Fix errorbar extension arrows

lib/matplotlib/axes/_axes.py

@@ -2923,9 +2923,9 @@ def xywhere(xs, ys, mask):
                 barcols.append(self.hlines(yo, lo, ro, **lines_kw))
                 rightup, yup = xywhere(right, y, xlolims & everymask)
                 if self.xaxis_inverted():
-                    marker = mlines.CARETLEFT
+                    marker = mlines.CARETLEFTBASE
                 else:
-                    marker = mlines.CARETRIGHT
+                    marker = mlines.CARETRIGHTBASE
                 caplines.extend(
                     self.plot(rightup, yup, ls='None', marker=marker,
                               **plot_kw))
@@ -2939,9 +2939,9 @@ def xywhere(xs, ys, mask):
                 barcols.append(self.hlines(yo, lo, ro, **lines_kw))
                 leftlo, ylo = xywhere(left, y, xuplims & everymask)
                 if self.xaxis_inverted():
-                    marker = mlines.CARETRIGHT
+                    marker = mlines.CARETRIGHTBASE
                 else:
-                    marker = mlines.CARETLEFT
+                    marker = mlines.CARETLEFTBASE
                 caplines.extend(
                     self.plot(leftlo,  ylo, ls='None', marker=marker,
                               **plot_kw))
@@ -2987,9 +2987,9 @@ def xywhere(xs, ys, mask):
                 barcols.append(self.vlines(xo, lo, uo, **lines_kw))
                 xup, upperup = xywhere(x, upper, lolims & everymask)
                 if self.yaxis_inverted():
-                    marker = mlines.CARETDOWN
+                    marker = mlines.CARETDOWNBASE
                 else:
-                    marker = mlines.CARETUP
+                    marker = mlines.CARETUPBASE
                 caplines.extend(
                     self.plot(xup, upperup, ls='None', marker=marker,
                               **plot_kw))
@@ -3003,9 +3003,9 @@ def xywhere(xs, ys, mask):
                 barcols.append(self.vlines(xo, lo, uo, **lines_kw))
                 xlo, lowerlo = xywhere(x, lower, uplims & everymask)
                 if self.yaxis_inverted():
-                    marker = mlines.CARETUP
+                    marker = mlines.CARETUPBASE
                 else:
-                    marker = mlines.CARETDOWN
+                    marker = mlines.CARETDOWNBASE
                 caplines.extend(
                     self.plot(xlo, lowerlo, ls='None', marker=marker,
                               **plot_kw))

lib/matplotlib/lines.py

@@ -30,7 +30,9 @@
 # Imported here for backward compatibility, even though they don't
 # really belong.
 from matplotlib.markers import TICKLEFT, TICKRIGHT, TICKUP, TICKDOWN
-from matplotlib.markers import CARETLEFT, CARETRIGHT, CARETUP, CARETDOWN
+from matplotlib.markers import (
+    CARETLEFT, CARETRIGHT, CARETUP, CARETDOWN,
+    CARETLEFTBASE, CARETRIGHTBASE, CARETUPBASE, CARETDOWNBASE)
 
 
 def segment_hits(cx, cy, x, y, radius):

lib/matplotlib/markers.py

@@ -35,10 +35,13 @@
 TICKRIGHT                      tickright
 TICKUP                         tickup
 TICKDOWN                       tickdown
-CARETLEFT                      caretleft
-CARETRIGHT                     caretright
-CARETUP                        caretup
-CARETDOWN                      caretdown
+CARETLEFT                      caretleft (centered at tip)
+CARETRIGHT                     caretright (centered at tip)
+CARETUP                        caretup (centered at tip)
+CARETDOWN                      caretdown (centered at tip)
+CARETLEFTBASE                  caretleft (centered at base)
+CARETRIGHTBASE                 caretright (centered at base)
+CARETUPBASE                    caretup (centered at base)
 "None"                         nothing
 None                           nothing
 " "                            nothing
@@ -91,7 +94,8 @@
 
 # special-purpose marker identifiers:
 (TICKLEFT, TICKRIGHT, TICKUP, TICKDOWN,
- CARETLEFT, CARETRIGHT, CARETUP, CARETDOWN) = list(xrange(8))
+ CARETLEFT, CARETRIGHT, CARETUP, CARETDOWN,
+ CARETLEFTBASE, CARETRIGHTBASE, CARETUPBASE, CARETDOWNBASE) = list(xrange(12))
 
 
 class MarkerStyle(object):
@@ -128,6 +132,10 @@ class MarkerStyle(object):
         CARETRIGHT: 'caretright',
         CARETUP: 'caretup',
         CARETDOWN: 'caretdown',
+        CARETLEFTBASE: 'caretleftbase',
+        CARETRIGHTBASE: 'caretrightbase',
+        CARETUPBASE: 'caretupbase',
+        CARETDOWNBASE: 'caretdownbase',
         "None": 'nothing',
         None: 'nothing',
         ' ': 'nothing',
@@ -779,6 +787,36 @@ def _set_caretright(self):
         self._path = self._caret_path
         self._joinstyle = 'miter'
 
+    _caret_path_base = Path([[-1.0, 0.0], [0.0, -1.5], [1.0, 0]])
+
+    def _set_caretdownbase(self):
+        self._transform = Affine2D().scale(0.5)
+        self._snap_threshold = 3.0
+        self._filled = False
+        self._path = self._caret_path_base
+        self._joinstyle = 'miter'
+
+    def _set_caretupbase(self):
+        self._transform = Affine2D().scale(0.5).rotate_deg(180)
+        self._snap_threshold = 3.0
+        self._filled = False
+        self._path = self._caret_path_base
+        self._joinstyle = 'miter'
+
+    def _set_caretleftbase(self):
+        self._transform = Affine2D().scale(0.5).rotate_deg(270)
+        self._snap_threshold = 3.0
+        self._filled = False
+        self._path = self._caret_path_base
+        self._joinstyle = 'miter'
+
+    def _set_caretrightbase(self):
+        self._transform = Affine2D().scale(0.5).rotate_deg(90)
+        self._snap_threshold = 3.0
+        self._filled = False
+        self._path = self._caret_path_base
+        self._joinstyle = 'miter'
+
     _x_path = Path([[-1.0, -1.0], [1.0, 1.0],
                     [-1.0, 1.0], [1.0, -1.0]],
                    [Path.MOVETO, Path.LINETO,