画图板的开发代码,Java代码库,德仔网

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【Java】画图板的开发
作者:huadong123 / 发布于2012/11/20/ 462
package drawingpanel;

import java.awt.*;
import java.awt.geom.*;
import java.awt.event.*;
import javax.swing.*;
import java.io.*;
import java.util.*;


public class MiniDrawPad extends JFrame     //主类，扩展了JFrame类，用来生成主界面
 {
  private ObjectInputStream  input;
  private ObjectOutputStream output; //定义输入输出流，用来调用和保存图像文件

  private JButton choices[];         //按钮数组，存放以下名称的功能按钮

  private String names[]={
          "New",
          "Open",
          "Save",    //这三个是基本操作按钮，包括"新建"、"打开"、"保存"

        /*接下来是我们的画图板上面有的基本的几个绘图单元按钮*/

          "Pencil",		//铅笔画，也就是用鼠标拖动着随意绘图
          "Line",		//绘制直线
          "Rect",		//绘制空心矩形
          "fRect",		//绘制以指定颜色填充的实心矩形
          "Oval",		//绘制空心椭圆
          "fOval",		//绘制以指定颜色填充的实心椭圆
          "Circle",		//绘制圆形
          "fCircle",	//绘制以指定颜色填充的实心圆形
          "RoundRect",	//绘制空心圆角矩形
          "frRect",		//绘制以指定颜色填充的实心圆角矩形
          "Rubber",		//橡皮擦，可用来擦去已经绘制好的图案
          "Color",		//选择颜色按钮，可用来选择需要的颜色
          "Stroke",		//选择线条粗细的按钮，输入需要的数值可以实现绘图线条粗细的变化
          "Word"		//输入文字按钮，可以在绘图板上实现文字输入
          };

  private String styleNames[]={
            " 宋体 " , " 隶书 " , " 华文彩云 " , " 仿宋_GB2312 " , " 华文行楷 " ,
            " 方正舒体 " , " Times New Roman " , " Serif " , " Monospaced " ,
            " SonsSerif " , " Garamond "
            };            //可供选择的字体项
                          //当然这里的灵活的结构可以让读者自己随意添加系统支持的字体

  private Icon items[];

  private String tipText[]={
                  //这里是鼠标移动到相应按钮上面上停留时给出的提示说明条
                  //读者可以参照上面的按钮定义对照着理解
                "Draw a new picture",
                "Open a saved picture",
                "Save current drawing",
                "Draw at will",
                "Draw a straight line",
                "Draw a rectangle",
                "Fill a ractangle",
                "Draw an oval",
                "Fill an oval",
                "Draw a circle",
                "Fill a circle",
                "Draw a round rectangle",
                "Fill a round rectangle",
                "Erase at will",
                "Choose current drawing color",
                "Set current drawing stroke",
                "Write down what u want"
              };

  JToolBar buttonPanel ;		       //定义按钮面板
  private JLabel statusBar;            //显示鼠标状态的提示条

  private DrawPanel drawingArea;       //画图区域
  private int width=800,height=550;    //定义画图区域初始大小

  drawings[] itemList=new drawings[5000]; //用来存放基本图形的数组
  private int currentChoice=3;            //设置默认画图状态为随笔画
  int index=0;                         //当前已经绘制的图形数目
  private Color color=Color.black;     //当前画笔颜色
  int R,G,B;                           //用来存放当前色彩值

  int f1,f2;                  //用来存放当前字体风格
  String style1;              //用来存放当前字体
  private float stroke=1.0f;  //设置画笔粗细，默认值为1.0f

  JCheckBox bold,italic;      //定义字体风格选择框
                              //bold为粗体，italic为斜体，二者可以同时使用
  JComboBox styles;

  public MiniDrawPad()        //构造函数
  {
   super("Drawing Pad");
   JMenuBar bar=new JMenuBar();		//定义菜单条
   JMenu fileMenu=new JMenu("File");
   fileMenu.setMnemonic('F');

//新建文件菜单条
   JMenuItem newItem=new JMenuItem("New");
   newItem.setMnemonic('N');
   newItem.addActionListener(
          new ActionListener(){
                  public void actionPerformed(ActionEvent e)
                  {
                   newFile();		//如果被触发，则调用新建文件函数段
                  }
          }
   );
   fileMenu.add(newItem);

