Verify that the value assigned to window_size in the config has an expected value

Author: henrikmidtiby

manim/_config/utils.py

@@ -143,6 +143,25 @@ def _determine_quality(qual: str | None) -> str:
     return qual
 
 
+def _parse_window_size(window_size: str | tuple[int, ...]) -> tuple[int, int] | str:
+    invalid_window_size_error_message = (
+        "window_size must be specified either as 'default', a string of the form "
+        "'width,height', or a tuple of 2 ints of the form (width, height)."
+    )
+
+    if isinstance(window_size, tuple):
+        if len(window_size) != 2:
+            raise ValueError(invalid_window_size_error_message)
+        return window_size
+    elif len(window_size.split(",")) == 2:
+        (window_width, window_height) = tuple(map(int, window_size.split(",")))
+        return (window_width, window_height)
+    elif window_size == "default":
+        return window_size
+    else:
+        raise ValueError(invalid_window_size_error_message)
+
+
 class ManimConfig(MutableMapping):
     """Dict-like class storing all config options.
 
@@ -1431,7 +1450,8 @@ def window_size(self) -> str | tuple[int, ...]:
 
     @window_size.setter
     def window_size(self, value: str | tuple[int, ...]) -> None:
-        self._d.__setitem__("window_size", value)
+        window_size = _parse_window_size(value)
+        self._d.__setitem__("window_size", window_size)
 
     def resolve_movie_file_extension(self, is_transparent: bool) -> None:
         prev_file_extension = self.movie_file_extension