panel1.java

Java灵感编程1-101之61-80

package controlarc;

import java.awt.*;
import javax.swing.JPanel;
import java.awt.event.*;
import java.awt.geom.*;
import java.util.*;
/**
 * <p>Title: Control Arc Demo</p>
 * <p>Description: This is a Control Arc 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 = 4;//一个弧角度有四个控制点
    int current = -1;//当前的控制点
    static   double SIZE = 12.0;//控制点大小
    Point2D []   points = new Point2D[4];//四个控制点

  public Panel1() {
    try {
      jbInit();
    }
    catch(Exception ex) {
      ex.printStackTrace();
    }
  }
  void jbInit() throws Exception {
    this.setForeground(Color.red);
    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
         //产生四个初始的点，两个用于控制大小，另外两个用于控制角度
         points[0] = new Point2D.Double(100.0, 100.0);
         points[1] = new Point2D.Double(200.0, 200.0);
         points[2] = new Point2D.Double(150.0, 250.0);
         points[3] = new Point2D.Double(250.0, 150.0);
  }

  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
  }
  protected void paintComponent(Graphics g) {
    /**@todo: Override this javax.swing.JComponent method*/
      super.paintComponent( g);
      if (points == 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));
      }
      //重画弧角度
      //计算中心位置
      double centerX = (points[0].getX() + points[1].getX()) / 2;
      double centerY = (points[0].getY() + points[1].getY()) / 2;
      //计算高度和宽度
      double width = Math.abs(points[1].getX() - points[0].getX());
      double height = Math.abs(points[1].getY() - points[0].getY());
       //计算起始角度
      double distortedStartAngle
         = Math.toDegrees(Math.atan2(-(points[2].getY() - centerY)
            * width, (points[2].getX() - centerX) * height));
      //计算结束角度
      double distortedEndAngle
         = Math.toDegrees(Math.atan2(-(points[3].getY() - centerY)
            * width, (points[3].getX() - centerX) * height));
      //计算角度差，纠正角度偏差
      double distortedAngleDifference
         = distortedEndAngle - distortedStartAngle;
      if (distortedStartAngle < 0)
         distortedStartAngle += 360;
      if (distortedAngleDifference < 0)
         distortedAngleDifference += 360;
      //创建弧对象
      Arc2D Arc = new Arc2D.Double(0, 0, 0, 0,
         distortedStartAngle, distortedAngleDifference,
         Arc2D.OPEN);
      Arc.setFrameFromDiagonal(points[0], points[1]);
      //创建两边控制线和角度控制线
      GeneralPath gPath = new GeneralPath();
      gPath.append(Arc, false);
      Rectangle2D Rectangle = new Rectangle2D.Double();
      Rectangle.setFrameFromDiagonal(points[0], points[1]);
      gPath.append(Rectangle, false);
      Point2D center = new Point2D.Double(centerX, centerY);
      gPath.append(new Line2D.Double(center, points[2]), false);
      gPath.append(new Line2D.Double(center, points[3]), false);
      g2.draw(gPath);
      g2.drawString("中心点："+String.valueOf(center)+"  角度差："+String.valueOf(distortedAngleDifference),10,10);
  }
}