简单画笔

Command.java

/**
 * @author aassd
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */

public interface Command {
 public final static int LINE = 2;
 public final static int CIRCLE = 4;
 public final static int RECTANGLE = 8;
}

 

ICircle.java

import java.awt.*;

/**
 * @author aassd
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */
public class ICircle implements Shape {
 private Color color;
 private int x;
 private int y;
 private int width;
 private int height;

 public ICircle(int x, int y, int width, int height, Color color) {
  this.x = x;
  this.y = y;
  this.width = width;
  this.height = height;
  this.color = color;
 }
 public void draw(Graphics g) {
  g.setColor(color);
  g.drawArc(x, y, width, height, 0, 360);
 }

}

ILine.java

import java.awt.*;

/**
 * @author aassd
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */
public class ILine implements Shape {
 private int x1;
 private int y1;
 private int x2;
 private int y2;
 private Color color;

 public ILine(int x1, int y1, int x2, int y2, Color color) {
  this.x1 = x1;
  this.y1 = y1;
  this.x2 = x2;
  this.y2 = y2;
  this.color = color;
 }

 public void draw(Graphics g) {
  g.setColor(color);
  g.drawLine(x1, y1, x2, y2);
 }
}

IRectangle.java

import java.awt.*;
import java.awt.event.*;
import java.util.Vector;

/**
 * @author aassd
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */
public class IRectangle implements Shape {
 private int x;
    private int y;
    private int width;
    private int height;
    private Color color;

    public IRectangle(int x, int y, int width, int height, Color color) {
     this.x = x;
     this.y = y;
     this.width = width;
     this.height = height;
     this.color = color;
    }

 public void draw(Graphics g) {
  g.setColor(color);
  g.drawRect(x, y, width, height);
 }

}

 

PaintApp.java

import java.awt.*;
import java.awt.event.*;
import java.util.*;

/**
 * @author aassd
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */
public class PaintApp extends Frame {
 Panel commandPanel = new Panel();
 Panel colorPanel = new Panel();
 Panel shapePanel = new Panel();

 Button btnRed = new Button("Red");
 Button btnGreen = new Button("Green");
 Button btnBlue = new Button("Blue");

 Button btnLine = new Button("Line");
 Button btnRectangle = new Button("Rectangle");
 Button btnCircle = new Button("Circle");

 Button btnUndo = new Button("Undo");
 Button btnRedo = new Button("Redo");
 Button btnExit = new Button("Exit");

 PaintBoard paintBoard = new PaintBoard();

 public PaintApp() {
  this.setLayout(new BorderLayout());

  btnLine.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnLine_actionPerformed(e);
   }
  });
  btnRectangle.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnRectangle_actionPerformed(e);
   }
  });
  btnCircle.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnCircle_actionPerformed(e);
   }
  });

  btnExit.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnExit_actionPerformed(e);
   }
  });
  btnUndo.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnUndo_actionPerformed(e);
   }
  });
  btnRedo.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnRedo_actionPerformed(e);
   }
  });

  shapePanel.setLayout(new FlowLayout());
  shapePanel.add(btnLine, null);
  shapePanel.add(btnRectangle, null);
  shapePanel.add(btnCircle, null);

  shapePanel.add(btnUndo, null);
  shapePanel.add(btnRedo, null);
  shapePanel.add(btnExit,null);

  btnRed.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnRed_actionPerformed(e);
   }
  });
  btnGreen.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnGreen_actionPerformed(e);
   }
  });
  btnBlue.addActionListener(new ActionListener() {
   public void actionPerformed(ActionEvent e) {
       btnBlue_actionPerformed(e);
   }
  });

  colorPanel.setLayout(new FlowLayout());
  colorPanel.add(btnRed, null);
  colorPanel.add(btnGreen, null);
  colorPanel.add(btnBlue, null);

  commandPanel.setLayout(new BorderLayout());
  commandPanel.add(shapePanel, BorderLayout.NORTH);
  commandPanel.add(colorPanel, BorderLayout.CENTER);

  this.add(commandPanel, BorderLayout.SOUTH);
  this.add(paintBoard, BorderLayout.CENTER);

        ///////////////////////////////////////////////////////////////////////////

        btnLine.setForeground(Color.red);
        paintBoard.setCommand(Command.LINE);

        btnRed.setForeground(Color.red);
        paintBoard.setColor(Color.red);
        ///////////////////////////////////////////////////////////////////////////

 }

 void btnExit_actionPerformed(ActionEvent e) {
  System.exit(0);
 }

 void btnUndo_actionPerformed(ActionEvent e) {
  paintBoard.undo();
 }

 void btnRedo_actionPerformed(ActionEvent e) {
  paintBoard.redo();
 }

 void btnLine_actionPerformed(ActionEvent e) {
  btnLine.setForeground(Color.red);
  btnRectangle.setForeground(Color.black);
  btnCircle.setForeground(Color.black);
  paintBoard.setCommand(Command.LINE);
 }
 void btnRectangle_actionPerformed(ActionEvent e) {
  btnLine.setForeground(Color.black);
  btnRectangle.setForeground(Color.red);
  btnCircle.setForeground(Color.black);
  paintBoard.setCommand(Command.RECTANGLE);
 }
 void btnCircle_actionPerformed(ActionEvent e) {
  btnLine.setForeground(Color.black);
  btnRectangle.setForeground(Color.black);
  btnCircle.setForeground(Color.red);
  paintBoard.setCommand(Command.CIRCLE);
 }

 void btnRed_actionPerformed(ActionEvent e) {
  btnRed.setForeground(Color.red);
  btnGreen.setForeground(Color.black);
  btnBlue.setForeground(Color.black);
  paintBoard.setColor(Color.red);
 }
 void btnGreen_actionPerformed(ActionEvent e) {
  btnRed.setForeground(Color.black);
  btnGreen.setForeground(Color.red);
  btnBlue.setForeground(Color.black);
  paintBoard.setColor(Color.green);
 }
 void btnBlue_actionPerformed(ActionEvent e) {
  btnRed.setForeground(Color.black);
  btnGreen.setForeground(Color.black);
  btnBlue.setForeground(Color.red);
  paintBoard.setColor(Color.blue);
 }

 public static void main(String[] args) {
  PaintApp paintApp = new PaintApp();
  paintApp.setSize(600, 500);
  paintApp.setVisible(true);
 }

