go-qrcode/ProjectHome.md

go-qrcode

Package qrcode implements a QR Code encoder.

A QR Code is a matrix (two-dimensional) barcode. Arbitrary content may be encoded, with URLs being a popular choice :)

Each QR Code contains error recovery information to aid reading damaged or obscured codes. There are four levels of error recovery: Low, medium, high and highest. QR Codes with a higher recovery level are more robust to damage, at the cost of being physically larger.

Usage

import qrcode "code.google.com/p/go-qrcode"

• Create a PNG image:

  var png []byte
  
  
  png, err := qrcode.Encode("https://example.org", qrcode.Medium, 256)
  
  
  

• Create a PNG image and write to a file:

  err := qrcode.WriteFile("https://example.org", qrcode.Medium, 256, "qr.png")
  
  
  

Both examples use the qrcode.Medium error Recovery Level and create a 256x256 pixel, black on white QR Code.

The maximum capacity of a QR Code varies according to the content encoded and
the error recovery level. The maximum capacity is 2,953 bytes, 4,296
alphanumeric characters, 7,089 numeric digits, or a combination of these.

Documentation

Demo app

http://go-qrcode.appspot.com

Links

• http://en.wikipedia.org/wiki/QR_code
• ISO/IEC 18004:2006 - Main QR Code specification (approx CHF 198,00)
  
• https://github.com/qpliu/qrencode-go/ - alternative Go QR encoding library based on ZXing