func MakeBarcode(rw http.ResponseWriter, req *http.Request) {
var id = req.FormValue("id")
var bigint *big.Int = big.NewInt(0)
var code barcode.Barcode
var uuid cassandra.UUID
var err error
if id == "" {
http.NotFound(rw, req)
return
}
uuid, err = cassandra.ParseUUID(id)
if err != nil {
log.Print("Error parsing UUID: ", err)
rw.WriteHeader(http.StatusInternalServerError)
rw.Write([]byte("Error parsing UUID: " + err.Error()))
return
}
bigint.SetBytes([]byte(uuid))
id = bigint.String()
code, err = code128.Encode(id)
if err != nil {
log.Print("Error generating barcode: ", err)
rw.WriteHeader(http.StatusInternalServerError)
rw.Write([]byte("Error generating barcode: " + err.Error()))
return
}
code, err = barcode.Scale(code, code.Bounds().Max.X, 24*code.Bounds().Max.Y)
if err != nil {
log.Print("Error scaling barcode: ", err)
rw.WriteHeader(http.StatusInternalServerError)
rw.Write([]byte("Error scaling barcode: " + err.Error()))
return
}
rw.Header().Set("Content-Type", "image/png")
rw.Header().Set("Content-Disposition", "inline; filename="+uuid.String()+".png")
err = png.Encode(rw, code)
if err != nil {
log.Print("Error writing out image: ", err)
rw.Header().Set("Content-Type", "text/plain; charset=utf8")
rw.Header().Set("Content-Disposition", "inline")
rw.Write([]byte("Error writing out image: " + err.Error()))
}
}
func NewBitmap(code barcode.Barcode) *Bitmap {
dim := code.Bounds().Max
b := &Bitmap{data: make([]bool, dim.X*dim.Y), height: dim.Y, width: dim.X}
for y := 0; y < dim.Y; y++ {
for x := 0; x < dim.X; x++ {
if code.At(x, y) == color.Black {
b.Set(x, y, true)
}
}
}
return b
}
// barcodeKey combines the code type and code value into a unique identifier for
// a barcode type. This is so that we can store several barcodes with the same
// code but different type in the barcodes map.
func barcodeKey(bcode barcode.Barcode) string {
return bcode.Metadata().CodeKind + bcode.Content()
}