// Oval.java
// Class for an oval.

// Written by THC for CS 5 Lab Assignment 3.

import java.awt.*;

public class Oval extends Shape {
  private int left, top; // left and top of Oval
  private int width, height; // Oval's height and width

  // Constructor just saves the parameters in the instance variables.
  public Oval(int left, int top, int width, int height, Color color) {
    super(color);
    this.left = left;
    this.top = top;
    this.width = width;
    this.height = height;
  }

  // Have the Oval draw itself.
  public void drawShape(Graphics page) {
    page.fillOval(left, top, width, height);
  }

  // Return true if the Oval contains Point p, false otherwise.
  public boolean containsPoint(Point p) {
    return pointInOval(p, left, top, width, height);
  }

  // Helper method that returns whether Point p is in an Oval with the given
  // top left corner and size.
  private static boolean pointInOval(Point p, int left, int top, int width,
      int height) {
    double a = width / 2.0; // half of the width
    double b = height / 2.0; // half of the height
    double centerx = left + a; // x-coord of the center
    double centery = top + b; // y-coord of the center
    double x = p.x - centerx; // horizontal distance between p and center
    double y = p.y - centery; // vertical distance between p and center

    // Now we just apply the standard geometry formula.
    // (See CRC, 29th edition, p. 178.)
    return Math.pow(x / a, 2) + Math.pow(y / b, 2) <= 1;
  }

  // Have the Oval move itself.
  public void move(int deltaX, int deltaY) {
    left += deltaX;
    top += deltaY;
  }

  // Return the Oval's center.
  public Point getCenter() {
    return new Point(left + (width / 2), top + (height / 2));
  }
}