//保存文件菜单项
   JMenuItem saveItem=new JMenuItem("Save");
   saveItem.setMnemonic('S');
   saveItem.addActionListener(
          new ActionListener(){
                  public void actionPerformed(ActionEvent e)
                  {
                   saveFile();		//如果被触发，则调用保存文件函数段
                  }
          }
   );
   fileMenu.add(saveItem);

//打开文件菜单项
   JMenuItem loadItem=new JMenuItem("Load");
   loadItem.setMnemonic('L');
   loadItem.addActionListener(
          new ActionListener(){
                  public void actionPerformed(ActionEvent e)
                  {
                   loadFile();		//如果被触发，则调用打开文件函数段
                  }
          }
   );
   fileMenu.add(loadItem);

   fileMenu.addSeparator();

//退出菜单项
   JMenuItem exitItem=new JMenuItem("Exit");
   exitItem.setMnemonic('X');
   exitItem.addActionListener(
          new ActionListener(){
                  public void actionPerformed(ActionEvent e)
                  {
                   System.exit(0);	//如果被触发，则退出画图板程序
                  }
          }
   );
   fileMenu.add(exitItem);
   bar.add(fileMenu);

//设置颜色菜单条
   JMenu colorMenu=new JMenu("Color");
   colorMenu.setMnemonic('C');

//选择颜色菜单项
   JMenuItem colorItem=new JMenuItem("Choose Color");
   colorItem.setMnemonic('O');
   colorItem.addActionListener(
           new ActionListener(){
                   public void actionPerformed(ActionEvent e)
                   {
                    chooseColor();	//如果被触发，则调用选择颜色函数段
                   }
       }
      );
   colorMenu.add(colorItem);
   bar.add(colorMenu);

//设置线条粗细菜单条
    JMenu strokeMenu=new JMenu("Stroke");
    strokeMenu.setMnemonic('S');

//设置线条粗细菜单项
    JMenuItem strokeItem=new JMenuItem("Set Stroke");
    strokeItem.setMnemonic('K');
    strokeItem.addActionListener(
           new ActionListener(){
                   public void actionPerformed(ActionEvent e)
                    {
                     setStroke();
                     }
                   }
              );
           strokeMenu.add(strokeItem);
           bar.add(strokeMenu);

//设置提示菜单条
    JMenu helpMenu=new JMenu("Help");
    helpMenu.setMnemonic('H');

//设置提示菜单项
    JMenuItem aboutItem=new JMenuItem("About this Drawing Pad!");
    aboutItem.setMnemonic('A');
    aboutItem.addActionListener(
           new ActionListener(){
                   public void actionPerformed(ActionEvent e)
                    {
                     JOptionPane.showMessageDialog(null,
                        "This is a mini drawing pad!\nCopyright (c) 2002 Tsinghua University ",
                        " 画图板程序说明 ",
                         JOptionPane.INFORMATION_MESSAGE );
                     }
                   }
              );
    helpMenu.add(aboutItem);
    bar.add(helpMenu);

    items=new ImageIcon[names.length];

//创建各种基本图形的按钮
    drawingArea=new DrawPanel();
    choices=new JButton[names.length];
    buttonPanel = new JToolBar( JToolBar.VERTICAL ) ;
    buttonPanel = new JToolBar( JToolBar.HORIZONTAL) ;
    ButtonHandler handler=new ButtonHandler();
    ButtonHandler1 handler1=new ButtonHandler1();

//导入我们需要的图形图标，这些图标都存放在与源文件相同的目录下面
    for(int i=0;i<choices.length;i++)
    {//items[i]=new ImageIcon( MiniDrawPad.class.getResource(names[i] +".gif"));
                       //如果在jbuilder下运行本程序，则应该用这条语句导入图片
     items[i]=new ImageIcon(names[i] + ".gif");
                   //默认的在jdk或者jcreator下运行，用此语句导入图片
     choices[i]=new JButton("",items[i]);
     choices[i].setToolTipText(tipText[i]);
     buttonPanel.add(choices[i]);
    }

