fix the problem that --tex_template flag didn't handle. (#969)

* fix the problem that --tex_template flag didn't handle.

* 1. Fixes TexTemplateFromFile filename parameter inconsistent with docuemnt.
2. Fixes --tex_template CLI flag didn't handle.

Author: algebnaly

manim/_config/utils.py

@@ -699,6 +699,10 @@ def digest_args(self, args: argparse.Namespace) -> "ManimConfig":
             if hasattr(args, "media_dir") and args.media_dir:
                 self.media_dir = args.media_dir
 
+        # Handle --tex_template
+        if args.tex_template:
+            self.tex_template = TexTemplateFromFile(tex_filename=args.tex_template)
+
         return self
 
     def digest_file(self, filename: str) -> "ManimConfig":

manim/utils/tex.py

@@ -265,7 +265,7 @@ class TexTemplateFromFile(TexTemplate):
     """
 
     def __init__(self, **kwargs):
-        self.template_file = kwargs.pop("filename", "tex_template.tex")
+        self.template_file = kwargs.pop("tex_filename", "tex_template.tex")
         super().__init__(**kwargs)
 
     def _rebuild(self):