/*
 * @(#)GradAnim.java	1.7 98/06/29
 *
 * Copyright 1998 by Sun Microsystems, Inc.,
 * 901 San Antonio Road, Palo Alto, California, 94303, U.S.A.
 * All rights reserved.
 *
 * This software is the confidential and proprietary information
 * of Sun Microsystems, Inc. ("Confidential Information").  You
 * shall not disclose such Confidential Information and shall use
 * it only in accordance with the terms of the license agreement
 * you entered into with Sun.
 */

package demos.Paint;

import java.awt.*;
import java.awt.event.*;
import J2DCanvas;


/**
 * GradientPaint animation.
 */
public class GradAnim extends J2DCanvas {

    private animval x1, y1, x2, y2;
    private int hue = (int) (Math.random() * MAX_HUE);
    static final int MAX_HUE = 256 * 6;


    public GradAnim() {
	setBackground(Color.white);
	x1 = new animval(0, 300, 2, 10);
	y1 = new animval(0, 300, 2, 10);
	x2 = new animval(0, 300, 2, 10);
	y2 = new animval(0, 300, 2, 10);
	runnable = true;
    }


    public static Color getColor(int hue) {
	int leg = (hue / 256) % 6;
	int step = (hue % 256) * 2;
	int falling = (step < 256) ? 255 : 511 - step;
	int rising = (step < 256) ? step : 255;
	int r, g, b;
	r = g = b = 0;
	switch (leg) {
	case 0:
	    r = 255;
	    break;
	case 1:
	    r = falling;
	    g = rising;
	    break;
	case 2:
	    g = 255;
	    break;
	case 3:
	    g = falling;
	    b = rising;
	    break;
	case 4:
	    b = 255;
	    break;
	case 5:
	    b = falling;
	    r = rising;
	    break;
	}
	return new Color(r, g, b);
    }


    public void drawDemo(Graphics2D g2) {

	if (newBufferedImage) {
	    x1.newlimits(0, w);
	    y1.newlimits(0, h);
	    x2.newlimits(0, w);
	    y2.newlimits(0, h);
	}
        Color c1 = getColor(hue);
        Color c2 = getColor(hue + 256 * 3);
        GradientPaint gp = new GradientPaint(x1.getFlt(), y1.getFlt(), c1,
					 x2.getFlt(), y2.getFlt(), c2,
					 true);
        g2.setPaint(gp);
        g2.fillRect(0, 0, w, h);
        g2.setColor(Color.yellow);
        g2.drawLine(x1.getInt(), y1.getInt(), x2.getInt(), y2.getInt());
        x1.anim(); y1.anim();
        x2.anim(); y2.anim();
	hue = (hue + (int) (Math.random() * 10)) % MAX_HUE;
    }


    public class animval {
	float curval;
	float lowval;
	float highval;
	float currate;
	float lowrate;
	float highrate;

	public animval(int lowval, int highval,
		       int lowrate, int highrate) {
	    this.lowval = lowval;
	    this.highval = highval;
	    this.lowrate = lowrate;
	    this.highrate = highrate;
	    this.curval = randval(lowval, highval);
	    this.currate = randval(lowrate, highrate);
	}

	public float randval(float low, float high) {
	    return (float) (low + Math.random() * (high - low));
	}

	public float getFlt() {
	    return curval;
	}

	public int getInt() {
	    return (int) curval;
	}

	public void anim() {
	    curval += currate;
	    clip();
	}

	public void clip() {
	    if (curval > highval) {
		curval = highval - (curval - highval);
		if (curval < lowval) {
		    curval = highval;
		}
		currate = - randval(lowrate, highrate);
	    } else if (curval < lowval) {
		curval = lowval + (lowval - curval);
		if (curval > highval) {
		    curval = lowval;
		}
		currate = randval(lowrate, highrate);
	    }
	}

	public void newlimits(int lowval, int highval) {
	    this.lowval = lowval;
	    this.highval = highval;
	    clip();
	}
    }


    public static void main(String s[]) {
	final GradAnim demo = new GradAnim();
	WindowListener l = new WindowAdapter() {
	    public void windowClosing(WindowEvent e) {System.exit(0);}
	    public void windowDeiconified(WindowEvent e) { demo.start(); }
	    public void windowIconified(WindowEvent e) { demo.stop(); }
	};
	Frame f = new Frame("Java2D Demo - GradAnim");
	f.addWindowListener(l);
	f.add("Center", demo);
	f.pack();
	f.setSize(new Dimension(400,300));
	f.show();
	demo.start();
    }
}