VB.NET 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. VB.NET

Dim success As Boolean = False

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

Dim json As New Chilkat.JsonObject
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")

Dim fmt As New Chilkat.Formats
Dim jsonOut As New Chilkat.JsonObject
success = fmt.QrCode("generate",json,jsonOut)
If (success = False) Then
    Debug.WriteLine(fmt.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("caption: " & jsonOut.StringOf("measurements[0].text"))
Debug.WriteLine("caption scale: " & jsonOut.IntOf("measurements[0].textScale"))
Debug.WriteLine("height added for the caption: " & jsonOut.IntOf("measurements[0].textBandPx") & " pixels")
Debug.WriteLine("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