Implement support for better ndarray copy management in `colour.con…

…tinuous.Signal` class.

colour/continuous/signal.py

@@ -50,6 +50,8 @@
     full,
     is_pandas_installed,
     multiline_repr,
+    ndarray_copy,
+    ndarray_copy_enable,
     optional,
     required,
     runtime_warning,
@@ -329,7 +331,7 @@ def domain(self) -> NDArrayFloat:
             Continuous signal independent domain variable :math:`x`.
         """
 
-        return np.copy(self._domain)
+        return ndarray_copy(self._domain)
 
     @domain.setter
     def domain(self, value: ArrayLike):
@@ -372,7 +374,7 @@ def range(self) -> NDArrayFloat:  # noqa: A003
             Continuous signal corresponding range variable :math:`y`.
         """
 
-        return np.copy(self._range)
+        return ndarray_copy(self._range)
 
     @range.setter
     def range(self, value: ArrayLike):  # noqa: A003
@@ -531,7 +533,7 @@ def function(self) -> Callable:
             if self._domain.size != 0 and self._range.size != 0:
                 self._function = self._extrapolator(
                     self._interpolator(
-                        self.domain, self.range, **self._interpolator_kwargs
+                        self._domain, self._range, **self._interpolator_kwargs
                     ),
                     **self._extrapolator_kwargs,
                 )
@@ -590,7 +592,7 @@ def __str__(self) -> str:
          [   9.  100.]]
         """
 
-        return str(tstack([self.domain, self.range]))
+        return str(tstack([self._domain, self._range]))
 
     def __repr__(self) -> str:
         """
@@ -629,17 +631,17 @@ def __repr__(self) -> str:
             [
                 {
                     "formatter": lambda x: repr(  # noqa: ARG005
-                        tstack([self.domain, self.range])
+                        tstack([self._domain, self._range])
                     ),
                 },
                 {
                     "name": "interpolator",
-                    "formatter": lambda x: self.interpolator.__name__,  # noqa: ARG005
+                    "formatter": lambda x: self._interpolator.__name__,  # noqa: ARG005
                 },
                 {"name": "interpolator_kwargs"},
                 {
                     "name": "extrapolator",
-                    "formatter": lambda x: self.extrapolator.__name__,  # noqa: ARG005
+                    "formatter": lambda x: self._extrapolator.__name__,  # noqa: ARG005
                 },
                 {"name": "extrapolator_kwargs"},
             ],
@@ -657,12 +659,12 @@ def __hash__(self) -> int:
 
         return hash(
             (
-                self.domain.tobytes(),
-                self.range.tobytes(),
-                self.interpolator.__name__,
-                repr(self.interpolator_kwargs),
-                self.extrapolator.__name__,
-                repr(self.extrapolator_kwargs),
+                self._domain.tobytes(),
+                self._range.tobytes(),
+                self._interpolator.__name__,
+                repr(self._interpolator_kwargs),
+                self._extrapolator.__name__,
+                repr(self._extrapolator_kwargs),
             )
         )
 
@@ -842,6 +844,7 @@ def __contains__(self, x: ArrayLike) -> bool:
             )
         )
 
+    @ndarray_copy_enable(False)
     def __eq__(self, other: Any) -> bool:
         """
         Return whether the continuous signal is equal to given other object.
@@ -948,7 +951,7 @@ def _fill_domain_nan(
             variable.
         """
 
-        self.domain = fill_nan(self.domain, method, default)
+        self.domain = fill_nan(self._domain, method, default)
 
     def _fill_range_nan(
         self,
@@ -973,8 +976,9 @@ def _fill_range_nan(
             variable.
         """
 
-        self.range = fill_nan(self.range, method, default)
+        self.range = fill_nan(self._range, method, default)
 
+    @ndarray_copy_enable(False)
     def arithmetical_operation(
         self,
         a: ArrayLike | AbstractContinuousFunction,
@@ -1073,7 +1077,7 @@ def arithmetical_operation(
                 exclusive_or = np.setxor1d(self._domain, a.domain)
                 self[exclusive_or] = full(exclusive_or.shape, np.nan)
             else:
-                self.range = ioperator(self.range, a)
+                self.range = ioperator(self._range, a)
 
             return self
         else:

colour/utilities/__init__.py

@@ -99,6 +99,10 @@
     from_range_100,
     from_range_degrees,
     from_range_int,
+    is_ndarray_copy_enabled,
+    set_ndarray_copy_enable,
+    ndarray_copy_enable,
+    ndarray_copy,
     closest_indexes,
     closest,
     interval,
@@ -217,6 +221,10 @@
     "from_range_100",
     "from_range_degrees",
     "from_range_int",
+    "is_ndarray_copy_enabled",
+    "set_ndarray_copy_enable",
+    "ndarray_copy_enable",
+    "ndarray_copy",
     "closest_indexes",
     "closest",
     "normalise_maximum",

colour/utilities/array.py

@@ -88,6 +88,10 @@
     "from_range_100",
     "from_range_degrees",
     "from_range_int",
+    "is_ndarray_copy_enabled",
+    "set_ndarray_copy_enable",
+    "ndarray_copy_enable",
+    "ndarray_copy",
     "closest_indexes",
     "closest",
     "interval",
@@ -1788,6 +1792,142 @@ def from_range_int(
     return a
 
