请java高手注释一下这段程序_CMS教程

public class Ctianchong extends tool {

@Override

实现图像填充功能，从to中鼠标对应的一个位置将周围填充为颜色c

参数e表示鼠标事件，to表示对象，c表示颜色对象

public void mousepress(MouseEvent e, BufferedImage to,Color c) {

// TODO Auto-generated method stub

int[] dx={0,1,0,-1}; //水平偏移

int[] dy={1,0,-1,0}; //竖直偏移

int lim_x=togetWidth(),lim_y=togetHeight(); //获得的宽度和高度。

LinkedList<node> q=new LinkedList<node>(); //节点类型为node的链表

node a=new node(); //node应该有一个参数x表示水平坐标，y表示竖直坐标

node b;

ax=egetX();

ay=egetY(); //获得鼠标的水平与竖直坐标

int initrgb=togetRGB(ax, ay); //initrgb表示图像在水平坐标为x，竖直坐标为y处的灰度值。

int drawrgb=cgetRGB(); //颜色c对应的RGB值

if(initrgb==drawrgb) return; //如果此处颜色一致，直接返回

tosetRGB(ax, ay, drawrgb); //直接填充颜色

qaddLast(a); //将a加入到链表q中去

while(!qisEmpty()) //链表是否为空

{

a=qpollFirst(); //d出链表首位的node

for(int i=0;i<4;i++) //表示填充坐标(x,y)上、下、左、右的颜色,填充时对应的偏移量分别为dx[i],dy[i]

{

b=new node();

bx=ax+dx[i];

by=ay+dy[i];

if(bx<0 || by<0 || bx>=lim_x || by>=lim_y) continue;

if(togetRGB(bx, by)!=initrgb) continue;

tosetRGB(bx, by, drawrgb);

qaddLast(b); //将b加入链表中，

}

import javaapplet;

import javaawt;

import javaawtevent;

import javautil;

import javaxswing;

import javaawtgeom;

import javaio;

class Point implements Serializable

{

int x,y;

Color col;

int tool;

int boarder;

Point(int x, int y, Color col, int tool, int boarder)

{

thisx = x;

thisy = y;

thiscol = col;

thistool = tool;

thisboarder = 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,BasicStrokeCAP_BUTT,BasicStrokeJOIN_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();

ColChoiceadd("black");

ColChoiceadd("red");

ColChoiceadd("blue");

ColChoiceadd("green");

ColChoiceaddItemListener(this);

//画笔大小选择

SizeChoice = new Choice();

SizeChoiceadd("1");

SizeChoiceadd("3");

SizeChoiceadd("5");

SizeChoiceadd("7");

SizeChoiceadd("9");

SizeChoiceaddItemListener(this);

//橡皮大小选择

EraserChoice = new Choice();

EraserChoiceadd("5");

EraserChoiceadd("9");

EraserChoiceadd("13");

EraserChoiceadd("17");

EraserChoiceaddItemListener(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

clearaddActionListener(this);

eraseraddActionListener(this);

penaddActionListener(this);

drLineaddActionListener(this);

drCircleaddActionListener(this);

drRectaddActionListener(this);

openPicaddActionListener(this);

savePicaddActionListener(this);

colchooseraddActionListener(this);

颜色 = new Label("画笔颜色",LabelCENTER);

大小B = new Label("画笔大小",LabelCENTER);

大小E = new Label("橡皮大小",LabelCENTER);

//面板添加组件

toolPaneladd(openPic);

toolPaneladd(savePic);

toolPaneladd(pen);

toolPaneladd(drLine);

toolPaneladd(drCircle);

toolPaneladd(drRect);

toolPaneladd(颜色); toolPaneladd(ColChoice);

toolPaneladd(大小B); toolPaneladd(SizeChoice);

toolPaneladd(colchooser);

toolPaneladd(eraser);

toolPaneladd(大小E); toolPaneladd(EraserChoice);

toolPaneladd(clear);

//工具面板到APPLET面板

add(toolPanel,BorderLayoutNORTH);

setBounds(60,60,900,600); setVisible(true);

validate();

//dialog for save and load

openPicture = new FileDialog(this,"打开图画",FileDialogLOAD);

openPicturesetVisible(false);

savePicture = new FileDialog(this,"保存图画",FileDialogSAVE);

savePicturesetVisible(false);

openPictureaddWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e)

{ openPicturesetVisible(false); }

});

savePictureaddWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e)

{ savePicturesetVisible(false); }

});

addWindowListener(new WindowAdapter()

{

public void windowClosing(WindowEvent e)

{ Systemexit(0);}

});

}

public void paint(Graphics g)

{

Graphics2D g2d = (Graphics2D)g;

Point p1,p2;

n = paintInfosize();

if(toolFlag==2)

gclearRect(0,0,getSize()width,getSize()height);//清除

for(int i=0; i<n ;i++){

p1 = (Point)paintInfoelementAt(i);

p2 = (Point)paintInfoelementAt(i+1);

size = new BasicStroke(p1boarder,BasicStrokeCAP_BUTT,BasicStrokeJOIN_BEVEL);

g2dsetColor(p1col);

g2dsetStroke(size);

if(p1tool==p2tool)

{

switch(p1tool)

{

case 0://画笔

Line2D line1 = new Line2DDouble(p1x, p1y, p2x, p2y);

g2ddraw(line1);

break;

case 1://橡皮

gclearRect(p1x, p1y, p1boarder, p1boarder);

break;

case 3://画直线

Line2D line2 = new Line2DDouble(p1x, p1y, p2x, p2y);

g2ddraw(line2);

break;

case 4://画圆

Ellipse2D ellipse = new Ellipse2DDouble(p1x, p1y, Mathabs(p2x-p1x) , Mathabs(p2y-p1y));

g2ddraw(ellipse);

break;

case 5://画矩形

Rectangle2D rect = new Rectangle2DDouble(p1x, p1y, Mathabs(p2x-p1x) , Mathabs(p2y-p1y));

g2ddraw(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(egetSource()==ColChoice)//预选颜色

{

String name = ColChoicegetSelectedItem();

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(egetSource()==SizeChoice)//画笔大小

{

String selected = SizeChoicegetSelectedItem();

if(selected=="1")

{

con = 1;