Android：使用Zxing生成的二维码有边距(不适合该区域)

如果我将屏幕宽度设置为QR码的宽度尺寸,我会得到更小的QR码.看截图(它是320×240分辨率).我想要QR码适合黑色区域.为什么QR码红色这么小？

如何将其拉伸到黑色区域？

我的代码：

display display = getwindowManager().getDefaultdisplay();
Point size = new Point();
display.getSize(size);
int width = size.x; 

Bitmap bm = encodeAsBitmap(mGeneratedURL,BarcodeFormat.QR_CODE,width,width);
qrcodeImage.setimageBitmap(bm);

生成QR码：

private Bitmap encodeAsBitmap(String contents,BarcodeFormat format,int img_width,int img_height) throws WriterException {
    String contentsToEncode = contents;
    if (contentsToEncode == null) {
        return null;
    }
    Map<EncodeHintType,Object> hints = null;
    String encoding = guessAppropriateEncoding(contentsToEncode);
    if (encoding != null) {
        hints = new EnumMap<EncodeHintType,Object>(EncodeHintType.class);
        //hints.put(EncodeHintType.CHaraCTER_SET,encoding);
        hints.put(EncodeHintType.MARGIN,0); /* default = 4 */
    }
    MultiFormatWriter writer = new MultiFormatWriter();
    BitMatrix result;
    try {
        result = writer.encode(contentsToEncode,format,img_width,img_height,hints);
    } catch (IllegalArgumentException iae) {
        // Unsupported format
        return null;
    }

    int width = result.getWidth();
    int height = result.getHeight();
    int[] pixels = new int[width * height];
    for (int y = 0; y < height; y++) {
        int offset = y * width;
        for (int x = 0; x < width; x++) {
            pixels[offset + x] = result.get(x,y) ? RED : Color.BLACK;
        }
    }

    Bitmap bitmap = Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
    bitmap.setPixels(pixels,height);
    return bitmap;
}