C++ 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. C++

#include <CkJsonObject.h>
#include <CkFormats.h>

void ChilkatSample(void)
    {
    bool success = false;

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

    CkJsonObject json;
    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");

    CkFormats fmt;
    CkJsonObject jsonOut;
    success = fmt.QrCode("generate",json,jsonOut);
    if (success == false) {
        std::cout << fmt.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "caption: " << jsonOut.stringOf("measurements[0].text") << "\r\n";
    std::cout << "caption scale: " << jsonOut.IntOf("measurements[0].textScale") << "\r\n";
    std::cout << "height added for the caption: " << jsonOut.IntOf("measurements[0].textBandPx") << " pixels" << "\r\n";
    std::cout << "image: " << jsonOut.IntOf("measurements[0].canvasWidth") << " x " << jsonOut.IntOf("measurements[0].canvasHeight") << " pixels" << "\r\n";

    //  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
    }