Further optimize "colour.SpectralDistribution.shape" computation by e…

…xpecting and assuming that the domain is monotonic.

colour/colorimetry/spectrum.py

@@ -836,26 +836,17 @@ def shape(self) -> SpectralShape:
         SpectralShape(500.0, 600.0, 10.0)
         """
 
-        wavelengths_interval = interval(self.wavelengths)
+        wavelengths = self.wavelengths
+        wavelengths_interval = interval(wavelengths)
         if wavelengths_interval.size != 1:
             runtime_warning(
                 f'"{self.name}" spectral distribution is not uniform, using '
                 f"minimum interval!"
             )
 
-        # If wavelengths is sorted, then go fast. Otherwise compute the shape.
-        if np.all(self.domain[:-1] <= self.domain[1:]):
-            return SpectralShape(
-                self.domain[0],
-                self.domain[-1],
-                min(wavelengths_interval),
-            )
-        else:
-            return SpectralShape(
-                min(self.domain),
-                max(self.domain),
-                min(wavelengths_interval),
-            )
+        return SpectralShape(
+            wavelengths[0], wavelengths[-1], min(wavelengths_interval)
+        )
 
     def interpolate(
         self,

colour/continuous/signal.py

@@ -343,6 +343,11 @@ def domain(self, value: ArrayLike):
                 f'"{self.name}" new "domain" variable is not finite: {value}, '
                 f"unpredictable results may occur!"
             )
+        else:
+            attest(
+                np.all(value[:-1] <= value[1:]),
+                "The new domain value is not monotonic! ",
+            )
 
         if value.size != self._range.size:
             self._range = np.resize(self._range, value.shape)

colour/utilities/common.py

@@ -36,6 +36,7 @@
     Boolean,
     Callable,
     Dict,
+    DTypeBoolean,
     Generator,
     Integer,
     Iterable,
@@ -366,7 +367,7 @@ def wrapper(*args: Any, **kwargs: Any) -> Any:
     return wrapper
 
 
-def attest(condition: Boolean, message: str = ""):
+def attest(condition: Union[Boolean, DTypeBoolean], message: str = ""):
     """
     Provide the `assert` statement functionality without being disabled by
     optimised Python execution.