package ch.werner_randelshofer.gui;

/*
Copyright (C) 1999 Werner Randelshofer
werner.randelshofer@mythen.ch
http://www.mythen.ch/w.randelshofer/
    
Permission to use this release of HorizontalSlider is hereby
granted without fee provided that the complete copyright
notice and this permission notice appear in all copies
and in supporting documentation.
*/

import java.awt.Canvas;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Event;
import ch.werner_randelshofer.gui.event.ChangeListener;
import ch.werner_randelshofer.gui.event.ChangeEvent;
import ch.werner_randelshofer.gui.event.EventListenerList;
import ch.werner_randelshofer.gui.model.BoundedRangeModel;
import ch.werner_randelshofer.gui.model.DefaultBoundedRangeModel;

/**
@author	Werner Randelshofer, Staldenmattweg 2, CH-6405 Immensee, Switzerland
@version	1999-02-28	Setter/getter for thumb width added. ComputeThumbPos
						made protected (was private).
<br>history	1999-02-21	Revised.
*/
public class HorizontalSlider
extends Canvas
implements ChangeListener
	{
	private BoundedRangeModel model_;
	private int thumbWidth_ = 11, thumbHeight_ = 11;
	/**
	Last painted position of the thumb.
	*/
	protected int thumbPos_ = -1;
	
	public HorizontalSlider()
		{
		model_ = new DefaultBoundedRangeModel();
		model_.addChangeListener(this);
		}
	
	public void setThumbWidth(int width)
		{ thumbWidth_ = width; }
	public int getThumbWidth()
		{ return thumbWidth_; }
	public void setThumbHeight(int height)
		{ thumbHeight_ = height; }
	public int getThumbHeight()
		{ return thumbHeight_; }
	
	public synchronized void setModel(BoundedRangeModel m)
		{
		if (model_ != null)
			{ model_.removeChangeListener(this); }
		model_ = m == null ? new DefaultBoundedRangeModel() : m;
		if (model_ != null)
			{ model_.addChangeListener(this); }
		repaint();
		}

    public Dimension preferredSize()
		{
        return new Dimension(100, thumbHeight_ + 2);
		}

    public Dimension minimumSize()
		{
        return new Dimension(thumbWidth_ * 2 + 2, thumbHeight_ + 2);
		}

	public void paint(Graphics g)
		{
		int width = size().width - 1;
		int halfThumb = getThumbWidth() / 2;
		int thumbPos = computeThumbPos();
		thumbPos_ = thumbPos;
		g.drawLine(halfThumb,0,width - halfThumb ,0);
		g.drawLine(thumbPos,1,thumbPos + halfThumb,halfThumb + 1);
		g.drawLine(thumbPos + halfThumb,halfThumb + 1,thumbPos - halfThumb,halfThumb + 1);
		g.drawLine(thumbPos - halfThumb,halfThumb + 1,thumbPos,1);
		}

    public boolean mouseDown(Event e, int x, int y)
	    {
		moveThumb(x);
        return true;
		}
    public boolean mouseDrag(Event e, int x, int y)
	    {
        moveThumb(x);
        return true;
		}
    public boolean mouseUp(Event e, int x, int y)
	    {
        moveThumb(x);
        return true;
		}
	protected void moveThumb(int mousePosition)
		{
		int width = size().width;
		int halfThumb = getThumbWidth() / 2;
		if (mousePosition <= halfThumb) { mousePosition = halfThumb + 1; }
		if (mousePosition >= width - halfThumb) { mousePosition = width - halfThumb - 1; }
		float thumbPos = (mousePosition - halfThumb - 1) / (float)(width - (halfThumb * 2 + 2));
		model_.setValue((int)(thumbPos * (model_.getMaximum() - model_.getMinimum())));
		}
	
	protected int computeThumbPos()
		{
		int halfThumb = getThumbWidth() / 2;
		BoundedRangeModel m = model_;
		if (m == null)
			{ return halfThumb; }
		int width = size().width - getThumbWidth()-1;
		float thumbPos = m.getValue() / (float)((m.getMaximum() - m.getMinimum()));
		return (int)(width * thumbPos) + halfThumb;
		}
	
	public void stateChanged(ChangeEvent event)
		{
		if (computeThumbPos() != thumbPos_)
			{ repaint(); }
		}
	}