Add @ shorthand for CoordinateSystem methods coords_to_point (c2p) and point_to_coords (p2c) (#3754)

* Add shorthand for axes

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

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

* Add spacing

Co-authored-by: Victorien <[email protected]>

* Convert CoordinateSystem example, and add to NumberLine

* Add doctest for NumberLine

* Add test

* Fix typehint for c2p

Co-authored-by: Victorien <[email protected]>

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Victorien <[email protected]>
Co-authored-by: Francisco Manríquez Novoa <[email protected]>

Author: 4 people

manim/mobject/graphing/coordinate_systems.py

@@ -27,6 +27,7 @@
 from manim.mobject.graphing.functions import ImplicitFunction, ParametricFunction
 from manim.mobject.graphing.number_line import NumberLine
 from manim.mobject.graphing.scale import LinearBase
+from manim.mobject.mobject import Mobject
 from manim.mobject.opengl.opengl_compatibility import ConvertToOpenGL
 from manim.mobject.opengl.opengl_surface import OpenGLSurface
 from manim.mobject.text.tex_mobject import MathTex
@@ -96,10 +97,10 @@ def construct(self):
                     )
 
                 # Extra lines and labels for point (1,1)
-                graphs += grid.get_horizontal_line(grid.c2p(1, 1, 0), color=BLUE)
-                graphs += grid.get_vertical_line(grid.c2p(1, 1, 0), color=BLUE)
-                graphs += Dot(point=grid.c2p(1, 1, 0), color=YELLOW)
-                graphs += Tex("(1,1)").scale(0.75).next_to(grid.c2p(1, 1, 0))
+                graphs += grid.get_horizontal_line(grid @ (1, 1, 0), color=BLUE)
+                graphs += grid.get_vertical_line(grid @ (1, 1, 0), color=BLUE)
+                graphs += Dot(point=grid @ (1, 1, 0), color=YELLOW)
+                graphs += Tex("(1,1)").scale(0.75).next_to(grid @ (1, 1, 0))
                 title = Title(
                     # spaces between braces to prevent SyntaxError
                     r"Graphs of $y=x^{ {1}\over{n} }$ and $y=x^n (n=1,2,3,...,20)$",
@@ -145,7 +146,7 @@ def __init__(
         self.y_length = y_length
         self.num_sampled_graph_points_per_tick = 10
 
-    def coords_to_point(self, *coords: Sequence[ManimFloat]):
+    def coords_to_point(self, *coords: ManimFloat):
         raise NotImplementedError()
 
     def point_to_coords(self, point: Point3D):
@@ -570,7 +571,7 @@ def get_horizontal_line(self, point: Sequence[float], **kwargs) -> Line:
             class GetHorizontalLineExample(Scene):
                 def construct(self):
                     ax = Axes().add_coordinates()
-                    point = ax.c2p(-4, 1.5)
+                    point = ax @ (-4, 1.5)
 
                     dot = Dot(point)
                     line = ax.get_horizontal_line(point, line_func=Line)
@@ -1790,6 +1791,14 @@ def construct(self):
 
         return T_label_group
 
+    def __matmul__(self, coord: Point3D | Mobject):
+        if isinstance(coord, Mobject):
+            coord = coord.get_center()
+        return self.coords_to_point(*coord)
+
+    def __rmatmul__(self, point: Point3D):
+        return self.point_to_coords(point)
+
 
 class Axes(VGroup, CoordinateSystem, metaclass=ConvertToOpenGL):
     """Creates a set of axes.
@@ -1990,6 +1999,7 @@ def coords_to_point(
         self, *coords: float | Sequence[float] | Sequence[Sequence[float]] | np.ndarray
     ) -> np.ndarray:
         """Accepts coordinates from the axes and returns a point with respect to the scene.
+        Equivalent to `ax @ (coord1)`
 
         Parameters
         ----------
@@ -2018,6 +2028,8 @@ def coords_to_point(
             >>> ax = Axes()
             >>> np.around(ax.coords_to_point(1, 0, 0), 2)
             array([0.86, 0.  , 0.  ])
+            >>> np.around(ax @ (1, 0, 0), 2)
+            array([0.86, 0.  , 0.  ])
             >>> np.around(ax.coords_to_point([[0, 1], [1, 1], [1, 0]]), 2)
             array([[0.  , 0.75, 0.  ],
                    [0.86, 0.75, 0.  ],

manim/mobject/graphing/number_line.py

@@ -2,6 +2,7 @@
 
 from __future__ import annotations
 
+from manim.mobject.mobject import Mobject
 from manim.mobject.opengl.opengl_vectorized_mobject import OpenGLVMobject
 
 __all__ = ["NumberLine", "UnitInterval"]
@@ -12,6 +13,7 @@
 
 if TYPE_CHECKING:
     from manim.mobject.geometry.tips import ArrowTip
+    from manim.typing import Point3D
 
 import numpy as np
 
@@ -344,6 +346,7 @@ def get_tick_range(self) -> np.ndarray:
     def number_to_point(self, number: float | np.ndarray) -> np.ndarray:
         """Accepts a value along the number line and returns a point with
         respect to the scene.
+        Equivalent to `NumberLine @ number`
 
         Parameters
         ----------
@@ -364,6 +367,8 @@ def number_to_point(self, number: float | np.ndarray) -> np.ndarray:
             array([0., 0., 0.])
             >>> number_line.number_to_point(1)
             array([1., 0., 0.])
+            >>> number_line @ 1
+            array([1., 0., 0.])
             >>> number_line.number_to_point([1, 2, 3])
             array([[1., 0., 0.],
                    [2., 0., 0.],
@@ -642,6 +647,14 @@ def _decimal_places_from_step(step) -> int:
             return 0
         return len(step.split(".")[-1])
 
+    def __matmul__(self, other: float):
+        return self.n2p(other)
+
+    def __rmatmul__(self, other: Point3D | Mobject):
+        if isinstance(other, Mobject):
+            other = other.get_center()
+        return self.p2n(other)
+
 
 class UnitInterval(NumberLine):
     def __init__(

tests/module/mobject/graphing/test_coordinate_system.py

@@ -7,7 +7,7 @@
 
 from manim import LEFT, ORIGIN, PI, UR, Axes, Circle, ComplexPlane
 from manim import CoordinateSystem as CS
-from manim import NumberPlane, PolarPlane, ThreeDAxes, config, tempconfig
+from manim import Dot, NumberPlane, PolarPlane, ThreeDAxes, config, tempconfig
 
 
 def test_initial_config():
@@ -119,7 +119,15 @@ def test_coords_to_point():
 
     # a point with respect to the axes
     c2p_coord = np.around(ax.coords_to_point(2, 2), decimals=4)
-    np.testing.assert_array_equal(c2p_coord, (1.7143, 1.5, 0))
+    c2p_coord_matmul = np.around(ax @ (2, 2), decimals=4)
+
+    expected = (1.7143, 1.5, 0)
+
+    np.testing.assert_array_equal(c2p_coord, expected)
+    np.testing.assert_array_equal(c2p_coord_matmul, c2p_coord)
+
+    mob = Dot().move_to((2, 2, 0))
+    np.testing.assert_array_equal(np.around(ax @ mob, decimals=4), expected)
 
 
 def test_coords_to_point_vectorized():