resize bitmap android

activity

    public Bitmap resizeBitmap(Bitmap b, int newWidthDp){
        Float density = getResources().getDisplayMetrics().density;
        int newWidth = newWidthDp * Math.round(density);

        int width = b.getWidth();
        int height = b.getHeight();

        float scaleWidth = ((float) newWidth) / width;
        float ratio = (float) width / newWidth;
        int newHeight = (int) (height / ratio);
        float scaleHeight = ((float) newHeight) / height;

        Matrix matrix = new Matrix();
        matrix.postScale(scaleWidth, scaleHeight);

        Bitmap resizedBitmap = Bitmap.createBitmap(b, 0, 0,
                width, height, matrix, true);
        return (resizedBitmap);
    }