Tcl 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. Tcl

load ./chilkat.dll

set success 0

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

set json [new_CkJsonObject]

CkJsonObject_UpdateString $json "payload.text" "https://www.chilkatsoft.com/order/12345"
CkJsonObject_UpdateInt $json "render.moduleSize" 6

#  The caption.  It need not be the same as the text in the QR code.
CkJsonObject_UpdateBool $json "render.text.enabled" 1
CkJsonObject_UpdateString $json "render.text.value" "ORDER 12345"
#  position is "below" (the default) or "above".  alignment is "center" (the default), "left" or "right".
CkJsonObject_UpdateString $json "render.text.position" "below"
#  Each dot of the caption's font is drawn this many pixels wide.
CkJsonObject_UpdateInt $json "render.text.scale" 3

CkJsonObject_UpdateString $json "output.path" "qa_output/qr_caption.png"
CkJsonObject_UpdateBool $json "output.overwrite" 1
CkJsonObject_UpdateString $json "output.return" "none"

set fmt [new_CkFormats]

set jsonOut [new_CkJsonObject]

set success [CkFormats_QrCode $fmt "generate" $json $jsonOut]
if {$success == 0} then {
    puts [CkFormats_lastErrorText $fmt]
    delete_CkJsonObject $json
    delete_CkFormats $fmt
    delete_CkJsonObject $jsonOut
    exit
}

puts "caption: [CkJsonObject_stringOf $jsonOut {measurements[0].text}]"
puts "caption scale: [CkJsonObject_IntOf $jsonOut {measurements[0].textScale}]"
puts "height added for the caption: [CkJsonObject_IntOf $jsonOut {measurements[0].textBandPx}] pixels"
puts "image: [CkJsonObject_IntOf $jsonOut {measurements[0].canvasWidth}] x [CkJsonObject_IntOf $jsonOut {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

delete_CkJsonObject $json
delete_CkFormats $fmt
delete_CkJsonObject $jsonOut