/******************************************************************************
 * Copyright (C) 2007  Curran Kelleher
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 3
 * of the License, or (at your option) any later version.
 *
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *******************************************************************************/
package sampleCode;

import java.awt.Graphics;
import java.awt.event.KeyAdapter;
import java.awt.event.KeyEvent;

import javax.swing.JApplet;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JSplitPane;
import javax.swing.JTextField;

import mathParser.EvaluationTree;
import mathParser.MathParser;
import mathParser.MathParserException;
import mathParser.Variable;

/**
 * An animated 2D grapher which uses the math parser
 * 
 * @author Curran Kelleher
 * 
 */
@SuppressWarnings("serial")
public class GrapherExample extends JApplet {
	/**
	 * The number of points used to create the graphed curve
	 */
	int numberOfPoints = 300;

	/**
	 * The initial function string
	 */
	String initialFunction = "y = sin(x*sin(t/10)+t)*x";

	/**
	 * The parser used to parse the function
	 */
	MathParser parser = new MathParser();

	/**
	 * The function which assigns y from the current value of x
	 */
	EvaluationTree function = parser.parse(initialFunction);

	public void init() {
		// create the text field
		final JTextField textField = new JTextField(initialFunction);
		textField.addKeyListener(new KeyAdapter() {
			public void keyPressed(KeyEvent e) {
				if (e.getKeyChar() == '\n')
					try {
						function = parser.parse(textField.getText());
					} catch (MathParserException x) {
						JOptionPane.showMessageDialog(null, x.message, "Parse Error", JOptionPane.ERROR_MESSAGE);
					}
			}
		});

		// create the graphing panel
		final JPanel panel = new JPanel() {
			Variable xVariable = parser.getVariable("x");
			Variable yVariable = parser.getVariable("y");

			public void paint(Graphics g) {
				int width = getWidth();
				int height = getHeight();
				g.clearRect(0, 0, width, height);
				int currentYPixel, previousYPixel = 0;
				for (int xPixel = 0; xPixel < width; xPixel++) {
					// translate from [0,width] to [-10,10] and
					// put the value in the x variable
					xVariable.value = ((double) xPixel / width) * 20 - 10;

					// calculate y by evaluating the function
					function.evaluate();

					// translate from [-10,10] to [0,height]
					currentYPixel = (int) ((yVariable.value + 10) / 20 * height);

					// draw the line if we have calculated the previous y
					if (xPixel != 0)
						g.drawLine(xPixel - 1, previousYPixel, xPixel,
								currentYPixel);

					// make the previous y the current y
					previousYPixel = currentYPixel;
				}
			}
		};

		// add the text field and panel to the applet using a split pane
		JSplitPane splitPane = new JSplitPane(JSplitPane.VERTICAL_SPLIT, textField, panel);
		splitPane.setDividerSize(0);
		add(splitPane);

		// create and start the animation thread
		(new Thread(new Runnable() {
			public void run() {
				Variable tVariable = parser.getVariable("t");
				while (true) {
					tVariable.value += 0.05;
					if (!panel.isPaintingTile())
						panel.repaint();
					try {
						Thread.sleep(5);
					} catch (InterruptedException e) {
						e.printStackTrace();
					}
				}
			}
		})).start();
	}
}

/*
 * CVS Log
 * 
 * $Log: GrapherExample.java,v $
 * Revision 1.2  2007/11/30 01:33:02  curran
 * Added exception handling with error dialogs to the grapher example applet, and made the split pane have no border to it looks nicer
 * Revision 1.1 2007/11/27 23:55:21 curran Created
 * the grapher example applet
 * 
 * 
 */