我在練習座標轉換的簡單繪圖程式,讓矩形每按一次button就左或右旋轉45度, 可是debug不出來到底是哪邊造成矩形座標越轉越奇怪?請各位大大指導!    package event02_2;    import java.awt.*; import javax.swing.*; import java.awt.event.*; import java.math.*; public class home24 extends Frame {   a p2 = new a();   JButton btn1 = new JButton("Turn left 45");   JButton btn2 = new JButton("Turn right 45");   static int array_x[] = {50,100,100,50};   static int array_y[] = {50,50,100,100};   public class a extends JPanel   {       public void paint(Graphics g)       {         super.paint(g);         g.setColor(Color.red);         g.drawPolygon(array_x,array_y,4);       }   }   class listen implements ActionListener   {       public void actionPerformed(ActionEvent e)       {         int temp_x[] = new int[4];         int temp_y[] = new int[4];         for(int x=0 ; x<4 ; x ) { temp_x[x]=array_x[x]-100; } for(int x=0 ; x<4 ; x ) { temp_y[x]=array_y[x]-100; } if(e.getSource() == btn1) { for(int x=0;x<4;x ) { array_x[x] = 100 (int)(temp_x[x] * (Math.cos(Math.PI/4)) temp_y[x] * (Math.sin(Math.PI/4))); System.out.println(array_x[x]); array_y[x] = 100 (int)(-temp_x[x] * (Math.cos(Math.PI/4)) temp_y[x] * (Math.sin(Math.PI/4))); System.out.println(array_y[x]); } } else if(e.getSource() == btn2) { for(int x=0;x<4;x ) { array_x[x] = 100 (int)(temp_x[x] * (Math.cos(Math.PI/4)) - temp_y[x] * (Math.sin(Math.PI/4))); System.out.println(array_x[x]); array_y[x] = 100 (int)(temp_x[x] * (Math.cos(Math.PI/4)) temp_y[x] * (Math.sin(Math.PI/4))); System.out.println(array_y[x]); } } p2.repaint(); } } public home24() { JFrame frm = new JFrame(); JPanel p1 = new JPanel(); p1.add(btn1); p1.add(btn2); listen lis = new listen(); btn1.addActionListener(lis); btn2.addActionListener(lis); frm.getContentPane().setLayout(new BorderLayout()); frm.getContentPane().add(p1,new BorderLayout().NORTH); frm.getContentPane().add(p2,new BorderLayout().CENTER); frm.setSize(400,400); frm.setLocation(100,100); frm.setVisible(true); } public static void main ( String arg[] ) { home24 mine = new home24(); } }

Onz 您好：    您因為一直用旋轉後的座標，所以誤差一再累積，終致圖形變形。 不好意思，我修改了您的程式，您參考看看！     

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
import java.math.*;
public class home24 extends Frame
{
  a p2 = new a();
  JButton btn1 = new JButton("Turn left 45");
  JButton btn2 = new JButton("Turn right 45");
  static int array_x[] = {0,100,100,0};
  static int array_y[] = {0,0,-100,-100};      int temp_x[] = new int[4];
  int temp_y[] = new int[4];
  static int dir=0;      public class a extends JPanel
  {
      public void paint(Graphics g)
      {
        super.paint(g);
        g.setColor(Color.red);
        //g.drawPolygon(array_x,array_y,4);
        g.drawPolygon(temp_x, temp_y, 4);
      }
  }
  class listen implements ActionListener
  {
      public void actionPerformed(ActionEvent e)
      {
        if(e.getSource() == btn1)
          dir--;
        else if(e.getSource() == btn2)
          dir  ;            double angle = dir*Math.PI/4;            for(int x=0;x<4;x  )
          { double tx,ty;
            tx = array_x[x];
            ty = array_y[x];
            temp_x[x] = 150   (int)(tx * (Math.cos(angle)) - ty * (Math.sin(angle)));
            System.out.println(temp_x[x]);
            temp_y[x] = 150   (int)(tx * (Math.sin(angle))   ty * (Math.cos(angle)));
            System.out.println(temp_y[x]);
          }
        p2.repaint();
      }
  }
  public home24()
  {
     JFrame frm = new JFrame();         JPanel p1 = new JPanel();
     p1.add(btn1);
     p1.add(btn2);         listen lis = new listen();
     btn1.addActionListener(lis);
     btn2.addActionListener(lis);         frm.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);  // Exit the program completely.
     for (int k=0; k<4; k  )
        { temp_x[k] = 150 array_x[k];
         temp_y[k] = 150 array_y[k];
        }         frm.getContentPane().setLayout(new BorderLayout());
     frm.getContentPane().add(p1,new BorderLayout().NORTH);
     frm.getContentPane().add(p2,new BorderLayout().CENTER);
     frm.setSize(400,400);
     frm.setLocation(100,100);
     frm.setVisible(true);
  }
  public static void main ( String arg[] )
  {
    home24 mine = new home24();
  }    }
 

RichTop 敬上 =====***** 把數學當工具，可以解決問題；將數學變能力，能夠發現並解決問題！ =====##### 發表人 - richtop 於 2004/12/09 23:19:46

嗯嗯...我懂了,感謝richtop大的指教!^^