middot.java

使用java语言编写的画图板

/*
 * linepanel.java
 *
 * Created on 2005年12月10日, 下午6:32
 */
package painttool;

import java.io.*;
import java.awt.*;
import java.awt.event.*;

public class middot 
{
    public static int dotnumber=1;
    public static TextField t1=new TextField();
    public static TextField t2=new TextField();
    public static TextField t3=new TextField();
    public static TextField t4=new TextField();
    public static TextField t5=new TextField();    
    public static Button drawline=new Button("drawline");
    public static Button clear=new Button("clear");
    public middot()
    {
        BorderLayout bl=new BorderLayout();            
        Button b1=new Button("start-x");
        Button b2=new Button("start-y");
        Button b3=new Button("end-x");
        Button b4=new Button("end-y");
        Button b5=new Button("xl");
        Panel p=new Panel();
        Panel p1=new Panel();
        Panel p2=new Panel();
        Main.linep.setLayout(new BorderLayout()); 
        Main.linep.add(p,bl.SOUTH);        
        p.setLayout(new GridLayout(1,2));
        p.setVisible(true);
        p1.setVisible(true);p2.setVisible(true);
        p1.setLayout(new GridLayout(1,2));
        p2.setLayout(new GridLayout(2,5));
        p.add(p1);p.add(p2);         
        p1.add(drawline);p1.add(clear);
        p2.add(b1);p2.add(b2);p2.add(b3);p2.add(b4);p2.add(b5);
        p2.add(t1);p2.add(t2);p2.add(t3);p2.add(t4);p2.add(t5);  
        monitor1 watch=new monitor1();
        clear.addActionListener(watch);
        drawline.addActionListener(watch);
        Main.linep.addMouseListener(watch);
        Main.card.show(Main.mainFrame,"second");
        Main.card.show(Main.mainFrame,"first");        
    }
}
class monitor1 extends Canvas implements MouseListener,ActionListener
{
    int x1=0,x2=0,y1=0,y2=0;
    String s1,s2,s3,s4;
    public void actionPerformed(ActionEvent e)
    {
        Graphics g=Main.linep.getGraphics();
        if(e.getSource()==linepanel.drawline)   //画直线
        {
        	if(linepanel.dotnumber==1)
        	{
        		s1=linepanel.t1.getText();
        		s2=linepanel.t2.getText();
        		s3=linepanel.t3.getText();
        		s4=linepanel.t4.getText();
        		x1=Integer.parseInt(s1);
        		y1=Integer.parseInt(s2);
        		x2=Integer.parseInt(s3);
        		y2=Integer.parseInt(s4);
        		middot(x1,x2,y1,y2);      		
        	}
        	else 
        	{
                        middot(x1,x2,y1,y2); 
                }
        }
        if(e.getSource()==linepanel.clear)     //清除画板内的点或者直线,以及所获得的坐标
        {
            g.clearRect(0,0,400,350);
            linepanel.t1.setText("");
            linepanel.t2.setText("");
            linepanel.t3.setText("");
            linepanel.t4.setText("");
            linepanel.t5.setText("");
            linepanel.dotnumber=1;
            this.x1=0;this.x2=0;
            this.y1=0;this.y2=0;            
        }
    }
    
    public void mouseClicked(MouseEvent e)
    {   
        Graphics g=Main.linep.getGraphics();
        if(linepanel.dotnumber<=2)
        {
            
            if(linepanel.dotnumber==1)
            {  
                x1=e.getX();y1=e.getY();
                linepanel.t1.setText(""+e.getX());
                linepanel.t2.setText(""+e.getY());     
                g.drawString("start", e.getX()-20,e.getY());
            }
            if(linepanel.dotnumber==2)
            { 
                x2=e.getX();y2=e.getY();
                linepanel.t3.setText(""+e.getX());
                linepanel.t4.setText(""+e.getY()); 
                g.drawString("end", e.getX(),e.getY());
            }
            g.drawLine(e.getX(),e.getY(),e.getX(),e.getY());
            linepanel.dotnumber++;
        }        
    } 
    
    public void mouseReleased(MouseEvent e){   }  
    public void mousePressed(MouseEvent e){   } 
    public void mouseEntered(MouseEvent e){   } 
    public void mouseExited(MouseEvent e){   }   
    
    public void middot(int x0,int x1,int y0,int y1)
    {
        Graphics g=Main.linep.getGraphics();
        int a=0,b=0,midx=0,midy=0,delta1=0,delta2=0,d=0,x=0,y=0,yt=0,xt=0;
        float k=0;        
        linepanel.t5.setText(""+k);
        if(x1>x0&&y1<y0||x1<x0&&y1>y0)
        {
            if(x1<x0&&y1>y0)
            {
                midx=x0;midy=y0;
                x0=x1;y0=y1;
                x1=midx;y1=midy;
            }
            a=y0-y1;
            b=x1-x0;            
            k=a/b;
            if(k<1)
            {
                d=-2*a+b;
                delta1=-2*a;
                delta2=2*(-a+b);
                x=x0;y=y0;
                while(x<x1)
                {
                    if(d<0)
                    {
                        x++;y--;
                        d=delta2+d;
                    }
                    else
                    {
                        x++;
                        d=delta1+d;
                    }
                    g.drawLine(x,y,x,y);
                }
            }
            if(k>=1)
            {
                d=-a+2*b;
                delta1=2*b;
                delta2=-2*a+2*b;
                x=x0;y=y0;
                while(y>y1)
                {
                    if(d<0)
                    {
                        y--;
                        d=delta1+d;
                    }
                    else
                    {
                        x++;y--;
                        d=delta2+d;
                    }
                    g.drawLine(x,y,x,y);
                }
            }
        }
        else
        {
        if(x1<x0&&y1<y0)
        {
            a=y1-y0;
            b=x0-x1;
            k=a/b;
            x=x1;
            y=y1;    
            yt=y0;
            xt=x0;
        }
        if(x1>x0&&y1>y0)
        {
            a=y0-y1;
            b=x1-x0;
            k=a/b;  
            x=x0;
            y=y0;
            xt=x1;
            yt=y1;
        }        
        g.drawLine(x,y,x,y);
        if(k<-1)
        {
            d=a+2*b;
            delta1=2*b;
            delta2=2*a+2*b;
            while(y<yt)
            {
                if(d<0)
                {
                    y++;
                    d=delta1+d;
                }
                else
                {
                    x++;y++;
                    d=d+delta2;                
                }
                g.drawLine(x,y,x,y);
            }
        }
        if(k>=-1&&k<=0)
        {
            d=2*a+b;
            delta1=2*a;
            delta2=2*(a+b);
            while(x<xt)
            {
                if(d<0)
                {
                    x++;y++;
                    d=delta2+d;
                }
                else
                {
                    x++;
                    d=delta1+d;
                }
                g.drawLine(x,y,x,y);
            }
        }
        
        }
   
   
    }
}