New LatexTip for latex-style arrows

00README.md

LatexTip

Manim provides few styles of arrow tips, basically a filled triangle and the "stealth".

This python module implements Latex-style arrow tips. The shape is a perfect copy of the one used by Computer Modern fonts. It was produced by exporting to svg a latex document containing $\to$, and editing the resulting SVG using Inkscape to remove the arrow stem and leave only the tip. This SVG was read into manim to extract the array of points used to define this class.

This is an example of several arrows with several kinds of tips pointing in all directions (the code is the file example.py in this gist.

example.py

from manim import *
from latex_tip import LatexTip

class Test(Scene):
    def construct(self):
        tips = [LatexTip, ArrowTriangleFilledTip, StealthTip]
        c = Circle().scale(4)
        for i in range(40):
            tip = tips[i % 3]
            a = Arrow(ORIGIN, c.point_from_proportion(i / 40), tip_shape=tip)
            self.add(a)

latex_tip.py

from manim import *

class LatexTip(ArrowTip):
    def __init__(
        self,
        fill_opacity=1,
        stroke_width=3,
        length=DEFAULT_ARROW_TIP_LENGTH / 2,
        start_angle=PI,
        **kwargs,
    ):
        self.start_angle = start_angle
        VMobject.__init__(
            self, fill_opacity=fill_opacity, stroke_width=stroke_width, **kwargs
        )
        pts = [
            [0.13040412163656126, -0.15336252690279117, 1.8781492768065307e-17],
            [-0.29132632741912245, -0.4748715152945279, 5.815498812116969e-17],
            [-0.4979583035543512, -0.789178398566812, 9.664647997610804e-17],
            [-0.559258018625476, -0.8889401215389154, 1.088637674476292e-16],
            [-0.559258018625476, -0.8889401215389154, 1.088637674476292e-16],
            [-0.9042122731429533, -1.417547152496847, 1.7359945829457088e-16],
            [-0.9655043033165742, -1.900239633186283, 2.3271223843945216e-16],
            [-0.9655043033165742, -1.9079322155875946, 2.3365430808094653e-16],
            [-0.9655043033165742, -1.9079322155875946, 2.3365430808094653e-16],
            [-0.9655043033165742, -1.9999999999999993, 2.4492935982947054e-16],
            [-0.873443299696082, -1.9999999999999993, 2.4492935982947054e-16],
            [-0.8121426805193717, -1.9999999999999993, 2.4492935982947054e-16],
            [-0.8121426805193717, -1.9999999999999993, 2.4492935982947054e-16],
            [-0.6818502159230145, -1.9999999999999993, 2.4492935982947054e-16],
            [-0.6741580855744985, -1.9846166434085502, 2.430454419884845e-16],
            [-0.6436350288477489, -1.8466347607804396, 2.261475348984003e-16],
            [-0.6436350288477489, -1.8466347607804396, 2.261475348984003e-16],
            [-0.46742710987730773, -1.0956706451833076, 1.341809548543453e-16],
            [-0.015265370812125336, -0.4521630952235609, 5.537400872580937e-17],
            [0.8505965514700535, -0.0995162583047747, 1.2187226719606352e-17],
            [0.8505965514700535, -0.0995162583047747, 1.2187226719606352e-17],
            [0.9424274602182247, -0.06898461257493264, 8.448178498031151e-18],
            [0.9655043033165771, -0.05359944777230632, 6.564039215042066e-18],
            [0.9655043033165771, -9.041055885253818e-07, 1.1072100150788427e-22],
            [0.9655043033165771, -9.041055885253818e-07, 1.1072100150788427e-22],
            [0.9655043033165771, 0.05360894088098726, -6.565201785558075e-18],
            [0.9195874927841087, 0.07668352371536691, -9.391023186536422e-18],
            [0.9042041361926566, 0.08437565406388865, -1.033303746753056e-17],
            [0.9042041361926566, 0.08437565406388865, -1.033303746753056e-17],
            [0.5669424640764967, 0.21466811866024282, -2.6289262439625056e-17],
            [-0.3602196253296055, 0.597599328430368, -7.318481047348581e-17],
            [-0.6513276112490635, 1.8848612491755692, -2.3082892956397423e-16],
            [-0.6513276112490635, 1.8848612491755692, -2.3082892956397423e-16],
            [-0.6741607978912669, 1.9769231569016499, -2.421032616259886e-16],
            [-0.6818456953950748, 1.9999999999999993, -2.4492935982947054e-16],
            [-0.8121426805193745, 1.9999999999999993, -2.4492935982947054e-16],
            [-0.8121426805193745, 1.9999999999999993, -2.4492935982947054e-16],
            [-0.8734432996960849, 1.9999999999999993, -2.4492935982947054e-16],
            [-0.9655043033165771, 1.9999999999999993, -2.4492935982947054e-16],
            [-0.9655043033165771, 1.9079385443267172, -2.3365508312795747e-16],
            [-0.9655043033165771, 1.9079385443267172, -2.3365508312795747e-16],
            [-0.9655043033165771, 1.8925506672073253, -2.317706116819638e-16],
            [-0.8965201427944373, 1.4098613508874478, -1.7265821906058763e-16],
            [-0.5746427313753123, 0.8963994446983478, -1.0977727107072965e-16],
            [-0.5746427313753123, 0.8963994446983478, -1.0977727107072965e-16],
            [-0.4215193404007274, 0.6665911738500118, -8.163387473952938e-17],
            [-0.18624755947997798, 0.41500616373985083, -5.0823597005043066e-17],
            [0.13040412163655557, 0.15312971971370742, -1.875298211017232e-17],
            [0.13040412163655557, 0.15312971971370742, -1.875298211017232e-17],
            [0.22087977610729068, 0.07830458503587787, -9.589545942274956e-18],
            [0.26830825118403845, 0.03783862709758074, -4.633895355918257e-18],
            [0.26940357510472646, -0.001999429509370092, 2.4485949487708463e-19],
            [0.26940357510472646, -0.001999429509370092, 2.4485949487708463e-19],
            [0.2704885018111478, -0.041838842274707994, 5.123780427175211e-18],
            [0.2252606197372555, -0.08104809344473542, 9.925528821409081e-18],
            [0.13040412163655557, -0.15336252690278834, 1.878149276806496e-17],
        ]
        self.set_points(pts)
        self.scale(length / self.length)

    @property
    def length(self):
        # The 5 factor was fine-tuned to provide a good length
        return np.linalg.norm(self.vector) * 5
    
    @property
    def tip_point(self):
        a = self.get_anchors()
        return a[len(a)//2-2]
    
    @property
    def base(self):
        a = self.get_anchors()
        return a[-2]