// ColorSlider.java - originally SliderFrame.java
//     from text by Cay Horstmann: Java Concepts, 2005.
// modified and converted to applet by cmc, 6/3/07

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;
import javax.swing.JApplet;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.event.ChangeListener;
import javax.swing.event.ChangeEvent;

public class ColorSlider extends JApplet
{  
   public ColorSlider()
   {  
      colorPanel = new JPanel();
      
      add(colorPanel, BorderLayout.CENTER);
      createControlPanel();
      setSampleColor();
   }

   public void createControlPanel()
   {
      class ColorListener implements ChangeListener
      {  
         public void stateChanged(ChangeEvent event)
         {  
            setSampleColor();
         }
      }   

      ChangeListener listener = new ColorListener();

      redSlider = new JSlider(0, 255, 255);
      redSlider.addChangeListener(listener);

      greenSlider = new JSlider(0, 255, 175);
      greenSlider.addChangeListener(listener);

      blueSlider = new JSlider(0, 255, 175);
      blueSlider.addChangeListener(listener);
      
      JPanel controlPanel = new JPanel();
      controlPanel.setLayout(new GridLayout(3, 2));

      redLabel = new JLabel("Red: " + 255);
      controlPanel.add(redLabel);
      controlPanel.add(redSlider);

      greenLabel = new JLabel("Green: " + 175);
      controlPanel.add(greenLabel);
      controlPanel.add(greenSlider);

      blueLabel = new JLabel("Blue: " + 175);
      controlPanel.add(blueLabel);
      controlPanel.add(blueSlider);

      add(controlPanel, BorderLayout.SOUTH);      
   }
   
   /**
      Reads the slider values and sets the panel to
      the selected color.
   */
   public void setSampleColor()
   {  
      // Read slider values
      int red = redSlider.getValue();
      int green = greenSlider.getValue();
      int blue = blueSlider.getValue();

      // Set panel background to selected color      
      colorPanel.setBackground(new Color(red, green, blue));
      colorPanel.repaint();

      // cmc: set label text
      redLabel.setText(String.format("Red: %d (out of 255)", red));
      greenLabel.setText(String.format("Green: %d", green));
      blueLabel.setText(String.format("Blue: %d", blue));
   }
   
   private JPanel colorPanel;
   private JSlider redSlider;
   private JSlider greenSlider;
   private JSlider blueSlider;

   // cmc: so labels can show levels too
   private JLabel redLabel;
   private JLabel greenLabel;
   private JLabel blueLabel;
}