feat(VGroup): Make VGroup Generic in VMobjectT

Author: JasonGrace2282

docs/source/contributing/docs/typings.rst

@@ -141,6 +141,14 @@ Typing guidelines
        from manim.typing import Vector3D
    # type stuff with Vector3D
 
+* When typing something like ``VGroup``, type it as if it were a list, not as if it was a tuple.
+
+.. code:: py
+    # not VGroup[Line, Line]
+    def get_two_lines() -> VGroup[Line]:
+        return VGroup(Line(), Line().shift(LEFT))
+
+
 Missing Sections for typehints are:
 -----------------------------------
 

manim/animation/changing.py

@@ -7,7 +7,7 @@
 from typing import Callable
 
 from manim.mobject.opengl.opengl_compatibility import ConvertToOpenGL
-from manim.mobject.types.vectorized_mobject import VGroup, VMobject
+from manim.mobject.types.vectorized_mobject import VGroup, VMobject, VMobjectT
 from manim.utils.color import (
     BLUE_B,
     BLUE_D,
@@ -19,7 +19,7 @@
 from manim.utils.rate_functions import smooth
 
 
-class AnimatedBoundary(VGroup):
+class AnimatedBoundary(VGroup[VMobjectT]):
     """Boundary of a :class:`.VMobject` with animated color change.
 
     Examples
@@ -38,11 +38,11 @@ def construct(self):
 
     def __init__(
         self,
-        vmobject,
-        colors=[BLUE_D, BLUE_B, BLUE_E, GREY_BROWN],
-        max_stroke_width=3,
-        cycle_rate=0.5,
-        back_and_forth=True,
+        vmobject: VMobjectT,
+        colors: list[ParsableManimColor] = [BLUE_D, BLUE_B, BLUE_E, GREY_BROWN],
+        max_stroke_width: float = 3,
+        cycle_rate: float = 0.5,
+        back_and_forth: bool = True,
         draw_rate_func=smooth,
         fade_rate_func=smooth,
         **kwargs,
@@ -60,7 +60,7 @@ def __init__(
         ]
         self.add(*self.boundary_copies)
         self.total_time = 0
-        self.add_updater(lambda m, dt: self.update_boundary_copies(dt))
+        self.add_updater(lambda _, dt: self.update_boundary_copies(dt))
 
     def update_boundary_copies(self, dt):
         # Not actual time, but something which passes at

manim/mobject/geometry/shape_matchers.py

@@ -4,9 +4,7 @@
 
 __all__ = ["SurroundingRectangle", "BackgroundRectangle", "Cross", "Underline"]
 
-from typing import Any
-
-from typing_extensions import Self
+from typing import TYPE_CHECKING, Any
 
 from manim import config, logger
 from manim.constants import *
@@ -16,6 +14,9 @@
 from manim.mobject.types.vectorized_mobject import VGroup
 from manim.utils.color import BLACK, RED, YELLOW, ManimColor, ParsableManimColor
 
+if TYPE_CHECKING:
+    from typing_extensions import Self
+
 
 class SurroundingRectangle(RoundedRectangle):
     r"""A rectangle surrounding a :class:`~.Mobject`
@@ -133,7 +134,7 @@ def get_fill_color(self) -> ManimColor:
         return self.color
 
 
-class Cross(VGroup):
+class Cross(VGroup[Line]):
     """Creates a cross.
 
     Parameters
@@ -166,9 +167,7 @@ def __init__(
         scale_factor: float = 1.0,
         **kwargs,
     ) -> None:
-        super().__init__(
-            Line(UP + LEFT, DOWN + RIGHT), Line(UP + RIGHT, DOWN + LEFT), **kwargs
-        )
+        super().__init__(Line(UL, DR), Line(UR, DL), **kwargs)
         if mobject is not None:
             self.replace(mobject, stretch=True)
         self.scale(scale_factor)

manim/mobject/logo.py

@@ -16,7 +16,7 @@
 from ..animation.creation import Create, SpiralIn
 from ..animation.fading import FadeIn
 from ..mobject.svg.svg_mobject import VMobjectFromSVGPath
-from ..mobject.types.vectorized_mobject import VGroup
+from ..mobject.types.vectorized_mobject import VGroup, VMobjectT
 from ..utils.rate_functions import ease_in_out_cubic, smooth
 
 MANIM_SVG_PATHS: list[se.Path] = [
@@ -100,7 +100,7 @@
 ]
 
 
-class ManimBanner(VGroup):
+class ManimBanner(VGroup[VMobjectT]):
     r"""Convenience class representing Manim's banner.
 
     Can be animated using custom methods.

manim/mobject/mobject.py

@@ -2979,8 +2979,6 @@ def set_z_index_by_z_Point3D(self) -> Self:
         self.set_z_index(z_coord)
         return self
 
-    def __class_getitem__(cls, item: type) -> str:
-        return f"{cls.__name__}[{item.__name__}]"
 
 class Group(Mobject, metaclass=ConvertToOpenGL):
     """Groups together multiple :class:`Mobjects <.Mobject>`.

manim/mobject/table.py

@@ -78,12 +78,12 @@ def construct(self):
 from ..animation.composition import AnimationGroup
 from ..animation.creation import Create, Write
 from ..animation.fading import FadeIn
-from ..mobject.types.vectorized_mobject import VGroup, VMobject
+from ..mobject.types.vectorized_mobject import VGroup, VMobject, VMobjectT
 from ..utils.color import BLACK, YELLOW, ManimColor, ParsableManimColor
 from .utils import get_vectorized_mobject_class
 
 
-class Table(VGroup):
+class Table(VGroup[VMobjectT]):
     """A mobject that displays a table on the screen.
 
     Parameters

manim/mobject/text/code_mobject.py

@@ -23,13 +23,13 @@
 from manim.mobject.geometry.polygram import RoundedRectangle
 from manim.mobject.geometry.shape_matchers import SurroundingRectangle
 from manim.mobject.text.text_mobject import Paragraph
-from manim.mobject.types.vectorized_mobject import VGroup
+from manim.mobject.types.vectorized_mobject import VGroup, VMobjectT
 from manim.utils.color import WHITE
 
 __all__ = ["Code"]
 
 
-class Code(VGroup):
+class Code(VGroup[VMobjectT]):
     """A highlighted source code listing.
 
     An object ``listing`` of :class:`.Code` is a :class:`.VGroup` consisting

manim/mobject/text/text_mobject.py

@@ -71,7 +71,7 @@ def construct(self):
 from manim.constants import *
 from manim.mobject.geometry.arc import Dot
 from manim.mobject.svg.svg_mobject import SVGMobject
-from manim.mobject.types.vectorized_mobject import VGroup, VMobject
+from manim.mobject.types.vectorized_mobject import VGroup, VMobject, VMobjectT
 from manim.utils.color import ManimColor, ParsableManimColor, color_gradient
 from manim.utils.deprecation import deprecated
 
@@ -116,7 +116,7 @@ def remove_invisible_chars(mobject: SVGMobject) -> SVGMobject:
     return mobject_without_dots
 
 
-class Paragraph(VGroup):
+class Paragraph(VGroup[VMobjectT]):
     r"""Display a paragraph of text.
 
     For a given :class:`.Paragraph` ``par``, the attribute ``par.chars`` is a

manim/mobject/three_d/polyhedra.py

@@ -9,15 +9,15 @@
 from manim.mobject.geometry.polygram import Polygon
 from manim.mobject.graph import Graph
 from manim.mobject.three_d.three_dimensions import Dot3D
-from manim.mobject.types.vectorized_mobject import VGroup
+from manim.mobject.types.vectorized_mobject import VGroup, VMobjectT
 
 if TYPE_CHECKING:
     from manim.mobject.mobject import Mobject
 
 __all__ = ["Polyhedron", "Tetrahedron", "Octahedron", "Icosahedron", "Dodecahedron"]
 
 
-class Polyhedron(VGroup):
+class Polyhedron(VGroup[VMobjectT]):
     """An abstract polyhedra class.
 
     In this implementation, polyhedra are defined with a list of vertex coordinates in space, and a list

manim/mobject/three_d/three_dimensions.py

@@ -31,7 +31,7 @@
 from manim.mobject.mobject import *
 from manim.mobject.opengl.opengl_compatibility import ConvertToOpenGL
 from manim.mobject.opengl.opengl_mobject import OpenGLMobject
-from manim.mobject.types.vectorized_mobject import VGroup, VMobject
+from manim.mobject.types.vectorized_mobject import VGroup, VMobject, VMobjectT
 from manim.utils.color import (
     BLUE,
     BLUE_D,
@@ -463,7 +463,7 @@ def __init__(
         self.set_color(color)
 
 
-class Cube(VGroup):
+class Cube(VGroup[VMobjectT]):
     """A three-dimensional cube.
 
     Parameters

manim/mobject/types/vectorized_mobject.py

@@ -18,6 +18,7 @@
     TYPE_CHECKING,
     Callable,
     Generator,
+    Generic,
     Hashable,
     Iterable,
     Literal,
@@ -522,7 +523,7 @@ def get_fill_colors(self) -> list[ManimColor | None]:
     def get_fill_opacities(self) -> npt.NDArray[ManimFloat]:
         return self.get_fill_rgbas()[:, 3]
 
-    def get_stroke_rgbas(self, background: bool = False) -> RGBA_Array_float | Zeros:
+    def get_stroke_rgbas(self, background: bool = False) -> RGBA_Array_Float | Zeros:
         try:
             if background:
                 self.background_stroke_rgbas: RGBA_Array_Float
@@ -1934,7 +1935,10 @@ def force_direction(self, target_direction: Literal["CW", "CCW"]) -> Self:
         return self
 
 
-class VGroup(VMobject, metaclass=ConvertToOpenGL):
+VMobjectT = TypeVar("VMobjectT", bound=VMobject, default=VMobject)
+
+
+class VGroup(VMobject, Generic[VMobjectT], metaclass=ConvertToOpenGL):
     """A group of vectorized mobjects.
 
     This can be used to group multiple :class:`~.VMobject` instances together
@@ -1991,7 +1995,7 @@ def construct(self):
 
     """
 
-    def __init__(self, *vmobjects, **kwargs):
+    def __init__(self, *vmobjects: VMobjectT, **kwargs):
         super().__init__(**kwargs)
         self.add(*vmobjects)
 
@@ -2478,7 +2482,7 @@ def set_location(self, new_loc: Point3D):
         self.set_points(np.array([new_loc]))
 
 
-class CurvesAsSubmobjects(VGroup):
+class CurvesAsSubmobjects(VGroup[VMobject]):
     """Convert a curve's elements to submobjects.
 
     Examples