ENH/API: pass cycler into to_rgba to resolve CN

tacaswell · tacaswell · commit 5e7708562780 · 2016-05-29T18:39:56.000-04:00
Be able to over-ride the global property cycler for CN lookup by
passing in a kwarg.
diff --git a/lib/matplotlib/axes/_base.py b/lib/matplotlib/axes/_base.py
@@ -44,7 +44,7 @@
 is_sequence_of_strings = cbook.is_sequence_of_strings
 
 
-def _process_plot_format(fmt):
+def _process_plot_format(fmt, prop_cycler=None):
     """
     Process a MATLAB style color/line style format string.  Return a
     (*linestyle*, *color*) tuple as a result of the processing.  Default
@@ -68,7 +68,7 @@ def _process_plot_format(fmt):
 
     # Is fmt just a colorspec?
     try:
-        color = mcolors.to_rgba(fmt)
+        color = mcolors.to_rgba(fmt, prop_cycler=prop_cycler)
 
         # We need to differentiate grayscale '1.0' from tri_down marker '1'
         try:
@@ -119,7 +119,8 @@ def _process_plot_format(fmt):
             color = c
         elif c == 'C' and i < len(chars) - 1:
             color_cycle_number = int(chars[i + 1])
-            color = mcolors.to_rgba("C{}".format(color_cycle_number))
+            color = mcolors.to_rgba("C{}".format(color_cycle_number),
+                                    prop_cycler=prop_cycler)
             i += 1
         else:
             raise ValueError(
@@ -168,6 +169,8 @@ def set_prop_cycle(self, *args, **kwargs):
             prop_cycler = cycler(*args, **kwargs)
 
         self.prop_cycler = itertools.cycle(prop_cycler)
+        # keep a private copy of it
+        self._prop_cycler_obj = prop_cycler
         # This should make a copy
         self._prop_keys = prop_cycler.keys
 
@@ -350,7 +353,8 @@ def _makefill(self, x, y, kw, kwargs):
     def _plot_args(self, tup, kwargs):
         ret = []
         if len(tup) > 1 and is_string_like(tup[-1]):
-            linestyle, marker, color = _process_plot_format(tup[-1])
+            linestyle, marker, color = _process_plot_format(
+                tup[-1], self._prop_cycler_obj)
             tup = tup[:-1]
         elif len(tup) == 3:
             raise ValueError('third arg must be a format string')
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -118,15 +118,16 @@ def is_color_like(c):
         return True
 
 
-def to_rgba(c, alpha=None):
+def to_rgba(c, alpha=None, prop_cycler=None):
     """Convert `c` to an RGBA color.
 
     If `alpha` is not `None`, it forces the alpha value.
     """
     # Special-case nth color syntax because it should not be cached.
     if _is_nth_color(c):
-        from matplotlib import rcParams
-        prop_cycler = rcParams['axes.prop_cycle']
+        if prop_cycler is None:
+            from matplotlib import rcParams
+            prop_cycler = rcParams['axes.prop_cycle']
         colors = prop_cycler.by_key().get('color', ['k'])
         c = colors[int(c[1]) % len(colors)]
     try:
@@ -211,8 +212,8 @@ def to_rgba_array(c, alpha=None):
     # Special-case inputs that are already arrays, for performance.  (If the
     # array has the wrong kind or shape, raise the error during one-at-a-time
     # conversion.)
-    if (isinstance(c, np.ndarray) and c.dtype.kind in "if"
-            and c.ndim == 2 and c.shape[1] in [3, 4]):
+    if (isinstance(c, np.ndarray) and c.dtype.kind in "if" and
+            c.ndim == 2 and c.shape[1] in [3, 4]):
         if c.shape[1] == 3:
             result = np.column_stack([c, np.zeros(len(c))])
             result[:, -1] = alpha if alpha is not None else 1.
@@ -230,10 +231,10 @@ def to_rgba_array(c, alpha=None):
     return result
 
 
-def to_rgb(c):
+def to_rgb(c, prop_cycler=None):
     """Convert `c` to an RGB color, silently dropping the alpha channel.
     """
-    return to_rgba(c)[:3]
+    return to_rgba(c, prop_cycler=prop_cycler)[:3]
 
 
 def to_hex(c, keep_alpha=False):
@@ -248,8 +249,7 @@ def to_hex(c, keep_alpha=False):
     return "#" + "".join(format(int(np.round(val * 255)), "02x")
                          for val in c)
 
-
-### Backwards-compatible color-conversion API
+# ## Backwards-compatible color-conversion API
 
 cnames = CSS4_COLORS
 COLOR_NAMES = {'xkcd': XKCD_COLORS, 'css4': CSS4_COLORS}
