/**
 * @(#)RGBscrollbars.java 1.0 21/11/02
 *
 * Uses scrollbars (contained in a panel with null layout) to set RGB color
 * of the main applet background. RGB components are given separately, and also
 * as a combined hex value (useful for web programmers).
 *
 * Andy Murray 21/11/02
 *
 */

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


public class RGBscrollbars extends Applet implements AdjustmentListener
{
	Panel sbPanel;		//panel (for scrollbars only)
	Scrollbar [] sb;	//scrollbars themselves
	Label [] RGBLabel;	//labels for color values
	Label hexLabel;		//for hex color value
	int r, g, b,		//color values
		panelWidth, border;
	
	public void init()
	{
		panelWidth=320;
		border = 10;
		sbPanel=new Panel();
		sbPanel.setSize(panelWidth,100);
		sbPanel.setLayout(null);	//this is a key line to keep scrollbars inflated
		sb = new Scrollbar [3];
		RGBLabel = new Label [3];
		hexLabel = new Label("Hex value = #000000");
		hexLabel.setBackground(Color.white);
		
		for (int i=0;i<3;i++)
		{
			sb[i] = new Scrollbar(Scrollbar.HORIZONTAL,0,20,0,275);
			sb[i].addAdjustmentListener(this);
			sb[i].setSize(panelWidth-2*border,20);
			switch (i)
			{
				case 0 :
					{
						sb[i].setBackground(Color.red);
						RGBLabel[i]=new Label("R = 0  ");
						break;
					}
				case 1 :
					{
						sb[i].setBackground(Color.green);
						RGBLabel[i]=new Label("G = 0  ");
						break;
					}
				case 2 :
					{
						sb[i].setBackground(Color.blue);
						RGBLabel[i]=new Label("B = 0  ");
					}
			}
			RGBLabel[i].setBackground(Color.white);
			sb[i].setLocation(border,border+i*30);
			sbPanel.add(sb[i]);
			this.add(RGBLabel[i]);
		}
		sbPanel.setBackground(Color.lightGray);
		add(sbPanel);	//the applet still has flow layout
		add(hexLabel);
		this.setBackground(Color.black);	//initially
		this.setSize(400,300);
	}
	
	public void adjustmentValueChanged(AdjustmentEvent ae)
	{
		Adjustable adjusted = ae.getAdjustable();
		int val = ae.getValue();
		if (adjusted.equals(sb[0])) {r=val;RGBLabel[0].setText("R = "+r);}
		if (adjusted.equals(sb[1])) {g=val;RGBLabel[1].setText("G = "+g);}
		if (adjusted.equals(sb[2])) {b=val;RGBLabel[2].setText("B = "+b);}
		this.setBackground(new Color(r,g,b));
		hexLabel.setText("Hex value = #"+getHex(this.getBackground()));
	}
	
	String getHex(Color c)
	{
		return Integer.toHexString(c.getRGB()).substring(2);
	}
}