Class AbstractTrail

src/org/opensourcephysics/display/AbstractTrail.java:20–183

AbstractTrail defines a trail of pixels on the screen. This object is often used to show the path of a moving object. @author Wolfgang Christian @version 1.0

 * @version 1.0
 */
public abstract class AbstractTrail implements Drawable, Measurable {
  public Color color = Color.black; // changing the color is harmless so this can be public
  protected boolean enableMeasure = false;
  protected double xmin = Double.MAX_VALUE, xmax = -Double.MAX_VALUE, ymin = Double.MAX_VALUE, ymax = -Double.MAX_VALUE;
  protected double xmaxLogscale = -Double.MAX_VALUE;
  // the maximum x value in the trail when using a log scale

  protected double ymaxLogscale = -Double.MAX_VALUE;
  // the maximum y value in the trail when using a log scale

  protected double xminLogscale = Double.MAX_VALUE;
  // the minimum x value in the trail when using a log scale

  protected double yminLogscale = Double.MAX_VALUE;
  // the minimum y value in the trail when using a log scale  

  protected int numpts = 0;         // the number of points in the trail
  protected boolean closed = false;
  protected Stroke drawingStroke;

  /**
   * Adds a point to the trail.
   * @param x double
   * @param y double
   */
  public abstract void addPoint(double x, double y);

  /**
   * Closes the path by connecting the first point to the last point.
   * Points cannot be added to a closed path;
   */
  public abstract void closeTrail();

  /**
   * Clears all points from the trail.
   */
  public abstract void clear();

  /**
   * Sets the drawing stroke.
   * @param stroke Stroke
   */
  public void setStroke(Stroke stroke) {
    drawingStroke = stroke;
  }

  /**
   * Sets the the dash line stroke.
   *
   * @param int dashPoint
   * @param int dashLength
   */
  public void setDashedStroke(int dashPoint, int dashLength) {
    if(dashLength==0) {
      drawingStroke = new BasicStroke(dashPoint, 0, 1, 0, null, 0);                     //regular line
    } else {
      drawingStroke = new BasicStroke(dashPoint, 0, 1, 0, new float[] {dashLength}, 0); //dashes
    }