JAVA实现简单的画图板
楼主写一个html，很容易把下面代码嵌入到applet，可以google一下实现，
还有copy自己不知道算不算复制。。。-_-!
——————————————————————–
楼主给你一个我的，直接保存成pb.java编译运行，就是你要的画图功能 ，可以参考一下
____________________________________________________________________
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import java.awt.geom.*;
import java.io.*;
class Point implements Serializable
{
int x,y;
Color col;
int tool;
int boarder;
Point(int x, int y, Color col, int tool, int boarder)
{
this.x = x;
this.y = y;
this.col = col;
this.tool = tool;
this.boarder = boarder;
}
}
class paintboard extends Frame implements ActionListener,MouseMotionListener,MouseListener,ItemListener
{
int x = -1, y = -1;
int con = 1;//画笔大小
int Econ = 5;//橡皮大小
int toolFlag = 0;//toolFlag:工具标记
//toolFlag工具对应表：
//（0–画笔）；（1–橡皮）；（2–清除）；
//（3–直线）；（4–圆）；（5–矩形）；
Color c = new Color(0,0,0); //画笔颜色
BasicStroke size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);//画笔粗细
Point cutflag = new Point(-1, -1, c, 6, con);//截断标志
Vector paintInfo = null;//点信息向量组
int n = 1;
FileInputStream picIn = null;
FileOutputStream picOut = null;
ObjectInputStream VIn = null;
ObjectOutputStream VOut = null;
// *工具面板–画笔，直线，圆，矩形，多边形,橡皮，清除*/
Panel toolPanel;
Button eraser, drLine,drCircle,drRect;
Button clear ,pen;
Choice ColChoice,SizeChoice,EraserChoice;
Button colchooser;
Label 颜色,大小B,大小E;
//保存功能
Button openPic,savePic;
FileDialog openPicture,savePicture;
paintboard(String s)
{
super(s);
addMouseMotionListener(this);
addMouseListener(this);
paintInfo = new Vector();
/*各工具按钮及选择项*/
//颜色选择
ColChoice = new Choice();
ColChoice.add(“black“);
ColChoice.add(“red“);
ColChoice.add(“blue“);
ColChoice.add(“green“);
ColChoice.addItemListener(this);
//画笔大小选择
SizeChoice = new Choice();
SizeChoice.add(“1“);
SizeChoice.add(“3“);
SizeChoice.add(“5“);
SizeChoice.add(“7“);
SizeChoice.add(“9“);
SizeChoice.addItemListener(this);
//橡皮大小选择
EraserChoice = new Choice();
EraserChoice.add(“5“);
EraserChoice.add(“9“);
EraserChoice.add(“13“);
EraserChoice.add(“17“);
EraserChoice.addItemListener(this);
////////////////////////////////////////////////////
toolPanel = new Panel();
clear = new Button(“清除“);
eraser = new Button(“橡皮“);
pen = new Button(“画笔“);
drLine = new Button(“画直线“);
drCircle = new Button(“画圆形“);
drRect = new Button(“画矩形“);
openPic = new Button(“打开图画“);
savePic = new Button(“保存图画“);
colchooser = new Button(“显示调色板“);
//各组件事件监听
clear.addActionListener(this);
eraser.addActionListener(this);
pen.addActionListener(this);
drLine.addActionListener(this);
drCircle.addActionListener(this);
drRect.addActionListener(this);
openPic.addActionListener(this);
savePic.addActionListener(this);
colchooser.addActionListener(this);
颜色 = new Label(“画笔颜色“,Label.CENTER);
大小B = new Label(“画笔大小“,Label.CENTER);
大小E = new Label(“橡皮大小“,Label.CENTER);
//面板添加组件
toolPanel.add(openPic);
toolPanel.add(savePic);
toolPanel.add(pen);
toolPanel.add(drLine);
toolPanel.add(drCircle);
toolPanel.add(drRect);
toolPanel.add(颜色); toolPanel.add(ColChoice);
toolPanel.add(大小B); toolPanel.add(SizeChoice);
toolPanel.add(colchooser);
toolPanel.add(eraser);
toolPanel.add(大小E); toolPanel.add(EraserChoice);
toolPanel.add(clear);
//工具面板到APPLET面板
add(toolPanel,BorderLayout.NORTH);
setBounds(60,60,900,600); setVisible(true);
validate();
//dialog for save and load
openPicture = new FileDialog(this,“打开图画“,FileDialog.LOAD);
openPicture.setVisible(false);
savePicture = new FileDialog(this,“保存图画“,FileDialog.SAVE);
savePicture.setVisible(false);
openPicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ openPicture.setVisible(false); }
});
savePicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ savePicture.setVisible(false); }
});
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ System.exit(0);}
});
}
public void paint(Graphics g)
{
Graphics2D g2d = (Graphics2D)g;
Point p1,p2;
n = paintInfo.size();
if(toolFlag==2)
g.clearRect(0,0,getSize().width,getSize().height);//清除
for(int i=0; i《n ;i++){
p1 = (Point)paintInfo.elementAt(i);
p2 = (Point)paintInfo.elementAt(i+1);
size = new BasicStroke(p1.boarder,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
g2d.setColor(p1.col);
g2d.setStroke(size);
if(p1.tool==p2.tool)
{
switch(p1.tool)
{
case 0://画笔
Line2D line1 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line1);
break;
case 1://橡皮
g.clearRect(p1.x, p1.y, p1.boarder, p1.boarder);
break;
case 3://画直线
Line2D line2 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line2);
break;
case 4://画圆
Ellipse2D ellipse = new Ellipse2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(ellipse);
break;
case 5://画矩形
Rectangle2D rect = new Rectangle2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(rect);
break;
case 6://截断，跳过
i=i+1;
break;
default :
}//end switch
}//end if
}//end for
}
public void itemStateChanged(ItemEvent e)
{
if(e.getSource()==ColChoice)//预选颜色
{
String name = ColChoice.getSelectedItem();
if(name==“black“)
{c = new Color(0,0,0); }
else if(name==“red“)
{c = new Color(255,0,0);}
else if(name==“green“)
{c = new Color(0,255,0);}
else if(name==“blue“)
{c = new Color(0,0,255);}
}
else if(e.getSource()==SizeChoice)//画笔大小
{
String selected = SizeChoice.getSelectedItem();
if(selected==“1“)
{
con = 1;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“3“)
{
con = 3;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“5“)
{con = 5;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“7“)
