解决方法
您需要使用
Area类.这个例子将演示如何做你所要求的：
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Area;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Test extends JPanel {
public static void main(String[] args) {
JFrame f = new JFrame();
Test t = new Test();
f.getContentPane().setLayout(new BorderLayout());
f.getContentPane().add(t,BorderLayout.CENTER);
f.pack();
f.setDefaultCloSEOperation(JFrame.EXIT_ON_CLOSE);
f.setVisible(true);
}
public Test() {
setPreferredSize(new Dimension(300,300));
}
public void paintComponent(Graphics g) {
Graphics2D g2 = (Graphics2D)g.create();
Rectangle2D rectangleNotToDrawIn = new Rectangle2D.Double(100,100,20,30);
Area outside = calculateRectOutside(rectangleNotToDrawIn);
g2.setPaint(Color.white);
g2.fillRect(0,getWidth(),getHeight());
g2.setPaint(Color.black);
g2.setClip(outside);
g2.drawLine(0,getHeight());
}
private Area calculateRectOutside(Rectangle2D r) {
Area outside = new Area(new Rectangle2D.Double(0,getHeight()));
outside.subtract(new Area(r));
return outside;
}
}
