java - Swing:保存当前图形

Question

我有创建一些图形的 SWing 代码。我有一个按钮“再次运行”，可以重新创建图形。

SwingUtilities.invokeLater(new Runnable() {

            public void run() {

                final GraphicsDemo_noborders_ML demo = new GraphicsDemo_noborders_ML();

                final JFrame jFrame = new JFrame();

                jFrame.setTitle("Latest Programic Art");
                jFrame.setSize(canvasW, canvasH);

                JButton save = new JButton("Save");
                JButton run = new JButton("Run Again");

                save.setBounds(50, 100, 100, 50);
                run.setBounds(50, 500, 100, 50);

                final JPanel panel = new JPanel();

                panel.add(save);
                panel.add(run);

                final JComponent canvas = new JComponent() {

                    @Override
                    protected void paintComponent(Graphics g) {
                        demo.paint(g);
                    }
                };

                jFrame.getContentPane().add(canvas, BorderLayout.CENTER);
                jFrame.getContentPane().add(panel, BorderLayout.PAGE_START);


                run.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e) {

                        Graphics g = canvas.getGraphics();
                        demo.paint(g);
                    }
                });

                save.addActionListener(new ActionListener() {

                    public void actionPerformed(ActionEvent e) {

                        JFileChooser chooser = new JFileChooser();
                        chooser.setFileSelectionMode(JFileChooser.DIRECTORIES_ONLY);
                        chooser.showSaveDialog(null);

                        String location = chooser.getSelectedFile().toString();
                        demo.saveImageToLocalDisk(jFrame, location);
                    }
                });

                jFrame.setVisible(true);
                jFrame.setDefaultCloseOperation(EXIT_ON_CLOSE);
            }
        });

保存按钮用于将当前图形保存为图像。但是，当我保存时，它不会保存当前图形，而是仅保存初始图形。

下面提供了保存的方法，

private void saveImageToLocalDisk(JFrame jFrame, String location) {

        BufferedImage image = null;

        try {

            Rectangle rectangle = jFrame.getBounds();
            image = new Robot().createScreenCapture(rectangle);

        } catch (AWTException e1) {
            e1.printStackTrace();
        }

        Graphics2D graphics2D = image.createGraphics();
        jFrame.paint(graphics2D);

        try {
            ImageIO.write(image, "jpeg", new File(location + "/Graphics.jpeg"));
        } catch (Exception e) {
            System.out.println("error");
        }
    }

我该如何纠正这个问题？

Answer 1

这是一个小例子，我将如何实现您的应用程序(重新创建+保存图像)。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.WindowConstants;

/**
 * <code>PaintDemo</code>.
 */
public class PaintDemo {

    private int recreateIndex = 1;

    private BufferedImage image;

    private final JLabel imageLabel = new JLabel();

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new PaintDemo()::startUp);
    }

    private void startUp() {
        recreateImage();
        JFrame frm = new JFrame("Paint app");
        frm.add(imageLabel);
        JPanel buttonBar = new JPanel();
        JButton recreate = new JButton("Recreate");
        recreate.addActionListener(e -> recreateImage());
        buttonBar.add(recreate);
        JButton save = new JButton("Save");
        save.addActionListener(e -> save());
        buttonBar.add(save);
        frm.add(buttonBar, BorderLayout.NORTH);
        frm.pack();
        frm.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
        frm.setLocationRelativeTo(null);
        frm.setVisible(true);
    }

    private void recreateImage() {
        image = new BufferedImage(400, 300, BufferedImage.TYPE_INT_ARGB);
        Graphics2D g = image.createGraphics();
        g.setColor(Color.BLUE);
        g.fillRect(20, 30, 100, 50);
        g.setColor(Color.ORANGE);
        g.drawOval(200, 150, 50, 50);
        g.setColor(Color.GREEN);
        g.drawString("Recreated image: " + recreateIndex++, 200, 250);
        imageLabel.setIcon(new ImageIcon(image));
    }

    private void save() {
        JFileChooser chooser = new JFileChooser();
        int result = chooser.showSaveDialog(imageLabel);
        if (result == JFileChooser.APPROVE_OPTION) {
            File f = chooser.getSelectedFile();
            try {
                ImageIO.write(image, "jpeg", f);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
}