drawpad.java

画图工具

        break;
      case 6:
        itemList[index]=new Oval();
        break;
      case 7:
        itemList[index]=new fillOval();
        break;
      case 8:
        itemList[index]=new Circle();
        break;
      case 9:
        itemList[index]=new fillCircle();
        break;
      case 10:
        itemList[index]=new RoundRect();
        break;
      case 11:
        itemList[index]=new fillRoundRect();
        break;
      case 12:
        itemList[index]=new Triangle();
        break;
      case 13:
        itemList[index]=new Rubber();
        break;
    }
    itemList[index].R=R;
    itemList[index].G=G;
    itemList[index].B=B;
    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=0;
  color=Color.black;
  //stroke=1.0f;
  createNewItem();
  repaint();//将有关值设置为初始状态，并且重画
 }
 
 	//选择当前颜色程序段
	public void chooseColor()
 {
    color=JColorChooser.showDialog(DrawPad.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;
  }
  
  //选择线条粗细程序段
    public void setStroke()
   		{
   			String input;
   			input=JOptionPane.showInputDialog("Input a stroke value(>0):");
   			stroke=Integer.parseInt(input);
   			itemList[index].stroke=stroke;
   		}


//用主函数main()来测试   		
   	public static void main(String s[]){
		DrawPad example = new DrawPad();
		example.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
  int stroke=1;     //定义笔画粗细属性
  void draw(Graphics2D g2d){};//定义绘图函数
 }



  //各种基本图形单元的子类，都继承父类drawings，

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


 class Rect extends drawings//空心矩形类
 {
 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.fillRect(Math.min(x1,x2),Math.min(y1,y2),
              Math.abs(x1-x2),Math.abs(y1-y2));
  }
 }

 
 class Square extends Rect//空心正方形类
 {
 	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(x1-x2));	
 	}
 }
 
 class fillSquare extends fillRect//实心正方形类
 {
 	void draw(Graphics2D g2d){
  		g2d.setPaint(new Color(R,G,B));
    	g2d.fillRect(Math.min(x1,x2),Math.min(y1,y2),
              Math.abs(x1-x2),Math.abs(x1-x2));
     }
 }
  

 class Oval extends drawings//空心椭圆类
  {
    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.fillOval(Math.min(x1,x2),Math.min(y1,y2),
                Math.abs(x1-x2),Math.abs(y1-y2));
         }
 }


 class Circle extends drawings//空心圆类
 {
   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.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//空心圆角矩形类
 {
  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.fillRoundRect(Math.min(x1,x2),Math.min(y1,y2),
                   Math.abs(x1-x2),Math.abs(y1-y2),
                   50,35);
         }
 }


class Triangle extends drawings//空心直角三角形类
{
	void draw(Graphics2D g2d){
		g2d.setPaint(new Color(R,G,B));
		g2d.setStroke(new BasicStroke(stroke));
		g2d.drawLine(x1,y1,x2,y1);
		g2d.drawLine(x1,y1,x1,y2);
		g2d.drawLine(x1,y2,x2,y1);
		}
}

 
 class Rubber extends drawings//橡皮擦类
 {
  void draw(Graphics2D g2d){
  	  g2d.setPaint(new Color(255,255,255));
      g2d.setStroke(new BasicStroke(10,
                BasicStroke.CAP_ROUND,BasicStroke.JOIN_BEVEL));
      g2d.drawLine(x1,y1,x2,y2);
         }
 }