箭头

限定名称: manim.mobject.geometry.line.Arrow

class Arrow(*args, stroke_width=6, buff=0.25, max_tip_length_to_length_ratio=0.25, max_stroke_width_to_length_ratio=5, **kwargs)[来源]

基础类: Line

一个箭头。

Parameters:

  • args – 传递给 Line 的参数。

  • stroke_width (float) – 箭头的厚度。受max_stroke_width_to_length_ratio影响。

  • buff (float) – 箭头从其起点和终点的距离。

  • max_tip_length_to_length_ratio (float) – tip_length 随着箭头的长度缩放。增加这个比例会提高 tip_length 的最大值。

  • max_stroke_width_to_length_ratio (float) – stroke_width 随着箭头的长度缩放。增加这个比例会增加 stroke_width 的最大值。

  • kwargs – 传递给Line的额外参数。

另请参阅

ArrowTip CurvedArrow

示例

示例：ArrowExample

../_images/ArrowExample-1.png 
from manim import *

from manim.mobject.geometry.tips import ArrowSquareTip
class ArrowExample(Scene):
    def construct(self):
        arrow_1 = Arrow(start=RIGHT, end=LEFT, color=GOLD)
        arrow_2 = Arrow(start=RIGHT, end=LEFT, color=GOLD, tip_shape=ArrowSquareTip).shift(DOWN)
        g1 = Group(arrow_1, arrow_2)

        # the effect of buff
        square = Square(color=MAROON_A)
        arrow_3 = Arrow(start=LEFT, end=RIGHT)
        arrow_4 = Arrow(start=LEFT, end=RIGHT, buff=0).next_to(arrow_1, UP)
        g2 = Group(arrow_3, arrow_4, square)

        # a shorter arrow has a shorter tip and smaller stroke width
        arrow_5 = Arrow(start=ORIGIN, end=config.top).shift(LEFT * 4)
        arrow_6 = Arrow(start=config.top + DOWN, end=config.top).shift(LEFT * 3)
        g3 = Group(arrow_5, arrow_6)

        self.add(Group(g1, g2, g3).arrange(buff=2))

from manim.mobject.geometry.tips import ArrowSquareTip
class ArrowExample(Scene):
    def construct(self):
        arrow_1 = Arrow(start=RIGHT, end=LEFT, color=GOLD)
        arrow_2 = Arrow(start=RIGHT, end=LEFT, color=GOLD, tip_shape=ArrowSquareTip).shift(DOWN)
        g1 = Group(arrow_1, arrow_2)

        # the effect of buff
        square = Square(color=MAROON_A)
        arrow_3 = Arrow(start=LEFT, end=RIGHT)
        arrow_4 = Arrow(start=LEFT, end=RIGHT, buff=0).next_to(arrow_1, UP)
        g2 = Group(arrow_3, arrow_4, square)

        # a shorter arrow has a shorter tip and smaller stroke width
        arrow_5 = Arrow(start=ORIGIN, end=config.top).shift(LEFT * 4)
        arrow_6 = Arrow(start=config.top + DOWN, end=config.top).shift(LEFT * 3)
        g3 = Group(arrow_5, arrow_6)

        self.add(Group(g1, g2, g3).arrange(buff=2))

示例：ArrowExample

../_images/ArrowExample-2.png 
from manim import *

class ArrowExample(Scene):
    def construct(self):
        left_group = VGroup()
        # As buff increases, the size of the arrow decreases.
        for buff in np.arange(0, 2.2, 0.45):
            left_group += Arrow(buff=buff, start=2 * LEFT, end=2 * RIGHT)
        # Required to arrange arrows.
        left_group.arrange(DOWN)
        left_group.move_to(4 * LEFT)

        middle_group = VGroup()
        # As max_stroke_width_to_length_ratio gets bigger,
        # the width of stroke increases.
        for i in np.arange(0, 5, 0.5):
            middle_group += Arrow(max_stroke_width_to_length_ratio=i)
        middle_group.arrange(DOWN)

        UR_group = VGroup()
        # As max_tip_length_to_length_ratio increases,
        # the length of the tip increases.
        for i in np.arange(0, 0.3, 0.1):
            UR_group += Arrow(max_tip_length_to_length_ratio=i)
        UR_group.arrange(DOWN)
        UR_group.move_to(4 * RIGHT + 2 * UP)

