QRLogo

A command line tool and library written in Go to generate QR Codes with logos/images embedded. The logos can be padded in different ways to make them stand out.

Contents

• QRLogo
  • Contents
  • Installation
  • Quickstart
  • Options
    • BackgroundColor
    • CodeColour
    • DisableBorder
    • LogoCoverage
    • PaddingType
    • PaddingWeight
    • QRSize

Installation

1. Go needs to be installed then the following command can be used to add qrlogo to your project:

go get -u github.com/alexandernorth/qrlogo

2. Import qrlogo into your code:

import "github.com/alexandernorth/qrlogo"

Quickstart

Create a file with the following contents:

package main

import (
  "os"
  "path"

  "github.com/alexandernorth/qrlogo"
)

func main() {

	logo, err := qrlogo.OpenImage("logo.png")
	if err != nil {
		panic(err)
	}
	
	qlg := qrlogo.NewQRLogo(logo)
    
	qrLogo, err := qlg.QRCodeForURL("https://github.com/alexandernorth/qrlogo")
    if err != nil {
        panic(err)
    }
	
	outputDir := "qrcodes"
	
    err = os.MkdirAll(outputDir, 0755)
    if err != nil {
        panic(err)
    }
    err = qrlogo.SaveToPNGFile(qrLogo, path.Join(outputDir, "qr.png"))
    if err != nil {
        panic(err)
    }
}

Options

QRLogo can be configured with several options:

BackgroundColor

Sets the background color of the code

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.BackgroundColor(colornames.Map["white"]),
)

CodeColour

Sets the colour of the QRCode bars

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.CodeColour(colornames.Map["black"]),
)

DisableBorder

Sets whether there is a border around the whole QRCode

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.DisableBorder(false),
)

LogoCoverage

Sets the percentage of the QRCode to be covered in range [0,1] with 1 being 100%. The error correction ability of a QRCode is at max 30%, so this value should not be exceeded, but other factors may force this value down

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.LogoCoverage(0.2),
)

PaddingType

Sets the type of padding to use when rendering the logo.

Valid options are:

• dilate
• none
• square
• circle

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.PaddingType(qrlogo.LogoPaddingDilate),
)

LogoPaddingType is a string, so it is also possible to specify the type through a string:

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.PaddingType(qrlogo.LogoPaddingType("dilate")),
)

PaddingWeight

Sets the amount of padding around the logo

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.PaddingWeight(20),
)

QRSize

Sets the size of the output image

qlg := qrlogo.NewQRLogo(
  logo,
  qrlogo.QRSize(2048),
)