{con = 7;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“9“)
{con = 9;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
}
else if(e.getSource()==EraserChoice)//橡皮大小
{
String Esize = EraserChoice.getSelectedItem();
if(Esize==“5“)
{ Econ = 5*2; }
else if(Esize==“9“)
{ Econ = 9*2; }
else if(Esize==“13“)
{ Econ = 13*2; }
else if(Esize==“17“)
{ Econ = 17*3; }
}
}
public void mouseDragged(MouseEvent e)
{
Point p1 ;
switch(toolFlag){
case 0://画笔
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p1);
repaint();
break;
case 1://橡皮
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, null, toolFlag, Econ);
paintInfo.addElement(p1);
repaint();
break;
default :
}
}
public void mouseMoved(MouseEvent e) {}
public void update(Graphics g)
{
paint(g);
}
public void mousePressed(MouseEvent e)
{
Point p2;
switch(toolFlag){
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
default :
}
}
public void mouseReleased(MouseEvent e)
{
Point p3;
switch(toolFlag){
case 0://画笔
paintInfo.addElement(cutflag);
break;
case 1: //eraser
paintInfo.addElement(cutflag);
break;
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
default:
}
}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mouseClicked(MouseEvent e){}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==pen)//画笔
{toolFlag = 0;}
if(e.getSource()==eraser)//橡皮
{toolFlag = 1;}
if(e.getSource()==clear)//清除
{
toolFlag = 2;
paintInfo.removeAllElements();
repaint();
}
if(e.getSource()==drLine)//画线
{toolFlag = 3;}
if(e.getSource()==drCircle)//画圆
{toolFlag = 4;}
if(e.getSource()==drRect)//画矩形
{toolFlag = 5;}
if(e.getSource()==colchooser)//调色板
{
Color newColor = JColorChooser.showDialog(this,“调色板“,c);
c = newColor;
}
if(e.getSource()==openPic)//打开图画
{
openPicture.setVisible(true);
if(openPicture.getFile()!=null)
{
int tempflag;
tempflag = toolFlag;
toolFlag = 2 ;
repaint();
try{
paintInfo.removeAllElements();
File filein = new File(openPicture.getDirectory(),openPicture.getFile());
picIn = new FileInputStream(filein);
VIn = new ObjectInputStream(picIn);
paintInfo = (Vector)VIn.readObject();
VIn.close();
repaint();
toolFlag = tempflag;
}
catch(ClassNotFoundException IOe2)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read object“);
}
catch(IOException IOe)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read file“);
}
}
}
if(e.getSource()==savePic)//保存图画
{
savePicture.setVisible(true);
try{
File fileout = new File(savePicture.getDirectory(),savePicture.getFile());
picOut = new FileOutputStream(fileout);
VOut = new ObjectOutputStream(picOut);
VOut.writeObject(paintInfo);
VOut.close();
}
catch(IOException IOe)
{
System.out.println(“can not write object“);
}
}
}
}//end paintboard
public class pb
{
public static void main(String args)
{ new paintboard(“画图程序“); }
}
JAVA编译简易画图板代码
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import java.awt.geom.*;
import java.io.*;
class Point implements Serializable
{
int x,y;
Color col;
int tool;
int boarder;
Point(int x, int y, Color col, int tool, int boarder)
{
this.x = x;
this.y = y;
this.col = col;
this.tool = tool;
this.boarder = boarder;
}
}
class paintboard extends Frame implements ActionListener,MouseMotionListener,MouseListener,ItemListener
{
int x = -1, y = -1;
int con = 1;//画笔大小
int Econ = 5;//橡皮大小
int toolFlag = 0;//toolFlag:工具标记
//toolFlag工具对应表：
//（0–画笔）；（1–橡皮）；（2–清除）；
//（3–直线）；（4–圆）；（5–矩形）；
Color c = new Color(0,0,0); //画笔颜色
BasicStroke size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);//画笔粗细
Point cutflag = new Point(-1, -1, c, 6, con);//截断标志
Vector paintInfo = null;//点信息向量组
int n = 1;
FileInputStream picIn = null;
FileOutputStream picOut = null;
ObjectInputStream VIn = null;
ObjectOutputStream VOut = null;
// *工具面板–画笔，直线，圆，矩形，多边形,橡皮，清除*/
Panel toolPanel;
Button eraser, drLine,drCircle,drRect;
Button clear ,pen;
Choice ColChoice,SizeChoice,EraserChoice;
Button colchooser;
Label 颜色,大小B,大小E;
//保存功能
Button openPic,savePic;
FileDialog openPicture,savePicture;
paintboard(String s)
{
super(s);
addMouseMotionListener(this);
addMouseListener(this);
paintInfo = new Vector();
/*各工具按钮及选择项*/
//颜色选择
ColChoice = new Choice();
ColChoice.add(“black“);
ColChoice.add(“red“);
ColChoice.add(“blue“);
ColChoice.add(“green“);
ColChoice.addItemListener(this);
//画笔大小选择
SizeChoice = new Choice();
SizeChoice.add(“1“);
SizeChoice.add(“3“);
SizeChoice.add(“5“);
SizeChoice.add(“7“);
SizeChoice.add(“9“);
SizeChoice.addItemListener(this);
//橡皮大小选择
EraserChoice = new Choice();
EraserChoice.add(“5“);
EraserChoice.add(“9“);
EraserChoice.add(“13“);
EraserChoice.add(“17“);
EraserChoice.addItemListener(this);
////////////////////////////////////////////////////
toolPanel = new Panel();
clear = new Button(“清除“);
eraser = new Button(“橡皮“);
pen = new Button(“画笔“);
drLine = new Button(“画直线“);
drCircle = new Button(“画圆形“);
drRect = new Button(“画矩形“);
openPic = new Button(“打开图画“);
savePic = new Button(“保存图画“);
colchooser = new Button(“显示调色板“);
//各组件事件监听
clear.addActionListener(this);
eraser.addActionListener(this);
pen.addActionListener(this);
drLine.addActionListener(this);
drCircle.addActionListener(this);
drRect.addActionListener(this);
openPic.addActionListener(this);
savePic.addActionListener(this);
colchooser.addActionListener(this);
颜色 = new Label(“画笔颜色“,Label.CENTER);
大小B = new Label(“画笔大小“,Label.CENTER);
大小E = new Label(“橡皮大小“,Label.CENTER);
//面板添加组件
