/*
		Name:		Chris Johnson
					johnson@dcs.gla.ac.uk
		
		Last modified:	27/10/98
		
		Description:	

	                        Part of an applet to illustrate the use of scroll bars to
                                mix proportyions of RGB colors.    Based on a program in
                                G.W. Rouse's An Introduction to Data Structures and
                                Algorithms with Java, Prentice Hall, Hemel Hemstead, 1998.
                                pp 120-126.
 
                                ScrollCanvas implements a scrollable area that is
                                painted with colours that reflect the settings on
                                three scroll bars (one each for Red, Green and Blue
                                values).
 
                                ColorCanvas implements a small area of the screen that
                                is updated with the colour that a user selects by
                                clicking their mouse on a pixel within the ScrollCanvas.
 
                                Labels are used to provide a textual message of the
                                exact RGB value for that pixel.


*/

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

public class ColorChooser extends Applet
{
	
	private ScrollCanvas redGreenCanvas = new ScrollCanvas(this);
	private ColorCanvas chosenColorCanvas = new ColorCanvas();
	private Scrollbar redScroll, greenScroll, blueScroll;
	private Label redLabel, greenLabel, blueLabel;
	private NewGridBagLayout layout;
	
	static boolean DEBUG = true;
	
	
	public void init()
	{

			
		layout = new NewGridBagLayout();

			
		setLayout(layout);
		layout.setRareConstraints(GridBagConstraints.CENTER,
					  GridBagConstraints.NONE,
					new Insets(0,0,0,0),
				 	0,0,1,1);
									
		redScroll = new Scrollbar(Scrollbar.VERTICAL, 0, 128, 0, 128);
		greenScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 128, 0, 128);
		blueScroll = new Scrollbar(Scrollbar.HORIZONTAL, 0, 255, 0, 255);
		redGreenCanvas.resize(128, 128);

			
		Panel redGreenPanel = new Panel();
		redGreenPanel.setLayout(new BorderLayout());
		redGreenPanel.add("West", redScroll);
		redGreenPanel.add("South", greenScroll);
		redGreenPanel.add("Center", redGreenCanvas);
		
		Panel redGreenFrame = new Panel();
		
		NewGridBagLayout redGreenFrameLayout = new NewGridBagLayout();
		redGreenFrame.setLayout(redGreenFrameLayout);
		redGreenFrameLayout.setRareConstraints(	GridBagConstraints.CENTER,
												GridBagConstraints.NONE,
												new Insets(0,10,0,0),
												0,0,1,1);
		
		Label redScrollLabel = new Label("Red");
		Label greenScrollLabel = new Label("Green");
		redGreenFrameLayout.setPositionSizeAdd(redScrollLabel, redGreenFrame, 0,0,1,1);
		redGreenFrameLayout.setPositionSizeAdd(redGreenPanel, redGreenFrame, 1,0,1,1);
		redGreenFrameLayout.setPositionSizeAdd(greenScrollLabel, redGreenFrame, 1,1,1,1);
		layout.setPositionSizeAdd(redGreenFrame, this, 0,0,1,1);
		
		Panel bluePanel = new Panel();
		NewGridBagLayout bluePanelLayout = new NewGridBagLayout();
		bluePanel.setLayout(bluePanelLayout);
		bluePanelLayout.setRareConstraints(GridBagConstraints.CENTER,
						GridBagConstraints.HORIZONTAL,
						new Insets(0,0,0,0),
						0,0,1,1);
		Label blueScrollLabel = new Label("Use this scrollbar to adjust blue component");
		bluePanelLayout.setPositionSizeAdd(blueScrollLabel, bluePanel, 0, 0, 1, 1);
		bluePanelLayout.setPositionSizeAdd(blueScroll, bluePanel, 0, 1, 1, 1);
		layout.setPositionSizeAdd(bluePanel, this, 0, 1, 1, 1);
		
		Panel selectedColorPanel = new Panel();
		NewGridBagLayout selectedColorPanelLayout = new NewGridBagLayout();
		selectedColorPanel.setLayout(selectedColorPanelLayout);
		selectedColorPanelLayout.setRareConstraints(	GridBagConstraints.WEST,
														GridBagConstraints.NONE,
														new Insets(0,10,0,0),
														0,0,1,1);
														
