Open agudbrand opened 5 years ago
Elteoremadebeethoven
commented
5 years ago The code are in "old_proyects / eoc / chapter_1.py" in the line 2122: AreaUnderParabola in the method move_right_point_to, but probably you will not be able to compile them because the version of manim that he used is very old, I recommend you use this version or an earlier one (this version works with Python 2):
https://github.com/3b1b/manim/tree/e4d44bf2bfdd1343da75041b215c9675b8018a79
Elteoremadebeethoven
commented
5 years ago This will work for the the version:
https://github.com/3b1b/manim/tree/3b088b12843b7a4459fe71eba96b70edafb7aa78
class AreaUnderParabola(GraphScene):
CONFIG = {
"x_max" : 4,
"x_labeled_nums" : list(range(-1, 5)),
"y_min" : 0,
"y_max" : 15,
"y_tick_frequency" : 2.5,
"y_labeled_nums" : list(range(5, 20, 5)),
"n_rect_iterations" : 6,
"default_right_x" : 3,
"func" : lambda x : x**2,
"graph_label_tex" : "x^2",
"graph_label_x_val" : 3.8,
}
def construct(self):
self.setup_axes()
self.show_graph()
self.show_area()
self.ask_about_area()
self.show_confusion()
self.show_variable_endpoint()
self.name_integral()
def show_graph(self):
graph = self.get_graph(self.func)
graph_label = self.get_graph_label(
graph, self.graph_label_tex,
direction = LEFT,
x_val = self.graph_label_x_val,
)
self.play(ShowCreation(graph))
self.play(Write(graph_label))
self.wait()
self.graph = graph
self.graph_label = graph_label
def show_area(self):
dx_list = [0.25/(2**n) for n in range(self.n_rect_iterations)]
rect_lists = [
self.get_riemann_rectangles(
self.graph,
x_min = 0,
x_max = self.default_right_x,
dx = dx,
stroke_width = 4*dx,
)
for dx in dx_list
]
rects = rect_lists[0]
foreground_mobjects = [self.axes, self.graph]
self.play(
DrawBorderThenFill(
rects,
run_time = 2,
rate_func = smooth,
submobject_mode = "lagged_start",
),
*list(map(Animation, foreground_mobjects))
)
self.wait()
for new_rects in rect_lists[1:]:
self.play(
Transform(
rects, new_rects,
submobject_mode = "lagged_start",
),
*list(map(Animation, foreground_mobjects))
)
self.wait()
self.rects = rects
self.dx = dx_list[-1]
self.foreground_mobjects = foreground_mobjects
def ask_about_area(self):
rects = self.rects
question = TextMobject("Area?")
question.move_to(rects.get_top(), DOWN)
mid_rect = rects[int(2*len(rects)/3)]
arrow = Arrow(question.get_bottom(), mid_rect.get_center())
v_lines = VGroup(*[
DashedLine(
FRAME_HEIGHT*UP, ORIGIN,
color = RED
).move_to(self.coords_to_point(x, 0), DOWN)
for x in (0, self.default_right_x)
])
self.play(
Write(question),
ShowCreation(arrow)
)
self.wait()
self.play(ShowCreation(v_lines, run_time = 2))
self.wait()
self.foreground_mobjects += [question, arrow]
self.question = question
self.question_arrow = arrow
self.v_lines = v_lines
def show_confusion(self):
morty = Mortimer()
morty.to_corner(DOWN+RIGHT)
self.play(FadeIn(morty))
self.play(
morty.change_mode, "confused",
morty.look_at, self.question,
)
self.play(morty.look_at, self.rects.get_bottom())
self.play(Blink(morty))
self.play(morty.look_at, self.question)
self.wait()
self.play(Blink(morty))
self.play(FadeOut(morty))
def show_variable_endpoint(self):
triangle = RegularPolygon(
n = 3,
start_angle = np.pi/2,
stroke_width = 0,
fill_color = WHITE,
fill_opacity = 1,
)
triangle.set_height(0.25)
triangle.move_to(self.v_lines[1].get_bottom(), UP)
x_label = TexMobject("x")
x_label.next_to(triangle, DOWN)
self.right_point_slider = VGroup(triangle, x_label)
A_func = TexMobject("A(x)")
A_func.move_to(self.question, DOWN)
self.play(FadeOut(self.x_axis.numbers))
self.x_axis.remove(*self.x_axis.numbers)
self.foreground_mobjects.remove(self.y_axis)
self.foreground_mobjects.remove(self.x_axis[1])
self.play(DrawBorderThenFill(self.right_point_slider))
self.move_right_point_to(2)
self.wait()
self.move_right_point_to(self.default_right_x)
self.wait()
self.play(ReplacementTransform(self.question, A_func))
self.wait()
self.A_func = A_func
def name_integral(self):
f_tex = "$%s$"%self.graph_label_tex
words = TextMobject("``Integral'' of ", f_tex)
words.set_color_by_tex(f_tex, self.graph_label.get_color())
brace = Brace(self.A_func, UP)
words.next_to(brace, UP)
self.play(
Write(words),
GrowFromCenter(brace)
)
self.wait()
for x in 4, 2, self.default_right_x:
self.move_right_point_to(x, run_time = 2)
self.integral_words_group = VGroup(brace, words)
####
def move_right_point_to(self, target_x, **kwargs):
v_line = self.v_lines[1]
slider = self.right_point_slider
rects = self.rects
curr_x = self.x_axis.point_to_number(v_line.get_bottom())
group = VGroup(rects, v_line, slider)
def update_group(group, alpha):
rects, v_line, slider = group
new_x = interpolate(curr_x, target_x, alpha)
new_rects = self.get_riemann_rectangles(
self.graph,
x_min = 0,
x_max = new_x,
dx = self.dx*new_x/3.0,
stroke_width = rects[0].get_stroke_width(),
)
point = self.coords_to_point(new_x, 0)
v_line.move_to(point, DOWN)
slider.move_to(point, UP)
Transform(rects, new_rects).update(1)
return VGroup(rects, v_line, slider)
self.play(
UpdateFromAlphaFunc(
group, update_group,
**kwargs
),
*list(map(Animation, self.foreground_mobjects))
)Manim is going through an update process, so many of its functions are not longer as they were before and therefore should be rewritten. The version: https://github.com/3b1b/manim/tree/3b088b12843b7a4459fe71eba96b70edafb7aa78 Is the most stable.
The title is very vague but I can't think of the right way to phrase it. My issue is that I have an area under a graph and I would like to animate the upper end of the interval to move back and forth as to make the area move back and forth. What I mean is how Grant did in Essence of Calculus, Chapter One, https://youtu.be/WUvTyaaNkzM?t=634 like this. How do I update the end of the interval to move the way he does? I have no code to give, apologies, but I can't figure out how I would do it.
I tried figuring out how he did it in the old eoc project file, but I couldn't.