Merge pull request matplotlib#30583 from timhoffm/cmap-ensure_inited

MNT: Streamline deferred initialization of Colormap

Author: rcomer

lib/matplotlib/colors.py

@@ -805,8 +805,7 @@ def _get_rgba_and_mask(self, X, alpha=None, bytes=False):
         mask : np.ndarray
             Boolean array with True where the input is ``np.nan`` or masked.
         """
-        if not self._isinit:
-            self._init()
+        self._ensure_inited()
 
         xa = np.array(X, copy=True)
         if not xa.dtype.isnative:
@@ -863,16 +862,13 @@ def __eq__(self, other):
                 self.colorbar_extend != other.colorbar_extend):
             return False
         # To compare lookup tables the Colormaps have to be initialized
-        if not self._isinit:
-            self._init()
-        if not other._isinit:
-            other._init()
+        self._ensure_inited()
+        other._ensure_inited()
         return np.array_equal(self._lut, other._lut)
 
     def get_bad(self):
         """Get the color for masked values."""
-        if not self._isinit:
-            self._init()
+        self._ensure_inited()
         return np.array(self._lut[self._i_bad])
 
     def set_bad(self, color='k', alpha=None):
@@ -881,8 +877,7 @@ def set_bad(self, color='k', alpha=None):
 
     def get_under(self):
         """Get the color for low out-of-range values."""
-        if not self._isinit:
-            self._init()
+        self._ensure_inited()
         return np.array(self._lut[self._i_under])
 
     def set_under(self, color='k', alpha=None):
@@ -891,8 +886,7 @@ def set_under(self, color='k', alpha=None):
 
     def get_over(self):
         """Get the color for high out-of-range values."""
-        if not self._isinit:
-            self._init()
+        self._ensure_inited()
         return np.array(self._lut[self._i_over])
 
     def set_over(self, color='k', alpha=None):
@@ -957,19 +951,21 @@ def with_alpha(self, alpha):
         if not 0 <= alpha <= 1:
             raise ValueError("'alpha' must be between 0 and 1, inclusive")
         new_cm = self.copy()
-        if not new_cm._isinit:
-            new_cm._init()
+        new_cm._ensure_inited()
         new_cm._lut[:, 3] = alpha
         return new_cm
 
     def _init(self):
         """Generate the lookup table, ``self._lut``."""
         raise NotImplementedError("Abstract class only")
 
-    def is_gray(self):
-        """Return whether the colormap is grayscale."""
+    def _ensure_inited(self):
         if not self._isinit:
             self._init()
+
+    def is_gray(self):
+        """Return whether the colormap is grayscale."""
+        self._ensure_inited()
         return (np.all(self._lut[:, 0] == self._lut[:, 1]) and
                 np.all(self._lut[:, 0] == self._lut[:, 2]))
 
@@ -1363,9 +1359,7 @@ def monochrome(self):
         # TODO: It's a separate discussion whether we need this property on
         #       colormaps at all (at least as public API). It's a very special edge
         #       case and we only use it for contours internally.
-        if not self._isinit:
-            self._init()
-
+        self._ensure_inited()
         return self.N <= 1 or np.all(self._lut[0] == self._lut[1:self.N])
 
     def resampled(self, lutsize):