//将动作侦听器加入按钮里面
    for(int i=3;i<choices.length-3;i++)
    {
     choices[i].addActionListener(handler);
    }

    choices[0].addActionListener(
          new ActionListener(){
                  public void actionPerformed(ActionEvent e)
                  {
                   newFile();
                  }
          }
     );

    choices[1].addActionListener(
          new ActionListener(){
                  public void actionPerformed(ActionEvent e)
                  {
                   loadFile();
                  }
          }
     );

    choices[2].addActionListener(
          new ActionListener(){
                  public void actionPerformed(ActionEvent e)
                  {
                   saveFile();
                  }
          }
     );
    choices[choices.length-3].addActionListener(handler1);
    choices[choices.length-2].addActionListener(handler1);
    choices[choices.length-1].addActionListener(handler1);

//字体风格选择
    styles=new JComboBox(styleNames);
    styles.setMaximumRowCount(8);
    styles.addItemListener(
            new ItemListener(){
                    public void itemStateChanged(ItemEvent e)
                    {
                      style1=styleNames[styles.getSelectedIndex()];
                    }
               }
            );
//字体选择
    bold=new JCheckBox("BOLD");
    italic=new JCheckBox("ITALIC");

    checkBoxHandler cHandler=new checkBoxHandler();
    bold.addItemListener(cHandler);
    italic.addItemListener(cHandler);

    JPanel wordPanel=new JPanel();
    buttonPanel.add(bold);
    buttonPanel.add(italic);
    buttonPanel.add(styles);
    styles.setMinimumSize(  new Dimension ( 50, 20 ) );
    styles.setMaximumSize(new Dimension ( 100, 20 ) );

    Container c=getContentPane();
    super.setJMenuBar( bar );
    c.add(buttonPanel,BorderLayout.NORTH);
    c.add(drawingArea,BorderLayout.CENTER);

    statusBar=new JLabel();
    c.add(statusBar,BorderLayout.SOUTH);
    statusBar.setText("     Welcome To The Little Drawing Pad!!!  :)");

    createNewItem();
    setSize(width,height);

    show();
  }


//按钮侦听器ButtonHanler类，内部类，用来侦听基本按钮的操作
public class ButtonHandler implements ActionListener
 {
  public void actionPerformed(ActionEvent e)
  {
   for(int j=3;j<choices.length-3;j++)
   {
      if(e.getSource()==choices[j])
         {currentChoice=j;
          createNewItem();
          repaint();}
        }
    }
 }

//按钮侦听器ButtonHanler1类，用来侦听颜色选择、画笔粗细设置、文字输入按钮的操作
public class ButtonHandler1 implements ActionListener
 {
  public void actionPerformed(ActionEvent e)
  {
    if(e.getSource()==choices[choices.length-3])
         {chooseColor();}
    if(e.getSource()==choices[choices.length-2])
         {setStroke();}
    if(e.getSource()==choices[choices.length-1])
         {JOptionPane.showMessageDialog(null,
             "Please hit the drawing pad to choose the word input position",
             "Hint",JOptionPane.INFORMATION_MESSAGE );
          currentChoice=14;
          createNewItem();
          repaint();
          }
    }
 }


//鼠标事件mouseA类，继承了MouseAdapter，用来完成鼠标相应事件操作
 class mouseA extends MouseAdapter
 {
   public void mousePressed(MouseEvent e)
    {statusBar.setText("     Mouse Pressed @:[" + e.getX() +
                              ", " + e.getY() + "]");//设置状态提示

     itemList[index].x1=itemList[index].x2=e.getX();
     itemList[index].y1=itemList[index].y2=e.getY();

    //如果当前选择的图形是随笔画或者橡皮擦，则进行下面的操作
    if(currentChoice==3||currentChoice==13)
    {
     itemList[index].x1=itemList[index].x2=e.getX();
     itemList[index].y1=itemList[index].y2=e.getY();
     index++;
     createNewItem();
     }

    //如果当前选择的图形式文字输入，则进行下面操作
     if(currentChoice==14)
     {
      itemList[index].x1=e.getX();
      itemList[index].y1=e.getY();

