def construct(self):
formula = TexMobject(*([
"{%d \\over %d} \\cdot" % (wallis_numer(n), wallis_denom(n))
for n in range(1, self.n_terms + 1)
] + ["\\cdots"]))
result = TexMobject("=", "{\\pi \\over 2}")
result.scale(2)
pi = result[-1][0]
pi.set_color(YELLOW)
circle = Circle(color=YELLOW)
circle.surround(pi)
question = TexMobject("?", color=YELLOW)
question.scale(2).next_to(circle, RIGHT, buff=0.4)
result_group = VGroup(result, circle, question)
result_group.next_to(formula, DOWN)
group = VGroup(formula, result_group)
group.center().set_width(10)
bg_rect = BackgroundRectangle(group, fill_opacity=0.5, buff=0.2)
random_walks = VGroup(*[
RandomWalk1DArrow(random_walk_string(30), step_size=0.5)
for k in range(self.n_walks)
])
for k, walk in enumerate(random_walks):
walk.shift(random.randrange(-5, 5) * 2 * walk.step_size * UP)
random_walks.center()
text = TextMobject(self.part).scale(3).set_color(YELLOW)
text.to_corner(RIGHT + DOWN)
self.add(random_walks)
self.add(FullScreenFadeRectangle())
self.add(bg_rect, group, text)
def add_background_rectangle(self, color=BLACK, opacity=0.75, **kwargs):
from mobject.shape_matchers import BackgroundRectangle
self.background_rectangle = BackgroundRectangle(
self, color=color,
fill_opacity=opacity,
**kwargs
)
self.add_to_back(self.background_rectangle)
return self
def add_background_rectangle(self):
#TODO, is this the best way to handle
#background rectangles?
self.background_rectangle = BackgroundRectangle(self)
self.submobjects = [
self.background_rectangle,
VGroup(*self.submobjects)
]
return self
def add_background_rectangle(self, color=BLACK, opacity=0.75, **kwargs):
# TODO, this does not behave well when the mobject has points,
# since it gets displayed on top
from mobject.shape_matchers import BackgroundRectangle
self.background_rectangle = BackgroundRectangle(self,
color=color,
fill_opacity=opacity,
**kwargs)
self.add_to_back(self.background_rectangle)
return self
def vector_coordinate_label(vector_mob, integer_labels=True,
n_dim=2, color=WHITE):
vect = np.array(vector_mob.get_end())
if integer_labels:
vect = np.round(vect).astype(int)
vect = vect[:n_dim]
vect = vect.reshape((n_dim, 1))
label = Matrix(vect, add_background_rectangles_to_entries=True)
label.scale(VECTOR_LABEL_SCALE_FACTOR)
shift_dir = np.array(vector_mob.get_end())
if shift_dir[0] >= 0: # Pointing right
shift_dir -= label.get_left() + DEFAULT_MOBJECT_TO_MOBJECT_BUFFER * LEFT
else: # Pointing left
shift_dir -= label.get_right() + DEFAULT_MOBJECT_TO_MOBJECT_BUFFER * RIGHT
label.shift(shift_dir)
label.set_color(color)
label.rect = BackgroundRectangle(label)
label.add_to_back(label.rect)
return label
def add_background_rectangle(self):
self.background_rectangle = BackgroundRectangle(self)
self.add_to_back(self.background_rectangle)