如何在摇摆中将面板保存为图像？

Question

嗨我想将包含标签和按钮等组件的面板转换为图像文件.

我已经完成了以下代码.图像已保存.但面板的内容不可见或保存.任何人都可以告诉我如何使用其组件保存面板.

码:

package PanelToImage;

import java.awt.Color;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.*;

public class sample extends JPanel {

public JPanel firstpanel;
public JPanel secondpanel;
JLabel label1, label2;
JButton button1, button2;

public sample() {
    firstpanel = new JPanel();
    firstpanel.setSize(400,300); 
    firstpanel.setBackground(Color.RED);
    secondpanel = new JPanel();
    secondpanel.setBackground(Color.GREEN);
    secondpanel.setSize(400,300); 

    label1 = new JLabel("label1");
    label2 = new JLabel("label2");
    button1 = new JButton("button1");
    button2 = new JButton("button2");

    firstpanel.add(label1);
    firstpanel.add(button1);

    secondpanel.add(label2);
    secondpanel.add(button2);

    saveImage(firstpanel);

    add(firstpanel);

    // add(secondpanel);
}

public static void main(String args[]) {

    JFrame frame = new JFrame();
    sample sam = new sample();
    frame.setContentPane(sam);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 300);

}

private void saveImage(JPanel panel) {
    BufferedImage img = new BufferedImage(panel.getWidth(), panel.getHeight(), BufferedImage.TYPE_INT_RGB);
    panel.paint(img.getGraphics());
    try {
        ImageIO.write(img, "png", new File("E://Screen.png"));
        System.out.println("panel saved as image");

    } catch (Exception e) {
        System.out.println("panel not saved" + e.getMessage());
    }
}
}

Answer 1

这段代码适用于我(在JFrame):

Container c = getContentPane();
BufferedImage im = new BufferedImage(c.getWidth(), c.getHeight(), BufferedImage.TYPE_INT_ARGB);
c.paint(im.getGraphics());
ImageIO.write(im, "PNG", new File("shot.png"));

也许您使用过自定义面板.如果为true,请尝试super.paint(g)在paint面板方法的开头添加.

编辑:你必须saveImage 在显示框架后调用:

public static void main(String args[]) {
    ...
    frame.setSize(400, 300);
    sam.saveImage(sam.firstpanel);
}

编辑2:这是保存的图像(因为布局很少,但证明它应该工作):

我调用了saveImage最后一个调用main,并在用户dir(new File("Screen.png"))中使用了一个文件,如nIcE cOw所说.

Answer 2

这里尝试,而不是使用这个例子程序,getGraphics()好像你必须使用createGraphics()对BufferedImage你即将作出.

import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
import javax.imageio.ImageIO;
import javax.swing.*;

public class SnapshotExample
{
    private JPanel contentPane;

    private void displayGUI()
    {
        JFrame frame = new JFrame("Snapshot Example");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        contentPane = new JPanel();
        contentPane.setOpaque(true);
        contentPane.setBackground(Color.WHITE);
        JLabel label = new JLabel("This JLabel will display"
                        + " itself on the SNAPSHOT", JLabel.CENTER);
        contentPane.add(label);

        frame.setContentPane(contentPane);
        frame.pack();
        frame.setLocationByPlatform(true);
        frame.setVisible(true);

        makePanelImage(contentPane);
    }

    private void makePanelImage(Component panel)
    {
        Dimension size = panel.getSize();
        BufferedImage image = new BufferedImage(
                    size.width, size.height 
                              , BufferedImage.TYPE_INT_RGB);
        Graphics2D g2 = image.createGraphics();
        panel.paint(g2);
        try
        {
            ImageIO.write(image, "png", new File("snapshot.png"));
            System.out.println("Panel saved as Image.");
        }
        catch(Exception e)
        {
            e.printStackTrace();
        }
    }

    public static void main(String... args)
    {
        SwingUtilities.invokeLater(new Runnable()
        {
            public void run()
            {           
                new SnapshotExample().displayGUI();
            }
        });
    }
}