Java，Swing，Awt - 在图像上绘制矩形并使其可见

Z时代
2024-01-10
分类：问答

我试图打开一个图像，在拖动鼠标的同时绘制一个矩形（鼠标拖动事件），并绘制最后一个矩形鼠标被释放。Java，Swing，Awt - 在图像上绘制矩形并使其可见

我实现拖动时绘制矩形，但我不能在此刻收集最终点的坐标以绘制矩形并存储其数据。你有什么想法来改进我的代码吗？（在背景中添加一个图像，即使在绘制几个图像时也会保留矩形）

我猜mousReleased Event可以帮助我，但我不知道该如何使用它。

编辑：在绘制第一个矩形后，如果绘制第二个矩形，我希望它保持可见。

package selectZone; 
import java.awt.event.*; 
import javax.swing.*; 
import java.awt.*; 
public class Rec extends JFrame { 
    public Rec() { 
     super("rectangle"); 
     setPreferredSize(new java.awt.Dimension(400, 400)); 
     setDefaultCloseOperation(EXIT_ON_CLOSE); 
     JPanel pane = new Pan(); 
     add(pane); 
     pack(); 
     setVisible(true); 
    } 
    public static void main(String[] args) { 
     new Rec(); 
    } 
} 
class Pan extends JPanel { 
    private Point origin; 
    private Point end; 
    private Point endFinal; 
    public Pan() { 
     MouseAdapter adapter = new Lis(); 
     addMouseMotionListener(adapter); 
     addMouseListener(adapter); 
    } 
    class Lis extends MouseAdapter { 
     public void mouseDragged(MouseEvent e) { 
      end = e.getPoint(); 
      repaint(); 
     } 
     public void mousePressed(MouseEvent e) { 
      origin = e.getPoint(); 
     } 
     public void mouseReleased(MouseEvent e, Graphics g) { 
      endFinal = e.getPoint(); 
      g.clearRect(0, 0, getWidth(), getHeight()); 
      g.setColor(Color.RED); 
      int x1 = (int) (origin.getX()); 
      int y1 = (int) (origin.getY()); 
      int x2 = (int) (endFinal.getX()); 
      int y2 = (int) (endFinal.getY()); 
      g.drawRect(x1, y1, x2 - x1, y2 - y1); 
     } 
    } 
    public void paint(Graphics g) { 
     g.clearRect(0, 0, getWidth(), getHeight()); 
     g.setColor(Color.RED); 
     if (origin != null) { 
      int tmp; 
      int x1 = (int) (origin.getX()); 
      int y1 = (int) (origin.getY()); 
      int x2 = (int) (end.getX()); 
      int y2 = (int) (end.getY()); 
      if (x1 > x2) { 
       tmp = x1; 
       x1 = x2; 
       x2 = tmp; 
      } 
      if (y1 > y2) { 
       tmp = y1; 
       y1 = y2; 
       y2 = tmp; 
      } 
      g.drawRect(x1, y1, x2 - x1, y2 - y1); 
     } 
    } 
}