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Generate Barcode with Golang

How to Generate Barcode in Golang?

Scan or generate QR code with Go language
2. Generate QR code from text with Go language
3. Scan QR code - Go language
Conclusion

Scan or generate QR code with Go language

In this tutorial, we will create a program in Golang which can read an image file as input and write the text to standard output.

What exactly is QR code?

QR code or Quick Response code is a type of matrix or two dimensional (2D) barcode developed in 1994 that can be read easily by a digital machine/device, such as a cell phone, and which stores information as a series of pixels in a square-shaped grid.

Follow these steps to write a program which could read and generate QR code purely with Go language:

Make sure you have installed Golang and properly set up the environment variable. Check out Golang installation tutorial here.

1. Start by creating a file `main.go` and import the required Golang packages:

fmt - To print extracted html comments.
os - To read HTML files from standard input (stdin)
image - Read an image file.
io/ioutil - impliments package input output utility functions.
bytes - manipulation of byte slices
image/png - write encoded QR code to a PNG image binary file.
github.com/boombuler/barcode - a barcode creation library. (here used to scale the code.)
github.com/boombuler/barcode/qr - a qr code creation library
github.com/liyue201/goqr - QR Code recognition and decoding

package main

import (
    "image/png"
    "os"
    "image"
    "io/ioutil"
    "bytes"
    "fmt"

    // github. com liyue201 GOQR
    "github.com/liyue201/goqr"
    // barcode scale 
    "github.com/boombuler/barcode"
    // Build the QRcode for the text
    "github.com/boombuler/barcode/qr"
)

2. Generate QR code from text with Go language

Import required packages.

import (
    "image/png"
    "os"
    
    // barcode scale 
    "github.com/boombuler/barcode"
    // Build the QRcode for the text
    "github.com/boombuler/barcode/qr"
)

Let's create a function which generates QR code for given string and write it to a image file.

func qrCodeGen(t string, filename string) (error) {}

Use qr.Encode() function to encode given text into a QR code.

func qrCodeGen(t string, filename string) (error) {

    // Create the barcode
    qrCode, _ := qr.Encode(t, qr.M, qr.Auto)

}

Scale the QR code to the 200*200 pixels with barcode.Scale() function.

func qrCodeGen(t string, filename string) (error) {

    // Create the barcode
    qrCode, _ := qr.Encode(t, qr.M, qr.Auto)

    // Scale the barcode to 200x200 pixels
    qrCode, _ = barcode.Scale(qrCode, 2000, 2000)


}

Create a file to write QR code to it with os.Create() function.

func qrCodeGen(t string, filename string) (error) {

    // Create the barcode
    qrCode, _ := qr.Encode(t, qr.M, qr.Auto)

    // Scale the barcode to 200x200 pixels
    qrCode, _ = barcode.Scale(qrCode, 2000, 2000)

    // create the output file
    file, err := os.Create(filename)
    defer file.Close()

}

Write the encoded image into a PNG image file with png.Encode() function.

func qrCodeGen(t string, filename string) (error) {
    // Create the barcode
    qrCode, _ := qr.Encode(t, qr.M, qr.Auto)

    // Scale the barcode to 200x200 pixels
    qrCode, _ = barcode.Scale(qrCode, 2000, 2000)

    // create the output file
    file, err := os.Create(filename)
    defer file.Close()

    // encode the barcode as png
    png.Encode(file, qrCode)

    return err
}

Finally call the function in your code to Generate the QR code.

package main

import (
    "image/png"
    "os"
    
    // barcode scale 
    "github.com/boombuler/barcode"
    // Build the QRcode for the text
    "github.com/boombuler/barcode/qr"
)


func qrCodeGen(t string, filename string) (error) {
    // Create the barcode
    qrCode, _ := qr.Encode(t, qr.M, qr.Auto)

    // Scale the barcode to 200x200 pixels
    qrCode, _ = barcode.Scale(qrCode, 2000, 2000)

    // create the output file
    file, err := os.Create(filename)
    defer file.Close()

    // encode the barcode as png
    png.Encode(file, qrCode)

    return err
}

func main() {
    
    // This is a text to encode
    t := "This is a text"
    // file to read from 
    filenameR := "qrcode.png"
    // qrCodeGen generates a QR Code
    qrCodeGen(t, filenameR)


}

3. Scan QR code - Go language

Import required packages.

package main

import (
    "image"
    "io/ioutil"
    "bytes"
    "fmt"

    // github. com liyue201 GOQR
    "github.com/liyue201/goqr"
)

Let's create a function to scan provided file, as a path, for QR code and extract text out of it.

func scanQRCode(path string) {}

Read the provided file (path) with ioutil.ReadFile() function.

