C Requires Chilkat v11.7.0+

Generate a QR Code PNG in Memory

See more QR Code Examples

Demonstrates getting a QR code image without writing a file. With no output options the result is a PNG returned as base64 in outputs[0].base64 of the response. The example decodes it into a BinData, which holds the bytes of the PNG to send in an HTTP response, store in a database, attach to an email, or save. C

#include <C_CkJsonObject.h>
#include <C_CkFormats.h>
#include <C_CkBinData.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkJsonObject json;
    HCkFormats fmt;
    HCkJsonObject jsonOut;
    HCkBinData bdPng;

    success = FALSE;

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

    json = CkJsonObject_Create();
    CkJsonObject_UpdateString(json,"payload.text","https://www.chilkatsoft.com/");
    CkJsonObject_UpdateInt(json,"render.moduleSize",6);

    fmt = CkFormats_Create();
    jsonOut = CkJsonObject_Create();
    success = CkFormats_QrCode(fmt,"generate",json,jsonOut);
    if (success == FALSE) {
        printf("%s\n",CkFormats_lastErrorText(fmt));
        CkJsonObject_Dispose(json);
        CkFormats_Dispose(fmt);
        CkJsonObject_Dispose(jsonOut);
        return;
    }

    printf("format: %s\n",CkJsonObject_stringOf(jsonOut,"outputs[0].format"));
    printf("MIME type: %s\n",CkJsonObject_stringOf(jsonOut,"outputs[0].mimeType"));
    printf("image: %d x %d pixels\n",CkJsonObject_IntOf(jsonOut,"outputs[0].width"),CkJsonObject_IntOf(jsonOut,"outputs[0].height"));

    //  outputs[0].base64 is the PNG file, base64 encoded.
    bdPng = CkBinData_Create();
    success = CkBinData_AppendEncoded(bdPng,CkJsonObject_stringOf(jsonOut,"outputs[0].base64"),"base64");
    if (success == FALSE) {
        printf("%s\n",CkBinData_lastErrorText(bdPng));
        CkJsonObject_Dispose(json);
        CkFormats_Dispose(fmt);
        CkJsonObject_Dispose(jsonOut);
        CkBinData_Dispose(bdPng);
        return;
    }

    printf("PNG bytes: %d\n",CkBinData_getNumBytes(bdPng));

    //  The BinData holds the image.  Here it is simply saved.
    success = CkBinData_WriteFile(bdPng,"qa_output/qr_in_memory.png");
    if (success == FALSE) {
        printf("%s\n",CkBinData_lastErrorText(bdPng));
        CkJsonObject_Dispose(json);
        CkFormats_Dispose(fmt);
        CkJsonObject_Dispose(jsonOut);
        CkBinData_Dispose(bdPng);
        return;
    }

    //  The PNG held in bdPng:

    //  

    //  Sample output:

    //  format: png
    //  MIME type: image/png
    //  image: 222 x 222 pixels
    //  PNG bytes: 877


    CkJsonObject_Dispose(json);
    CkFormats_Dispose(fmt);
    CkJsonObject_Dispose(jsonOut);
    CkBinData_Dispose(bdPng);

    }