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QR Code encoder (Go)
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skip2 Merge pull request #20 from warbaby/img_set_performance
Improve img bitmap fill performance
Latest commit dc11ecd Jan 10, 2019


Package qrcode implements a QR Code encoder. Build Status

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.


go get -u

A command-line tool qrcode will be built into $GOPATH/bin/.


import qrcode ""
  • Create a PNG image:

      var png []byte
      png, err := qrcode.Encode("", qrcode.Medium, 256)
  • Create a PNG image and write to a file:

      err := qrcode.WriteFile("", qrcode.Medium, 256, "qr.png")
  • Create a PNG image with custom colors and write to file:

      err := qrcode.WriteColorFile("", qrcode.Medium, 256, color.Black, color.White, "qr.png")

All examples use the qrcode.Medium error Recovery Level and create a fixed 256x256px size QR Code. The last function creates a white on black instead of 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.





A command-line tool qrcode will be built into $GOPATH/bin/.

qrcode -- QR Code encoder in Go

  -o string
        out PNG file prefix, empty for stdout
  -s int
        image size (pixel) (default 256)

  1. Arguments except for flags are joined by " " and used to generate QR code.
     Default output is STDOUT, pipe to imagemagick command "display" to display
     on any X server.

       qrcode hello word | display

  2. Save to file if "display" not available:

       qrcode "homepage:" > out.png


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