Class Circle

src/org/opensourcephysics/display/Circle.java:19–146

A Drawable circle that uses awt drawing. @author Wolfgang Christian @version 1.0

 * @version 1.0
 */
public class Circle implements Drawable {
  public Color color = Color.red; // the drawing color
  public int pixRadius = 6;
  protected double x = 0;
  protected double y = 0;

  /**
   * Constructs a fixed radius circle at the origin.
   */
  public Circle() {
    this(0, 0);
  }

  /**
   * Constructs a fixed radius circle at the given coordinates.
   *
   * The default radius is 6 pixels.
   *
   * @param _x
   * @param _y
   */
  public Circle(double _x, double _y) {
    x = _x;
    y = _y;
  }

  /**
   * Constructs a fixed radius circle at the given coordinates with the given radius.
   *
   * The radius is given in pixels.
   *
   * @param _x
   * @param _y
   * @param _r
   */
  public Circle(double _x, double _y, int _r) {
    x = _x;
    y = _y;
    pixRadius = _r;
  }

  /**
   * Draws the circle.
   *
   * @param panel
   * @param g
   */
  @Override
public void draw(DrawingPanel panel, Graphics g) {
    int xpix = panel.xToPix(x)-pixRadius;
    int ypix = panel.yToPix(y)-pixRadius;
    g.setColor(color);
    g.fillOval(xpix, ypix, 2*pixRadius, 2*pixRadius); // draw the circle onto the screen
  }

  /**
   * Gets the x coordinate.
   *