chore(lib): warn about non-preferred-qt-version (#373)

Closes #371

manim_slides/present/__init__.py

@@ -11,6 +11,23 @@ from ..commons import config_path_option, folder_path_option, verbosity_option
 from ..config import Config, PresentationConfig
 from ..logger import logger
 
+PREFERRED_QT_VERSIONS = ("6.5.1", "6.5.2")
+
+
+def warn_if_non_desirable_pyside6_version() -> None:
+    from qtpy import API, QT_VERSION
+
+    if sys.version_info < (3, 12) and (
+        API != "pyside6" or QT_VERSION not in PREFERRED_QT_VERSIONS
+    ):
+        logger.warn(
+            f"You are using {API = }, {QT_VERSION = }, "
+            "but we recommend installing 'PySide6==6.5.2', mainly to avoid "
+            "flashing screens between slides, "
+            "see issue https://github.com/jeertmans/manim-slides/issues/293. "
+            "You can do so with `pip install 'manim-slides[pyside6]'`."
+        )
+
 
 @click.command()
 @folder_path_option
@@ -276,6 +293,8 @@ def present(
     if start_at[1]:
         start_at_slide_number = start_at[1]
 
+    warn_if_non_desirable_pyside6_version()
+
     from ..qt_utils import qapp
 
     app = qapp()