class NumberLineScene(Scene):
def construct(self, **number_line_config):
self.number_line = NumberLine(**number_line_config)
self.displayed_numbers = self.number_line.default_numbers_to_display()
self.number_mobs = self.number_line.get_number_mobjects(
*self.displayed_numbers)
self.add(self.number_line, *self.number_mobs)
def zoom_in_on(self, number, zoom_factor, run_time=2.0):
unit_length_to_spatial_width = self.number_line.unit_length_to_spatial_width * zoom_factor
radius = SPACE_WIDTH / unit_length_to_spatial_width
tick_frequency = 10**(np.floor(np.log10(radius)))
left_tick = tick_frequency * (np.ceil(
(number - radius) / tick_frequency))
new_number_line = NumberLine(
numerical_radius=radius,
unit_length_to_spatial_width=unit_length_to_spatial_width,
tick_frequency=tick_frequency,
leftmost_tick=left_tick,
number_at_center=number)
new_displayed_numbers = new_number_line.default_numbers_to_display()
new_number_mobs = new_number_line.get_number_mobjects(
*new_displayed_numbers)
transforms = []
additional_mobjects = []
squished_new_line = new_number_line.copy()
squished_new_line.scale(1.0 / zoom_factor)
squished_new_line.shift(self.number_line.number_to_point(number))
squished_new_line.points[:, 1] = self.number_line.number_to_point(0)[1]
transforms.append(Transform(squished_new_line, new_number_line))
for mob, num in zip(new_number_mobs, new_displayed_numbers):
point = Point(self.number_line.number_to_point(num))
point.shift(new_number_line.get_vertical_number_offset())
transforms.append(Transform(point, mob))
for mob in self.mobjects:
if mob == self.number_line:
new_mob = mob.copy()
new_mob.shift(-self.number_line.number_to_point(number))
new_mob.stretch(zoom_factor, 0)
transforms.append(Transform(mob, new_mob))
continue
mob_center = mob.get_center()
number_under_center = self.number_line.point_to_number(mob_center)
new_point = new_number_line.number_to_point(number_under_center)
new_point += mob_center[1] * UP
if mob in self.number_mobs:
transforms.append(Transform(mob, Point(new_point)))
else:
transforms.append(
ApplyMethod(mob.shift, new_point - mob_center))
additional_mobjects.append(mob)
line_to_hide_pixelation = Line(self.number_line.get_left(),
self.number_line.get_right(),
color=self.number_line.get_color())
self.add(line_to_hide_pixelation)
self.play(*transforms, run_time=run_time)
self.clear()
self.number_line = new_number_line
self.displayed_numbers = new_displayed_numbers
self.number_mobs = new_number_mobs
self.add(self.number_line, *self.number_mobs)
self.add(*additional_mobjects)
def show_multiplication(self, num, **kwargs):
if "path_func" not in kwargs:
if num > 0:
kwargs["path_func"] = straight_path
else:
kwargs["path_func"] = counterclockwise_path()
self.play(*[ApplyMethod(self.number_line.stretch, num, 0, **kwargs)] +
[
ApplyMethod(mob.shift, (num - 1) * mob.get_center()[0] *
RIGHT, **kwargs) for mob in self.number_mobs
])
