main.java

1。我们要实现一个比较简单的用鼠标画图工具

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.JColorChooser;
import javax.swing.JOptionPane;
import java.awt.geom.*;
import com.sun.image.codec.jpeg.*;
import java.awt.image.*;
import java.io.*;
import java.util.*;
class Window extends Frame implements ActionListener
{String path1=new String("1");
	MenuBar menubar;
	Menu menu;
	MyCanvas can;
	Graphics g;
	MenuItem a,b,c;
	FileDialog filed,files;
	Image image;
class panell extends Panel implements ItemListener
{Checkbox box1,box2,box3,box4,box5;
Choice choice;
Color backcolor;
int typebox=0;
int typebox1=0;
String name=new String("1");
CheckboxGroup sex1;
panell()
{
sex1=new CheckboxGroup();
box4=new Checkbox("填充",false,sex1); 
box5=new Checkbox("不填充",true,sex1); 
choice=new Choice();
choice.add("1");
choice.add("2");
choice.add("3");
choice.add("4");
choice.add("5");
add(box4);
add(box5);
add(choice);

setBackground(Color.pink);
backcolor=getBackground();
box4.addItemListener(this);
box5.addItemListener(this);
choice.addItemListener(this);
}
public void itemStateChanged(ItemEvent e)//获取选择的颜色和填充模式
{	
 if(e.getSource()==box4)
 { typebox1=4; 
 }

else if(e.getSource()==box5)
 { typebox1=5;
 } 
 else if(e.getSource()==choice)
 { name=choice.getSelectedItem();
 } 
}
}  
class panel extends Panel implements ActionListener//画板
{
Button button1,button2,button3,button4,button5,button6,button7,button8;
Color backcolor;
int typebutton=0;

panel()
{
button1=new Button("直线");
button2=new Button("矩形");
button3=new Button("圆角矩形");
button4=new Button("椭圆");
button5=new Button("圆");
button6=new Button("圆弧");
button7=new Button("颜色板");
button8=new Button("画笔");

add(button1);
add(button2);
add(button3);
add(button4);
add(button5);
add(button6);
add(button7);
add(button8);

setBackground(Color.pink);
backcolor=getBackground();
button1.addActionListener(this);
button2.addActionListener(this);
button3.addActionListener(this);
button4.addActionListener(this);
button5.addActionListener(this);
button6.addActionListener(this);
button7.addActionListener(this);
button8.addActionListener(this);
}
public void actionPerformed(ActionEvent e)//判断鼠标点击那个按钮  
{
if(e.getSource()==button1)
{typebutton=1; 
}
else if(e.getSource()==button2)
{typebutton=2;
}
else if(e.getSource()==button3)
{typebutton=3;
}
else if(e.getSource()==button4)
{typebutton=4;
}
else if(e.getSource()==button5)
{typebutton=5;
}
else if(e.getSource()==button6)
{typebutton=6;
}
else if(e.getSource()==button7)
{typebutton=7;
}
else if(e.getSource()==button8)
{typebutton=8;
}
}
}
class MyCanvas extends Canvas//画布
implements MouseListener
{panel pan;
panell panl;
BufferedImage image;
int typebutton=1;
int x2=-1,y2=-1;
int x=-1,y=-1;
int x1=-1,y1=-1;
int typebox=0;
int k=0;  
int d=0;
String path=new String("1");  
Toolkit tool;
Image image1;
Graphics2D g2D;
Vector v=new Vector();                     
Point p;
Color color;
MyCanvas()
{setSize(200,200);
tool=getToolkit();
image=new BufferedImage(600,600,BufferedImage.TYPE_INT_RGB); 
g2D=image.createGraphics();
image1=tool.getImage(path);
g2D.setColor(Color.white);  
g2D.fillRect(0,0,600,600);
pan=new panel();
panl=new panell();
p=new Point(0,0);
typebutton=1;
g2D.setColor(Color.black);

