Go Requires Chilkat v11.7.0+

QR Code with a Text Caption

See more QR Code Examples

Demonstrates printing a line of text under a QR code, such as the order number or the address the code holds, so that a person can read it too. render.text turns the caption on and gives its value, which is printable ASCII and is drawn in a built-in font that needs no font files. The caption can go above or below the symbol, be aligned left, center or right, and be scaled. Go

    success := false

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    json := chilkat.NewJsonObject()
    json.UpdateString("payload.text","https://www.chilkatsoft.com/order/12345")
    json.UpdateInt("render.moduleSize",6)

    //  The caption.  It need not be the same as the text in the QR code.
    json.UpdateBool("render.text.enabled",true)
    json.UpdateString("render.text.value","ORDER 12345")
    //  position is "below" (the default) or "above".  alignment is "center" (the default), "left" or "right".
    json.UpdateString("render.text.position","below")
    //  Each dot of the caption's font is drawn this many pixels wide.
    json.UpdateInt("render.text.scale",3)

    json.UpdateString("output.path","qa_output/qr_caption.png")
    json.UpdateBool("output.overwrite",true)
    json.UpdateString("output.return","none")

    fmt := chilkat.NewFormats()
    jsonOut := chilkat.NewJsonObject()
    success = fmt.QrCode("generate",json,jsonOut)
    if success == false {
        fmt.Println(fmt.LastErrorText())
        json.DisposeJsonObject()
        fmt.DisposeFormats()
        jsonOut.DisposeJsonObject()
        return
    }

    fmt.Println("caption: ", *jsonOut.StringOf("measurements[0].text"))
    fmt.Println("caption scale: ", jsonOut.IntOf("measurements[0].textScale"))
    fmt.Println("height added for the caption: ", jsonOut.IntOf("measurements[0].textBandPx"), " pixels")
    fmt.Println("image: ", jsonOut.IntOf("measurements[0].canvasWidth"), " x ", jsonOut.IntOf("measurements[0].canvasHeight"), " pixels")

    //  The image written to qa_output/qr_caption.png:

    //  

    //  Sample output:

    //  caption: ORDER 12345
    //  caption scale: 3
    //  height added for the caption: 21 pixels
    //  image: 222 x 243 pixels

    json.DisposeJsonObject()
    fmt.DisposeFormats()
    jsonOut.DisposeJsonObject()