// Draw a sine curve in a box
// extra support to have the box change its size in a sinusoidal pattern
// also draws in a funky way - rows of dots

import java.lang.Math;
import java.lang.Object;
import java.awt.*;

public class SinBox extends Object {
  double a, p, ph;			     // amplitude, period, phase

  public double sizePhase = .75;		  // 0..1
  public double sizeSpeed;

  int overlaps, overlapSpacing;
  int numPoints = 50;

  Dimension maxSize;
  Point center;
  public Rectangle box;
  
  public SinBox(int x, int y, double phase, double speed) {
    a = 1.0;
    p = 4.0;
    ph = phase;
    overlaps = 5; overlapSpacing = 4;
    sizeSpeed = speed;

    center = new Point(x, y);
    maxSize = new Dimension(600, 200);
    box = new Rectangle();
    updateCurve();
  }

  // takes a number between 0 and 1.
  public void setSize(double size) {
    box.width = (int)(maxSize.width * size);
    box.height = (int)(maxSize.height * size);
    box.x = center.x - box.width / 2;
    box.y = center.y - box.height / 2;
  }
    
  public void updateCurve() {
    ph += 0.5;
    sizePhase += sizeSpeed;
    double theta = (sizePhase * 2 * Math.PI);
    setSize((1 + Math.sin(theta)) / 2);
  }

  public boolean nearMaximum() {
    return (maxSize.height - box.height) <  maxSize.height / 5;
  }
  
  public void render(Graphics g) {
    g.setColor(Color.black);

    int screenX, screenY;
    double x, y;
    int xshift;

    int i;
    for (i = 0; i < numPoints; i++) {
      x = i / (double)numPoints;
      y = a * Math.sin(x * 2 * Math.PI * p + ph);
      screenX = (int)(x * box.width + box.x);
      screenY = (int)(((y + 1) / 2) * box.height + box.y);
      for (xshift = -overlaps*overlapSpacing/2;
	   xshift < overlaps*overlapSpacing/2;
	   xshift += overlapSpacing)
	g.fillRect(screenX - xshift - 1, screenY - 1, 3, 3);
    }	
  }
}