      String input;
      input=JOptionPane.showInputDialog(
          "Please input the text you want!");
      itemList[index].s1=input;
      itemList[index].x2=f1;
      itemList[index].y2=f2;
      itemList[index].s2=style1;

      index++;
      currentChoice=14;
      createNewItem();
      drawingArea.repaint();
      }
    }

   public void mouseReleased(MouseEvent e)
    {statusBar.setText("     Mouse Released @:[" + e.getX() +
                              ", " + e.getY() + "]");

    if(currentChoice==3||currentChoice==13)
    {
     itemList[index].x1=e.getX();
     itemList[index].y1=e.getY();
    }
     itemList[index].x2=e.getX();
     itemList[index].y2=e.getY();
     repaint();
     index++;
     createNewItem();
    }

   public void mouseEntered(MouseEvent e)
   {
           statusBar.setText("     Mouse Entered @:[" + e.getX() +
                              ", " + e.getY() + "]");
           }

   public void mouseExited(MouseEvent e)
   {
           statusBar.setText("     Mouse Exited @:[" + e.getX() +
                              ", " + e.getY() + "]");
           }
  }


//鼠标事件mouseB类继承了MouseMotionAdapter，用来完成鼠标拖动和鼠标移动时的相应操作
 class mouseB extends MouseMotionAdapter
 {
  public void mouseDragged(MouseEvent e)
  {statusBar.setText("     Mouse Dragged @:[" + e.getX() +
                              ", " + e.getY() + "]");

   if(currentChoice==3||currentChoice==13)
   {
    itemList[index-1].x1=itemList[index].x2=itemList[index].x1=e.getX();
    itemList[index-1].y1=itemList[index].y2=itemList[index].y1=e.getY();
    index++;
    createNewItem();
   }
   else
    {
     itemList[index].x2=e.getX();
     itemList[index].y2=e.getY();
    }
   repaint();
   }

  public void mouseMoved(MouseEvent e)
   {statusBar.setText("     Mouse Moved @:[" + e.getX() +
                              ", " + e.getY() + "]");}
  }


//选择字体风格时候用到的事件侦听器类，加入到字体风格的选择框中
private class checkBoxHandler implements ItemListener
 {
  public void itemStateChanged(ItemEvent e)
  {
   if(e.getSource()==bold)
     if(e.getStateChange()==ItemEvent.SELECTED)
        f1=Font.BOLD;
      else
        f1=Font.PLAIN;
   if(e.getSource()==italic)
     if(e.getStateChange()==ItemEvent.SELECTED)
        f2=Font.ITALIC;
      else
        f2=Font.PLAIN;
          }
 }


//画图面板类，用来画图
 class DrawPanel extends JPanel
 {
   public DrawPanel()
  {
   setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));
   setBackground(Color.white);
   addMouseListener(new mouseA());
   addMouseMotionListener(new mouseB());
  }

    public void paintComponent(Graphics g)
    {
      super.paintComponent(g);

      Graphics2D g2d=(Graphics2D)g;	//定义画笔

      int j=0;
      while (j<=index)
      {
        draw(g2d,itemList[j]);
        j++;
      }
    }

    void draw(Graphics2D g2d,drawings i)
    {
      i.draw(g2d);//将画笔传入到各个子类中，用来完成各自的绘图
    }
 }


//新建一个画图基本单元对象的程序段
 void createNewItem()
  { if(currentChoice==14)//进行相应的游标设置
          drawingArea.setCursor(Cursor.getPredefinedCursor(Cursor.TEXT_CURSOR));
          else
          drawingArea.setCursor(Cursor.getPredefinedCursor(Cursor.CROSSHAIR_CURSOR));

    switch (currentChoice)
    {
      case 3:
        itemList[index]=new Pencil();
        break;
      case 4:
        itemList[index]=new Line();
        break;
      case 5:
        itemList[index]=new Rect();
        break;
      case 6:
        itemList[index]=new fillRect();
        break;
      case 7:
        itemList[index]=new Oval();
        break;
      case 8:
        itemList[index]=new fillOval();
        break;
      case 9:
        itemList[index]=new Circle();
        break;
      case 10:
        itemList[index]=new fillCircle();
        break;
      case 11:
        itemList[index]=new RoundRect();
        break;
      case 12:
        itemList[index]=new fillRoundRect();
        break;
      case 13:
        itemList[index]=new Rubber();
        break;
      case 14:
        itemList[index]=new Word();
        break;
    }
    itemList[index].type=currentChoice;
    itemList[index].R=R;
    itemList[index].G=G;
    itemList[index].B=B;
    itemList[index].stroke=stroke;
  }


