take capsize from rcParams, key: errorbar.capsize

Author: Hans Dembinski

lib/matplotlib/axes/_axes.py

@@ -1862,7 +1862,8 @@ def bar(self, left, height, width=0.8, bottom=None, **kwargs):
 
         capsize : integer, optional
            determines the length in points of the error bar caps
-           default: 3
+           default: None, which will take the value from the
+           ``errorbar.capsize`` :data:`rcParam<matplotlib.rcParams>`.
 
         error_kw : dict, optional
             dictionary of kwargs to be passed to errorbar method. *ecolor* and
@@ -1928,7 +1929,7 @@ def bar(self, left, height, width=0.8, bottom=None, **kwargs):
         yerr = kwargs.pop('yerr', None)
         error_kw = kwargs.pop('error_kw', dict())
         ecolor = kwargs.pop('ecolor', None)
-        capsize = kwargs.pop('capsize', 3)
+        capsize = kwargs.pop('capsize', rcParams["errorbar.capsize"])
         error_kw.setdefault('ecolor', ecolor)
         error_kw.setdefault('capsize', capsize)
 
@@ -2189,8 +2190,10 @@ def barh(self, bottom, width, height=0.8, left=None, **kwargs):
         ecolor : scalar or array-like, optional, default: None
             specifies the color of errorbar(s)
 
-        capsize : integer, optional, default: 3
+        capsize : integer, optional
            determines the length in points of the error bar caps
+           default: None, which will take the value from the
+           ``errorbar.capsize`` :data:`rcParam<matplotlib.rcParams>`.
 
         error_kw :
             dictionary of kwargs to be passed to errorbar method. `ecolor` and
@@ -2583,7 +2586,7 @@ def pie(self, x, explode=None, labels=None, colors=None,
 
     @docstring.dedent_interpd
     def errorbar(self, x, y, yerr=None, xerr=None,
-                 fmt='', ecolor=None, elinewidth=None, capsize=3,
+                 fmt='', ecolor=None, elinewidth=None, capsize=None,
                  barsabove=False, lolims=False, uplims=False,
                  xlolims=False, xuplims=False, errorevery=1, capthick=None,
                  **kwargs):
@@ -2630,7 +2633,8 @@ def errorbar(self, x, y, yerr=None, xerr=None,
             The linewidth of the errorbar lines. If *None*, use the linewidth.
 
           *capsize*: scalar
-            The length of the error bar caps in points
+            The length of the error bar caps in points; if *None*, it will
+            take the value from ``errorbar.capsize`` :data:`rcParam<matplotlib.rcParams>`.
 
           *capthick*: scalar
             An alias kwarg to *markeredgewidth* (a.k.a. - *mew*). This
@@ -2783,6 +2787,8 @@ def xywhere(xs, ys, mask):
             return xs, ys
 
         plot_kw = {'label': '_nolegend_'}
+        if capsize is None:
+            capsize = rcParams["errorbar.capsize"]
         if capsize > 0:
             plot_kw['ms'] = 2. * capsize
         if capthick is not None:

lib/matplotlib/rcsetup.py

@@ -623,6 +623,9 @@ def __call__(self, s):
                                     validate_negative_linestyle_legacy],
     'contour.corner_mask':        [True, validate_corner_mask],
 
+    # errorbar props
+    'errorbar.capsize':      [3, validate_float],
+
     # axes props
     'axes.axisbelow':        [False, validate_bool],
     'axes.hold':             [True, validate_bool],

matplotlibrc.template

@@ -363,6 +363,9 @@ backend      : %(backend)s
 #contour.negative_linestyle : dashed # dashed | solid
 #contour.corner_mask        : True   # True | False | legacy
 
+### ERRORBAR PLOTS
+#errorbar.capsize : 3             # length of end cap on error bars in pixels
+
 ### Agg rendering
 ### Warning: experimental, 2008/10/10
 #agg.path.chunksize : 0           # 0 to disable; values in the range