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package seng302.Model;
import seng302.GPSCoordinate;
/**
* A TrackPoint is a point plotted to display the track a
* {@link seng302.Model.Boat Boat} has travelled in a race. <br>
* TrackPoints are displayed on a
* {@link seng302.Model.ResizableRaceCanvas ResizableRaceCanvas}, via the
* {@link seng302.Controllers.RaceController RaceController}. <br>
* Track points can be made visible or hidden via the RaceController's
* {@link seng302.Model.Annotations Annotations}.
*/
public class TrackPoint {
private final GPSCoordinate coordinate;
private final long timeAdded;
private final long expiry;
private final double minAlpha;
/**
* Creates a new track point with fixed GPS coordinates and time, to reach minimum opacity on expiry.
*
* @param coordinate position of point on physical race map
* @param timeAdded system clock at time of addition
* @param expiry time to minimum opacity after added
*/
public TrackPoint(GPSCoordinate coordinate, long timeAdded, long expiry) {
this.coordinate = coordinate;
this.timeAdded = timeAdded;
this.expiry = expiry;
this.minAlpha = 0.1;
}
/**
* Gets the position of the point on physical race map.
*
* @return GPS coordinate of point
*/
public GPSCoordinate getCoordinate() {
return coordinate;
}
/**
* Gets opacity of point scaled by age in proportion to expiry, between 1 and minimum opacity inclusive.
*
* @return greater of minimum opacity and scaled opacity
*/
public double getAlpha() {
return Double.max(minAlpha, 1.0 - (double) (System.currentTimeMillis() - timeAdded) / expiry);
}
/**
* Gets time point was added to track.
*
* @return system clock at time of addition
*/
public long getTimeAdded() {
return timeAdded;
}
}