獲取圖片座標：

img標籤中加入

@click='tapMap($event)'

和Graphics2D座標不一致需要減去偏移量。

Graphics2D讀取圖片並畫圖：

    public void createImg() throws IOException {
        BufferedImage bufferedImage = null;
        try {
            bufferedImage = ImageIO.read(new FileInputStream("D:\\1.png"));
        } 
 
catch (FileNotFoundException e1) {
            e1.printStackTrace();
        } catch (IOException e1) {
            e1.printStackTrace();
        }
        Graphics2D graphics2D = (Graphics2D) bufferedImage.getGraphics();
        graphics2D.setBackground(Color.RED);
        graphics2D.clearRect(33,34,20,20);
        graphics2D.setPaint(Color.BLUE);
        graphics2D.drawRect(
 
33, 34, 20, 20);
        try {
            ImageIO.write(bufferedImage, "png",new FileOutputStream("D:\\2.png"));
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }