package aima.core.util.math.geom.shapes;
/**
* This class implements a ray in a two-dimensional Cartesian plot.<br/>
* A ray is represented by a {@link Point2D} and a directional {@link Vector2D}.
*
* @author Arno von Borries
* @author Jan Phillip Kretzschmar
* @author Andreas Walscheid
*
*/
public final class Ray2D {
private final Point2D start;
private final Vector2D direction;
/**
* @param start the initial point from that the ray originates.
* @param direction the direction in which the ray beams.
*/
public Ray2D(Point2D start, Vector2D direction) {
this.start = start;
this.direction = direction;
}
/**
* @param startX the X coordinate of the initial point from which the ray originates.
* @param startY the Y coordinate of the initial point from which the ray originates.
* @param endX the X coordinate of any point on the ray that is different from the start.
* @param endY the Y coordinate of any point on the ray that is different from the start.
*/
public Ray2D(double startX, double startY, double endX, double endY) {
this.start = new Point2D(startX, startY);
this.direction = new Vector2D(endX - startX, endY - startY);
}
/**
* @return the origin of the ray.
*/
public Point2D getStart() {
return start;
}
/**
* @return the direction of the ray.
*/
public Vector2D getDirection() {
return direction;
}
/**
* Calculates a transformation matrix onto the ray.
*
* @param matrix the {@link TransformMatrix2D} that gets calculated into this ray.
* @return the transformed ray.
*/
public Ray2D transform(TransformMatrix2D matrix) {
Point2D startNew = matrix.multiply(start);
Vector2D directionNew = startNew.vec(matrix.multiply(start.add(direction)));
return new Ray2D(startNew,directionNew);
}
}