fix(cli/convert): ensure dest path can be written

CHANGELOG.md

@@ -65,6 +65,9 @@ In an effort to better document changes, this CHANGELOG document is now created.
   [#253](https://github.com/jeertmans/manim-slides/discussions/253), caused by
   Python 3.11's change in how `Enum` work.
   [#257](https://github.com/jeertmans/manim-slides/pull/257).
+- Fixed potential non-existing parent path issue in
+  `manim convert`'s destination path.
+  [#262](https://github.com/jeertmans/manim-slides/pull/262)
 
 ### Removed
 

manim_slides/convert.py

@@ -378,6 +378,8 @@ def convert_to(self, dest: Path) -> None:
             for presentation_config in self.presentation_configs:
                 presentation_config.copy_to(full_assets_dir)
 
+        dest.parent.mkdir(parents=True, exist_ok=True)
+
         with open(dest, "w") as f:
             revealjs_template = Template(self.load_template())
 
@@ -434,6 +436,8 @@ def read_image_from_video_file(file: Path, frame_index: FrameIndex) -> Image:
                     read_image_from_video_file(slide_config.file, self.frame_index)
                 )
 
+        dest.parent.mkdir(parents=True, exist_ok=True)
+
         images[0].save(
             dest,
             "PDF",
@@ -524,6 +528,7 @@ def save_first_image_from_video_file(file: Path) -> Optional[str]:
                 if self.auto_play_media:
                     auto_play_media(movie, loop=slide_config.is_loop())
 
+        dest.parent.mkdir(parents=True, exist_ok=True)
         prs.save(dest)