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

/**
* Class ColorSelector Applet
*
* Class for determining the Red Green Blue (RGB) values for selected colors
*
* @see #init
*
* @version	1.0
* @author	Michael D. baker Jr.
*/
public class ColorSelector extends Applet
{
	private DisplayArea rgbDisplay;
	private ControlArea	rgbControls;
	private RGBadjustmentHandler rgbHandler;

	/**
	* Method init()
	*
	* initialization method for the applet
	*
	* @param	none
	*
	* @return	none
	*
	* @since 1.1
	*/
	public void init()
	{
		rgbDisplay 	= new DisplayArea();
		rgbControls = new ControlArea();
		rgbHandler = new RGBadjustmentHandler( rgbDisplay, rgbControls );

		rgbControls.addAdjustmentListener( rgbHandler );

		setLayout( new BorderLayout() );
		add( rgbDisplay,  BorderLayout.CENTER);
		add( rgbControls, BorderLayout.EAST );

		rgbDisplay.setColor( rgbControls.getColor() );
	}
}

/**
* Class DisplayArea
*
* Class for displaying colors in a large area
*
* @version	1.0
* @author	Michael D. baker Jr.
*
* @see #DisplayArea
* @see #setColor
*/
class DisplayArea extends Canvas
{

	/**
	* Method DisplayArea()
	*
	* Creates a large display area object for displaying colors
	*
	* @param	none
	*
	* @return	none
	*
	* @since 1.1
	*/
	public DisplayArea()
	{
		super();
	}

	/**
	* Method setColor()
	*
	* Set the color of the display area canvas
	*
	* @param Color myColor	target color to use
	*
	* @return	none
	*
	* @since 1.1
	*/
	public void setColor( Color myColor )
	{
		setBackground( myColor );
	}
}

/**
* Class ControlArea
*
* Class for providing Red Green Blue (RGB) selection controls and displaying
* the current selection numerically
*
* @version	1.0
* @author	Michael D. baker Jr.
*
* @see #ControlArea
* @see #addAdjustmentListener
* @see #getColor
* @see #displayColor
*/
class ControlArea extends Panel
{
	final private int RED   = 0;
	final private int GREEN = 1;
	final private int BLUE  = 2;
	final private String rgbLabels[] = { "RED", "GREEN", "BLUE" };

	private Scrollbar		control[];
	private Label			title[];
	private Label			value[];

	private Panel			controlPanel[];
	private Panel			controlDisplay[];

	/**
	* Method ControlArea()
	*
	* Creates a ControlArea object for adjusting rgb colors with sliders
	* and presenting the numerical values as text
	*
	* @param	none
	*
	* @return	none
	*
	* @since 1.1
	*/
	public ControlArea()
	{
		int			maxTitleWidth = 0;
		Dimension 	titleDim;
		Dimension	scrollDim;

		controlPanel    = new Panel[3];
		controlDisplay	= new Panel[3];
		control			= new Scrollbar[3];
		title			= new Label[3];
		value			= new Label[3];


		setLayout( new GridLayout( 1, 3 ) );

		for( int i=0; i<3; i++ )
		{
			control[i] = new Scrollbar( Scrollbar.VERTICAL, 0, 1, 0, 256 );
			title[i]   = new Label( rgbLabels[i] );
			value[i]   = new Label( "0" );
			controlPanel[i]   = new Panel();
			controlDisplay[i] = new Panel();

			titleDim = title[i].getSize();
			if( titleDim.width > maxTitleWidth )
				maxTitleWidth = titleDim.width;

			controlDisplay[i].setLayout( new GridLayout( 2,1 ) );
			controlDisplay[i].add( title[i] );
			controlDisplay[i].add( value[i] );

			controlPanel[i].setLayout( new BorderLayout() );
			controlPanel[i].add( control[i],        BorderLayout.CENTER );
			controlPanel[i].add( controlDisplay[i], BorderLayout.SOUTH );

			add( controlPanel[i] );
		}

		titleDim = title[0].getSize();
		titleDim.width = maxTitleWidth;
		scrollDim = control[0].getSize();
		scrollDim.width = 5;
		for( int i=0; i<3; i++ )
		{
			title[i].setSize( titleDim );
			title[i].setAlignment( Label.CENTER );

			value[i].setSize( titleDim );
			value[i].setAlignment( Label.CENTER );

			control[i].setSize( scrollDim );
		}
	}

	/**
	* Method addAdjustmentListener()
	*
	* register a target object with this control object to be notified whenever
	* the user adjusts any of the slider controls
	*
	* @param AdjustmentListener  l	object to notify when controls adjusted
	*
	* @return	none
	*
	* @since 1.1
	*/
	public void addAdjustmentListener( AdjustmentListener l )
	{
		for( int i=0; i<3; i++ )
			control[i].addAdjustmentListener( l );
	}

	/**
	* Method getColor()
	*
	* get the current color settings of this control object
	*
	* @param	none
	*
	* @return Color 
	*
	* @since 1.1
	*/
	public Color getColor()
	{
		Color current = new Color(	control[RED  ].getValue(), 
									control[GREEN].getValue(),
									control[BLUE ].getValue() );
		return( current );
	}

	/**
	* Method displayColor()
	*
	* update the numerical display for the color controls
	*
	* @param	none
	*
	* @return	none
	*
	* @since 1.1
	*/
	public void displayColor()
	{
		for( int i=0; i<3; i++ )
		{
			value[i].setText( String.valueOf( control[i].getValue() ) );
		}
	}
}

/**
* Class RGBadjustmentHander
*
* Class to watch for changes to controls and updating displays
*
* @version	1.0
* @author	Michael D. baker Jr.
*
* @see #RGBadjustmentHandler
* @see #adjustmentValueChanged
*/
class RGBadjustmentHandler implements AdjustmentListener
{
	private DisplayArea d;
	private ControlArea c;

	/**
	* Method RGBadjustmentHander()
	*
	* Create a controller class to handle events and update appropriate 
	* objects.  Graphical areas will be updated with the color.  Control
	* areas will be monitored for adjustment to any controls and numerical 
	* displays updated.
	*
	* @param	DisplayArea	object handle for graphical area to update
	* @param	ControlArea	object handle for control area to watch & update
	*
	* @return	none
	*
	* @since 1.1
	*/
	public RGBadjustmentHandler( DisplayArea display, ControlArea controls )
	{
		d = display;
		c = controls;
	}

	/**
	* Method adjustmentValueChanged()
	*
	* method called whenever one of the controls is adjusted.
	*
	* @param	AdjustmentEvent	event object containing adjustment information 
	*
	* @return	none
	*
	* @since 1.1
	*/
	public void adjustmentValueChanged( AdjustmentEvent e )
	{
		d.setColor( c.getColor() );
		c.displayColor();
	}
}