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 <CkJsonObject.h>
#include <CkFormats.h>
#include <CkBinData.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/");
    json.UpdateInt("render.moduleSize",6);

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

    std::cout << "format: " << jsonOut.stringOf("outputs[0].format") << "\r\n";
    std::cout << "MIME type: " << jsonOut.stringOf("outputs[0].mimeType") << "\r\n";
    std::cout << "image: " << jsonOut.IntOf("outputs[0].width") << " x " << jsonOut.IntOf("outputs[0].height") << " pixels" << "\r\n";

    //  outputs[0].base64 is the PNG file, base64 encoded.
    CkBinData bdPng;
    success = bdPng.AppendEncoded(jsonOut.stringOf("outputs[0].base64"),"base64");
    if (success == false) {
        std::cout << bdPng.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "PNG bytes: " << bdPng.get_NumBytes() << "\r\n";

    //  The BinData holds the image.  Here it is simply saved.
    success = bdPng.WriteFile("qa_output/qr_in_memory.png");
    if (success == false) {
        std::cout << bdPng.lastErrorText() << "\r\n";
        return;
    }

    //  The PNG held in bdPng:

    //  

    //  Sample output:

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