		Label selectedColorLabel = new Label("Selected color:");
		selectedColorPanelLayout.setPositionSizeAdd(selectedColorLabel, selectedColorPanel, 0,0,1,1);
		chosenColorCanvas.resize(32, 32);
		selectedColorPanelLayout.setPositionSizeAdd(chosenColorCanvas, selectedColorPanel, 1,0,1,1);
		
		redLabel = new Label("Red Component " + redGreenCanvas.getRed() + "    ");
		greenLabel = new Label("Green Component " + redGreenCanvas.getGreen() + "    ");
		blueLabel = new Label("Blue Component " + redGreenCanvas.getBlue() + "    ");
		selectedColorPanelLayout.setPositionSizeAdd(redLabel, selectedColorPanel, 0,1,1,1);

		selectedColorPanelLayout.setPositionSizeAdd(greenLabel, selectedColorPanel, 0,2,1,1);
		selectedColorPanelLayout.setPositionSizeAdd(blueLabel, selectedColorPanel, 0,3,1,1);
		layout.setPositionSizeAdd(selectedColorPanel, this, 1, 0, 1, 1);
	
	}
	
	public void updateSelectedColor(int selRed, int selGreen, int selBlue)
	{
		chosenColorCanvas.setBackground(new Color(selRed, selGreen, selBlue));
		chosenColorCanvas.repaint();
		redLabel.setText("Red component: " + selRed);
		greenLabel.setText("Green component: " + selGreen);
		blueLabel.setText("Blue component: " + selBlue);
	}
	
	public boolean handleEvent(Event event)
	{
		switch (event.id) 
		{
          case Event.SCROLL_LINE_UP:
          case Event.SCROLL_LINE_DOWN:
          case Event.SCROLL_PAGE_UP:
          case Event.SCROLL_PAGE_DOWN:
          case Event.SCROLL_ABSOLUTE:
			if (event.target == redScroll || event.target == greenScroll)
			{
				redGreenCanvas.setWindow(redScroll.getValue(), greenScroll.getValue());
				
				return true;
			}
			else if (event.target == blueScroll)
			{
				redGreenCanvas.setBlue(blueScroll.getValue());
				
				return true;
			}
		}
		return super.handleEvent(event);
	}
}

/*
		Name:		Chris Johnson
					johnson@dcs.gla.ac.uk
		
		Last modified:	27/10/98
		
		Description:	Part of an applet to illustrate the use of scroll bars to
					mix proportyions of RGB colors.    Based on a program in
					G.W. Rouse's An Introduction to Data Structures and
					Algorithms with Java, Prentice Hall, Hemel Hemstead, 1998.
					pp 120-126.

*/

class ScrollCanvas extends Canvas
{

	private int startRed, startGreen, blue;
	private int selRed, selGreen;
	private ColorChooser parent;
	
	ScrollCanvas (ColorChooser owner)
	{
		
		super();
		parent = owner;
		startRed = startGreen = blue = 0;
		selRed = selGreen = 0;
	}


	public void setWindow(int offsetRed, int offsetGreen)
	{
		startRed = offsetRed;
		startGreen = offsetGreen;
		repaint();
	}

	public void setBlue(int offsetBlue)
	{
		blue = offsetBlue;
		repaint();
	}

	public int getRed()
	{
		return selRed;
	}
	
		public int getBlue()
	{
		return blue;
	}
	
		public int getGreen()
	{
		return selGreen;
	}

	public boolean mouseDown(Event event, int x, int y)
	{
		selRed = y + startRed;
		selGreen = x + startGreen;
		parent.updateSelectedColor(selRed, selGreen, blue);
		return true;
	}

	public void paint(Graphics canvasG)
	{
		for (int redPixel = 0; redPixel < 128; ++redPixel)
			for (int greenPixel = 0; greenPixel < 128; ++greenPixel)
			{
				canvasG.setColor(new Color(redPixel + startRed, greenPixel + startGreen, blue));
				canvasG.drawRect(greenPixel, redPixel, 1, 1);
			}
	}

}

/*
		Name:		Chris Johnson
					johnson@dcs.gla.ac.uk
		
		Last modified:	27/10/98
		
		Description:	Part of an applet to illustrate the use of scroll bars to
					mix proportyions of RGB colors.    Based on a program in
					G.W. Rouse's An Introduction to Data Structures and
					Algorithms with Java, Prentice Hall, Hemel Hemstead, 1998.
					pp 120-126.

*/


class ColorCanvas extends Canvas
{
	
	ColorCanvas()
	{
		super();
		setBackground(Color.black);
	}
	
}