toolPanel.add(openPic);
toolPanel.add(savePic);
toolPanel.add(pen);
toolPanel.add(drLine);
toolPanel.add(drCircle);
toolPanel.add(drRect);
toolPanel.add(颜色); toolPanel.add(ColChoice);
toolPanel.add(大小B); toolPanel.add(SizeChoice);
toolPanel.add(colchooser);
toolPanel.add(eraser);
toolPanel.add(大小E); toolPanel.add(EraserChoice);
toolPanel.add(clear);
//工具面板到APPLET面板
add(toolPanel,BorderLayout.NORTH);
setBounds(60,60,900,600); setVisible(true);
validate();
//dialog for save and load
openPicture = new FileDialog(this,“打开图画“,FileDialog.LOAD);
openPicture.setVisible(false);
savePicture = new FileDialog(this,“保存图画“,FileDialog.SAVE);
savePicture.setVisible(false);
openPicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ openPicture.setVisible(false); }
});
savePicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ savePicture.setVisible(false); }
});
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ System.exit(0);}
});
}
public void paint(Graphics g)
{
Graphics2D g2d = (Graphics2D)g;
Point p1,p2;
n = paintInfo.size();
if(toolFlag==2)
g.clearRect(0,0,getSize().width,getSize().height);//清除
for(int i=0; i《n ;i++){
p1 = (Point)paintInfo.elementAt(i);
p2 = (Point)paintInfo.elementAt(i+1);
size = new BasicStroke(p1.boarder,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
g2d.setColor(p1.col);
g2d.setStroke(size);
if(p1.tool==p2.tool)
{
switch(p1.tool)
{
case 0://画笔
Line2D line1 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line1);
break;
case 1://橡皮
g.clearRect(p1.x, p1.y, p1.boarder, p1.boarder);
break;
case 3://画直线
Line2D line2 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line2);
break;
case 4://画圆
Ellipse2D ellipse = new Ellipse2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(ellipse);
break;
case 5://画矩形
Rectangle2D rect = new Rectangle2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(rect);
break;
case 6://截断，跳过
i=i+1;
break;
default :
}//end switch
}//end if
}//end for
}
public void itemStateChanged(ItemEvent e)
{
if(e.getSource()==ColChoice)//预选颜色
{
String name = ColChoice.getSelectedItem();
if(name==“black“)
{c = new Color(0,0,0); }
else if(name==“red“)
{c = new Color(255,0,0);}
else if(name==“green“)
{c = new Color(0,255,0);}
else if(name==“blue“)
{c = new Color(0,0,255);}
}
else if(e.getSource()==SizeChoice)//画笔大小
{
String selected = SizeChoice.getSelectedItem();
if(selected==“1“)
{
con = 1;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“3“)
{
con = 3;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“5“)
{con = 5;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“7“)
{con = 7;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“9“)
{con = 9;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
}
else if(e.getSource()==EraserChoice)//橡皮大小
{
String Esize = EraserChoice.getSelectedItem();
if(Esize==“5“)
{ Econ = 5*2; }
else if(Esize==“9“)
{ Econ = 9*2; }
else if(Esize==“13“)
{ Econ = 13*2; }
else if(Esize==“17“)
{ Econ = 17*3; }
}
}
public void mouseDragged(MouseEvent e)
{
Point p1 ;
switch(toolFlag){
case 0://画笔
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p1);
repaint();
break;
case 1://橡皮
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, null, toolFlag, Econ);
paintInfo.addElement(p1);
repaint();
break;
default :
}
}
public void mouseMoved(MouseEvent e) {}
public void update(Graphics g)
{
paint(g);
}
public void mousePressed(MouseEvent e)
{
Point p2;
switch(toolFlag){
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
default :
}
}
public void mouseReleased(MouseEvent e)
{
Point p3;
switch(toolFlag){
case 0://画笔
paintInfo.addElement(cutflag);
break;
case 1: //eraser
paintInfo.addElement(cutflag);
break;
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
default:
}
}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mouseClicked(MouseEvent e){}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==pen)//画笔
{toolFlag = 0;}
if(e.getSource()==eraser)//橡皮
{toolFlag = 1;}
if(e.getSource()==clear)//清除
{
toolFlag = 2;
paintInfo.removeAllElements();
repaint();
}
if(e.getSource()==drLine)//画线
{toolFlag = 3;}
if(e.getSource()==drCircle)//画圆
{toolFlag = 4;}
if(e.getSource()==drRect)//画矩形
{toolFlag = 5;}
if(e.getSource()==colchooser)//调色板
{
Color newColor = JColorChooser.showDialog(this,“调色板“,c);
c = newColor;
}
if(e.getSource()==openPic)//打开图画
{
openPicture.setVisible(true);
if(openPicture.getFile()!=null)
{
int tempflag;
tempflag = toolFlag;
toolFlag = 2 ;
repaint();
try{
paintInfo.removeAllElements();
File filein = new File(openPicture.getDirectory(),openPicture.getFile());
picIn = new FileInputStream(filein);
VIn = new ObjectInputStream(picIn);
paintInfo = (Vector)VIn.readObject();
VIn.close();
repaint();
toolFlag = tempflag;
}
catch(ClassNotFoundException IOe2)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read object“);
}
catch(IOException IOe)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read file“);
}
}
}
if(e.getSource()==savePic)//保存图画
{
savePicture.setVisible(true);
try{
File fileout = new File(savePicture.getDirectory(),savePicture.getFile());
picOut = new FileOutputStream(fileout);
VOut = new ObjectOutputStream(picOut);
VOut.writeObject(paintInfo);
VOut.close();
}
catch(IOException IOe)
{
System.out.println(“can not write object“);
}
}
}
}//end paintboard
public class pb
{
public static void main(String args)
{ new paintboard(“画图程序“); }
}
基于Java的画图板具体要解决什么