 
+_NDARRAY_COPY_ENABLED: bool = True
+"""
+Global variable storing the current *Colour* state for
+:class:`numpy.ndarray` copy.
+"""
+
+
+def is_ndarray_copy_enabled() -> bool:
+    """
+    Return whether *Colour* :class:`numpy.ndarray` copy is enabled: Various API
+    objects return a copy of their internal :class:`numpy.ndarray` for safety
+    purposes but this can be a slow operation impacting performance.
+
+    Returns
+    -------
+    :class:`bool`
+        Whether *Colour* :class:`numpy.ndarray` copy is enabled.
+
+    Examples
+    --------
+    >>> with ndarray_copy_enable(False):
+    ...     is_ndarray_copy_enabled()
+    ...
+    False
+    >>> with ndarray_copy_enable(True):
+    ...     is_ndarray_copy_enabled()
+    ...
+    True
+    """
+
+    return _NDARRAY_COPY_ENABLED
+
+
+def set_ndarray_copy_enable(enable: bool):
+    """
+    Set *Colour* :class:`numpy.ndarray` copy enabled state.
+
+    Parameters
+    ----------
+    enable
+        Whether to enable *Colour* :class:`numpy.ndarray` copy.
+
+    Examples
+    --------
+    >>> with ndarray_copy_enable(is_ndarray_copy_enabled()):
+    ...     print(is_ndarray_copy_enabled())
+    ...     set_ndarray_copy_enable(False)
+    ...     print(is_ndarray_copy_enabled())
+    ...
+    True
+    False
+    """
+
+    global _NDARRAY_COPY_ENABLED
+
+    _NDARRAY_COPY_ENABLED = enable
+
+
+class ndarray_copy_enable:
+    """
+    Define a context manager and decorator temporarily setting *Colour*
+    :class:`numpy.ndarray` copy enabled state.
+
+    Parameters
+    ----------
+    enable
+        Whether to enable or disable *Colour* :class:`numpy.ndarray` copy.
+    """
+
+    def __init__(self, enable: bool) -> None:
+        self._enable = enable
+        self._previous_state = is_ndarray_copy_enabled()
+
+    def __enter__(self) -> ndarray_copy_enable:
+        """
+        Set the *Colour* :class:`numpy.ndarray` copy enabled state
+        upon entering the context manager.
+        """
+
+        set_ndarray_copy_enable(self._enable)
+
+        return self
+
+    def __exit__(self, *args: Any):
+        """
+        Set the *Colour* :class:`numpy.ndarray` copy enabled state
+        upon exiting the context manager.
+        """
+
+        set_ndarray_copy_enable(self._previous_state)
+
+    def __call__(self, function: Callable) -> Callable:
+        """Call the wrapped definition."""
+
+        @functools.wraps(function)
+        def wrapper(*args: Any, **kwargs: Any) -> Any:
+            with self:
+                return function(*args, **kwargs)
+
+        return wrapper
+
+
+def ndarray_copy(a: NDArray) -> NDArray:
+    """
+    Return a :class:`numpy.ndarray` copy if the relevant *Colour* state is
+    enabled: Various API objects return a copy of their internal
+    :class:`numpy.ndarray` for safety purposes but this can be a slow operation
+    impacting performance.
+
+    Parameters
+    ----------
+    a
+        Array :math:`a` to return a copy of.
+
+    Returns
+    -------
+    :class:`numpy.ndarray`
+        Array :math:`a` copy according to *Colour* state.
+
+    Examples
+    --------
+    >>> a = np.linspace(0, 1, 10)
+    >>> id(a) == id(ndarray_copy(a))
+    False
+    >>> with ndarray_copy_enable(False):
+    ...     id(a) == id(ndarray_copy(a))
+    ...
+    True
+    """
+
+    if _NDARRAY_COPY_ENABLED:
+        return np.copy(a)
+    else:
+        return a
+
+
 def closest_indexes(a: ArrayLike, b: ArrayLike) -> NDArray:
     """
     Return the array :math:`a` closest element indexes to the reference array