func scanQRCode(path string) {
    
    // Reads imgdata from a file.
    imgdata, err := ioutil.ReadFile(path)
    if err != nil {
        fmt.Printf("%v\n", err)
        return
    }

}

Try to decode the file as image:

func scanQRCode(path string) {
    
    // Reads imgdata from a file.
    imgdata, err := ioutil.ReadFile(path)
    if err != nil {
        fmt.Printf("%v\n", err)
        return
    }

    // Decodes an image.
    img, _, err := image.Decode(bytes.NewReader(imgdata))
    if err != nil {
        fmt.Printf("image.Decode error: %v\n", err)
        return
    }

}

Check if any QR code exist in the provided image.

func scanQRCode(path string) {
    
    // Reads imgdata from a file.
    imgdata, err := ioutil.ReadFile(path)
    if err != nil {
        fmt.Printf("%v\n", err)
        return
    }

    // Decodes an image.
    img, _, err := image.Decode(bytes.NewReader(imgdata))
    if err != nil {
        fmt.Printf("image.Decode error: %v\n", err)
        return
    }

    // Recognize QR Codes.
    qrCodes, err := goqr.Recognize(img)
    if err != nil {
        fmt.Printf("Recognize failed: %v\n", err)
        return
    }

}

Extract data from the image and print it to standard output.

func scanQRCode(path string) {
    
    // Reads imgdata from a file.
    imgdata, err := ioutil.ReadFile(path)
    if err != nil {
        fmt.Printf("%v\n", err)
        return
    }

    // Decodes an image.
    img, _, err := image.Decode(bytes.NewReader(imgdata))
    if err != nil {
        fmt.Printf("image.Decode error: %v\n", err)
        return
    }

    // Recognize QR Codes.
    qrCodes, err := goqr.Recognize(img)
    if err != nil {
        fmt.Printf("Recognize failed: %v\n", err)
        return
    }
    
    // Prints a list of QR Codes.
    for _, qrCode := range qrCodes {
        fmt.Printf("qrCode text: %s\n", qrCode.Payload)
    }
    return
}

Finally, call the function in your code and provide the image file to decode.

package main

import (
    "image"
    "io/ioutil"
    "bytes"
    "fmt"

    // github. com liyue201 GOQR
    "github.com/liyue201/goqr"
)


func scanQRCode(path string) {
    
    // Reads imgdata from a file.
    imgdata, err := ioutil.ReadFile(path)
    if err != nil {
        fmt.Printf("%v\n", err)
        return
    }

    // Decodes an image.
    img, _, err := image.Decode(bytes.NewReader(imgdata))
    if err != nil {
        fmt.Printf("image.Decode error: %v\n", err)
        return
    }

    // Recognize QR Codes.
    qrCodes, err := goqr.Recognize(img)
    if err != nil {
        fmt.Printf("Recognize failed: %v\n", err)
        return
    }
    
    // Prints a list of QR Codes.
    for _, qrCode := range qrCodes {
        fmt.Printf("qrCode text: %s\n", qrCode.Payload)
    }
    return
}

func main() {
    

    // file to write to
    filenameW := "qrcode.png"
    // scanQRCode scans a QR code image file.
    scanQRCode(filenameW)

}

Conclusion

In this tutorial, we used Golang to write a program which can encode or decode QR code image files. You can modify the code to use other types of bar codes.

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How to Generate Barcode in Golang?

Contents

Scan or generate QR code with Go language

What exactly is QR code?

1. Start by creating a file `main.go` and import the required Golang packages:

2. Generate QR code from text with Go language

3. Scan QR code - Go language

Conclusion

Go Language Tutorial

Recommended Handbooks

C++ Handbook

Python Basics Handbook

Javascript Handbook

ReactJS Projects Handbook

Computer Networks Tutorial

Operating System Tutorial

DBMS and SQL Tutorial

Java Tutorial

C Language Tutorial

PHP Tutorial

Android Tutorial

Linux Guide Tutorial

Data Structures and Algorithms Tutorial

Computer Architecture

Docker Tutorial

GIT (Using Github) Tutorial

How to Generate Barcode in Golang?

Contents

Scan or generate QR code with Go language

What exactly is QR code?

1. Start by creating a file **main.go** and import the required Golang packages:

2. Generate QR code from text with Go language

3. Scan QR code - Go language

Conclusion

Go Language Tutorial

Recommended Handbooks

C++ Handbook

Python Basics Handbook

Javascript Handbook

ReactJS Projects Handbook

Computer Networks Tutorial

Operating System Tutorial

DBMS and SQL Tutorial

Java Tutorial

C Language Tutorial

PHP Tutorial

Android Tutorial

Linux Guide Tutorial

Data Structures and Algorithms Tutorial

Computer Architecture

Docker Tutorial

GIT (Using Github) Tutorial

1. Start by creating a file `main.go` and import the required Golang packages: