/***
 * 
 * Copyright (C) 2008 Alessandro La Rosa
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * Contact: alessandro.larosa@gmail.com
 *
 * Author: Alessandro La Rosa
 */

import javax.microedition.lcdui.Canvas;
import javax.microedition.lcdui.Display;
import javax.microedition.lcdui.Graphics;

public class CanvasSlideFx extends Canvas implements Runnable
{
	// time related properties
	long startTime = 0;
	long duration = 0;
	
	// current state of the transition
	boolean running = false;
	
	// direction of sliding
	int direction = LEFT;
	
	// the previous and next Canvas instances
	FxBaseCanvas fromCanvas = null;
	FxBaseCanvas toCanvas = null;
	
	// the current Display object
	Display display = null;
	
	// properties used to correctly place the 2 Canvas
	int deltaX = 0;
	int deltaY = 0;
	
	public CanvasSlideFx(Display display, FxBaseCanvas toCanvas, int direction, long duration)
	{
		this.display = display;
		this.fromCanvas = (FxBaseCanvas)display.getCurrent();
		this.toCanvas = toCanvas;
		this.direction = direction;
		this.duration = duration;
		
		switch(direction)
		{
		case UP:
			deltaY = - getHeight(); break;
		case RIGHT:
			deltaX = getWidth(); break;
		case DOWN:
			deltaY = getHeight(); break;
		case LEFT:
			deltaX = - getWidth(); break;
		}
	}
	void startTransition()
	{
		this.startTime = System.currentTimeMillis();
		
		running = true;
		
		new Thread(this).start();
	}
	
	protected void paint(Graphics g)
	{
		if(!running)
			startTransition();
		
		long diff = System.currentTimeMillis() - startTime;
		
		if(diff > duration)
		{
			running = false;
			
			diff = duration;
		}
		
		int perc = (int)(100 * diff / duration);
		
		int dx = deltaX * perc / 100;
		int dy = deltaY * perc / 100;
		
		g.translate(dx, dy);
		
		fromCanvas.paint(g);
		
		g.translate(- deltaX, - deltaY);
		
		toCanvas.paint(g);
		
		g.translate(deltaX - dx, deltaY - dy);
	}
	public void run()
	{
		try
		{
			while(running)
			{
				repaint();
				
				synchronized(this)
				{
					wait(50L);
				}
			}
		}
		catch(Exception e)
		{
			e.printStackTrace();
		}
		display.setCurrent(toCanvas);
	}
}