How to add a logo to QR code in android

Question

I have seen few QR codes with company logo at the center. Is it possible to generate a QR code with a any logo in android? If possible kindly explain the way for doing it. Currently I am using Zxing for generating QR codes.

Answer 1

With reference to the guide and source code provided at Generating a qr code with a logo please find the sample Android code that I use to achieve similar result on Android.

I am sure that this code can be optimised, specifically with regards to image overlay opacity by making use of the Paint class but this code works effectively in this regard.

    /**
 * Writes the given Overlay on a new Bitmap object.
 * @param Bitmap the Bitmap to overlay.
 * @return the new {@link Bitmap}-object.
 */ 
public static Bitmap overlayBitmap(Bitmap overlay) {        
    BitMatrix matrix = null;
    QRCodeWriter writer = new QRCodeWriter();

    //Error correction

    //Sometimes your QRCode will get damaged or covered up by something – like an image overlay for instance – 
    //therefore the designers of the QRCode has added four levels; 7% (L), 15 % (M), 25% (Q), 30% (H) of error 
    //correction were a error correction of level H should result in a QRCode that are still valid even when it’s 
    //30% obscured – for more info on error correction check this       

    Map<EncodeHintType,  Object> hints; 

    hints = new HashMap<EncodeHintType, Object>();
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);             

    //create qr code matrix
    writer = new  QRCodeWriter();
    try {
        matrix = writer.encode(redirectUrl, 
                                 BarcodeFormat.QR_CODE,
                                 QRCODE_IMAGE_WIDTH,
                                 QRCODE_IMAGE_HEIGHT,
                                 hints);
    } catch (WriterException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } 

    Bitmap image = toBitmap(matrix);
    int height = image.getHeight();
    int width = image.getWidth();

    Bitmap combined = Bitmap.createBitmap(width, height, image.getConfig());

    Canvas canvas = new Canvas(combined);
    int canvasWidth = canvas.getWidth();
    int canvasHeight = canvas.getHeight();

    canvas.drawBitmap(image, new Matrix(), null);

    int centreX = (canvasWidth  - overlay.getWidth()) /2;
    int centreY = (canvasHeight - overlay.getHeight()) /2 ; 

    //http://stackoverflow.com/a/12235235/1635441
    //http://stackoverflow.com/a/5119093/1635441        
    //Paint p = new Paint();
    //p.setXfermode(new PorterDuffXfermode(Mode.DST_ATOP)); //http://stackoverflow.com/a/17553502/1635441
    //p.setAlpha(180);
    //p.setARGB(a, r, g, b);

    //canvas.drawBitmap(bitmapToBeOverlay, 0, 0, p);        

    //canvas.drawBitmap(overlay, new Matrix(), null);
    canvas.drawBitmap(overlay, centreX, centreY, null);

    return combined;
}

    /**
 * Writes the given Matrix to a new colour Bitmap object.
 * @param matrix the matrix to write.
 * @param Color the Color to be added.
 * @return the new {@link Bitmap}-object.
 */
public static Bitmap toBitmapColour(BitMatrix matrix, int colour){
    int height = matrix.getHeight();
    int width = matrix.getWidth();
    Bitmap bmp = Bitmap.createBitmap(width, height, Bitmap.Config.RGB_565);
    for (int x = 0; x < width; x++){
        for (int y = 0; y < height; y++){
            bmp.setPixel(x, y, matrix.get(x,y) ? colour : Color.WHITE);
        }
    }
    return bmp;
}

HTH