graphics4.java

Java applet: 画图板的演示程序

//<applet code="Graphics4" width=450 height=550></applet>

import java.applet.*;

import java.awt.*;

import java.awt.event.*;

import java.util.*;

import java.text.*;

 

class Mycanvas extends Canvas
{  
  int x1,x2,y1,y2,model,tempx,tempy;
  Color mycolor;
  
  Mycanvas()
  {
	  setSize(420,420);
	  setBackground(Color.pink);
   }  
  public void setX1(int x1)
	{this.x1=x1;
     }
  public void setY1(int y1)
	{this.y1=y1;
     }
  public void setX2(int x2)
	{this.x2=x2;
     }
  public void setY2(int y2)
	{this.y2=y2;
     }
  public void setColor(Color mycolor)
	{this.mycolor=mycolor;
     }
  public void setModel(int model)           //作图类型
	{this.model=model;
     }

//算法

  public void paint(Graphics g)
	{
	  Color c1=new Color(255,255,240);
	  setBackground(c1);
      g.setColor(mycolor);
	  g.drawLine(x1,420-y1,x2,420-y2);
//做线宽5的直线—正方形刷子
      if (model==1)                        
	  {
	  float dx,dy,k;
	  dx=x2-x1;
	  dy=y2-y1;
	  k=dy/dx;
	  
	 

		if (Math.abs(k)<=1)                 //|k|<=1
		 {  g.setColor(mycolor);
			int x;
			

            if (x1>x2)                            //保证第2个大于第一个点
			{
				tempx=x2;
				x2=x1;
				x1=tempx;
				tempy=y2;
				y2=y1;
				y1=tempy;
			}
            
            float y=y1;
			for(x=x1;x<=x2;x++)
			{
		     
			g.fillRect(x-5,415-(int)Math.round(y+0.5),10,10);
			y=y+k;
			}
		} 
		else                              //|k|>1
		{   g.setColor(mycolor);
			int y;
			
			if (y1>y2)                            //保证第2个大于第一个点
			{   
			    tempx=x2;
				x2=x1;
				x1=tempx;
				tempy=y2;
				y2=y1;
				y1=tempy;
			}
			
			float x=x1;
			for(y=y1;y<=y2;y++)
			{
		  
			g.fillRect((int)Math.round(x+0.5)-5,415-y,10,10);
			x=x+1/k;
			}
		}
      }

//做线宽5的直线—圆形刷子
      if (model==2)                        
	  {
	  float dx,dy,k;
	  dx=x2-x1;
	  dy=y2-y1;
	  k=dy/dx;
	  
	 

		if (Math.abs(k)<=1)                 //|k|<=1
		 {  g.setColor(mycolor);
			int x;
			

            if (x1>x2)                            //保证第2个大于第一个点
			{
				tempx=x2;
				x2=x1;
				x1=tempx;
				tempy=y2;
				y2=y1;
				y1=tempy;
			}
            
            float y=y1;
			for(x=x1;x<=x2;x++)
			{
		     
			g.fillOval(x-5,415-(int)Math.round(y+0.5),10,10);
			y=y+k;
			}
		} 
		else                              //|k|>1
		{   g.setColor(mycolor);
			int y;
			
			if (y1>y2)                            //保证第2个大于第一个点
			{   
			    tempx=x2;
				x2=x1;
				x1=tempx;
				tempy=y2;
				y2=y1;
				y1=tempy;
			}
			
			float x=x1;
			for(y=y1;y<=y2;y++)
			{
		  
			g.fillOval((int)Math.round(x+0.5)-5,415-y,10,10);
			x=x+1/k;
			}
		}
      }


	
	}
}

 

public class Graphics4 extends Applet implements ActionListener

{   
   Label lab1;
   Label labx1,laby1,labx2,laby2;
   TextField inputx1,inputy1,inputx2,inputy2;
   Choice mychoice,colorchoice;
   Button button1;
  
   Mycanvas canvas;
   public void init()

    {  	   	   
	   labx1=new Label("第1端点的X坐标：");
	   laby1=new Label("第1端点的y坐标：");
	   labx2=new Label("第2端点的X坐标：");
	   laby2=new Label("第2端点的y坐标：");
	   lab1=new Label("请选择填充的颜色：");
	   inputx1=new TextField("0",10);
	   inputy1=new TextField("0",10);
	   inputx2=new TextField("0",10);
	   inputy2=new TextField("0",10);


	   mychoice=new Choice();
	   mychoice.addItem("做直线");
	   mychoice.addItem("做线宽10的直线—正方形刷子");
	   mychoice.addItem("做线宽10的直线—圆形刷子");
	   colorchoice=new Choice();
       colorchoice.addItem("黑色");
	   colorchoice.addItem("红色");
	   colorchoice.addItem("绿色");
	   colorchoice.addItem("蓝色");

	   button1=new Button("作图");

	   canvas=new Mycanvas();

	   add(labx1);
	   add(inputx1);
	   add(laby1);
	   add(inputy1);
	   add(labx2);
	   add(inputx2);
	   add(laby2);
	   add(inputy2);
       
       add(mychoice);
	   add(colorchoice);
	   add(button1);
	   add(canvas);
       
	   button1.addActionListener(this);

       

       
   
    }

  
    
    public void actionPerformed(ActionEvent e)

    {
	  int x1,x2,y1,y2,model;
	  Color mycolor=Color.black;
	  model=0;
	 try{
	    x1=Integer.parseInt(inputx1.getText());
		y1=Integer.parseInt(inputy1.getText());
		x2=Integer.parseInt(inputx2.getText());
		y2=Integer.parseInt(inputy2.getText());
		
        
		
		if (mychoice.getSelectedIndex()==0)
		{model=0;
		}
		if (mychoice.getSelectedIndex()==1)
		{model=1;
		}
		if (mychoice.getSelectedIndex()==2)
		{model=2;
		}
		
        
		if (colorchoice.getSelectedIndex()==0)
		{mycolor=Color.black;
		}
		if (colorchoice.getSelectedIndex()==1)
		{mycolor=Color.red;
		}
		if (colorchoice.getSelectedIndex()==2)
		{mycolor=Color.green;
		}
		if (colorchoice.getSelectedIndex()==3)
		{mycolor=Color.blue;
		}
		canvas.setX1(x1);
		canvas.setY1(y1);
		canvas.setX2(x2);
		canvas.setY2(y2);
		
        canvas.setModel(model);
		
        canvas.setColor(mycolor);
		canvas.repaint();
	    }
     catch(NumberFormatException ee)
	   {x1=0;y1=0;x2=0;y2=0;model=0;
	    }

    }

}