另一个我回答了，加了运行截图没有显示。看看下面代码，新建类T拷进去，看看是不是你要的。packagetest;importjava.awt.*;importjava.awt.event.*;importjava.util.*;importjavax.swing.*;importjava.awt.geom.*;importjava.io.*;@SuppressWarnings({“serial“,“unused“})classPointimplementsSerializable{intx,y;Colorcol;inttool;intboarder;Point(intx,inty,Colorcol,inttool,intboarder){this.x=x;this.y=y;this.col=col;this.tool=tool;this.boarder=boarder;}}@SuppressWarnings({“serial“,“unused“})classpaintboardextendsFrameimplementsActionListener,MouseMotionListener,MouseListener,ItemListener{intx=-1,y=-1;intcon=1;//画笔大小intEcon=5;//橡皮大小inttoolFlag=0;//toolFlag:工具标记//toolFlag工具对应表：//（0–画笔）；（1–橡皮）；（2–清除）；//（3–直线）；（4–圆）；（5–矩形）；Colorc=newColor(0,0,0);//画笔颜色BasicStrokesize=newBasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);//画笔粗细Pointcutflag=newPoint(-1,-1,c,6,con);//截断标志@SuppressWarnings(“unchecked“)VectorpaintInfo=null;//点信息向量组intn=1;FileInputStreampicIn=null;FileOutputStreampicOut=null;ObjectInputStreamVIn=null;ObjectOutputStreamVOut=null;//*工具面板–画笔，直线，圆，矩形，多边形,橡皮，清除*/PaneltoolPanel;Buttoneraser,drLine,drCircle,drRect;Buttonclear,pen;ChoiceColChoice,SizeChoice,EraserChoice;Buttoncolchooser;Label颜色,大小B,大小E;//保存功能//ButtonopenPic,savePic;FileDialogopenPicture,savePicture;@SuppressWarnings(“unchecked“)paintboard(Strings){super(s);addMouseMotionListener(this);addMouseListener(this);paintInfo=newVector();/*各工具按钮及选择项*///颜色选择ColChoice=newChoice();ColChoice.add(“black“);ColChoice.add(“red“);ColChoice.add(“blue“);ColChoice.add(“green“);ColChoice.addItemListener(this);//画笔大小选择SizeChoice=newChoice();SizeChoice.add(“1“);SizeChoice.add(“3“);SizeChoice.add(“5“);SizeChoice.add(“7“);SizeChoice.add(“9“);SizeChoice.addItemListener(this);//橡皮大小选择EraserChoice=newChoice();EraserChoice.add(“5“);EraserChoice.add(“9“);EraserChoice.add(“13“);EraserChoice.add(“17“);EraserChoice.addItemListener(this);////////////////////////////////////////////////////toolPanel=newPanel();clear=newButton(“清除“);eraser=newButton(“橡皮“);pen=newButton(“画笔“);drLine=newButton(“画直线“);drCircle=newButton(“画圆形“);drRect=newButton(“画矩形“);colchooser=newButton(“显示调色板“);clear.setBackground(Color.GREEN);drRect.setBackground(Color.GREEN);pen.setBackground(Color.GREEN);eraser.setBackground(Color.GREEN);drLine.setBackground(Color.GREEN);drCircle.setBackground(Color.GREEN);colchooser.setBackground(Color.GREEN);//各组件事件监听clear.addActionListener(this);eraser.addActionListener(this);pen.addActionListener(this);drLine.addActionListener(this);drCircle.addActionListener(this);drRect.addActionListener(this);colchooser.addActionListener(this);颜色=newLabel(“画笔颜色“,Label.CENTER);大小B=newLabel(“画笔大小“,Label.CENTER);大小E=newLabel(“橡皮大小“,Label.CENTER);颜色.setBackground(Color.gray);大小B.setBackground(Color.gray);大小E.setBackground(Color.gray);//面板添加组件toolPanel.add(pen);toolPanel.add(drLine);toolPanel.add(drCircle);toolPanel.add(drRect);toolPanel.add(颜色);toolPanel.add(ColChoice);toolPanel.add(大小B);toolPanel.add(SizeChoice);toolPanel.add(colchooser);toolPanel.add(eraser);toolPanel.add(大小E);toolPanel.add(EraserChoice);toolPanel.add(clear);//工具面板到APPLET面板add(toolPanel,BorderLayout.NORTH);setBounds(60,60,900,600);setVisible(true);validate();//dialogforsaveandloadopenPicture=newFileDialog(this,“打开图画“,FileDialog.LOAD);openPicture.setVisible(false);savePicture=newFileDialog(this,“保存图画“,FileDialog.SAVE);savePicture.setVisible(false);openPicture.addWindowListener(newWindowAdapter(){publicvoidwindowClosing(WindowEvente){openPicture.setVisible(false);}});savePicture.addWindowListener(newWindowAdapter(){publicvoidwindowClosing(WindowEvente){savePicture.setVisible(false);}});addWindowListener(newWindowAdapter(){publicvoidwindowClosing(WindowEvente){System.exit(0);}});}publicvoidpaint(Graphicsg){Graphics2Dg2d=(Graphics2D)g;Pointp1,p2;n=paintInfo.size();if(toolFlag==2)g.clearRect(0,0,getSize().width,getSize().height);//清除for(inti=1;i
java画板
//有问题的话，给我发百度消息
import java.awt.Color;
import java.awt.Cursor;
import java.awt.Graphics;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.util.LinkedList;
import java.util.List;
import javax.swing.JFrame;
import javax.swing.JPanel;
/**功能介绍
* 1.改变线条长度时鼠标形状的改变(鼠标位于线条两端时，四种鼠标状态)
* 2.移动线条时鼠标形状的改变(鼠标位于线条中间)
* 3.删除时鼠标形状的改变
* 4.最后一条直线颜色的不同
* 5.最大化、最小化、窗口大小改变时，线条的重绘
*
*/
public class LineDraw extends JFrame{
/**
*我需要在一个背景下能在任意位置添加线条，
能通过鼠标左键拉长，并且如果当鼠标点到直线中央时能拖动线条，当用鼠标右键点击直线时直线能消失。
*/
private LineDrawPanel drawPanel=new LineDrawPanel();
public static void main(String args) {
new LineDraw(“画图面板“);
}
public LineDraw(String title) {
super(title);
setBounds(300, 100, 500, 400);
setVisible(true);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
add(drawPanel);
validate();
}
}
class LineDrawPanel extends JPanel{
private int x1;
private int y1;
private Line lastLine;//最后一条线，也是当前正在画的线，注意线的颜色
private boolean isDrawing;//是否正在画的标记
private Line moveLine;//正在移动的线条
private Line changeLine;//正在改变长度的线条
private List《Line》 list=new LinkedList《Line》();
public LineDrawPanel() {
init();
}
public void init() {
MouseAdapter adapter=new MouseAdapter() {
@Override
public void mousePressed(MouseEvent e) {
if(e.getButton()==MouseEvent.BUTTON1){
x1 = e.getX();
y1 = e.getY();
moveLine=getMoveLine(x1, y1);
if(moveLine!=null){
setCursor(Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR));
setToolTipText(“移动“);
return;
}
changeLine=getChangeLine(x1, y1);
if(changeLine!=null){
return;
