java简易画图板代码 制作一个简单的画板java

谁有简单的JAVA画图程序

////保存一个pb.java文件直接编译执行

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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; in ;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"); }

}

求Java简单画图工具

///保存一个pb.java文件直接编译执行

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; in ;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"); }

}

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