java - 如何将 JPanel 变成 BufferedImage Java

Question

我有一个半工作的绘画/turtle 图形程序，但我遇到了一些问题。 我需要保存在某个时刻绘制的图像 - 我知道我需要使用 BufferedImage 但我该如何处理呢？我在下面附上了一些代码。

简而言之，我有一个带有文本字段的 JFrame，其下方有一个白色的 JPanel。当用户输入命令时，线将通过另一个类绘制并显示在 JPanel 上。我知道我无法将它们从 JPanel 保存到图像中，但不了解如何实现缓冲图像以及我需要/不需要更改什么。

请客气，我是编程新手，尚未完成代码的某些部分。

提前致谢

public class Turtle2 extends JFrame implements ActionListener, KeyListener{

    JMenuBar menuBar;
    JMenu help, file;
    JPanel panel, panel2;
    JMenuItem newO, load, save, exitO, about;
    JTextField text;
    int savecounter = 0, newcounter = 1, part2I = 0;
    int x1 = 0, x2 = 0, y1 = 0, y2 = 0;
    int trigger = 1, turnleftconstant = 0, turnrightconstant =0, direction =0;
    int col = 0;

        public  Turtle2() {
            setLayout(new FlowLayout());
            setSize(1000, 1000);
            setTitle("Graphic");
            setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


        //menu bar

            //sets up general look of window
            panel = new JPanel();
            panel.setBackground(Color.darkGray); 

            //implements box layout
            panel.setLayout(new BoxLayout(panel, BoxLayout.Y_AXIS));

            //sets up drawing area
            panel2 = new JPanel();
            panel2.setPreferredSize(new Dimension(500, 500));;
            panel2.setBackground(Color.WHITE);
            panel2.setBorder(BorderFactory.createLineBorder(Color.darkGray, 3));

            //starting point on drawing area co-ordinates
            x1 = 15; x2 = 15; y1 = 230; y2 =230;

            //starting point implemented
            LinePen first = new LinePen(x1, y1, x2, y2, col);
            panel2.add(first);

            //sets up user input text box
            text = new JTextField(30);

            //add action listener to text box - ready for input and details responses
            text.addActionListener(new ActionListener(){

                    public void actionPerformed(ActionEvent e){

                         //retrieves user input
                         String actions = text.getText();
                         first.setVisible(true);

                        //commands from text

                //add the command line textfeild to the interface
                panel.add(text);

                //uses border layout to set the layout of the interface
                getContentPane().add(BorderLayout.NORTH, panel);
                getContentPane().add(BorderLayout.CENTER, panel2);

                //set the size of the interface
                setSize(600,600);
                //ensure the interface is visible
                setVisible(true);

                }

Answer 1

我将保留所有线条的数组，然后迭代它们，然后使用 img.createGraphics() 绘制线条和其他图形。