def position_endpoints_on(self, start, end):
curr_vect = self.points[-1] - self.points[0]
if np.all(curr_vect == 0):
raise Exception("Cannot position endpoints of closed loop")
target_vect = end - start
self.scale(get_norm(target_vect) / get_norm(curr_vect))
self.rotate(angle_of_vector(target_vect) - angle_of_vector(curr_vect))
self.shift(start - self.points[0])
return self
def get_vector_movement(self, func):
for v in self.moving_vectors:
v.target = Vector(func(v.get_end()), color=v.get_color())
norm = get_norm(v.target.get_end())
if norm < 0.1:
v.target.get_tip().scale_in_place(norm)
return self.get_piece_movement(self.moving_vectors)
def get_vector_label(self,
vector,
label,
at_tip=False,
direction="left",
rotate=False,
color=None,
label_scale_factor=VECTOR_LABEL_SCALE_FACTOR):
if not isinstance(label, TexMobject):
if len(label) == 1:
label = "\\vec{\\textbf{%s}}" % label
label = TexMobject(label)
if color is None:
color = vector.get_color()
label.set_color(color)
label.scale(label_scale_factor)
label.add_background_rectangle()
if at_tip:
vect = vector.get_vector()
vect /= get_norm(vect)
label.next_to(vector.get_end(), vect, buff=SMALL_BUFF)
else:
angle = vector.get_angle()
if not rotate:
label.rotate(-angle, about_point=ORIGIN)
if direction is "left":
label.shift(-label.get_bottom() + 0.1 * UP)
else:
label.shift(-label.get_top() + 0.1 * DOWN)
label.rotate(angle, about_point=ORIGIN)
label.shift((vector.get_end() - vector.get_start()) / 2)
return label
def look(self, direction):
norm = get_norm(direction)
if norm == 0:
return
direction /= norm
self.purposeful_looking_direction = direction
for pupil, eye in zip(self.pupils.split(), self.eyes.split()):
c = eye.get_center()
right = eye.get_right() - c
up = eye.get_top() - c
vect = direction[0] * right + direction[1] * up
v_norm = get_norm(vect)
p_radius = 0.5 * pupil.get_width()
vect *= (v_norm - 0.75 * p_radius) / v_norm
pupil.move_to(c + vect)
self.pupils[1].align_to(self.pupils[0], DOWN)
return self
def __init__(self, car, target_point, **kwargs):
assert isinstance(car, Car)
ApplyMethod.__init__(self, car.move_to, target_point, **kwargs)
displacement = self.target_mobject.get_right() - self.starting_mobject.get_right()
distance = get_norm(displacement)
if not self.moving_forward:
distance *= -1
tire_radius = car.get_tires()[0].get_width() / 2
self.total_tire_radians = -distance / tire_radius
def path_along_arc(arc_angle, axis=OUT):
"""
If vect is vector from start to end, [vect[:,1], -vect[:,0]] is
perpendicular to vect in the left direction.
"""
if abs(arc_angle) < STRAIGHT_PATH_THRESHOLD:
return straight_path
if get_norm(axis) == 0:
axis = OUT
unit_axis = axis / get_norm(axis)
def path(start_points, end_points, alpha):
vects = end_points - start_points
centers = start_points + 0.5 * vects
if arc_angle != np.pi:
centers += np.cross(unit_axis, vects / 2.0) / np.tan(arc_angle / 2)
rot_matrix = rotation_matrix(alpha * arc_angle, unit_axis)
return centers + np.dot(start_points - centers, rot_matrix.T)
return path
def add_line(self, start, end, color=None):
start, end = list(map(np.array, [start, end]))
length = get_norm(end - start)
if length == 0:
points = [start]
else:
epsilon = self.epsilon / length
points = [
interpolate(start, end, t)
for t in np.arange(0, 1, epsilon)
]
self.add_points(points, color=color)
def set_submobject_colors_by_radial_gradient(self,
center=None,
radius=1,
inner_color=WHITE,
outer_color=BLACK):
if center is None:
center = self.get_center()
for mob in self.family_members_with_points():
t = get_norm(mob.get_center() - center) / radius
t = min(t, 1)
mob_color = interpolate_color(inner_color, outer_color, t)
mob.set_color(mob_color, family=False)
return self
def align_to(self, mobject_or_point, direction=ORIGIN, alignment_vect=UP):
"""
Examples:
mob1.align_to(mob2, UP) moves mob1 vertically so that its
top edge lines ups with mob2's top edge.
mob1.align_to(mob2, alignment_vector = RIGHT) moves mob1
horizontally so that it's center is directly above/below
the center of mob2
"""
if isinstance(mobject_or_point, Mobject):
mob = mobject_or_point
target_point = mob.get_critical_point(direction)
else:
target_point = mobject_or_point
direction_norm = get_norm(direction)
if direction_norm > 0:
alignment_vect = np.array(direction) / direction_norm
reference_point = self.get_critical_point(direction)
else:
reference_point = self.get_center()
diff = target_point - reference_point
self.shift(alignment_vect * np.dot(diff, alignment_vect))
return self
def func(point):
centered = point + vect
return radius * centered / get_norm(centered)
def get_direction(self):
vect = self.get_tip() - self.get_center()
return vect / get_norm(vect)
def is_closed(points):
return get_norm(points[0] - points[-1]) < CLOSED_THRESHOLD