//选择当前颜色程序段
public void chooseColor()
 {
    color=JColorChooser.showDialog(MiniDrawPad.this,
                          "Choose a color",color);
    R=color.getRed();
    G=color.getGreen();
    B=color.getBlue();
    itemList[index].R=R;
    itemList[index].G=G;
    itemList[index].B=B;
  }

//选择当前线条粗细程序段
public void setStroke()
 {
  String input;
  input=JOptionPane.showInputDialog(
          "Please input a float stroke value! ( >0 )");
  stroke=Float.parseFloat(input);
  itemList[index].stroke=stroke;
  }

//保存图形文件程序段
 public void saveFile()
 {
    JFileChooser fileChooser=new JFileChooser();
    fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
    int result =fileChooser.showSaveDialog(this);
    if(result==JFileChooser.CANCEL_OPTION)
             return ;
    File fileName=fileChooser.getSelectedFile();
    fileName.canWrite();

    if (fileName==null||fileName.getName().equals(""))
    JOptionPane.showMessageDialog(fileChooser,"Invalid File Name",
            "Invalid File Name", JOptionPane.ERROR_MESSAGE);
    else{
      try {
       fileName.delete();
       FileOutputStream fos=new FileOutputStream(fileName);

       output=new ObjectOutputStream(fos);
       drawings record;

       output.writeInt( index );

       for(int i=0;i< index ;i++)
       {
               drawings p= itemList[ i ] ;
        output.writeObject(p);
        output.flush();    //将所有图形信息强制转换成父类线性化存储到文件中
               }
      output.close();
      fos.close();
      }
       catch(IOException ioe)
       {
         ioe.printStackTrace();
       }
      }
   }

//打开一个图形文件程序段
 public void loadFile()
 {

    JFileChooser fileChooser=new JFileChooser();
    fileChooser.setFileSelectionMode(JFileChooser.FILES_ONLY);
    int result =fileChooser.showOpenDialog(this);
    if(result==JFileChooser.CANCEL_OPTION)
          return ;
    File fileName=fileChooser.getSelectedFile();
    fileName.canRead();
    if (fileName==null||fileName.getName().equals(""))
       JOptionPane.showMessageDialog(fileChooser,"Invalid File Name",
            "Invalid File Name", JOptionPane.ERROR_MESSAGE);
    else {
      try {

          FileInputStream fis=new FileInputStream(fileName);

          input=new ObjectInputStream(fis);
          drawings inputRecord;

          int countNumber=0;
          countNumber=input.readInt();

          for(index=0;index< countNumber ;index++)
          {
            inputRecord=(drawings)input.readObject();
            itemList[ index ] = inputRecord ;

          }

          createNewItem();
          input.close();

          repaint();
          }
           catch(EOFException endofFileException){
            JOptionPane.showMessageDialog(this,"no more record in file",
                           "class not found",JOptionPane.ERROR_MESSAGE );
          }
          catch(ClassNotFoundException classNotFoundException){
            JOptionPane.showMessageDialog(this,"Unable to Create Object",
                           "end of file",JOptionPane.ERROR_MESSAGE );
          }
          catch (IOException ioException){
            JOptionPane.showMessageDialog(this,"error during read from file",
                           "read Error",JOptionPane.ERROR_MESSAGE );
            }
          }
       }


//新建一个文件程序段
 public void newFile()
 {
  index=0;
  currentChoice=3;
  color=Color.black;
  stroke=1.0f;
  createNewItem();
  repaint();//将有关值设置为初始状态，并且重画
 }



//主函数段
 public static void main(String args[])
  {try {
        UIManager.setLookAndFeel( UIManager.getSystemLookAndFeelClassName());
        }
     catch ( Exception e ) {}//将界面设置为当前windows风格