        DR_group = VGroup()
        DR_group += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareTip)
        DR_group += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareFilledTip)
        DR_group += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleTip)
        DR_group += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleFilledTip)
        DR_group.arrange(DOWN)
        DR_group.move_to(4 * RIGHT + 2 * DOWN)

        self.add(left_group, middle_group, UR_group, DR_group)

class ArrowExample(Scene):
    def construct(self):
        left_group = VGroup()
        # As buff increases, the size of the arrow decreases.
        for buff in np.arange(0, 2.2, 0.45):
            left_group += Arrow(buff=buff, start=2 * LEFT, end=2 * RIGHT)
        # Required to arrange arrows.
        left_group.arrange(DOWN)
        left_group.move_to(4 * LEFT)

        middle_group = VGroup()
        # As max_stroke_width_to_length_ratio gets bigger,
        # the width of stroke increases.
        for i in np.arange(0, 5, 0.5):
            middle_group += Arrow(max_stroke_width_to_length_ratio=i)
        middle_group.arrange(DOWN)

        UR_group = VGroup()
        # As max_tip_length_to_length_ratio increases,
        # the length of the tip increases.
        for i in np.arange(0, 0.3, 0.1):
            UR_group += Arrow(max_tip_length_to_length_ratio=i)
        UR_group.arrange(DOWN)
        UR_group.move_to(4 * RIGHT + 2 * UP)

        DR_group = VGroup()
        DR_group += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareTip)
        DR_group += Arrow(start=LEFT, end=RIGHT, color=BLUE, tip_shape=ArrowSquareFilledTip)
        DR_group += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleTip)
        DR_group += Arrow(start=LEFT, end=RIGHT, color=YELLOW, tip_shape=ArrowCircleFilledTip)
        DR_group.arrange(DOWN)
        DR_group.move_to(4 * RIGHT + 2 * DOWN)

        self.add(left_group, middle_group, UR_group, DR_group)

方法

get_default_tip_length

返回箭头的默认tip_length。

get_normal_vector

返回向量的法线。

reset_normal_vector

重置向量的法线

scale

缩放箭头，但保持描边宽度和箭头尖端大小不变。

属性

animate

用于动画化self的任何方法的应用。

animation_overrides

color

depth

mobject的深度。

fill_color

如果有多种颜色（用于渐变），则返回第一个颜色

height

mobject的高度。

n_points_per_curve

sheen_factor

stroke_color

width

mobject的宽度。
_original__init__(*args, stroke_width=6, buff=0.25, max_tip_length_to_length_ratio=0.25, max_stroke_width_to_length_ratio=5, **kwargs)

初始化自身。有关准确的签名，请参阅 help(type(self))。

Parameters:

  • stroke_width (float)

  • buff (float)

  • max_tip_length_to_length_ratio (float)

  • max_stroke_width_to_length_ratio (float)

Return type:

无

_set_stroke_width_from_length()[来源]

根据长度设置描边宽度。

Return type:

自我

get_default_tip_length()[来源]

返回箭头的默认tip_length。

示例

>>> Arrow().get_default_tip_length()
0.35
Return type:

浮点数

get_normal_vector()[来源]

返回向量的法线。

示例

>>> np.round(Arrow().get_normal_vector()) + 0. # add 0. to avoid negative 0 in output
array([ 0.,  0., -1.])
Return type:

Vector3D

reset_normal_vector()[source]

重置向量的法线

Return type:

自我

scale(factor, scale_tips=False, **kwargs)[来源]

缩放箭头，但保持描边宽度和箭头尖端大小不变。

另请参阅

scale()

示例

>>> arrow = Arrow(np.array([-1, -1, 0]), np.array([1, 1, 0]), buff=0)
>>> scaled_arrow = arrow.scale(2)
>>> np.round(scaled_arrow.get_start_and_end(), 8) + 0
array([[-2., -2.,  0.],
       [ 2.,  2.,  0.]])
>>> arrow.tip.length == scaled_arrow.tip.length
True

使用默认方法手动缩放对象 scale() 不具有相同的属性：

>>> new_arrow = Arrow(np.array([-1, -1, 0]), np.array([1, 1, 0]), buff=0)
>>> another_scaled_arrow = VMobject.scale(new_arrow, 2)
>>> another_scaled_arrow.tip.length == arrow.tip.length
False
Parameters:

  • factor (float)

  • scale_tips (bool)

Return type:

自我