode-container').appendChild(canvas);
});
}
}
In the above example code, the mounted hook function uses the create() method of the qrcode library to generate a QR code image and insert it into an HTML element with id 'qrcode-container'. The text content of the generated QR code image is '', the width and height are 200 pixels, the dark color is black, the bright color is white, and the error correction level is the highest.
5. QRCodeRenderersOptions() method
In Vue3, the qrcode library is a library used to generate QR codes. QRCodeRenderersOptions() is a method in this library to configure rendering options for QR codes.
The parameter of the method can be an object containing the following properties:
-
width: The width of the QR code can be an integer value, the default is 256. -
height: The height of the QR code can be an integer value, the default is 256. -
margin: The spacing between the QR code and the surrounding border can be an integer value, and the default is 4. -
color: The color of the QR code can be a CSS color value, which defaults to black. -
background: The background color of the QR code can be a CSS color value, which is white by default. -
scale: The magnification of the QR code can be an integer value, and the default is 4. -
type: The encoding type of the QR code can be a string value, the default is'image/png'。
Here is an example showing how to configure the rendering options for QR code using the QRCodeRenderersOptions() method:
import { createQrcode } from 'qrcode'
const options = {
width: 200,
height: 200,
margin: 2,
color: '#ff0000',
background: '#ffffff',
scale: 5,
type: 'image/jpeg'
}
const qrCodeData = ''
const canvas = ('qrCodeCanvas')
createQrcode(canvas, qrCodeData, options)
In the above example, we first imported the createQrcode method and the qrcode library. Then, we define an options object that contains various rendering options, such as width, height, color, etc. Next, we define a qrCodeData variable that stores the data to generate the QR code. Finally, we use the createQrcode method to draw the QR code on a canvas element, and pass the qrCodeData and options parameters at the same time.
In this way, you can use the QRCodeRenderersOptions() method to configure the rendering options of the QR code and generate a custom style QR code.
This is the end of this article about using the qrcode library to implement QR code generation in Vue3. For more related content on Vue3 qrcode QR code generation, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!