Colorize parts of a complex equation manim

user_12593767 0
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I want to paint variables of MathTex element in different colors, but Manim seems to have problems with comlicated Latex expressions.

Here is my scene.

from manim import *
config.frame_width = 260 

class Find_Path(Scene):
    def construct(self):
        obj = MathTex(r"minimize \quad \sum_{start}^{end}\frac{d_{i,i+1}}{v_{i,i+1}}", 
        font_size=1000, substrings_to_isolate="d" and "v")
        obj.set_color_by_tex("d", YELLOW)
        obj.set_color_by_tex("start", GREEN)
        obj.set_color_by_tex("end", GREEN)
        obj.set_color_by_tex("v", RED)
        self.play(Write(obj))
        self.wait(3)

Here is the result.

enter image description here

Specifically, I want to color d_{i,i+1} in YELLOW, v_{i,i+1} in RED, start and end in GREEN.

Any advice? Frankly, I do not want to create several MathTex object in different colors and then arrange them.

manim animation latex python
1 Answers

Manim does a bunch of tex rewriting under the covers, and it seems that over is preferred to frac because of that rewriting.

I was able to apply the colors that you wanted (although I suspect you didn't want the sum symbol colored) with:

from manim import *

class Find_Path(Scene):
    def construct(self):
        obj1 = MathTex(r"\text{minimize}", r"\quad \sum_{\text{start}}^{\text{end}}")
        obj2 = MathTex(r"d_{i,i+1}", r"\over", r"v_{i,i+1}")
        obj1.set_color_by_tex("start", GREEN)
        obj1.set_color_by_tex("end", GREEN)
        obj2.move_to(obj1, RIGHT)
        obj2.shift(1.5 * RIGHT)
        obj2[0].set_color(YELLOW)
        obj2[2].set_color(RED)
        self.play(AnimationGroup(Write(obj1), Write(obj2)))
        self.wait(3)

but I had to resort to separate objects. Worse still, I aligned them by hand with a fudge factor.

result

user_1892700
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