[big expression] Finding and manipulating parts of a large LaTeX expression in LaTeX. #manim #mathtex #latex #indexlabels

20251220_mathtex.py

from MF_Tools import ir
class bigeqn(Scene):
    def construct(self):
        eqn = MathTex(
            r"""1+\sum_{i=1}^{2}\left\lfloor\left(
            \frac{1}{\sum\limits_{j=1}^{i}\left\lfloor\left(\cos\left(\frac{(j-1)!\,+1}{j}\pi\right)^2\right)\right\rfloor}
            \right)^\frac{1}{1}\right\rfloor"""
        )
        # uncomment for index labels
        #self.add(eqn, index_labels(eqn[0]).set_color(RED))
        self.play(Write(eqn))
        self.wait()
        for grp in [
            [0],
            ir(2,6),
            [*ir(7,14),*ir(56,63)],
            [*ir(15,19),*ir(48,52)],
            [20],
            [21],
            ir(22,47)
        ]:
            self.play(Indicate(VGroup(eqn[0][i] for i in grp)))
        self.wait()
        self.play(Create(SurroundingRectangle(eqn[0][22:48], buff=0.05)))
        self.wait()

readme.md

showing the index labels

and the final animation

bigeqn.mp4