tex compiler options - PR feedback request.

[cobordism]

CC @PhilippImhof because of #48

There are things you might want to do in TeX that require a different compiler than just latex or a different format than just dvi.
We already have partial support for this in the form of TexTemplateFromFile.use_ctex.

I have added the option to choose between compilers latex, pdflatex, xelatex, luatex, lualatex and output formats .dvi, .xdv, .pdf.

Further I have allowed you to specify a TexTemplate and compiler to use on a per-SingleStringTexMobject basis. This is already something I needed in the past for the Latex Maths Fonts video at https://vimeo.com/435684836 .

The code is here: https://gitlab.com/co-bordism/manim/-/tree/tex_compilers

I'd welcome any feedback.

---

Note: These changes should be backward compatible with the exception that users who manually set TexTemplateFromFile.use_ctex = True should now also change the TexTemplateFromFile.tex_compiler option. (@PhilippImhof can you provide feedback here?)

To try it out:

git remote add cobordism https://gitlab.com:co-bordism/manim.git
git pull cobordism tex_compilers 

Example:

from manim import *

tex_compilers = {
        "latex": {
            "command": "latex",
            "output_format": ".dvi",
        },
        "pdflatex": {
            "command": "latex",
            "output_format": ".pdf",
        },
        "xelatex": {
            "command": "xelatex",
            "output_format": ".xdv",
        },
        "xelatex-with-pdf-option": {
            "command": "xelatex",
            "output_format": ".pdf",
        },
        "luatex": {
            "command": "luatex",
            "output_format": ".dvi",
        },
        "lualatex": {
            "command": "lualatex",
            "output_format": ".pdf",
        },
    }

class test(Scene):
    def construct(self):
        for k, v in tex_compilers.items():
            template = TexTemplate(tex_compiler=v)
            text = TextMobject(k, tex_template=v)
            self.play(FadeIn(text))
            self.wait(0.5)
            self.play(FadeOut(text))
        self.wait(3)

[leotrs]

This looks interesting, but very much outside of my expertise. (@PgBiel I know you're busy but maybe take a look when you can?)

[PhilippImhof]

I have actually never had the need of using another compiler (except for my documents where I always use pdflatex), but I can imagine cases where this could be desirable. I think, this is an absolutely nice idea. I always like when new features are added for the few without disturbing the many.

W.r.t use_ctex: that existed well before my first contact with manim. I have no idea how many people actually use this.

[cobordism]

I understand that it might be a niche use-case.
But I did think that using a blackboard background and a chalk tex font might be desirable -
example here https://vimeo.com/432852225 (all font demo: https://vimeo.com/435684836 )
for giving videos a more school feeling.

It was in that context that I stumbled upon something I could only compile with lualatex and only to pdf.

In any event, it can't hurt to add this to manim... and people do do crazy stuff in TeX :)

[PgBiel]

I believe this issue should be closed in favor of the pull request #215