Attempt to read tex_template from config file if needed (#505)

* Attempt to read tex_template from config file if not present in command line arguments.

* Updated changelog to mention that  is read from config.

* Small improvement when `tex_template` is empty in config file where it is interpreted as `None` instead of an empty string.

* Added default `tex_template` entry to default.cfg (None).

* Updated changelog.rst to better reflect the changes in the previous two commits.

Author: jvdoorn

docs/source/changelog.rst

@@ -30,6 +30,7 @@ Command line
 #. Re-implement GIF export with the :code:`-i` flag (using this flag outputs ONLY a .gif file, and no .mp4 file)
 #. Added a :code:`--verbose` flag
 #. You can save the logs to a file by using :code:`--log_to_file`
+#. Read :code:`tex_template` from config file if not specified by :code:`--tex_template`.
 #. Add experimental javascript rendering with :code:`--use_js_renderer`
 #. Add :code:`-q/--quality [k|h|m|l]` flag and removed :code:`-m/-l` flags.
 #. Removed :code:`--sound` flag

manim/config/config.py

@@ -135,8 +135,11 @@ def _parse_config(config_parser, args):
     config["left_side"] = config["frame_x_radius"] * constants.LEFT
     config["right_side"] = config["frame_x_radius"] * constants.RIGHT
 
-    # Handle the --tex_template flag.  Note we accept None if the flag is absent
-    tex_fn = os.path.expanduser(args.tex_template) if args.tex_template else None
+    # Handle the --tex_template flag, if the flag is absent read it from the config.
+    if args.tex_template:
+        tex_fn = os.path.expanduser(args.tex_template)
+    else:
+        tex_fn = default["tex_template"] if default["tex_template"] != "" else None
 
     if tex_fn is not None and not os.access(tex_fn, os.R_OK):
         # custom template not available, fallback to default

manim/config/default.cfg

@@ -108,6 +108,10 @@ max_files_cached = 100
 flush_cache = False
 disable_caching = False
 
+# Default tex_template
+# --tex_template
+tex_template =
+
 # These override the previous by using -t, --transparent
 [transparent]
 png_mode = RGBA