addMouseListener(this);
addMouseMotionListener(new MouseMotionAdapter()
	{
public void mouseDragged(MouseEvent e)
{if(pan.typebutton==8)
{d=pan.typebutton;		
x2=(int)e.getX();y2=(int)e.getY();
Point p=new Point(x2,y2);
v.addElement(p);
if(x!=-1&&y!=-1)
{
for(int i=0;i<v.size()-1;i++)
	{
	Point p1=(Point)v.elementAt(i);
	Point p2=(Point)v.elementAt(i+1);
	g2D.drawLine(p1.x,p1.y,p2.x,p2.y);
}
repaint();
}}              
if(pan.typebutton==1&&k==1)//直线
	{d=pan.typebutton;
    if(x1!=-1)
	g2D.drawLine(x,y,x1,y1);   
	k=0;
	}
else if(pan.typebutton==2&&k==1)//矩形
	{       d=pan.typebutton; 
            int i,j;
			i=x1-x;
			j=y1-y;
			if(i>=0&&j>=0){
			if(panl.typebox1==4)
		    {g2D.fillRect(x,y,i,j);
		    }
		    else g2D.drawRect(x,y,i,j);}
			else{
			if(panl.typebox1==4)
		    {g2D.fillRect(x1,y1,Math.abs(i),Math.abs(j));
		    }
		    else g2D.drawRect(x1,y1,Math.abs(i),Math.abs(j));}
		    k=0;
    }		
else if(pan.typebutton==3&&k==1)//圆角矩形
		{d=pan.typebutton;
			int i,j;
			i=x1-x;
			j=y1-y;
			if(i>=0&&j>=0){
			if(panl.typebox1==4)
		    {g2D.fillRoundRect(x,y,i,j,20,20);
		    }
		    else g2D.drawRoundRect(x,y,i,j,20,20);}
			else{
			if(panl.typebox1==4)
		    {g2D.fillRoundRect(x1,y1,Math.abs(i),Math.abs(j),20,20);
		    }
		    else g2D.drawRoundRect(x1,y1,Math.abs(i),Math.abs(j),20,20);}
		    k=0;
		}       
else if(pan.typebutton==4&&k==1)//椭圆
		{d=pan.typebutton;
			int i,j;
			i=x1-x;
			j=y1-y;
			if(i>=0&&j>=0){
			if(panl.typebox1==4)
		    {g2D.fillOval(x,y,i,j);
		    }
		    else g2D.drawOval(x,y,i,j);	}
			else{
			if(panl.typebox1==4)
		    {g2D.fillOval(x1,y1,Math.abs(i),Math.abs(j));
		    }
	        else g2D.drawOval(x1,y1,Math.abs(i),Math.abs(j));	}
	        k=0;
		 }		       
else if(pan.typebutton==5&&k==1)//圆
		{d=pan.typebutton;
			int i;
			i=x1-x;
			if(i>=0){
		    if(panl.typebox1==4)
		    {g2D.fillOval(x,y,i,i);
		    }
		    else g2D.drawOval(x,y,i,i);}
            else{
		    if(panl.typebox1==4)
		    {g2D.fillOval(x1,y1,Math.abs(i),Math.abs(i));
		    }
		    else g2D.drawOval(x1,y1,Math.abs(i),Math.abs(i));} 
		    k=0;  
		}              
else if(pan.typebutton==6&&k==1)//圆弧
		   {d=pan.typebutton;
		   	int i;
		   	i=x1-x;
		   	if(i>=0)
		   	{g2D.drawArc(x,y,i,i,60,60);
		   	}
		   	else
		   	{g2D.drawArc(x1,y1,Math.abs(i),Math.abs(i),60,60);
		   	}
		   	k=0;
		   }
		}
	