}
setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
setToolTipText(“画图“);
isDrawing=true;
}
}
@Override
public void mouseMoved(MouseEvent e) {
Line l=getChangeLine(e.getX(), e.getY());
if(l!=null){//设置四种鼠标形状
setToolTipText(“变长“);
if(Math.abs(l.x1-l.x2)《4){
setCursor(Cursor.getPredefinedCursor(Cursor.S_RESIZE_CURSOR));
}
else if(Math.abs(l.y1-l.y2)《4){
setCursor(Cursor.getPredefinedCursor(Cursor.E_RESIZE_CURSOR));
}
else{
double k=(l.y1-l.y2)*1.0/(l.x1-l.x2);
if(k《=0) setCursor(Cursor.getPredefinedCursor(Cursor.NE_RESIZE_CURSOR));
else setCursor(Cursor.getPredefinedCursor(Cursor.SE_RESIZE_CURSOR));
}
}else{
l=getMoveLine(e.getX(), e.getY());
if(l!=null) {
setCursor(Cursor.getPredefinedCursor(Cursor.MOVE_CURSOR));
setToolTipText(“移动“);
return;
}
l=getDelLine(e.getX(), e.getY());
if(l!=null){
setCursor(Cursor.getPredefinedCursor(Cursor.HAND_CURSOR));
setToolTipText(“右键删除“);
}else {
setCursor(Cursor.getDefaultCursor());
}
}
}
@Override
public void mouseDragged(MouseEvent e) {
if(moveLine!=null){
moveLine.move(e.getX()-x1, e.getY()-y1);
x1 = e.getX();
y1 = e.getY();
repaint();
return;
}
if(changeLine!=null){
int xVal=e.getX()-x1;
int yVal=e.getY()-y1;
if(Math.abs(xVal)《5||Math.abs(yVal)《5)
return;
changeLine.changeLength(xVal,yVal );
x1 = e.getX();
y1 = e.getY();
repaint();
return;
}
if(isDrawing){
int xVal=e.getX()-x1;
int yVal=e.getY()-y1;
if(Math.abs(xVal)《3||Math.abs(yVal)《3)
return;
lastLine=new Line(x1, y1, e.getX(), e.getY());
repaint();
}
}
@Override
public void mouseReleased(MouseEvent e) {
if(e.getButton()==MouseEvent.BUTTON1){
if(moveLine!=null){//移动
moveLine=null;
repaint();
return;
}
if(changeLine!=null){//改变长度
return;
}
if(isDrawing){//画线条
isDrawing=false;//重置
lastLine=null;
setCursor(Cursor.getDefaultCursor());
int xVal=e.getX()-x1;
int yVal=e.getY()-y1;
if(Math.abs(xVal)《3||Math.abs(yVal)《3)
return;
Line l=new Line(x1, y1, e.getX(), e.getY());
list.add(l);
}
}else if(e.getButton()==MouseEvent.BUTTON3){//鼠标右键
Line delLine=getDelLine(e.getX(), e.getY());//该删除的线
if(delLine!=null){
list.remove(delLine);
int size=list.size();
lastLine=(size》0?list.get(size-1):null);
repaint();
}
}
}
};
addMouseListener(adapter);//添加鼠标动作事件
addMouseMotionListener(adapter);//添加鼠标移动事件
}
public void paint(Graphics g) {
super.paint(g);//调用父类的方法
g.setColor(Color.BLUE);
for (Line l:list) {
l.drawLine(g);
}
g.setColor(Color.red);//画最后一个线条
if(lastLine!=null){
lastLine.drawLine(g);
}else {
if(list.size()》0) list.get(list.size()-1).drawLine(g);
}
}
public Line getChangeLine(int x,int y){//获取能够改变的直线
for (Line l:list) {
if(l.isCanChange(x,y))
return l;
}
return null;
}
public Line getDelLine(int x,int y){//获取能够删除的直线
for (Line l:list) {
if(l.isCanDel(x,y))
return l;
}
return null;
}
public Line getMoveLine(int x,int y){//获取能够移动的直线
for (Line l:list) {
if(l.isCanMove(x, y))
return l;
}
return null;
}
}
class Line{
public int x1;
public int y1;
public int x2;
public int y2;
public static boolean isStart;//决定改变的线条的那一端
public Line(int x1, int y1, int x2, int y2) {
this.x1 = x1;
this.y1 = y1;
this.x2 = x2;
this.y2 = y2;
}
public void drawLine(Graphics g){
g.drawLine(x1, y1, x2, y2);
}
public void move(int xVal,int yVal){//线条移动
x1+=xVal;
x2+=xVal;
y1+=yVal;
y2+=yVal;
}
public void changeLength(int xVal,int yVal){//改变长度 (该算法有点问题)
if(x1==x2){
xVal=0;
}else {
double k=(y1-y2)*1.0/(x1-x2);
System.out.println(k);
yVal=(int) Math.round(k*xVal);
}
if(isStart){
x1+=xVal;
y1+=yVal;
}else {
x2+=xVal;
y2+=yVal;
}
//x1=(x1《0?0:x1);
//y1=(y1《0?0:y1);
}
public boolean isLineValue(){//判断所画的线条是否有效
int len2=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
if(len2==0) return false;
if(Math.sqrt(len2)《=1)//长度小于1的，视为无效线条
return false;
return true;
}
public boolean isCanDel(int x,int y){//线条是否可被删除
int sideA2=(x-x1)*(x-x1)+(y-y1)*(y-y1);
int sideB2=(x-x2)*(x-x2)+(y-y2)*(y-y2);
int sideC2=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
if(sideA2==0||sideB2==0)return true;
double cosC=(sideA2+sideB2-sideC2)/(2*Math.sqrt(sideA2*sideB2));
if(cosC《-0.99) return true;
return false;
}
public boolean isCanChange(int x,int y){//线条是否可改变长度，仅鼠标位于线条两端时才可改变
if(Math.abs(x1-x)《2&&Math.abs(y1-y)《2){
isStart=true;
return true;
}
if(Math.abs(x2-x)《2&&Math.abs(y2-y)《2){
isStart=false;
return true;
}
return false;
}
public boolean isCanMove(int x,int y){//线条是否可移动
int midX=(x1+x2)/2;
int midY=(y1+y2)/2;
//if(midX==x&&midY==y) return false;
if(Math.abs(midX-x)《5&&Math.abs(midY-y)《5)
return true;
return false;
}
}
用Java实现画图板功能的程序，请问如何编写一个绘制三角形的程序段
class Triangle extends drawings//空心三角形类
{
void draw(Graphics2D g2d)
{g2d.setPaint(new Color(R,G,B));
g2d.setStroke(new BasicStroke(stroke,
BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL));
g2d.drawLine((int)((x1+x2)/2),Math.min(y1,y2),Math.max(x1,x2),Math.max(y1,y2));
g2d.drawLine(Math.max(x1,x2),Math.max(y1,y2),Math.min(x1,x2),Math.max(y1,y2));
g2d.drawLine(Math.min(x1,x2),Math.max(y1,y2),(int)((x1+x2)/2),Math.min(y1,y2));
}
}
以上是通过绘制三条直线作为三角形的三条边来绘制三角形.
class fillTriangle extends drawings//实心三角形
{
void draw(Graphics2D g2d)
{g2d.setPaint(new Color(R,G,B));
g2d.setStroke(new BasicStroke(stroke));
int mx=(int)((x1+x2)/2);
int x={mx,Math.max(x1,x2),Math.min(x1,x2)};
int y={Math.min(y1,y2),Math.max(y1,y2),Math.max(y1,y2)};
g2d.fillPolygon(x,y,3);
}
}
以上是用填充多边形的方式填充一个三角形,如果把最后的:g2d.fillPolygon(x,y,3)改为g2d.drawPolygon(x,y,3); 则是以绘制多边形的方式绘制空心三角形.
