feat(lib): add playback rate config options (#320)

* feat(lib): add playback rate config options

Basic playback rate config options, closes #309

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

CHANGELOG.md

@@ -18,6 +18,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added the `manim-slides render` command
   to render slides using correct Manim installation.
   [#317](https://github.com/jeertmans/manim-slides/pull/317)
+- Added the `playback-rate` and `reversed-playback-rate` options
+  to slide config.
+  [#320](https://github.com/jeertmans/manim-slides/pull/320)
 
 ## [v5](https://github.com/jeertmans/manim-slides/compare/v4.16.0...v5.0.0)
 

manim_slides/__main__.py

@@ -34,9 +34,7 @@ def cli(notify_outdated_version: bool) -> None:
         manim_info_url = "https://pypi.org/pypi/manim-slides/json"
         warn_prompt = "Cannot check if latest release of Manim Slides is installed"
         try:
-            req_info: requests.models.Response = requests.get(
-                manim_info_url, timeout=2
-            )
+            req_info: requests.models.Response = requests.get(manim_info_url, timeout=2)
             req_info.raise_for_status()
             stable = req_info.json()["info"]["version"]
             if stable != __version__:

manim_slides/config.py

@@ -140,6 +140,8 @@ class PreSlideConfig(BaseModel):  # type: ignore
     end_animation: int
     loop: bool = False
     auto_next: bool = False
+    playback_rate: float = 1.0
+    reversed_playback_rate: float = 1.0
 
     @field_validator("start_animation", "end_animation")
     @classmethod
@@ -190,6 +192,8 @@ class SlideConfig(BaseModel):  # type: ignore[misc]
     rev_file: FilePath
     loop: bool = False
     auto_next: bool = False
+    playback_rate: float = 1.0
+    reversed_playback_rate: float = 1.0
 
     @classmethod
     def from_pre_slide_config_and_files(
@@ -200,6 +204,8 @@ class SlideConfig(BaseModel):  # type: ignore[misc]
             rev_file=rev_file,
             loop=pre_slide_config.loop,
             auto_next=pre_slide_config.auto_next,
+            playback_rate=pre_slide_config.playback_rate,
+            reversed_playback_rate=pre_slide_config.reversed_playback_rate,
         )
 
 

manim_slides/present/player.py

@@ -236,6 +236,13 @@ class Player(QMainWindow):  # type: ignore[misc]
         url = QUrl.fromLocalFile(self.current_file)
         self.media_player.setSource(url)
 
+        if self.playing_reversed_slide:
+            self.media_player.setPlaybackRate(
+                self.current_slide_config.reversed_playback_rate
+            )
+        else:
+            self.media_player.setPlaybackRate(self.current_slide_config.playback_rate)
+
         if start_paused:
             self.media_player.pause()
         else:

manim_slides/slide/base.py

@@ -255,7 +255,13 @@ class BaseSlide:
         self._current_animation += 1
 
     def next_slide(
-        self, *, loop: bool = False, auto_next: bool = False, **kwargs: Any
+        self,
+        *,
+        loop: bool = False,
+        auto_next: bool = False,
+        playback_rate: float = 1.0,
+        reversed_playback_rate: float = 1.0,
+        **kwargs: Any,
     ) -> None:
         """
         Create a new slide with previous animations, and setup options
@@ -276,6 +282,14 @@ class BaseSlide:
 
             Note that this is only supported by ``manim-slides present``
             and ``manim-slides convert --to=html``.
+        :param playback_rate:
+            Playback rate at which the video is played.
+
+            Note that this is only supported by ``manim-slides present``.
+        :param reversed_playback_rate:
+            Playback rate at which the reversed video is played.
+
+            Note that this is only supported by ``manim-slides present``.
         :param kwargs:
             Keyword arguments to be passed to
             :meth:`Scene.next_section<manim.scene.scene.Scene.next_section>`,
@@ -375,7 +389,12 @@ class BaseSlide:
 
             self._current_slide += 1
 
-        self._pre_slide_config_kwargs = dict(loop=loop, auto_next=auto_next)
+        self._pre_slide_config_kwargs = dict(
+            loop=loop,
+            auto_next=auto_next,
+            playback_rate=playback_rate,
+            reversed_playback_rate=reversed_playback_rate,
+        )
         self._start_animation = self._current_animation
 
     def _add_last_slide(self) -> None:

manim_slides/slide/manim.py

@@ -80,10 +80,22 @@ class Slide(BaseSlide, Scene):  # type: ignore[misc]
         self.next_slide(*args, **kwargs)
 
     def next_slide(
-        self, *args: Any, loop: bool = False, auto_next: bool = False, **kwargs: Any
+        self,
+        *args: Any,
+        loop: bool = False,
+        auto_next: bool = False,
+        playback_rate: float = 1.0,
+        reversed_playback_rate: float = 1.0,
+        **kwargs: Any,
     ) -> None:
         Scene.next_section(self, *args, **kwargs)
-        BaseSlide.next_slide(self, loop=loop, auto_next=auto_next)
+        BaseSlide.next_slide(
+            self,
+            loop=loop,
+            auto_next=auto_next,
+            playback_rate=playback_rate,
+            reversed_playback_rate=reversed_playback_rate,
+        )
 
     def render(self, *args: Any, **kwargs: Any) -> None:
         """MANIM render."""

tests/test_slide.py

@@ -182,6 +182,20 @@ class TestSlide:
             with pytest.raises(ValidationError):
                 self.next_slide()
 
+    @assert_constructs
+    class TestPlaybackRate(Slide):
+        def construct(self) -> None:
+            text = Text("Some text")
+
+            self.add(text)
+
+            assert "playback_rate" not in self._pre_slide_config_kwargs
+
+            self.next_slide(playback_rate=2.0)
+            self.play(text.animate.scale(2))
+
+            assert self._pre_slide_config_kwargs["playback_rate"] == 2.0
+
     @assert_constructs
     class TestWipe(Slide):
         def construct(self) -> None: