Image scale with padding

/**
 * Like {@link #scaleWithMax(BufferedImage, int, int)} but the resulting image will include the scaled
 * image along with transparent (hopefully) background color as a filler to the sides or top/bottom
 * depending on the source img size.
 */
public static BufferedImage scaleWithPadding(BufferedImage img, int newWidth, int newHeight) {
    int currentWidth = img.getWidth();
    int currentHeight = img.getHeight();

    int scaledWidth;
    int scaledHeight;
    if (currentWidth == 0 || currentHeight == 0
            || (currentWidth == newWidth && currentHeight == newHeight)) {
        return img;
    } else if (currentWidth == currentHeight) {
        scaledWidth = newWidth;
        scaledHeight = newHeight;
    } else if (currentWidth >= currentHeight) {
        scaledWidth = newWidth;
        double scale = (double) newWidth / (double) currentWidth;
        scaledHeight = (int) Math.round(currentHeight * scale);
    } else {
        scaledHeight = newHeight;
        double scale = (double) newHeight / (double) currentHeight;
        scaledWidth = (int) Math.round(currentWidth * scale);
    }

    int x = (newWidth - scaledWidth) / 2;
    int y = (newHeight - scaledHeight) / 2;

    /*
     * This is _very_ painful. I've tried a large number of different permutations here trying to
         * get the white image background to be transparent without success. We've tried different
         * fills, composite types, image types, etc.. I'm moving on now.
     */
    BufferedImage newImg = new BufferedImage(newWidth, newHeight, img.getType());
    Graphics2D g = newImg.createGraphics();
    g.setColor(Color.WHITE);
    g.fillRect(0, 0, newWidth, newHeight);
    g.drawImage(img, x, y, x + scaledWidth, y + scaledHeight, 0, 0, currentWidth, currentHeight,
                    Color.WHITE, null);
    g.dispose();

    return newImg;
}