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 <C_CkFormatsW.h>
#include <C_CkJsonObjectW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkFormatsW fmt;
    HCkJsonObjectW jsonOut;
    HCkJsonObjectW json;
    HCkJsonObjectW json2;

    success = FALSE;

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

    fmt = CkFormatsW_Create();
    jsonOut = CkJsonObjectW_Create();

    //  Dark blue modules on a pale yellow background.
    json = CkJsonObjectW_Create();
    CkJsonObjectW_UpdateString(json,L"payload.text",L"https://www.chilkatsoft.com/");
    CkJsonObjectW_UpdateInt(json,L"render.moduleSize",6);
    CkJsonObjectW_UpdateString(json,L"render.foreground",L"#1B3A6B");
    CkJsonObjectW_UpdateString(json,L"render.background",L"#FFF8DC");
    CkJsonObjectW_UpdateString(json,L"output.path",L"qa_output/qr_blue.png");
    CkJsonObjectW_UpdateBool(json,L"output.overwrite",TRUE);
    CkJsonObjectW_UpdateString(json,L"output.return",L"none");
    success = CkFormatsW_QrCode(fmt,L"generate",json,jsonOut);
    if (success == FALSE) {
        wprintf(L"%s\n",CkFormatsW_lastErrorText(fmt));
        CkFormatsW_Dispose(fmt);
        CkJsonObjectW_Dispose(jsonOut);
        CkJsonObjectW_Dispose(json);
        return;
    }

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

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

    //  

    //  The same modules on a fully transparent background.
    json2 = CkJsonObjectW_Create();
    CkJsonObjectW_UpdateString(json2,L"payload.text",L"https://www.chilkatsoft.com/");
    CkJsonObjectW_UpdateInt(json2,L"render.moduleSize",6);
    CkJsonObjectW_UpdateString(json2,L"render.foreground",L"#1B3A6B");
    CkJsonObjectW_UpdateString(json2,L"render.background.color",L"#FFFFFF");
    CkJsonObjectW_UpdateNumber(json2,L"render.background.opacity",L"0");
    CkJsonObjectW_UpdateString(json2,L"output.path",L"qa_output/qr_transparent.png");
    CkJsonObjectW_UpdateBool(json2,L"output.overwrite",TRUE);
    CkJsonObjectW_UpdateString(json2,L"output.return",L"none");
    success = CkFormatsW_QrCode(fmt,L"generate",json2,jsonOut);
    if (success == FALSE) {
        wprintf(L"%s\n",CkFormatsW_lastErrorText(fmt));
        CkFormatsW_Dispose(fmt);
        CkJsonObjectW_Dispose(jsonOut);
        CkJsonObjectW_Dispose(json);
        CkJsonObjectW_Dispose(json2);
        return;
    }

    wprintf(L"transparent: %s, %d bytes\n",CkJsonObjectW_stringOf(jsonOut,L"outputs[0].path"),CkJsonObjectW_IntOf(jsonOut,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


    CkFormatsW_Dispose(fmt);
    CkJsonObjectW_Dispose(jsonOut);
    CkJsonObjectW_Dispose(json);
    CkJsonObjectW_Dispose(json2);

    }