Question

我对Java并不熟悉，而且我对当前的问题有点无能为力。我正在尝试在我的主JFrame的单独类中绘制一个图像，但它总是只绘制一小部分图片（可能是10x10px）。（使用标签进行的测试）

也许我没有正确使用g.drawImage方法，或者JPanel没有足够的空间？

主窗口：

public class Deconvolutioner extends JFrame {
Draw z;
Picturearea picturearea;

class Draw extends JPanel {
    public void paint(Graphics g) {


    }
}

public Deconvolutioner() {
    setTitle("Deconvolutioner");
    setLocation(30,1);
    setSize(1300,735);
    super.setFont(new Font("Arial",Font.BOLD,11));
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    FlowLayout flow = new FlowLayout(FlowLayout.CENTER);

    this.setLayout(flow);

    picturearea = new Picturearea();

    this.add(picturearea);

    add(z = new Draw());
    setVisible(true);

}

class Open implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        JFileChooser fileOpen = new JFileChooser();
        FileFilter filter = new FileNameExtensionFilter("png & jpg files", "png",  
        "jpg");
        fileOpen.addChoosableFileFilter(filter);
        int returnVal = fileOpen.showDialog(null, "Open file");
        if (returnVal == JFileChooser.APPROVE_OPTION)  {
            try {
                String path = fileOpen.getSelectedFile().getPath();
                URL url = new File(path).toURI().toURL();
                BufferedImage img = ImageIO.read(url);

                picturearea.setPicture(img);

            } catch (IOException ex)  {
                System.err.println("Some IOException accured (set the right path?): ");
                System.err.println(ex.getMessage());
            }
        } else   {

        }

        repaint();
    }
}

单独的课程：

public class Picturearea extends JPanel {
  public BufferedImage image;
  Draw z;

  public Picturearea() {
      add(z = new Draw());
      setVisible(true);
  }

class Draw extends JPanel {
    @Override
    public void paint(Graphics g) {
        g.drawImage(image, 0, 0, this);

    }
}

public void setPicture(BufferedImage picture) {
    try  {                
        image = picture;
    }  catch (Exception e)  {
        System.err.println("Some IOException accured (did you set the right path?): ");
        System.err.println(e.getMessage());
    }
    repaint();
}

}

我很感激你的每一个帮助谢谢你的时间。

Answer 1

您正在使用FlowLayout进行JFrame的{{1}}布局。 contentPane服从组件的FlowLayout。尝试在preferredSize课程中设置preferredSize pictureArea pictureArea.setPreferredSize(Dimension)或覆盖getPreferredSize(Dimension)功能。{/ p>
您正在使用PictureArea进行自定义绘画：
```
paint(Graphics g)
```
请勿覆盖自定义绘制覆盖@Override public void paint(Graphics g) { g.drawImage(image, 0, 0, this); }的{{1}}。并且您可能需要缩放图像以适合JPanel的大小。如果需要缩放图像，可以使用paint()功能。
```
paintComponent(Graphics g)
```

单独的jpanel中的drawImage只绘制了一块

1 个答案: