使用 java.awt.Graphics2D 畫線

使用 java.awt.Graphics2D 畫線，需要使用Line2D.Float方法，該方法的四個參數分別為起點的坐標x，y和終點的坐標x，y

import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Line2D;
/**


Displays a JFrame and draws a line on it using the Java 2D Graphics API
*
@author cn.outofmemory
*/
public class Java2DFrame extends javax.swing.JFrame {
/**

Creates a new instance of Java2DFrame
*/
public Java2DFrame() {
 initComponents();
}
/**

This is the method where the line is drawn.
*
@param g The graphics object
*/
public void paint(Graphics g) {
 Graphics2D g2 = (Graphics2D) g;
 Line2D lin = new Line2D.Float(100, 100, 250, 260);
 g2.draw(lin);
}
// <editor-fold defaultstate="collapsed" desc=" Generated Code "> 
private void initComponents() {
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
 org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
 getContentPane().setLayout(layout);
 layout.setHorizontalGroup(

 layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
 .add(0, 400, Short.MAX_VALUE)

);
 layout.setVerticalGroup(

 layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
 .add(0, 300, Short.MAX_VALUE)

);
 pack();
}// </editor-fold>
/**

Starts the program
@param args the command line arguments
*/
public static void main(String args[]) {
 java.awt.EventQueue.invokeLater(new Runnable() {
 public void run() {
     new Java2DFrame().setVisible(true);
 }

 });
}
}</pre>