public double slope() {
double x1 = c1.x();
double x2 = c2.x();
double y1 = c1.y();
double y2 = c2.y();
return (y2 - y1) / (x2 - x1);
}
public XY get(double fractionAlongLine) {
double deltaX = c2.x() - c1.x();
double deltaY = c2.y() - c1.y();
double deltaZ = c2.z() - c1.z();
double newX = c1.x() + fractionAlongLine * deltaX;
double newY = c1.y() + fractionAlongLine * deltaY;
double newZ = c1.z() + fractionAlongLine * deltaZ;
return new XY(newX, newY, newZ);
}
public static double interpolateY(Line line, double xValue) {
// if point1.x() == point2.x(), is a vertical line, will produce an infinity value
XY point1 = line.getStart();
XY point2 = line.getEnd();
double x1 = point1.x();
double x2 = point2.x();
double y1 = point1.y();
double y2 = point2.y();
return (y2 - y1) / (x2 - x1) * (xValue - x1) + y1;
}
double distance(XY a, XY b) {
a = new XY(a);
a.subtract(b);
return a.length();
}
public String toString() {
return "Line from " + c1.toString() + " to " + c2.toString();
}
public Line(XY start, XY end) {
c1 = start;
c2 = end;
hasZ = start.hasZ() && end.hasZ();
}
public Vector toVector() {
double deltaX = c2.x() - c1.x();
double deltaY = c2.y() - c1.y();
double deltaZ = c2.z() - c1.z();
return new Vector(deltaX, deltaY, deltaZ);
}
public XY getEnd() {
if (hasZ) return c2;
else return c2.ignoreZ();
}
public XY getStart() {
if (hasZ) return c1;
else return c1.ignoreZ();
}
private void checkPoint(XY actual, XY expected) {
assertThat(actual.getX()).isEqualTo(expected.getX(), offset(0.000001));
assertThat(actual.getY()).isEqualTo(expected.getY(), offset(0.000001));
}
/** Constructs a circle with the specified properties */
public Circle(XY p, double radius) {
this(p.x(), p.y(), radius);
}
