go-qrcode

QR code (abbreviated from Quick Response Code) is the trademark for a type of matrix barcode (or two-dimensional barcode) first designed in 1994 for the automotive industry in Japan. A barcode is a machine-readable optical label that contains information about the item to which it is attached. A QR code uses four standardized encoding modes (numeric, alphanumeric, byte/binary, and kanji) to store data efficiently; extensions may also be used

Features

• Normally generate QR code across version 1 to version 40.
• Automatically analyze QR version by source text.
• Specifying cell shape allowably with WithCustomShape, WithCircleShape (default is rectangle)
• Specifying output file's format with WithBuiltinImageEncoder, WithCustomImageEncoder (default is JPEG)
• Not only shape of cell, but also color of QR Code background and foreground color.
• WithLogoImage, WithLogoImageFilePNG, WithLogoImageFileJPEG help you add an icon at the central of QR Code.
• WithBorderWidth allows to specify any width of 4 sides around the qrcode.
• WebAssembly support, check out the Example and README for more detail.
• support Halftone QR Codes, check out the Example.

Install

go get -u github.com/yeqown/go-qrcode/v2

Quick Start

link to CODE

package main

import (
	"github.com/yeqown/go-qrcode/v2"
	"github.com/yeqown/go-qrcode/writer/standard"
)

func main() {
	qrc, err := qrcode.New("https://github.com/yeqown/go-qrcode")
	if err != nil {
		fmt.Printf("could not generate QRCode: %v", err)
		return
	}
	
	w, err := standard.New("../assets/repo-qrcode.jpeg")
	if err != nil {
		fmt.Printf("standard.New failed: %v", err)
		return
	}
	
	// save file
	if err = qrc.Save(w); err != nil {
		fmt.Printf("could not save image: %v", err)
	}
}

Options

const (
	// EncModeNone mode ...
	EncModeNone encMode = 1 << iota
	// EncModeNumeric mode ...
	EncModeNumeric
	// EncModeAlphanumeric mode ...
	EncModeAlphanumeric
	// EncModeByte mode ...
	EncModeByte
	// EncModeKanji mode ...
	EncModeKanji
)

// WithEncodingMode sets the encoding mode.
func WithEncodingMode(mode encMode) EncodeOption {}

const (
	// ErrorCorrectionLow :Level L: 7% error recovery.
	ErrorCorrectionLow ecLevel = iota + 1
	
	// ErrorCorrectionMedium :Level M: 15% error recovery. Good default choice.
	ErrorCorrectionMedium
	
	// ErrorCorrectionQuart :Level Q: 25% error recovery.
	ErrorCorrectionQuart
	
	// ErrorCorrectionHighest :Level H: 30% error recovery.
	ErrorCorrectionHighest
)

// WithErrorCorrectionLevel sets the error correction level.
func WithErrorCorrectionLevel(ecLevel ecLevel) EncodeOption {}

Samples

These samples are generated with standard writer, check out Example for more details.

A	B	C	D
bg-fg color	transparent	border padding	circle shape
fg gradient	using halftone	set logo image	block width
custom shape

Built-in Writers

• Standard Writer, prints QRCode into file and stream
• Terminal Writer, prints QRCode into terminal
• File Writer, prints QRCode into files
• Compressed Writer, It's generated on a very small scale

Of course, you can also code your own writer, just implement Writer interface.

Migrating from v1

go-qrcode.v2 is a major upgrade from v1, and it is not backward compatible. v2 redesigned the API, and it is more flexible and powerful. Features are split into different modules (according to functionality).

• github.com/yeqown/go-qrcode/v2 core
• github.com/yeqown/go-qrcode/writer/standard writer/imageFile
• github.com/yeqown/go-qrcode/writer/terminal writer/terminal

Check example/migrating-from-v1 for more details.

Links

• QRCode Tourist
• QRCode Wiki
• 二维码详解 (QRCode analysis in CN-zh)
• 数据编码 (How to encode data payload in QRCode in CN-zh)