本文介绍了在面板内绘制图像的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有一个带两个按钮的面板。我正在尝试在面板中插入图像，我想在单击按钮后在图像内部绘制线条。我使用了以下代码，但这似乎不起作用。
I have a panel with two buttons. I'm trying to insert an image inside the panel and I want to draw lines inside the image after clicking on a button. I have used the below code but this doesn't seem to work.
public class Try_Panel extends JFrame {
// start attributes
private JPanel jPanel1 = new JPanel(null, true);
private JButton jButton1 = new JButton();
private JButton jButton2 = new JButton();
// end attributes
public Try_Panel(String title) {
// Frame-Init
super(title);
setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
int frameWidth = 300;
int frameHeight = 300;
setSize(frameWidth, frameHeight);
Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
int x = (d.width - getSize().width) / 2;
int y = (d.height - getSize().height) / 2;
setLocation(x, y);
setResizable(false);
Container cp = getContentPane();
cp.setLayout(null);
// start components
jPanel1.setBounds(48, 24, 209, 145);
jPanel1.setOpaque(false);
cp.add(jPanel1);
jButton1.setBounds(88, 208, 75, 25);
jButton1.setText("jButton1");
jButton1.setMargin(new Insets(2, 2, 2, 2));
jButton1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jButton1_ActionPerformed(evt);
}
});
cp.add(jButton1);
jButton2.setBounds(184, 208, 75, 25);
jButton2.setText("jButton2");
jButton2.setMargin(new Insets(2, 2, 2, 2));
jButton2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jButton2_ActionPerformed(evt);
}
});
cp.add(jButton2);
// end components
setVisible(true);
} // end of public Try_Panel
// start methods
public void jButton1_ActionPerformed(ActionEvent evt) {
BufferedImage image=new BufferedImage(jPanel1.getWidth(), jPanel1.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
JLabel l=new JLabel(new ImageIcon(image));
Graphics graphics = image.getGraphics();
Graphics2D g = (Graphics2D) graphics;
g.fillRect(0, 0, image.getWidth(), image.getHeight());
g.setColor(Color.BLUE);
g.drawLine(0, 0, 300, 400);
jPanel1.add(l);
} // end of jButton1_ActionPerformed
public void jButton2_ActionPerformed(ActionEvent evt) {
// TODO add your code here
} // end of jButton2_ActionPerformed
// end methods
public static void main(String[] args) {
new Try_Panel("Try_Panel");
} // end of main
} // end of class Try_Panel
最大的问题是我的其他课程中使用的代码相同。
The biggest problem is the same code worked in my other class.
推荐答案
尝试在中包装更新后。此外，当您完成渲染到图形上下文时，还应该调用图像 ImageIcon Graphics＃dispose 。
Try wrapping the image inside the ImageIcon AFTER you have updated it. Also, you should also call Graphics#dispose when you are finished rendering to the graphics context.
public void jButton1_ActionPerformed(ActionEvent evt) {
BufferedImage image=new BufferedImage(jPanel1.getWidth(), jPanel1.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
Graphics2D g = image.createGraphics();
g.fillRect(0, 0, image.getWidth(), image.getHeight());
g.setColor(Color.BLUE);
g.drawLine(0, 0, 300, 400);
g.dispose();
JLabel l=new JLabel(new ImageIcon(image));
jPanel1.add(l);
}
您还应该依赖布局管理员，而不是自己动手，它只会让你的生活变得更轻松。
You should also rely on the layout managers rather the trying to do it yourself, it will simply make your life easier.
就个人而言，我认为直接绘制到自定义组件更容易，例如 JPanel 。查看了解更多详情
Personally, I think it would easier to paint directly to a custom component, like JPanel. Check out Performing Custom Painting for more details
更新示例
基本上，我将您的示例更改为
Basically, I changed your example to
- 使用布局管理器
- 在EDT上下文中加载UI
-
revalidatejPanel1
- Use layout managers
- Load the UI within the context of the EDT
revalidatethejPanel1
public class BadLabel extends JFrame {
// start attributes
private JPanel jPanel1 = new JPanel(new BorderLayout(), true);
private JButton jButton1 = new JButton();
private JButton jButton2 = new JButton();
// end attributes
public BadLabel(String title) {
// Frame-Init
super(title);
setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
int frameWidth = 300;
int frameHeight = 300;
setSize(frameWidth, frameHeight);
Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
int x = (d.width - getSize().width) / 2;
int y = (d.height - getSize().height) / 2;
setLocation(x, y);
// setResizable(false);
Container cp = getContentPane();
// cp.setLayout(null);
// start components
// jPanel1.setBounds(48, 24, 209, 145);
jPanel1.setOpaque(true);
jPanel1.setBackground(Color.RED);
cp.add(jPanel1);
JPanel buttons = new JPanel();
// jButton1.setBounds(88, 208, 75, 25);
jButton1.setText("jButton1");
jButton1.setMargin(new Insets(2, 2, 2, 2));
jButton1.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jButton1_ActionPerformed(evt);
}
});
buttons.add(jButton1);
// jButton2.setBounds(184, 208, 75, 25);
jButton2.setText("jButton2");
jButton2.setMargin(new Insets(2, 2, 2, 2));
jButton2.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent evt) {
jButton2_ActionPerformed(evt);
}
});
buttons.add(jButton2);
// end components
cp.add(buttons, BorderLayout.SOUTH);
setVisible(true);
} // end of public BadLabel
// start methods
public void jButton1_ActionPerformed(ActionEvent evt) {
BufferedImage image = new BufferedImage(jPanel1.getWidth(), jPanel1.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
Graphics2D g = image.createGraphics();
g.fillRect(0, 0, image.getWidth(), image.getHeight());
g.setColor(Color.BLUE);
g.drawLine(0, 0, 300, 400);
g.dispose();
JLabel l = new JLabel(new ImageIcon(image));
l.setBorder(new LineBorder(Color.BLUE));
jPanel1.add(l);
jPanel1.revalidate();
} // end of jButton1_ActionPerformed
public void jButton2_ActionPerformed(ActionEvent evt) {
// TODO add your code here
} // end of jButton2_ActionPerformed
// end methods
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (Exception exp) {
}
new BadLabel("BadLabel");
}
});
} // end of main
} // end of class BadLabel}
这篇关于在面板内绘制图像的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！