这里说明一下:因为(x1,y1,x2,y2)只能确定一个矩形区域,即鼠标拉动的起点和终点确定的矩形区域所以可以有多种方式确定三角形的三个顶点,我这个用的三个顶点是:
点1( (x1+x2)/2, min(y) ) 点2( max(x),max(y) ) 点3( min(x),max(y) )
你的补充内容太多了,没心情看啊,太累了
用java编写画图工具
要求比较多阿 给你个简单的供参考
import java.awt.*;
import java.awt.event.*;
class Mycanvas extends Canvas
{ int x,y,r;
Mycanvas()
{ setBackground(Color.cyan);
}
public void setX(int x)
{ this.x=x;
}
public void setY(int y)
{ this.y=y;
}
public void setR(int r)
{ this.r=r;
}
public void paint(Graphics g)
{ g.drawOval(x,y,2*r,2*r); //通过Graphics对象画圆
}
}
class WindowCanvas extends Frame implements ActionListener
{ Mycanvas canvas;
TextField inputR,inputX,inputY;
Button b;
WindowCanvas()
{ canvas=new Mycanvas();//创建画布对象
inputR=new TextField(5);
inputX=new TextField(4);
inputY=new TextField(4);
Panel pNorth=new Panel(), pSouth=new Panel();//创建两个面板
pNorth.add(new Label(“圆的位置坐标：“));
pNorth.add(inputX);
pNorth.add(inputY);
pSouth.add(new Label(“圆的半径：“));
pSouth.add(inputR);
b=new Button(“确定“);
b.addActionListener(this);
pSouth.add(b);
add(canvas,BorderLayout.CENTER); //添加画布对象到中央区域
add(pNorth,BorderLayout.NORTH);
add(pSouth,BorderLayout.SOUTH);
setBounds(100,100,300,200);
setVisible(true);
}
public void actionPerformed(ActionEvent e)
{ int x,y,r;
try { x=Integer.parseInt(inputX.getText());
y=Integer.parseInt(inputY.getText());
r=Integer.parseInt(inputR.getText());
canvas.setX(x); //设置自定义画布对象的实例变量x
canvas.setY(y);//设置自定义画布对象的实例变量y
canvas.setR(r);//设置自定义画布对象的实例变量r
canvas.repaint();//重画自定义画布对象
}
catch(NumberFormatException ee)
{ x=0;y=0;r=0;
}
}
}
public class Example18
{ public static void main(String args)
{ new WindowCanvas();
}
}
java 实现 简单画图功能(简单点的)
楼主给你一个我编的，直接保存成pb.java编译运行，就是你要的画图功能
____________________________________________________________________
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import java.awt.geom.*;
import java.io.*;
class Point implements Serializable
{
int x,y;
Color col;
int tool;
int boarder;
Point(int x, int y, Color col, int tool, int boarder)
{
this.x = x;
this.y = y;
this.col = col;
this.tool = tool;
this.boarder = boarder;
}
}
class paintboard extends Frame implements ActionListener,MouseMotionListener,MouseListener,ItemListener
{
int x = -1, y = -1;
int con = 1;//画笔大小
int Econ = 5;//橡皮大小
int toolFlag = 0;//toolFlag:工具标记
//toolFlag工具对应表：
//（0–画笔）；（1–橡皮）；（2–清除）；
//（3–直线）；（4–圆）；（5–矩形）；
Color c = new Color(0,0,0); //画笔颜色
BasicStroke size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);//画笔粗细
Point cutflag = new Point(-1, -1, c, 6, con);//截断标志
Vector paintInfo = null;//点信息向量组
int n = 1;
FileInputStream picIn = null;
FileOutputStream picOut = null;
ObjectInputStream VIn = null;
ObjectOutputStream VOut = null;
// *工具面板–画笔，直线，圆，矩形，多边形,橡皮，清除*/
Panel toolPanel;
Button eraser, drLine,drCircle,drRect;
Button clear ,pen;
Choice ColChoice,SizeChoice,EraserChoice;
Button colchooser;
Label 颜色,大小B,大小E;
//保存功能
Button openPic,savePic;
FileDialog openPicture,savePicture;
paintboard(String s)
{
super(s);
addMouseMotionListener(this);
addMouseListener(this);
paintInfo = new Vector();
/*各工具按钮及选择项*/
//颜色选择
ColChoice = new Choice();
ColChoice.add(“black“);
ColChoice.add(“red“);
ColChoice.add(“blue“);
ColChoice.add(“green“);
ColChoice.addItemListener(this);
//画笔大小选择
SizeChoice = new Choice();
SizeChoice.add(“1“);
SizeChoice.add(“3“);
SizeChoice.add(“5“);
SizeChoice.add(“7“);
SizeChoice.add(“9“);
SizeChoice.addItemListener(this);
//橡皮大小选择
EraserChoice = new Choice();
EraserChoice.add(“5“);
EraserChoice.add(“9“);
EraserChoice.add(“13“);
EraserChoice.add(“17“);
EraserChoice.addItemListener(this);
////////////////////////////////////////////////////
toolPanel = new Panel();
clear = new Button(“清除“);
eraser = new Button(“橡皮“);
pen = new Button(“画笔“);
drLine = new Button(“画直线“);
drCircle = new Button(“画圆形“);
drRect = new Button(“画矩形“);
openPic = new Button(“打开图画“);
savePic = new Button(“保存图画“);
colchooser = new Button(“显示调色板“);
//各组件事件监听
clear.addActionListener(this);
eraser.addActionListener(this);
pen.addActionListener(this);
drLine.addActionListener(this);
drCircle.addActionListener(this);
drRect.addActionListener(this);
openPic.addActionListener(this);
savePic.addActionListener(this);
colchooser.addActionListener(this);
颜色 = new Label(“画笔颜色“,Label.CENTER);
大小B = new Label(“画笔大小“,Label.CENTER);
大小E = new Label(“橡皮大小“,Label.CENTER);
//面板添加组件
toolPanel.add(openPic);
toolPanel.add(savePic);
toolPanel.add(pen);
toolPanel.add(drLine);
toolPanel.add(drCircle);
toolPanel.add(drRect);
toolPanel.add(颜色); toolPanel.add(ColChoice);
toolPanel.add(大小B); toolPanel.add(SizeChoice);
toolPanel.add(colchooser);
toolPanel.add(eraser);
toolPanel.add(大小E); toolPanel.add(EraserChoice);
toolPanel.add(clear);
//工具面板到APPLET面板
add(toolPanel,BorderLayout.NORTH);
setBounds(60,60,900,600); setVisible(true);
validate();
//dialog for save and load
openPicture = new FileDialog(this,“打开图画“,FileDialog.LOAD);
openPicture.setVisible(false);
savePicture = new FileDialog(this,“保存图画“,FileDialog.SAVE);
savePicture.setVisible(false);
openPicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ openPicture.setVisible(false); }
});
savePicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ savePicture.setVisible(false); }
});
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ System.exit(0);}
});
}
public void paint(Graphics g)
{
Graphics2D g2d = (Graphics2D)g;
Point p1,p2;
n = paintInfo.size();
if(toolFlag==2)
g.clearRect(0,0,getSize().width,getSize().height);//清除
for(int i=0; i《n ;i++){
p1 = (Point)paintInfo.elementAt(i);
p2 = (Point)paintInfo.elementAt(i+1);
size = new BasicStroke(p1.boarder,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
g2d.setColor(p1.col);
g2d.setStroke(size);
if(p1.tool==p2.tool)
{
switch(p1.tool)
{
case 0://画笔
Line2D line1 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line1);
break;
case 1://橡皮
g.clearRect(p1.x, p1.y, p1.boarder, p1.boarder);
break;
case 3://画直线
Line2D line2 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line2);
break;
case 4://画圆
Ellipse2D ellipse = new Ellipse2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(ellipse);
break;
case 5://画矩形
