panel1.java

Java灵感编程1-101之61-80

package drawimage;

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.geom.*;

/**
 * <p>Title: Draw Image Demo</p>
 * <p>Description: This is a Draw Image demo</p>
 * <p>Copyright: Copyright (c) 2002</p>
 * <p>Company: d6-125</p>
 * @author Liujun
 * @version 1.0
 */

public class Panel1 extends JPanel {
  BorderLayout borderLayout1 = new BorderLayout();
    //在此添加自己的变量
    int n = 2;//一个图像有两个控制点
    int current = -1;//当前的控制点
    static   double SIZE = 12.0;//控制点大小
    Point2D []   points = new Point2D[2];//两个控制点
    String FileName=null;//图像文件名称
    Image myImage=null;//图像变量
  public Panel1() {
    try {
      jbInit();
    }
    catch(Exception ex) {
      ex.printStackTrace();
    }
  }
  void jbInit() throws Exception {
    this.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
      public void mouseDragged(MouseEvent e) {
        this_mouseDragged(e);
      }
    });
    this.addMouseListener(new java.awt.event.MouseAdapter() {
      public void mousePressed(MouseEvent e) {
        this_mousePressed(e);
      }
      public void mouseReleased(MouseEvent e) {
        this_mouseReleased(e);
      }
    });
    this.setLayout(borderLayout1);
      //add code here
    //产生两个初始的点，用于放置图像
    points[0] = new Point2D.Double(10.0, 60.0);
    points[1] = new Point2D.Double(200.0, 200.0);
 }
 void SetFileName(String s){
   FileName=s;
  if(FileName!=null){
     myImage = Toolkit.getDefaultToolkit().getImage(FileName);
    }
  repaint();
 }
  protected void paintComponent(Graphics g) {
    /**@todo: Override this javax.swing.JComponent method*/
    super.paintComponent( g);
       if (points == null) return;
      if(myImage==null) return;
      Graphics2D g2 = (Graphics2D)g;//使用Java 2D
      for (int i = 0; i < n; i++)//画控制点
      {  double x = points[i].getX() - SIZE / 2;
         double y = points[i].getY() - SIZE / 2;
         g2.fill(new Rectangle2D.Double(x, y, SIZE, SIZE));
      }
      //计算高度和宽度
     int width = (int)Math.abs(points[1].getX() - points[0].getX());
     int height = (int)Math.abs(points[1].getY() - points[0].getY());
     g2.drawImage(myImage,(int)points[0].getX(),(int)points[0].getY(),
                     width,height,this);//绘制图像
   }


  void this_mousePressed(MouseEvent e) {
    Point p = e.getPoint();
      for (int i = 0; i < n; i++)
      {  double x = points[i].getX() - SIZE / 2;
         double y = points[i].getY() - SIZE / 2;
         Rectangle2D r = new Rectangle2D.Double(x, y, SIZE, SIZE);
         if (r.contains(p))//判断当前鼠标位置是否在控制点上
         {  current = i;//如果是，则设current为当前点
            return;
         }
      }
  }

  void this_mouseReleased(MouseEvent e) {
   current = -1;//鼠标被释放
  }

  void this_mouseDragged(MouseEvent e) {
     if (current == -1) return;//如果鼠标没有按下，则返回
      points[current] = e.getPoint();//设置当前点为鼠标的位置
      this.repaint();//重绘图形
  }
}