使用java捕获指定的屏幕区域

Question

我正在我已经工作的Java Web应用程序中实现截图捕获。但是我遇到了屏幕截图的问题，因为整个屏幕都采用了图像：

正如您所看到的，这是整个屏幕，我只想用图形（白色区域）捕捉区域。我用来捕获这个屏幕的代码是：

public void captureGraphs() {

        try {
            Dimension size = Toolkit.getDefaultToolkit().getScreenSize();
            Robot robot = new Robot();
            BufferedImage img = robot.createScreenCapture(new Rectangle(size));
            File f = new File("C:/capture");
            if (!f.exists()) {
                f.mkdir();
            }
            File[] flist = f.listFiles();
            for (File flist1 : flist) {
                flist1.delete();
            }
            ImageIO.write(img, "JPG", new File("C:/capture/screenShot.jpg"));
            System.out.println("Capture Successfull");
            FacesContext.getCurrentInstance().addMessage(
                    null,
                    new FacesMessage(FacesMessage.SEVERITY_INFO,
                            "Successful!",
                            "You have successfully taken a snapshot. Thank You"));
        } catch (HeadlessException e) {
            System.out.println(e.getMessage());
        } catch (AWTException e) {
            System.out.println(e.getMessage());
        } catch (IOException e) {
            System.out.println(e.getMessage());
        }
    }

有没有什么办法可以改变这段代码来捕捉中间部分只持有图表？