Unicode C++ Requires Chilkat v11.7.0+

QR Code Colors and Transparent Background

See more QR Code Examples

Demonstrates colored QR codes. render.foreground is the color of the dark modules and render.background the color behind them, each as #RRGGBB. Either can instead be an object with a color and an opacity from 0 to 1, and a background opacity of 0 gives a PNG with a transparent background to place over a page or a design. Readers need contrast: keep the modules clearly darker than whatever ends up behind them. Unicode C++

#include <CkFormatsW.h>
#include <CkJsonObjectW.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.

    CkFormatsW fmt;
    CkJsonObjectW jsonOut;

    //  Dark blue modules on a pale yellow background.
    CkJsonObjectW json;
    json.UpdateString(L"payload.text",L"https://www.chilkatsoft.com/");
    json.UpdateInt(L"render.moduleSize",6);
    json.UpdateString(L"render.foreground",L"#1B3A6B");
    json.UpdateString(L"render.background",L"#FFF8DC");
    json.UpdateString(L"output.path",L"qa_output/qr_blue.png");
    json.UpdateBool(L"output.overwrite",true);
    json.UpdateString(L"output.return",L"none");
    success = fmt.QrCode(L"generate",json,jsonOut);
    if (success == false) {
        wprintf(L"%s\n",fmt.lastErrorText());
        return;
    }

    wprintf(L"colored: %s, %d bytes\n",jsonOut.stringOf(L"outputs[0].path"),jsonOut.IntOf(L"outputs[0].byteCount"));

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

    //  

    //  The same modules on a fully transparent background.
    CkJsonObjectW json2;
    json2.UpdateString(L"payload.text",L"https://www.chilkatsoft.com/");
    json2.UpdateInt(L"render.moduleSize",6);
    json2.UpdateString(L"render.foreground",L"#1B3A6B");
    json2.UpdateString(L"render.background.color",L"#FFFFFF");
    json2.UpdateNumber(L"render.background.opacity",L"0");
    json2.UpdateString(L"output.path",L"qa_output/qr_transparent.png");
    json2.UpdateBool(L"output.overwrite",true);
    json2.UpdateString(L"output.return",L"none");
    success = fmt.QrCode(L"generate",json2,jsonOut);
    if (success == false) {
        wprintf(L"%s\n",fmt.lastErrorText());
        return;
    }

    wprintf(L"transparent: %s, %d bytes\n",jsonOut.stringOf(L"outputs[0].path"),jsonOut.IntOf(L"outputs[0].byteCount"));

    //  qa_output/qr_transparent.png, placed here over a checkerboard and over a colored page
    //  to show that whatever is behind the image shows through:

    //  

    //  Sample output:

    //  colored: qa_output/qr_blue.png, 1345 bytes
    //  transparent: qa_output/qr_transparent.png, 1377 bytes
    }