   MiniDrawPad newPad=new MiniDrawPad();
   newPad.addWindowListener(
        new WindowAdapter(){
           public void windowClosing(WindowEvent e)
           {System.exit(0);}});
  }
}


//定义画图的基本图形单元
class drawings implements Serializable//父类，基本图形单元，用到串行化接口，保存时所用
 {
  int x1,y1,x2,y2;	//定义坐标属性
  int R,G,B;		//定义色彩属性
  float stroke;		//定义线条粗细属性
  int type;		//定义字体属性
  String s1;
  String s2;		//定义字体风格属性

  void draw(Graphics2D g2d){};//定义绘图函数
 }


/*******************************************************************************
  下面是各种基本图形单元的子类，都继承自父类drawings，请仔细理解继承的概念
********************************************************************************/

 class Line extends drawings //直线类
 {
 void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke,
                BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL));
   g2d.drawLine(x1,y1,x2,y2);
   }
 }


 class Rect extends drawings//矩形类
 {
 void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke));
   g2d.drawRect(Math.min(x1,x2),Math.min(y1,y2),
              Math.abs(x1-x2),Math.abs(y1-y2));
  }
 }


 class fillRect extends drawings//实心矩形类
 {
 void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke));
   g2d.fillRect(Math.min(x1,x2),Math.min(y1,y2),
              Math.abs(x1-x2),Math.abs(y1-y2));
  }
 }


 class Oval extends drawings//椭圆类
  {
    void draw(Graphics2D g2d)
    {g2d.setPaint(new Color(R,G,B));
     g2d.setStroke(new BasicStroke(stroke));
     g2d.drawOval(Math.min(x1,x2),Math.min(y1,y2),
                  Math.abs(x1-x2),Math.abs(y1-y2));
    }
  }


 class fillOval extends drawings//实心椭圆
 {
  void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke));
   g2d.fillOval(Math.min(x1,x2),Math.min(y1,y2),
                Math.abs(x1-x2),Math.abs(y1-y2));
         }
 }


 class Circle extends drawings//圆类
 {
   void draw(Graphics2D g2d)
   {g2d.setPaint(new Color(R,G,B));
    g2d.setStroke(new BasicStroke(stroke));
    g2d.drawOval(Math.min(x1,x2),Math.min(y1,y2),
               Math.max(Math.abs(x1-x2),Math.abs(y1-y2)),
               Math.max(Math.abs(x1-x2),Math.abs(y1-y2))
               );
    }
 }


 class fillCircle extends drawings//实心圆
 {
  void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke));
   g2d.fillOval(Math.min(x1,x2),Math.min(y1,y2),
               Math.max(Math.abs(x1-x2),Math.abs(y1-y2)),
               Math.max(Math.abs(x1-x2),Math.abs(y1-y2))
               );
         }
 }


 class RoundRect extends drawings//圆角矩形类
 {
  void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke));
   g2d.drawRoundRect(Math.min(x1,x2),Math.min(y1,y2),
                   Math.abs(x1-x2),Math.abs(y1-y2),
                   50,35);
         }
 }


 class fillRoundRect extends drawings//实心圆角矩形类
 {
  void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke));
   g2d.fillRoundRect(Math.min(x1,x2),Math.min(y1,y2),
                   Math.abs(x1-x2),Math.abs(y1-y2),
                   50,35);
         }
 }


 class Pencil extends drawings//随笔画类
 {
  void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(R,G,B));
   g2d.setStroke(new BasicStroke(stroke,
                BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL));
   g2d.drawLine(x1,y1,x2,y2);
         }
 }


 class Rubber extends drawings//橡皮擦类
 {
  void draw(Graphics2D g2d)
  {g2d.setPaint(new Color(255,255,255));
   g2d.setStroke(new BasicStroke(stroke+4,
                BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL));
   g2d.drawLine(x1,y1,x2,y2);
         }
 }


 class Word extends drawings//输入文字类
 {
  void draw(Graphics2D g2d)
  {
          g2d.setPaint(new Color(R,G,B));
          g2d.setFont(new Font(s2,x2+y2,((int)stroke)*18));
          if (s1!= null )
          g2d.drawString(s1,x1,y1);
         }
 }
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