feat(lib): allow to insert external videos as slides

See #520

Author: jeertmans

manim_slides/config.py

@@ -161,6 +161,7 @@ class BaseSlideConfig(BaseModel):  # type: ignore
     notes: str = ""
     dedent_notes: bool = True
     skip_animations: bool = False
+    src: Optional[FilePath] = None
 
     @classmethod
     def wrapper(cls, arg_name: str) -> Callable[..., Any]:
@@ -205,14 +206,13 @@ def __wrapper__(*args: Any, **kwargs: Any) -> Any:  # noqa: N807
         return _wrapper_
 
     @model_validator(mode="after")
-    @classmethod
     def apply_dedent_notes(
-        cls, base_slide_config: "BaseSlideConfig"
+        self,
     ) -> "BaseSlideConfig":
-        if base_slide_config.dedent_notes:
-            base_slide_config.notes = dedent(base_slide_config.notes)
+        if self.dedent_notes:
+            self.notes = dedent(self.notes)
 
-        return base_slide_config
+        return self
 
 
 class PreSlideConfig(BaseSlideConfig):
@@ -242,25 +242,33 @@ def index_is_posint(cls, v: int) -> int:
         return v
 
     @model_validator(mode="after")
-    @classmethod
     def start_animation_is_before_end(
-        cls, pre_slide_config: "PreSlideConfig"
+        self,
     ) -> "PreSlideConfig":
-        if pre_slide_config.start_animation >= pre_slide_config.end_animation:
-            if pre_slide_config.start_animation == pre_slide_config.end_animation == 0:
-                raise ValueError(
-                    "You have to play at least one animation (e.g., `self.wait()`) "
-                    "before pausing. If you want to start paused, use the appropriate "
-                    "command-line option when presenting. "
-                    "IMPORTANT: when using ManimGL, `self.wait()` is not considered "
-                    "to be an animation, so prefer to directly use `self.play(...)`."
-                )
-
+        if self.start_animation > self.end_animation:
             raise ValueError(
                 "Start animation index must be strictly lower than end animation index"
             )
+        return self
+
+    @model_validator(mode="after")
+    def has_src_or_more_than_zero_animations(
+        self,
+    ) -> "PreSlideConfig":
+        if self.src is not None and self.start_animation != self.end_animation:
+            raise ValueError(
+                "A slide cannot have 'src=...' and more than zero animations at the same time."
+            )
+        elif self.src is None and self.start_animation == self.end_animation:
+            raise ValueError(
+                "You have to play at least one animation (e.g., 'self.wait()') "
+                "before pausing. If you want to start paused, use the appropriate "
+                "command-line option when presenting. "
+                "IMPORTANT: when using ManimGL, 'self.wait()' is not considered "
+                "to be an animation, so prefer to directly use 'self.play(...)'."
+            )
 
-        return pre_slide_config
+        return self
 
     @property
     def slides_slice(self) -> slice:

manim_slides/slide/base.py

@@ -348,6 +348,11 @@ def next_slide(
                 ``manim-slides convert --to=pptx``.
         :param dedent_notes:
             If set, apply :func:`textwrap.dedent` to notes.
+        :param src:
+            An optional path to a video file to include as next slide.
+
+            The video will be copied into the output folder, but no rescaling
+            is applied.
         :param kwargs:
             Keyword arguments passed to
             :meth:`Scene.next_section<manim.scene.scene.Scene.next_section>`,
@@ -471,6 +476,18 @@ def construct(self):
 
             self._current_slide += 1
 
+        if base_slide_config.src is not None:
+            self._slides.append(
+                PreSlideConfig.from_base_slide_config_and_animation_indices(
+                    base_slide_config,
+                    self._current_animation,
+                    self._current_animation,
+                )
+            )
+
+            base_slide_config = BaseSlideConfig()  # default
+            self._current_slide += 1
+
         if self._skip_animations:
             base_slide_config.skip_animations = True
 
@@ -540,7 +557,10 @@ def _save_slides(
         ):
             if pre_slide_config.skip_animations:
                 continue
-            slide_files = files[pre_slide_config.slides_slice]
+            if pre_slide_config.src:
+                slide_files = [pre_slide_config.src]
+            else:
+                slide_files = files[pre_slide_config.slides_slice]
 
             try:
                 file = merge_basenames(slide_files)

manim_slides/utils.py

@@ -1,5 +1,6 @@
 import hashlib
 import os
+import shutil
 import tempfile
 from collections.abc import Iterator
 from multiprocessing import Pool
@@ -14,6 +15,9 @@
 
 def concatenate_video_files(files: list[Path], dest: Path) -> None:
     """Concatenate multiple video files into one."""
+    if len(files) == 1:
+        shutil.copy(files[0], dest)
+        return
 
     def _filter(files: list[Path]) -> Iterator[Path]:
         """Patch possibly empty video files."""

tests/test_slide.py

@@ -589,6 +589,49 @@ def construct(self) -> None:
 
             assert len(config.slides) == 1
 
+    def test_next_slide_include_video(self) -> None:
+        class Foo(CESlide):
+            def construct(self) -> None:
+                circle = Circle(color=BLUE)
+                self.play(GrowFromCenter(circle))
+                self.next_slide()
+                square = Square(color=BLUE)
+                self.play(GrowFromCenter(square))
+                self.next_slide()
+                self.wait(2)
+
+        with tmp_cwd() as tmp_dir:
+            init_slide(Foo).render()
+
+            slides_folder = Path(tmp_dir) / "slides"
+
+            assert slides_folder.exists()
+
+            slide_file = slides_folder / "Foo.json"
+
+            config = PresentationConfig.from_file(slide_file)
+
+            assert len(config.slides) == 3
+
+            class Bar(CESlide):
+                def construct(self) -> None:
+                    self.next_slide(src=config.slides[0].file)
+                    self.wait(2)
+                    self.next_slide()
+                    self.wait(2)
+                    self.next_slide(src=config.slides[1].file, loop=True)
+                    self.wait(2)
+                    self.next_slide(src=config.slides[2].file)
+
+            init_slide(Bar).render()
+
+            slide_file = slides_folder / "Bar.json"
+
+            config = PresentationConfig.from_file(slide_file)
+
+            assert len(config.slides) == 6
+            assert config.slides[-3].loop
+
     def test_canvas(self) -> None:
         @assert_constructs
         class _(CESlide):