Java 将JPanel导出到图像
所以我一直在尝试将我在JPanel上绘制的图像导出到一个图像中。我一直在使用这种方法:Java 将JPanel导出到图像,java,swing,png,jpanel,bufferedimage,Java,Swing,Png,Jpanel,Bufferedimage,所以我一直在尝试将我在JPanel上绘制的图像导出到一个图像中。我一直在使用这种方法: BufferedImage image = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB); Graphics2D g = image.createGraphics(); paint(g); try { ImageIO.write(image, "png", new File([location goes here]
BufferedImage image = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
paint(g);
try { ImageIO.write(image, "png", new File([location goes here]); } catch (IOException e) {}
我在我预定的位置得到了一个图像,但我得到了我的JPanel显示的压缩版本。如果我尝试导出BMP也会发生同样的情况。有没有办法从JPanel导出像素完美的图像?提前感谢。面板需要根据其要求进行布局。如果面板还没有在屏幕上实现,它可能不会以您期望的方式呈现 以下示例假定面板未显示在屏幕上
setSize(getPreferredSize());
BufferedImage image = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
printAll(g);
g.dispose();
try {
ImageIO.write(image, "png", new File([location goes here]);
} catch (IOException e) {
e.printStackTrace();
}
您应该避免自己调用paint
,如果在屏幕上未实现组件,它可能会引发异常,请使用printAll
此外,如果您创建了一个资源,您应该处置它;)
已更新
我做了一个简单的例子。屏幕截图在顶部,jpeg在左侧,png在右侧
jpeg为30kb,png为320kb
我用这个来创造它
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Graphics2D;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTextField;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
public class PaintComponent {
public static void main(String[] args) {
new PaintComponent();
}
public PaintComponent() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
}
JFrame frame = new JFrame("Testing");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(new TestPane());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TestPane extends JPanel {
private JPanel paintPane;
public TestPane() {
paintPane = new JPanel(new GridBagLayout());
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridwidth = GridBagConstraints.REMAINDER;
paintPane.add(new JLabel("I'm a label"), gbc);
paintPane.add(new JTextField("I'm a text field", 20), gbc);
paintPane.add(new JLabel(new ImageIcon("some\pretty\picture")), gbc);
setLayout(new BorderLayout());
add(paintPane);
JButton paint = new JButton("Capture");
paint.addActionListener(new ActionListener() {
@Override
public void actionPerformed(ActionEvent e) {
BufferedImage image = new BufferedImage(paintPane.getWidth(), paintPane.getHeight(), BufferedImage.TYPE_INT_RGB);
Graphics2D g = image.createGraphics();
paintPane.printAll(g);
g.dispose();
try {
ImageIO.write(image, "jpg", new File("Paint.jpg"));
ImageIO.write(image, "png", new File("Paint.png"));
} catch (IOException exp) {
exp.printStackTrace();
}
}
});
add(paint, BorderLayout.SOUTH);
}
}
}
我会确保您实际查看的是正确的文件;) 如果您试图制作在窗口上看不到的面板图像,请退出。它将在面板上调用
doLayout()
,以确保组件正确显示 谢谢你的建议。不过,当我导出图像时,屏幕上会显示我的JPanel。此外,无论我以何种格式导出图像,它们的大小都是相同的(就内存而言)。这是意料之中的事吗?我想这并不意外。图像是你所期望的吗?是的,它只是与JPanel中显示的图像质量不一样。它对JPanel的所有内容都有效吗?例如,如果a有一个JLabel、一个JButton和另一个JPanel,它们是否都将被打印?@Jas如果您在父组件上调用printAll
,那么是,它将打印所有子组件及其子组件