用java画图

‘壹’ java 绘图程序

我基于你原来画图的方法，添加了事件触发的命令b[j].setActionCommand("b" + j);否则你不能在事件响应处理的方法中使用e.getActionCommand()，而且字符串的比较用equals方法比较好。现在可以运行了，你可以看一下：
import java.applet.Applet;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

public class drawing extends Applet implements ActionListener {
Button b[] = new Button[5];
String fontname = "仿宋_GB2312";
int style = Font.PLAIN;
int size = 24;
int index = 0;
Font myfont;

public void init() {
setSize(700,700);
myfont = new Font(fontname, style, size);
b[0] = new Button("扇形");
b[1] = new Button("圆形");
b[2] = new Button("三角形");
b[3] = new Button("长方形");
b[4] = new Button("椭圆形");
for (int j = 0; j < b.length; j++) {
b[j].setBounds(10, 10, 50, 20);
b[j].addActionListener(this);
b[j].setActionCommand("b" + j);
add(b[j]);
}
}

public void actionPerformed(ActionEvent e) {
if (e.getActionCommand().equals("b0")) {
index = 0;
repaint();
}
if (e.getActionCommand().equals("b1")) {
index = 1;
repaint();
}
if (e.getActionCommand().equals("b2")) {
index = 2;
repaint();
}
if (e.getActionCommand().equals("b3")) {
index = 3;
repaint();
}
if (e.getActionCommand().equals("b4")) {
index = 4;
repaint();
}
}

public void paint(Graphics g) {
switch (index) {
case 0:
g.fillArc(0, 60, 80, 60, 30, 120);
break;
case 1:
g.drawOval( 300, 50, 60, 60);
break;
case 2:
Polygon filledPolygon = new Polygon();
filledPolygon.addPoint(380, 50);
filledPolygon.addPoint(380, 110);
filledPolygon.addPoint(450, 90);
g.drawPolygon(filledPolygon);
break;
case 3:
g.drawRect( 200, 50, 80, 60);
break;
case 4:
g.drawOval(100, 50, 80, 60);
break;
default:
g.fillArc(0, 60, 80, 60, 30, 120);
break;
}

}
/*
* public void paint(Graphics g) { g.fillArc( 0, 60, 80, 60, 30, 120);
* //绘制扇形 g.drawOval( 100, 50, 80, 60); g.drawRect( 200, 50, 80, 60);
* g.drawOval( 300, 50, 60, 60); Polygon filledPolygon=new Polygon();
* filledPolygon.addPoint(380,50); filledPolygon.addPoint(380,110);
* filledPolygon.addPoint(450,90); g.drawPolygon(filledPolygon); }
*/
}

‘贰’ java实现画图工具颜色填充怎么实现或判断

可以用扫描线种子算法

扫描线种子填充算法的基本过程如下：当给定种子点(x, y)时，首先分别向左和向右两个方向填充种子点所在扫描线上的位于给定区域的一个区段，同时记下这个区段的范围[xLeft, xRight]，然后确定与这一区段相连通的上、下两条扫描线上位于给定区域内的区段，并依次保存下来。反复这个过程，直到填充结束。
扫描线种子填充算法可由下列四个步骤实现：

(1) 初始化一个空的栈用于存放种子点，将种子点(x, y)入栈；

(2) 判断栈是否为空，如果栈为空则结束算法，否则取出栈顶元素作为当前扫描线的种子点(x, y)，y是当前的扫描线；

(3) 从种子点(x, y)出发，沿当前扫描线向左、右两个方向填充，直到边界。分别标记区段的左、右端点坐标为xLeft和xRight；

(4) 分别检查与当前扫描线相邻的y - 1和y + 1两条扫描线在区间[xLeft, xRight]中的像素，从xLeft开始向xRight方向搜索，若存在非边界且未填充的像素点，则找出这些相邻的像素点中最右边的一个，并将其作为种子点压入栈中，然后返回第（2）步；

‘叁’ JAVA Graphics绫讳腑drawImage鏂规硶镐庝箞鐢

1銆佸厛鍦╡clipse涓鍒涘缓涓涓猨ava宸ョ▼鏂囦欢锛屽懡钖崭负UseFunction銆

‘肆’ 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

‘伍’ 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"); }
}