// Encode encodes a string using the given version, level, and mask.
func Encode(w http.ResponseWriter, req *http.Request) {
val := func(s string) int {
v, _ := strconv.Atoi(req.FormValue(s))
return v
}
l := coding.Level(val("l"))
v := coding.Version(val("v"))
enc := coding.String(req.FormValue("t"))
m := coding.Mask(val("m"))
p, err := coding.NewPlan(v, l, m)
if err != nil {
panic(err)
}
cc, err := p.Encode(enc)
if err != nil {
panic(err)
}
c := &qr.Code{Bitmap: cc.Bitmap, Size: cc.Size, Stride: cc.Stride, Scale: 8}
w.Header().Set("Content-Type", "image/png")
w.Header().Set("Cache-Control", "public, max-age=3600")
w.Write(c.PNG())
}
// Encode returns an encoding of text at the given error correction level.
func Encode(text string, level Level) (*Code, error) {
// Pick data encoding, smallest first.
// We could split the string and use different encodings
// but that seems like overkill for now.
var enc coding.Encoding
switch {
case coding.Num(text).Check() == nil:
enc = coding.Num(text)
case coding.Alpha(text).Check() == nil:
enc = coding.Alpha(text)
default:
enc = coding.String(text)
}
// Pick size.
l := coding.Level(level)
var v coding.Version
for v = coding.MinVersion; ; v++ {
if v > coding.MaxVersion {
return nil, errors.New("text too long to encode as QR")
}
if enc.Bits(v) <= v.DataBytes(l)*8 {
break
}
}
// Build and execute plan.
p, err := coding.NewPlan(v, l, 0)
if err != nil {
return nil, err
}
cc, err := p.Encode(enc)
if err != nil {
return nil, err
}
// TODO: Pick appropriate mask.
return &Code{cc.Bitmap, cc.Size, cc.Stride, 8}, nil
}