}

PaintBoard.java

import java.awt.*;
import java.awt.event.*;
import java.util.*;

/**
 * @author aassd
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */

public class PaintBoard extends Canvas implements java.awt.event.MouseListener, java.awt.event.MouseMotionListener {
    int srcX = 0;
    int srcY = 0;

    int lineToX = 0;
    int lineToY = 0;
   
    boolean bMousePressing = false;
   
    java.util.Stack vShapes = new java.util.Stack();
    java.util.Stack vDelShapes = new java.util.Stack();
   
    private int command = 0;
    private Color color;
   
    public void undo() {
     if (vShapes.size() > 0) {
   Object shape = vShapes.pop();
   vDelShapes.push(shape);
   repaint();
     }

    }
    public void redo() {
     if (vDelShapes.size() > 0) {
      Object shape =  vDelShapes.pop();
      vShapes.push(shape);
      repaint();
     }
    }
   
    public void setCommand(int command) {
     this.command = command;
    }
    public void setColor(Color color) {
     this.color = color;
    }

    public PaintBoard() {
        this.addMouseListener(this);
        this.addMouseMotionListener(this);
    }

    public void paint(Graphics g) {

        Dimension size = size();
        int width = size.width ;
        int height = size.height;
        g.setColor(Color.white);
        g.fillRect(0,0, width,height);

  Shape shape = null;
        java.util.Enumeration enum = vShapes.elements();
        g.setColor(Color.blue);
        while (enum.hasMoreElements()) {
            shape = (Shape) enum.nextElement();
   shape.draw(g);
        }

  
  if (bMousePressing) {
   g.setColor(color);
   switch (command) {
    case Command.LINE:
           g.drawLine(srcX, srcY, lineToX, lineToY);
     break;
    case Command.RECTANGLE:  
     if (lineToX < srcX) {
      if (lineToY < srcY) {
       g.drawRect(lineToX, lineToY, srcX - lineToX , srcY - lineToY); 
      }
      else {
       g.drawRect(lineToX, srcY, srcX - lineToX, lineToY - srcY);
      }
     }
     else {  
      if (lineToY < srcY) {
       g.drawRect(srcX, lineToY, lineToX - srcX, srcY - lineToY);
      }
      else {
       g.drawRect(srcX, srcY, lineToX - srcX, lineToY - srcY);
      }
     }
     break;
    case Command.CIRCLE:
 
     int w = (int)java.lang.Math.sqrt((srcX - lineToX) * (srcX - lineToX) + (srcY - lineToY) * (srcY - lineToY));
     g.drawArc(srcX - w/2, srcY - w/2, w, w, 0, 360);
     break;
   }//End switch(command)
  }  
    
    }

    public void mouseClicked(MouseEvent e) {
    }

    public void mousePressed(MouseEvent e) {
        srcX = e.getX();
        srcY = e.getY();
        bMousePressing = true;
    }

    public void mouseReleased(MouseEvent e) {
        lineToX = e.getX();
        lineToY = e.getY();
  bMousePressing = false;
        switch (command) {
         case Command.LINE:
       ILine line = new ILine(srcX, srcY, lineToX, lineToY, color);
    vShapes.push(line);          
          break;
         case Command.RECTANGLE:
          IRectangle rectangle = null;
          if (lineToX < srcX) {
     if (lineToY < srcY) {
      rectangle = new IRectangle(lineToX, lineToY, srcX - lineToX , srcY - lineToY, color); 
     }
     else {
      rectangle = new IRectangle(lineToX, srcY, srcX - lineToX, lineToY - srcY, color);
     }
    }
    else {  
     if (lineToY < srcY) {
      rectangle = new IRectangle(srcX, lineToY, lineToX - srcX, srcY - lineToY, color);
     }
     else {
      rectangle = new IRectangle(srcX, srcY, lineToX - srcX, lineToY - srcY, color);
     }
    }
          vShapes.push(rectangle);
          break;
         case Command.CIRCLE:
    int w = (int)java.lang.Math.sqrt((srcX - lineToX) * (srcX - lineToX) + (srcY - lineToY) * (srcY - lineToY));
    ICircle circle = new ICircle(srcX - w/2, srcY - w/2, w, w, color);             
    vShapes.push(circle);
          break;
        } //End switch(command)
       
        repaint();
    }

    public void mouseEntered(MouseEvent e) {
    }

    public void mouseExited(MouseEvent e) {
    }

    public void mouseDragged(MouseEvent e) {
        lineToX = e.getX();
        lineToY = e.getY();
        repaint();
    }

    public void mouseMoved(MouseEvent e) {
    }

  
}

Shape.java

import java.awt.*;
import java.awt.event.*;

/**
 * @author aassd
 *
 * To change this generated comment edit the template variable "typecomment":
 * Window>Preferences>Java>Templates.
 * To enable and disable the creation of type comments go to
 * Window>Preferences>Java>Code Generation.
 */
public interface Shape {
    public void draw(Graphics g);
}

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