def __init__(self, mobject_or_point, **kwargs): digest_config(self, kwargs) big_dot = Dot( radius=FRAME_X_RADIUS + FRAME_Y_RADIUS, stroke_width=0, fill_color=self.color, fill_opacity=0, ) little_dot = Dot(radius=0) little_dot.set_fill(self.color, opacity=self.opacity) little_dot.move_to(mobject_or_point) Transform.__init__(self, big_dot, little_dot, **kwargs)
def __init__(self, mobject_or_point, **kwargs): digest_config(self, kwargs) big_dot = Dot( radius=FRAME_X_RADIUS + FRAME_Y_RADIUS, stroke_width=0, fill_color=self.color, fill_opacity=0, ) little_dot = Dot(radius=0) little_dot.set_fill(self.color, opacity=self.opacity) little_dot.move_to(mobject_or_point) Transform.__init__(self, big_dot, little_dot, **kwargs)
def construct(self): # Setup axes_group = self.axes_group title_pq = self.title_pq walk_p = self.walk_p parts_p = self.parts_p r_arrow = self.r_arrow self.add(axes_group, title_pq, walk_p, r_arrow) walk_p_copy = walk_p.copy() # P_4 -> Q_4 steps_pq = VGroup(*[ TextMobject(text) for text in [ "1. 第一步是沿着正方向走的", "2. 找到第一次到达最大值的时刻", "3. 在这个时刻上进行分割", "4. 将第一段水平翻转", "5. 拼接两个片段" ] ]) for step in steps_pq: step.set_color(YELLOW) step.add_background_rectangle() step1_pq, step2_pq, step3_pq, step4_pq, step5_pq = steps_pq # 1. Check the first step of the walk step1_circle = Circle(color=YELLOW) first_arrow = walk_p.get_arrow_by_number(0) step1_circle.surround(first_arrow) step1_pq.next_to(step1_circle, RIGHT + DOWN) self.play(ShowCreation(step1_circle), Write(step1_pq), run_time=1) self.wait(1.5) self.play(FadeOut(step1_circle), FadeOut(step1_pq)) # 2. Find the first time it reaches the maximum peak = walk_p.get_arrow_end_point(3) horiz_line = DashedLine(2.5 * LEFT, 2.5 * RIGHT, color=YELLOW) horiz_line.move_to(peak) dot = Dot(color=YELLOW) dot.move_to(peak) step2_pq.next_to(horiz_line, UP) self.play(ShowCreation(horiz_line), DrawBorderThenFill(dot), Write(step2_pq), run_time=1) self.wait(1.5) self.play(FadeOut(horiz_line), FadeOut(step2_pq)) # 3. Split vert_line = DashedLine(2.5 * UP, 2.5 * DOWN, color=YELLOW) vert_line.move_to(peak) step3_pq.next_to(vert_line, DOWN) left_part_p, right_part_p = parts_p self.play(ShowCreation(vert_line), Write(step3_pq), run_time=1) self.play( FadeOut(dot), left_part_p.shift, 0.5 * DOWN + 0.5 * LEFT, right_part_p.shift, DOWN + 0.5 * RIGHT, ) self.wait(1.5) self.play(FadeOut(vert_line), FadeOut(step3_pq)) # 4. Flip the first segment horizontally flip_axis = DashedLine(2 * UP, 2 * DOWN, color=GREY) flip_axis.move_to(left_part_p) step4_pq.next_to(flip_axis, DOWN) self.play( ShowCreation(flip_axis), Write(step4_pq), run_time=1, ) self.play( left_part_p.flip, Animation(flip_axis), ) self.wait(1.5) self.play(FadeOut(step4_pq), FadeOut(flip_axis)) # 5. Put the pieces together step5_pq.move_to(dot) flip_arrow_anims = walk_p.get_flip_arrows_animation(3, color=GREEN) self.play(Write(step5_pq), run_time=1) self.wait(0.5) self.play(flip_arrow_anims, right_part_p.set_color, GREEN) self.wait(0.5) self.play( left_part_p.shift, 1.5 * DOWN + 0.5 * RIGHT, right_part_p.shift, 3 * DOWN + 0.5 * LEFT, Animation(step5_pq), ) self.wait(0.5) self.play(FadeOut(step5_pq)) self.wait(1.5) # Now Reset self.play(FadeOut(walk_p)) self.play(FadeIn(walk_p_copy)) self.wait()