Class HalfLine

numericals.py:318–371

Numerical ray.

class HalfLine(Line):
  """Numerical ray."""

  def __init__(self, tail: Point, head: Point):  # pylint: disable=super-init-not-called
    self.line = Line(tail, head)
    self.coefficients = self.line.coefficients
    self.tail = tail
    self.head = head

  def intersect(self, obj: Union[Line, HalfLine, Circle, HoleCircle]) -> Point:
    if isinstance(obj, (HalfLine, Line)):
      return line_line_intersection(self.line, obj)

    exclude = [self.tail]
    if isinstance(obj, HoleCircle):
      exclude += [obj.hole]

    a, b = line_circle_intersection(self.line, obj)
    if any([a.close(x) for x in exclude]):
      return b
    if any([b.close(x) for x in exclude]):
      return a

    v = self.head - self.tail
    va = a - self.tail
    vb = b - self.tail
    if v.dot(va) > 0:
      return a
    if v.dot(vb) > 0:
      return b
    raise InvalidLineIntersectError()

  def sample_within(self, points: list[Point], n: int = 5) -> list[Point]:
    center = sum(points, Point(0.0, 0.0)) * (1.0 / len(points))
    radius = max([p.distance(center) for p in points])
    if close_enough(center.distance(self.line), radius):
      center = center.foot(self)
    a, b = line_circle_intersection(self, Circle(center.foot(self), radius))

    if (a - self.tail).dot(self.head - self.tail) > 0:
      a, b = self.tail, a
    else:
      a, b = self.tail, b  # pylint: disable=self-assigning-variable

    result = None
    best = -1.0
    for _ in range(n):
      x = a + (b - a) * unif(0.0, 1.0)
      mind = min([x.distance(p) for p in points])
      if mind > best:
        best = mind
        result = x

    return [result]


def _perpendicular_bisector(p1: Point, p2: Point) -> Line: