`self.play(Write(MathTex))` with string split and `\\sqrt`

[HACHEDOSO]

Description of bug / unexpected behavior

Hi guys. I had a problem. I had a problem with the animation Write. When I split strings on MathTex and one of these contains \\sqrt or \\sqrt{ (I know if there is one of these strings, that represents two indexes), the mobject is written as you can see in the next video.

How to reproduce the issue

Code and video for reproducing the problem

Video.mp4

from manim import *

class Video(Scene):
    def construct(self):
        limit = MathTex("\\lim_{", "x", "\\to", "-\\infty}", "{", "\\sqrt{", "x", "^2", "+", "1}", "\\over", "x}").scale(2)
        limit[1].set_color(ORANGE)
        limit[6].set_color(ORANGE)
        limit[11].set_color(ORANGE)
        forsolve = Text("Para resolver este límite", font="Orbitron", weight=BOLD, color=BLACK).to_edge(UP)
        rec1 = SurroundingRectangle(forsolve, color=ORANGE, stroke_color=WHITE, fill_opacity=1.0, buff=0.3)
        self.play(Write(limit), DrawBorderThenFill(rec1), run_time=2)
        self.play(FadeIn(forsolve, shift=UP))

Additional media files

However, when I do the same thing with self.add, it's working fine.

from manim import *

class Thumbnail(Scene):
    def construct(self):
        title = Text("Calcula el siguiente límite",
        font="Orbitron",
        weight=BOLD,
        color=BLACK).to_edge(UP)
        rec = SurroundingRectangle(title,
        color=ORANGE,
        stroke_color=WHITE,
        fill_opacity=1.0,
        buff=0.3)
        limit = MathTex("\\lim_{", "x", "\\to", "-\\infty}", "{", "\\sqrt{", "x", "^2", "+", "1}", "\\over", "x}").scale(2)
        limit[1].set_color(ORANGE)
        limit[6].set_color(ORANGE)
        limit[11].set_color(ORANGE)
        svg = SVGMobject("deafness.svg").to_corner(DR)
        text = Tex("Video inclusivo", color=ORANGE).scale(1.5).to_edge(DOWN)
        self.add(rec, title, limit, svg, text)

[Viicos]

Does not fix the issue, but you could use tex_to_color_map instead:

limit = MathTex(
    r"\lim_{x\to-\infty}\frac{\sqrt{x^2+1}}{x}",
    tex_to_color_map={
        'x': ORANGE
    }
)

Which interestingly raises a LaTeX error: ERROR LaTeX compilation error: Argument of \align* has an extra }. (isn't happening without tex_to_color_map). Maybe playing with the tex_environment parameter could help.

Other solution:

limit = MathTex(r"\lim_{x\to-\infty}\frac{\sqrt{x^2+1}}{x}")
limit[0][3].set_color(ORANGE)
limit[0][9].set_color(ORANGE)
limit[0][14].set_color(ORANGE)

[kasztan2]

Same applies to exponentiation and logarithm, probably every expression that takes two arguments has this bug.

Test.mp4

from manim import *

class Test(Scene):
    def construct(self):
        m=MathTex(r"a^b", substrings_to_isolate=["a", "b"])
        m2=MathTex(r"{{a}}^{{b}}").next_to(m, DOWN)
        m3=MathTex(r"a", r"^", r"b").next_to(m2, DOWN)
        m4=MathTex(r"a^b").next_to(m3, DOWN)
        self.play(Write(m), Write(m2), Write(m3), Write(m4))
        self.wait()

No matter which way I separate the terms, it only writes "a".

add and FadeIn work normally and show the whole expression.

The way I'm able to get around this is that I simply iterate over every submobject instead of applying Write on the whole MathTex object:

for i in m:
    self.play(Write(i))
self.wait()

It seems that Create has the same bug.
DrawBorderThenFill has similar bug.