Rectangle2D rect = new Rectangle2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(rect);
break;
case 6://截断，跳过
i=i+1;
break;
default :
}//end switch
}//end if
}//end for
}
public void itemStateChanged(ItemEvent e)
{
if(e.getSource()==ColChoice)//预选颜色
{
String name = ColChoice.getSelectedItem();
if(name==“black“)
{c = new Color(0,0,0); }
else if(name==“red“)
{c = new Color(255,0,0);}
else if(name==“green“)
{c = new Color(0,255,0);}
else if(name==“blue“)
{c = new Color(0,0,255);}
}
else if(e.getSource()==SizeChoice)//画笔大小
{
String selected = SizeChoice.getSelectedItem();
if(selected==“1“)
{
con = 1;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“3“)
{
con = 3;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“5“)
{con = 5;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“7“)
{con = 7;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
else if(selected==“9“)
{con = 9;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
}
}
else if(e.getSource()==EraserChoice)//橡皮大小
{
String Esize = EraserChoice.getSelectedItem();
if(Esize==“5“)
{ Econ = 5*2; }
else if(Esize==“9“)
{ Econ = 9*2; }
else if(Esize==“13“)
{ Econ = 13*2; }
else if(Esize==“17“)
{ Econ = 17*3; }
}
}
public void mouseDragged(MouseEvent e)
{
Point p1 ;
switch(toolFlag){
case 0://画笔
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p1);
repaint();
break;
case 1://橡皮
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, null, toolFlag, Econ);
paintInfo.addElement(p1);
repaint();
break;
default :
}
}
public void mouseMoved(MouseEvent e) {}
public void update(Graphics g)
{
paint(g);
}
public void mousePressed(MouseEvent e)
{
Point p2;
switch(toolFlag){
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
default :
}
}
public void mouseReleased(MouseEvent e)
{
Point p3;
switch(toolFlag){
case 0://画笔
paintInfo.addElement(cutflag);
break;
case 1: //eraser
paintInfo.addElement(cutflag);
break;
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
default:
}
}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mouseClicked(MouseEvent e){}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==pen)//画笔
{toolFlag = 0;}
if(e.getSource()==eraser)//橡皮
{toolFlag = 1;}
if(e.getSource()==clear)//清除
{
toolFlag = 2;
paintInfo.removeAllElements();
repaint();
}
if(e.getSource()==drLine)//画线
{toolFlag = 3;}
if(e.getSource()==drCircle)//画圆
{toolFlag = 4;}
if(e.getSource()==drRect)//画矩形
{toolFlag = 5;}
if(e.getSource()==colchooser)//调色板
{
Color newColor = JColorChooser.showDialog(this,“调色板“,c);
c = newColor;
}
if(e.getSource()==openPic)//打开图画
{
openPicture.setVisible(true);
if(openPicture.getFile()!=null)
{
int tempflag;
tempflag = toolFlag;
toolFlag = 2 ;
repaint();
try{
paintInfo.removeAllElements();
File filein = new File(openPicture.getDirectory(),openPicture.getFile());
picIn = new FileInputStream(filein);
VIn = new ObjectInputStream(picIn);
paintInfo = (Vector)VIn.readObject();
VIn.close();
repaint();
toolFlag = tempflag;
}
catch(ClassNotFoundException IOe2)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read object“);
}
catch(IOException IOe)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read file“);
}
}
}
if(e.getSource()==savePic)//保存图画
{
savePicture.setVisible(true);
try{
File fileout = new File(savePicture.getDirectory(),savePicture.getFile());
picOut = new FileOutputStream(fileout);
VOut = new ObjectOutputStream(picOut);
VOut.writeObject(paintInfo);
VOut.close();
}
catch(IOException IOe)
{
System.out.println(“can not write object“);
}
}
}
}//end paintboard
public class pb
{
public static void main(String args)
{ new paintboard(“画图程序“); }
}
JAVA画图板程序，用netbeans做，要求画圆，椭圆，直线，三角形，矩形，可以填充颜色和擦除
import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import java.awt.geom.*;
import java.io.*;
import java.sql.Connection;
class Point implements Serializable
{
int x,y;
Color col;
int tool;
int boarder;
Point(int x, int y, Color col, int tool, int boarder)
{
this.x = x;
this.y = y;
this.col = col;
this.tool = tool;
this.boarder = boarder;
}
}
class paintboard extends Frame implements ActionListener,MouseMotionListener,MouseListener,ItemListener
{
int x = -1, y = -1;
int con = 1;//画笔大小
int Econ = 5;//橡皮大小
int toolFlag = 0;//toolFlag:工具标记
//toolFlag工具对应表：
//（0–画笔）；（1–橡皮）；（2–清除）；
//（3–直线）；（4–圆）；（5–矩形）；
Color c = new Color(0,0,0); //画笔颜色
BasicStroke size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);//画笔粗细
Point cutflag = new Point(-1, -1, c, 6, con);//截断标志
Vector paintInfo = null;//点信息向量组
int n = 1;
FileInputStream picIn = null;
FileOutputStream picOut = null;
ObjectInputStream VIn = null;
ObjectOutputStream VOut = null;
// *工具面板–画笔，直线，圆，矩形，多边形,橡皮，清除*/
Panel toolPanel;
Button eraser, drLine,drCircle,drRect;
Button clear ,pen;
Choice ColChoice,SizeChoice,EraserChoice;
Button colchooser;
Label 颜色,大小B,大小E;
//保存功能
Button openPic,savePic;
FileDialog openPicture,savePicture;
paintboard(String s)
{
super(s);
addMouseMotionListener(this);
addMouseListener(this);
paintInfo = new Vector();
/*各工具按钮及选择项*/
//颜色选择
ColChoice = new Choice();
ColChoice.add(“black“);
ColChoice.add(“red“);
ColChoice.add(“blue“);
ColChoice.add(“green“);
ColChoice.addItemListener(this);
//画笔大小选择
SizeChoice = new Choice();
SizeChoice.add(“1“);
SizeChoice.add(“3“);
SizeChoice.add(“5“);
SizeChoice.add(“7“);
SizeChoice.add(“9“);
SizeChoice.addItemListener(this);
//橡皮大小选择
EraserChoice = new Choice();
EraserChoice.add(“5“);
EraserChoice.add(“9“);
EraserChoice.add(“13“);
EraserChoice.add(“17“);
EraserChoice.addItemListener(this);
////////////////////////////////////////////////////
toolPanel = new Panel();
clear = new Button(“清除“);
eraser = new Button(“橡皮“);
pen = new Button(“画笔“);
drLine = new Button(“画直线“);
drCircle = new Button(“画圆形“);
drRect = new Button(“画矩形“);
openPic = new Button(“打开图画“);
savePic = new Button(“保存图画“);
colchooser = new Button(“显示调色板“);
//各组件事件监听
clear.addActionListener(this);
eraser.addActionListener(this);
pen.addActionListener(this);
drLine.addActionListener(this);
drCircle.addActionListener(this);
drRect.addActionListener(this);
openPic.addActionListener(this);
savePic.addActionListener(this);
colchooser.addActionListener(this);
颜色 = new Label(“画笔颜色“,Label.CENTER);
