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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 ListLine list=new LinkedListLine();
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=(size0?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=(x10?0:x1);
//y1=(y10?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)2Math.abs(y1-y)2){
isStart=true;
return true;
}
if(Math.abs(x2-x)2Math.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==xmidY==y) return false;
if(Math.abs(midX-x)5Math.abs(midY-y)5)
return true;
return false;
}
}
import java.awt.*;
/**
* @author Hardneedl
*/
interface Brush {
void doPaint(Graphics g);
}
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
/**
* @author Hardneedl
*/
final class StringPaintDemo extends JFrame {
public String getTitle() {return "String Paint";}
static private final Dimension size = new Dimension(600, 400);
public Dimension getPreferredSize() {return size;}
public Dimension getMaximumSize() {return size;}
public Dimension getMinimumSize() {return size;}
public Dimension getSize() {return size;}
private String s;
private Brush stringBrush = new Brush() {
public void doPaint(Graphics g) {
Graphics gg = g.create();
gg.setColor(Color.RED);
gg.drawString(s == null ? "null" : s , 58, 58);
gg.dispose();
}
};
private JTextField txtField;
private JComponent canvas = new JComponent(){
protected void paintComponent(Graphics g) {
super.paintComponent(g);
stringBrush.doPaint(g);
}
};
private StringPaintDemo() throws HeadlessException {
init();
attachListeners();
doLay();
}
private void init() {
txtField = new JTextField();
}
private void attachListeners() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
txtField.getDocument().addDocumentListener(new DocumentListener(){
private void update(){
s = txtField.getText();
canvas.paintImmediately(canvas.getBounds());
}
public void changedUpdate(DocumentEvent e) {update();}
public void insertUpdate(DocumentEvent e) {update();}
public void removeUpdate(DocumentEvent e) {update();}
});
}
private void doLay() {
Container container = getContentPane();
container.add(txtField,BorderLayout.NORTH);
container.add(canvas, BorderLayout.CENTER);
pack();
setVisible(true);
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
public void run() {
new StringPaintDemo();
}
});
}
}
这样满足你的要求么
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class Painter extends JFrame{
/**
*
*/
private static final long serialVersionUID = 8160427604782702376L;
CanvasPanel canvas = new CanvasPanel();;
public Painter() {
super("Star");
this.add(canvas);
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
this.pack();
this.setResizable(false);
this.setLocationRelativeTo(null);
this.setVisible(true);
}
public static void main(String[] args) {
new Painter();
}
}
class CanvasPanel extends JPanel implements ActionListener{
/**
*
*/
private static final long serialVersionUID = -4642528854538741028L;
private JButton[] btn = new JButton[4];
private String[] btn_name = {"+", "-", "R", "L"};
private int center_x = 200, center_y = 200, radius = 100, degree = 0;
public CanvasPanel() {
this.setPreferredSize(new Dimension(400, 500));
this.setLayout(null);
for(int i = 0; i 4; i++) {
btn[i] = new JButton(btn_name[i]);
btn[i].setBounds(160 + i * 60, 425, 50, 50);
btn[i].addActionListener(this);
this.add(btn[i]);
}
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
for(int i = 0; i 5; i++) {
g.drawLine( (int) (center_x + radius * Math.sin(Math.toRadians(degree + 72 * i))),
(int) (center_y - radius * Math.cos(Math.toRadians(degree + 72 * i))),
(int) (center_x + radius * Math.sin(Math.toRadians(degree + 72 * i + 144))),
(int) (center_y - radius * Math.cos(Math.toRadians(degree + 72 * i + 144))));
}
}
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
if(e.getActionCommand() == "+") {
if(radius 200)
radius += 2;
repaint();
} else if(e.getActionCommand() == "-") {
if(radius 0)
radius -= 2;
repaint();
} else if(e.getActionCommand() == "R") {
degree = (degree + 2) % 360;
repaint();
} else if(e.getActionCommand() == "L") {
degree = (degree - 2) % 360;
repaint();
}
}
}
看看下面的代码，新建类T，把代码拷进去便可运行。
有运行截图：
import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.swing.*;
import java.awt.geom.*;
import java.io.*;
@SuppressWarnings({"serial","unused"})
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;
}
}
@SuppressWarnings({"serial","unused"})
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
@SuppressWarnings("unchecked")
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;
@SuppressWarnings("unchecked")
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");
colchooser = new Button("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 = 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);
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();
//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=1; in ;i++){
p1 = (Point)paintInfo.elementAt(i-1);
p2 = (Point)paintInfo.elementAt(i);
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; }
}
}
@SuppressWarnings({"serial","unused", "unchecked"})
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);
}
@SuppressWarnings("unchecked")
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 :
}
}
@SuppressWarnings("unchecked")
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){}
@SuppressWarnings("unchecked")
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;
}
}
}
//end paintboard
public class T{
public static void main(String args[]){
new paintboard("画图程序"); }
}
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"); }
}
import java.awt.BasicStroke;
import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Label;
import java.awt.Panel;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
public class MouseDrawPanel extends Frame
{
private static final long serialVersionUID = 1L;
MouseEvent e = null;
int startX = -1;
int startY = -1;
int endX = -1;
int endY = -1;
boolean left = false;
public MouseDrawPanel ( String title )
{
setTitle (title);
setLayout (new BorderLayout ());
setResizable (false);
setSize (500, 400);
setLocationRelativeTo (null);
addWindowListener (new WindowAdapter ()
{
@Override
public void windowClosing ( WindowEvent e )
{
System.exit (0);
}
});
}
@Override
public void paintComponents ( Graphics g )
{
float lineWidth = 8.0f;
( (Graphics2D) g ).setStroke (new BasicStroke (lineWidth));
g.setColor (Color.YELLOW);
g.drawLine (startX, startY, endX, endY);
g.dispose ();
}
public static void main ( String[] args )
{
final MouseDrawPanel mdp = new MouseDrawPanel ("Use Mouse Draw");
Panel panel = new Panel ();
panel.setLayout (new FlowLayout (FlowLayout.LEFT));
Label startL = new Label ("start: ");
Label endL = new Label ("end: ");
final Label nowL = new Label ("now: ");
final Label startR = new Label ("000,000");
final Label endR = new Label ("000,000");
final Label nowN = new Label ("000,000");
panel.add (startL);
panel.add (startR);
panel.add (endL);
panel.add (endR);
panel.add (nowL);
panel.add (nowN);
mdp.add (panel, "South");
mdp.addMouseMotionListener (new MouseMotionListener ()
{
@Override
public void mouseMoved ( MouseEvent e )
{
if (mdp.left)
{
nowN.setText (e.getX () + " , " + e.getY ());
}
}
@Override
public void mouseDragged ( MouseEvent e )
{
if (mdp.left)
{
mdp.endX = e.getX ();
mdp.endY = e.getY ();
mdp.paintComponents (mdp.getGraphics ());
mdp.startX = mdp.endX;
mdp.startY = mdp.endY;
endR.setText (mdp.endX + " , " + mdp.endY);
}
}
});
mdp.addMouseListener (new MouseAdapter ()
{
@Override
public void mousePressed ( MouseEvent e )
{
if (e.getButton () == MouseEvent.BUTTON1)
{
mdp.startX = e.getX ();
mdp.startY = e.getY ();
startR.setText (mdp.startX + " , " + mdp.startY);
mdp.left = true;
}
else
{
mdp.left = false;
}
}
@Override
public void mouseReleased ( MouseEvent e )
{
if (mdp.left)
{
endR.setText (e.getX () + " , " + e.getY ());
}
}
});
mdp.setVisible (true);
}
}