速率函数¶
一系列速率函数，即动画的速度曲线。请在https://easings.net/找到标准列表。这里是非标准函数的图片
示例：RateFuncExample ¶
from manim import *
class RateFuncExample(Scene):
def construct(self):
x = VGroup()
for k, v in rate_functions.__dict__.items():
if "function" in str(v):
if (
not k.startswith("__")
and not k.startswith("sqrt")
and not k.startswith("bezier")
):
try:
rate_func = v
plot = (
ParametricFunction(
lambda x: [x, rate_func(x), 0],
t_range=[0, 1, .01],
use_smoothing=False,
color=YELLOW,
)
.stretch_to_fit_width(1.5)
.stretch_to_fit_height(1)
)
plot_bg = SurroundingRectangle(plot).set_color(WHITE)
plot_title = (
Text(rate_func.__name__, weight=BOLD)
.scale(0.5)
.next_to(plot_bg, UP, buff=0.1)
)
x.add(VGroup(plot_bg, plot, plot_title))
except: # because functions `not_quite_there`, `function squish_rate_func` are not working.
pass
x.arrange_in_grid(cols=8)
x.height = config.frame_height
x.width = config.frame_width
x.move_to(ORIGIN).scale(0.95)
self.add(x)
class RateFuncExample(Scene):
def construct(self):
x = VGroup()
for k, v in rate_functions.__dict__.items():
if "function" in str(v):
if (
not k.startswith("__")
and not k.startswith("sqrt")
and not k.startswith("bezier")
):
try:
rate_func = v
plot = (
ParametricFunction(
lambda x: [x, rate_func(x), 0],
t_range=[0, 1, .01],
use_smoothing=False,
color=YELLOW,
)
.stretch_to_fit_width(1.5)
.stretch_to_fit_height(1)
)
plot_bg = SurroundingRectangle(plot).set_color(WHITE)
plot_title = (
Text(rate_func.__name__, weight=BOLD)
.scale(0.5)
.next_to(plot_bg, UP, buff=0.1)
)
x.add(VGroup(plot_bg, plot, plot_title))
except: # because functions `not_quite_there`, `function squish_rate_func` are not working.
pass
x.arrange_in_grid(cols=8)
x.height = config.frame_height
x.width = config.frame_width
x.move_to(ORIGIN).scale(0.95)
self.add(x)
主要有3种标准缓动函数
缓入 (Ease In) - 动画平滑启动。
缓出 (Ease Out) - 动画平滑结束。
缓入缓出 (Ease In Out) - 动画平滑启动且平滑结束。
注意
标准函数未导出，因此要使用它们，您需要这样做：rate_func=rate_functions.ease_in_sine 另一方面，更常用的非标准函数已导出，可以直接使用。
示例：RateFunctions1Example ¶
from manim import *
class RateFunctions1Example(Scene):
def construct(self):
line1 = Line(3*LEFT, 3*RIGHT).shift(UP).set_color(RED)
line2 = Line(3*LEFT, 3*RIGHT).set_color(GREEN)
line3 = Line(3*LEFT, 3*RIGHT).shift(DOWN).set_color(BLUE)
dot1 = Dot().move_to(line1.get_left())
dot2 = Dot().move_to(line2.get_left())
dot3 = Dot().move_to(line3.get_left())
label1 = Tex("Ease In").next_to(line1, RIGHT)
label2 = Tex("Ease out").next_to(line2, RIGHT)
label3 = Tex("Ease In Out").next_to(line3, RIGHT)
self.play(
FadeIn(VGroup(line1, line2, line3)),
FadeIn(VGroup(dot1, dot2, dot3)),
Write(VGroup(label1, label2, label3)),
)
self.play(
MoveAlongPath(dot1, line1, rate_func=rate_functions.ease_in_sine),
MoveAlongPath(dot2, line2, rate_func=rate_functions.ease_out_sine),
MoveAlongPath(dot3, line3, rate_func=rate_functions.ease_in_out_sine),
run_time=7
)
self.wait()
class RateFunctions1Example(Scene):
def construct(self):
line1 = Line(3*LEFT, 3*RIGHT).shift(UP).set_color(RED)
line2 = Line(3*LEFT, 3*RIGHT).set_color(GREEN)
line3 = Line(3*LEFT, 3*RIGHT).shift(DOWN).set_color(BLUE)
dot1 = Dot().move_to(line1.get_left())
dot2 = Dot().move_to(line2.get_left())
dot3 = Dot().move_to(line3.get_left())
label1 = Tex("Ease In").next_to(line1, RIGHT)
label2 = Tex("Ease out").next_to(line2, RIGHT)
label3 = Tex("Ease In Out").next_to(line3, RIGHT)
self.play(
FadeIn(VGroup(line1, line2, line3)),
FadeIn(VGroup(dot1, dot2, dot3)),
Write(VGroup(label1, label2, label3)),
)
self.play(
MoveAlongPath(dot1, line1, rate_func=rate_functions.ease_in_sine),
MoveAlongPath(dot2, line2, rate_func=rate_functions.ease_out_sine),
MoveAlongPath(dot3, line3, rate_func=rate_functions.ease_in_out_sine),
run_time=7
)
self.wait()
类
函数
- smoothererstep(t)[source]¶
三阶平滑阶跃（SmoothStep）S形函数的实现。其一阶、二阶和三阶导数（速度、加速度和加加速度）在端点处均为零。https://en.wikipedia.org/wiki/Smoothstep
- 参数:
t (浮点数)
- 返回类型:
浮点数
- smootherstep(t)[source]¶
二阶平滑阶跃（SmoothStep）S形函数的实现。其一阶和二阶导数（速度和加速度）在端点处均为零。https://en.wikipedia.org/wiki/Smoothstep
- 参数:
t (浮点数)
- 返回类型:
浮点数
- smoothstep(t)[source]¶
一阶平滑阶跃（SmoothStep）S形函数的实现。其一阶导数（速度）在端点处为零。https://en.wikipedia.org/wiki/Smoothstep
- 参数:
t (浮点数)
- 返回类型:
浮点数