docs: private static BufferedImage draw(BufferedImage backgroundImg, Image img, Rectangle rectangle, float alpha) {
  		final Graphics2D g = backgroundImg.createGraphics();
  		g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_ATOP, alpha));
  		g.drawImage(img, rectangle.x, rectangle.y, rectangle.width, rectangle.height, null); // 绘制切割后的图
  		g.dispose();
  		return backgroundImg;
  	}