二维码 -- barcode/qrcode

生成：
boombuler/barcode

 package main
 import (
     "github.com/boombuler/barcode"
     "github.com/boombuler/barcode/qr"
     "image/png"
     "os"
 )
 func main() {
     qrCode, _ := qr.Encode("hello world", qr.M, qr.Auto)
     qrCode, _ = barcode.Scale(qrCode, 256, 256)
     file, _ := os.Create("qr.png")
     defer file.Close()
     png.Encode(file, qrCode)
 }

解析：
tuotoo/qrcode

 package main
 import (
     "fmt"
     "os"
     "github.com/tuotoo/qrcode"
 )
 func main() {
     fi, err := os.Open("qr.png")
     if err != nil {
         fmt.Println(err.Error())
         return
     }
     defer fi.Close()
     qrmatrix, err := qrcode.Decode(fi)
     if err != nil {
         fmt.Println(err.Error())
         return
     }
     fmt.Println(qrmatrix.Content)
 }