Исходный текст программы CustomButton.java

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// ==========================================
// CustomButton.java
//(C) Alexandr Frolov, 1998
// E-mail: frolov@glasnet.ru
// Web:    http://www.glasnet.ru/~frolov 
// ==========================================

import java.applet.Applet;
import java.awt.*;

// ===========================================
// Class CustomButton
// ===========================================
public class CustomButton extends Applet
{
  cButton btnRed;
  cButton btnBlue;
  cButton btnYellow;
  
  Image imgButtonUp;
  Image imgButtonDn;
  
  // ===========================================
  // init
  // ===========================================
  public void init()
  {
    setBackground(Color.yellow);
    setForeground(Color.black);
    
    imgButtonUp = 
      getImage(getCodeBase(), "btnup.gif");
      
    imgButtonDn = 
      getImage(getCodeBase(), "btndn.gif");
    
    btnRed =  new cButton(this, 
      imgButtonUp, imgButtonDn, 
      "Red", 80, 20);
    
    btnBlue =  new cButton(this, 
      imgButtonUp, imgButtonDn, 
      "Blue", 80, 20);
      
    btnYellow =  new cButton(this, 
      imgButtonUp, imgButtonDn, 
      "Yellow", 80, 20);
      
    add(btnRed);
    add(btnBlue);
    add(btnYellow);
  }
  
  // ===========================================
  // getAppletInfo
  // ===========================================
  public String getAppletInfo()
  {
    return "Name: Custom Button";
  }
  
  // ===========================================
  // doButtonAction
  // ===========================================
  public void doButtonAction(cButton btn)
  {
    if(btn.equals(btnRed))
      setBackground(Color.red);
      
    else if(btn.equals(btnBlue))
      setBackground(Color.blue);
      
    else if(btn.equals(btnYellow))
      setBackground(Color.yellow);
      
    repaint();
  }
}

// ===========================================
// Class cButton
// ===========================================
class cButton extends Canvas
  implements Runnable
{
  Image imgButtonUp;
  Image imgButtonDn;
  Container cont;
  int btnWidth;
  int btnHeight;
  Dimension dimMinSize;
  boolean bButtonUp = true;
  
  String btnTitle;
  
  Thread threadAnimate = null;
  Color clrTitleColor = Color.black;
    
  // ===========================================
  // cButton
  // ===========================================
  public cButton(Container parent,
    Image imgUp, Image imgDn,
    String btnTitle, int width, int height)
  {
    if(imgUp == null || imgDn == null)
    {
      System.err.println("Invalid image");
      return;
    }
    
    imgButtonUp = imgUp;
    imgButtonDn = imgDn;
    cont = parent;
    
    btnWidth  = width;
    btnHeight = height;
    this.btnTitle = btnTitle;
    
    dimMinSize = new Dimension(
      btnWidth, btnHeight);
  }  
  
  // ===========================================
  // getPreferredSize
  // ===========================================
  public Dimension getPreferredSize()
  {
    return dimMinSize;
  }
  
  // ===========================================
  // getMinimumSize
  // ===========================================
  public Dimension getMinimumSize()
  {
    return dimMinSize;
  }
  
  // ===========================================
  // preferredSize
  // ===========================================
  public Dimension preferredSize()
  {
    return dimMinSize;
  }
  
  // ===========================================
  // minimumSize
  // ===========================================
  public Dimension minimumSize()
  {
    return dimMinSize;
  }
  
  // ===========================================
  // paint
  // ===========================================
  public void paint(Graphics g)
  {
    FontMetrics fm = g.getFontMetrics();
    int nTitileWidth = 
      fm.stringWidth(btnTitle);
    int nTitleHeight = fm.getAscent() - 
      fm.getLeading() - fm.getDescent();
    
    int x0 = (btnWidth - nTitileWidth) / 2;
    int y0 = ((btnHeight - nTitleHeight) / 2) +
       nTitleHeight;
    
    if(bButtonUp)
    {
      g.drawImage(imgButtonUp, 0, 0, this);
      
      g.setColor(clrTitleColor);
      g.drawString(btnTitle, x0, y0);
    }
    else
    {
      g.drawImage(imgButtonDn, 0, 0, this);
      
      g.setColor(Color.blue);
      g.drawString(btnTitle, 
        x0 - 1, y0 - 1);
    }
  }
  
  // ===========================================
  // mouseDown
  // ===========================================
  public boolean mouseDown(
    Event ev, int x, int y)
  {
    if(bButtonUp)
    {
      bButtonUp = false;
      repaint();
      doButtonAction();
    }  
    
    return true;
  }

  // ===========================================
  // mouseUp
  // ===========================================
  public boolean mouseUp(
    Event ev, int x, int y)
  {
    if(!bButtonUp)
    {
      bButtonUp = true;
      repaint();
    }  
    return true;
  }
  
  // ===========================================
  // mouseEnter
  // ===========================================
  public boolean mouseEnter(
    Event ev, int x, int y)
  {
    if(threadAnimate == null)
    {
      threadAnimate = new Thread(this);
      threadAnimate.start();
    }
    return true;
  }
  
  // ===========================================
  // mouseExit
  // ===========================================
  public boolean mouseExit(
    Event ev, int x, int y)
  {
    if(threadAnimate != null)
    {
      threadAnimate.stop();
      threadAnimate = null;
      clrTitleColor = Color.black;
    }

    bButtonUp = true;
    repaint();
    
    return true;
  }
  
  // ===========================================
  // run
  // ===========================================
  public void run()
  {
    boolean bFlipFlop = true;
    
    while(true)
    {
      if(bFlipFlop)
      {
        clrTitleColor = Color.red;
	bFlipFlop = false;
      }
      else
      {
	clrTitleColor = Color.black;
        bFlipFlop = true;
      }
      
      repaint();
    
      try
      {
	Thread.sleep(300);
      }
      catch (InterruptedException ex)
      {
        threadAnimate.stop();
      }
    }
  }
  
  // ===========================================
  // doButtonAction
  // ===========================================
  public void doButtonAction()
  {
    ((CustomButton)cont).doButtonAction(this);
  }
}

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