	}	
);

addMouseMotionListener(new MouseMotionAdapter()
	{
public void mousePressed(MouseEvent e)
{
x=e.getX();
y=e.getY();
k=1;
}
}
);
addMouseMotionListener(new MouseMotionAdapter()
	{
public void mouseReleased(MouseEvent e){
 x1=e.getX();
 y1=e.getY();
 v.removeAllElements();
 repaint();
 }
});
}
public void paint(Graphics g)
{
 BasicStroke b1=new BasicStroke
(2,BasicStroke.CAP_SQUARE,BasicStroke.JOIN_MITER);
 BasicStroke b2=new BasicStroke
(4,BasicStroke.CAP_SQUARE,BasicStroke.JOIN_MITER);
 BasicStroke b3=new BasicStroke
(6,BasicStroke.CAP_SQUARE,BasicStroke.JOIN_MITER);
 BasicStroke b4=new BasicStroke
(8,BasicStroke.CAP_SQUARE,BasicStroke.JOIN_MITER);
g.drawImage(image,0,0,this);
if(path!="1")
{g.drawImage(image1,0,0,this);
	}
	if(panl.name=="1"){}
	else if(panl.name=="2")
	{g2D.setStroke(b1);}
	else if(panl.name=="3")
	{g2D.setStroke(b2);}
	else if(panl.name=="4")
	{g2D.setStroke(b3);}
	else if(panl.name=="5")
	{g2D.setStroke(b4);}   
 else if(pan.typebutton==7)//颜色板
{       
color=JColorChooser.showDialog(pan,"颜色板",pan.button8.getBackground());
g2D.setColor(color);
pan.typebutton=d;
} 
 else if(pan.typebutton==8)//画笔
 {      
 }            	                     	                  	   
}
public Image getImage()
{return image;
}	
public void mousePressed(MouseEvent e)
{
x=e.getX();
y=e.getY();
k=1;
}

public void mouseReleased(MouseEvent e){
 x1=e.getX();
 y1=e.getY();
 v.removeAllElements();
 repaint();
 }
public void mouseEntered(MouseEvent e){repaint();}
public void mouseExited(MouseEvent e)
{
repaint();
}
public void mouseClicked(MouseEvent e){}
public void update(Graphics g)
{if(typebutton!=0)
{paint(g);
}
else
{super.update(g);
}
}
}
	Window()
	{
		can=new MyCanvas();
		menubar=new MenuBar();
		menu=new Menu("文件");
		a=new MenuItem("打开");
		b=new MenuItem("保存");
		c=new MenuItem("退出");
		filed=new FileDialog(this,"打开文件对话框",FileDialog.LOAD);
		filed.setVisible(false);
		files=new FileDialog(this,"保存文件对话框",FileDialog.SAVE);
		files.setVisible(false);
		menu.add(a);
		menu.add(b);
		menu.add(c);
		menubar.add(menu);
		setMenuBar(menubar);
		setBounds(200,100,600,600);
		add(can.panl,BorderLayout.SOUTH);
		
add(can.pan,BorderLayout.NORTH);
setVisible(true);      
		add(can,BorderLayout.CENTER);
		validate();
		a.addActionListener(this);
		b.addActionListener(this);
		c.addActionListener(this);
		
	}
public void actionPerformed(ActionEvent e)
{if(e.getSource()==a)
{filed.setVisible(true);
path1=filed.getDirectory();
String name=filed.getFile();
int w=can.getWidth(); 
int h=can.getHeight(); 
g=can.g2D;
image=Toolkit.getDefaultToolkit().getImage(path1+"/"+name); 
g.drawImage(image,0,0,w,h,can);
	
	}
	else if(e.getSource()==b)
	{files.setVisible(true);
	path1=files.getDirectory();
	String name=filed.getFile();
	try{JPEGImageEncoder encoder=
		    JPEGCodec.createJPEGEncoder(new FileOutputStream(path1+"a.jpg"));
		    encoder.encode(can.image);
		    }
		catch(Exception ee){}    
	
	}
	else if(e.getSource()==c)
	{System.exit(0);}
	}
}
public class Main {
public Main() { }
public static void main(String[] args) {
Window f=new Window();
 
f.addWindowListener(new WindowAdapter()
{public void windowClosing(WindowEvent e)
{System.exit(0);}
});

}   
}