大小B = new Label(“画笔大小“,Label.CENTER);
大小E = new Label(“橡皮大小“,Label.CENTER);
//面板添加组件
toolPanel.add(openPic);
toolPanel.add(savePic);
toolPanel.add(pen);
toolPanel.add(drLine);
toolPanel.add(drCircle);
toolPanel.add(drRect);
toolPanel.add(颜色); toolPanel.add(ColChoice);
toolPanel.add(大小B); toolPanel.add(SizeChoice);
toolPanel.add(colchooser);
toolPanel.add(eraser);
toolPanel.add(大小E); toolPanel.add(EraserChoice);
toolPanel.add(clear);
//工具面板到APPLET面板
add(toolPanel,BorderLayout.NORTH);
setBounds(60,60,900,600); setVisible(true);
validate();
//dialog for save and load
openPicture = new FileDialog(this,“打开图画“,FileDialog.LOAD);
openPicture.setVisible(false);
savePicture = new FileDialog(this,“保存图画“,FileDialog.SAVE);
savePicture.setVisible(false);
openPicture.addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ openPicture.setVisible(false); }
});
savePicture.addWindowListener(new WindowAdapter()
{
@Override
public void windowClosing(WindowEvent e)
{ savePicture.setVisible(false); }
});
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{ System.exit(0);}
});
}
public void paint(Graphics g)
{
Graphics2D g2d = (Graphics2D)g;
Point p1,p2;
n = paintInfo.size();
if(toolFlag==2)
g.clearRect(0,0,getSize().width,getSize().height);//清除
for(int i=0; i《n ;i++){
p1 = (Point)paintInfo.elementAt(i);
p2 = (Point)paintInfo.elementAt(i+1);
size = new BasicStroke(p1.boarder,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
g2d.setColor(p1.col);
g2d.setStroke(size);
if(p1.tool==p2.tool)
{
switch(p1.tool)
{
case 0://画笔
Line2D line1 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line1);
break;
case 1://橡皮
g.clearRect(p1.x, p1.y, p1.boarder, p1.boarder);
break;
case 3://画直线
Line2D line2 = new Line2D.Double(p1.x, p1.y, p2.x, p2.y);
g2d.draw(line2);
break;
case 4://画圆
Ellipse2D ellipse = new Ellipse2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(ellipse);
break;
case 5://画矩形
Rectangle2D rect = new Rectangle2D.Double(p1.x, p1.y, Math.abs(p2.x-p1.x) , Math.abs(p2.y-p1.y));
g2d.draw(rect);
break;
case 6://截断，跳过
i=i+1;
break;
default :
}//end switch
}//end if
}//end for
}
public void itemStateChanged(ItemEvent e)
{
if(e.getSource()==ColChoice)//预选颜色
{
String name = ColChoice.getSelectedItem();
switch (name) {
case “black“:
c = new Color(0,0,0);
break;
case “red“:
c = new Color(255,0,0);
break;
case “green“:
c = new Color(0,255,0);
break;
case “blue“:
c = new Color(0,0,255);
break;
}
}
else if(e.getSource()==SizeChoice)//画笔大小
{
String selected = SizeChoice.getSelectedItem();
switch (selected) {
case “1“:
con = 1;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
break;
case “3“:
con = 3;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
break;
case “5“:
con = 5;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
break;
case “7“:
con = 7;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
break;
case “9“:
con = 9;
size = new BasicStroke(con,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);
break;
}
}
else if(e.getSource()==EraserChoice)//橡皮大小
{
String Esize = EraserChoice.getSelectedItem();
if(Esize==“5“)
{ Econ = 5*2; }
else if(Esize==“9“)
{ Econ = 9*2; }
else if(Esize==“13“)
{ Econ = 13*2; }
else if(Esize==“17“)
{ Econ = 17*3; }
}
}
public void mouseDragged(MouseEvent e)
{
Point p1 ;
switch(toolFlag){
case 0://画笔
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p1);
repaint();
break;
case 1://橡皮
x = (int)e.getX();
y = (int)e.getY();
p1 = new Point(x, y, null, toolFlag, Econ);
paintInfo.addElement(p1);
repaint();
break;
default :
}
}
public void mouseMoved(MouseEvent e) {}
public void update(Graphics g)
{
paint(g);
}
public void mousePressed(MouseEvent e)
{
Point p2;
switch(toolFlag){
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p2 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p2);
break;
default :
}
}
public void mouseReleased(MouseEvent e)
{
Point p3;
switch(toolFlag){
case 0://画笔
paintInfo.addElement(cutflag);
break;
case 1: //eraser
paintInfo.addElement(cutflag);
break;
case 3://直线
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 4: //圆
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
case 5: //矩形
x = (int)e.getX();
y = (int)e.getY();
p3 = new Point(x, y, c, toolFlag, con);
paintInfo.addElement(p3);
paintInfo.addElement(cutflag);
repaint();
break;
default:
}
}
public void mouseEntered(MouseEvent e){}
public void mouseExited(MouseEvent e){}
public void mouseClicked(MouseEvent e){}
public void actionPerformed(ActionEvent e)
{
if(e.getSource()==pen)//画笔
{toolFlag = 0;}
if(e.getSource()==eraser)//橡皮
{toolFlag = 1;}
if(e.getSource()==clear)//清除
{
toolFlag = 2;
paintInfo.removeAllElements();
repaint();
}
if(e.getSource()==drLine)//画线
{toolFlag = 3;}
if(e.getSource()==drCircle)//画圆
{toolFlag = 4;}
if(e.getSource()==drRect)//画矩形
{toolFlag = 5;}
if(e.getSource()==colchooser)//调色板
{
Color newColor = JColorChooser.showDialog(this,“调色板“,c);
c = newColor;
}
if(e.getSource()==openPic)//打开图画
{
openPicture.setVisible(true);
if(openPicture.getFile()!=null)
{
int tempflag;
tempflag = toolFlag;
toolFlag = 2 ;
repaint();
try{
paintInfo.removeAllElements();
File filein = new File(openPicture.getDirectory(),openPicture.getFile());
picIn = new FileInputStream(filein);
VIn = new ObjectInputStream(picIn);
paintInfo = (Vector)VIn.readObject();
VIn.close();
repaint();
toolFlag = tempflag;
}
catch(ClassNotFoundException IOe2)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read object“);
}
catch(IOException IOe)
{
repaint();
toolFlag = tempflag;
System.out.println(“can not read file“);
}
}
}
if(e.getSource()==savePic)//保存图画
{
savePicture.setVisible(true);
try{
File fileout = new File(savePicture.getDirectory(),savePicture.getFile());
picOut = new FileOutputStream(fileout);
VOut = new ObjectOutputStream(picOut);
VOut.writeObject(paintInfo);
VOut.close();
}
catch(IOException IOe)
{
System.out.println(“can not write object“);
}
}
}
}//end paintboard
public class Pb
{
public static void main(String args)
{ new paintboard(“画图程序“); }
}
java简单画图板程序 有个问题
因为你最后写的paint方法是JFrame 的，而不是Canvas的。
应该自己写个继承Canvas的类，然后重构paint方法，
然后在鼠标事件里调用Canvas对象的paint方法。
ps：希望你写程序时给变量起个有意义的名字，不然看着太累了