Make hatch colour an rcParam.

doc/users/dflt_style_changes.rst

@@ -597,17 +597,20 @@ To restore the previous behavior explicitly pass the keyword argument
 Hatching
 ========
 
-The width of the lines in a hatch pattern is now configurable by the
-rcParam `hatch.linewidth`, with a default of 1 point.  The old
-behavior was different depending on backend:
+The color and width of the lines in a hatch pattern are now configurable by the
+rcParams `hatch.color` and `hatch.linewidth`, with defaults of black and 1
+point, respectively.  The old behaviour for the color was to apply the edge
+color or use black, depending on the artist; the old behavior for the line
+width was different depending on backend:
 
     - PDF: 0.1 pt
     - SVG: 1.0 pt
     - PS:  1 px
     - Agg: 1 px
 
-The old behavior can not be restored across all backends simultaneously, but
-can be restored for a single backend by setting::
+The old color behavior can not be restored. The old line width behavior can not
+be restored across all backends simultaneously, but can be restored for a
+single backend by setting::
 
    mpl.rcParams['hatch.linewidth'] = 0.1  # previous pdf hatch linewidth
    mpl.rcParams['hatch.linewidth'] = 1.0  # previous svg hatch linewidth
@@ -620,7 +623,7 @@ The behavior of the PS and Agg backends was DPI dependent, thus::
    mpl.rcParams['hatch.linewidth'] = 1.0 / dpi  # previous ps and Agg hatch linewidth
 
 
-There is no API level control of the hatch linewidth.
+There is no API level control of the hatch color or linewidth.
 
 
 .. _default_changes_font:

lib/matplotlib/backend_bases.py

@@ -796,6 +796,7 @@ def __init__(self):
         self._linewidth = 1
         self._rgb = (0.0, 0.0, 0.0, 1.0)
         self._hatch = None
+        self._hatch_color = colors.to_rgba(rcParams['hatch.color'])
         self._hatch_linewidth = rcParams['hatch.linewidth']
         self._url = None
         self._gid = None
@@ -1104,6 +1105,12 @@ def get_hatch_path(self, density=6.0):
             return None
         return Path.hatch(self._hatch, density)
 
+    def get_hatch_color(self):
+        """
+        Gets the color to use for hatching.
+        """
+        return self._hatch_color
+
     def get_hatch_linewidth(self):
         """
         Gets the linewidth to use for hatching.

lib/matplotlib/backends/backend_pdf.py

@@ -2217,7 +2217,7 @@ def hatch_cmd(self, hatch):
             else:
                 return [Name('DeviceRGB'), Op.setcolorspace_nonstroke]
         else:
-            hatch_style = (self._rgb, self._fillcolor, hatch)
+            hatch_style = (self._hatch_color, self._fillcolor, hatch)
             name = self.file.hatchPattern(hatch_style)
             return [Name('Pattern'), Op.setcolorspace_nonstroke,
                     name, Op.setcolor_nonstroke]

lib/matplotlib/backends/backend_ps.py

@@ -897,7 +897,7 @@ def _draw_ps(self, ps, gc, rgbFace, fill=True, stroke=True, command=None):
         if hatch:
             hatch_name = self.create_hatch(hatch)
             write("gsave\n")
-            write("[/Pattern [/DeviceRGB]] setcolorspace %f %f %f " % gc.get_rgb()[:3])
+            write("[/Pattern [/DeviceRGB]] setcolorspace %f %f %f " % gc.get_hatch_color()[:3])
             write("%s setcolor fill grestore\n" % hatch_name)
 
         if stroke:

lib/matplotlib/backends/backend_svg.py

@@ -349,7 +349,7 @@ def _get_hatch(self, gc, rgbFace):
         """
         if rgbFace is not None:
             rgbFace = tuple(rgbFace)
-        edge = gc.get_rgb()
+        edge = gc.get_hatch_color()
         if edge is not None:
             edge = tuple(edge)
         dictkey = (gc.get_hatch(), rgbFace, edge)

lib/matplotlib/mpl-data/stylelib/classic.mplstyle

@@ -34,6 +34,7 @@ patch.force_edgecolor  : True
 patch.edgecolor        : k
 patch.antialiased      : True    # render patches in antialiased (no jaggies)
 
+hatch.color            : k
 hatch.linewidth        : 1.0
 
 hist.bins              : 10

lib/matplotlib/rcsetup.py

@@ -930,6 +930,7 @@ def validate_animation_writer_path(p):
     'patch.antialiased': [True, validate_bool],     # antialiased (no jaggies)
 
     ## hatch props
+    'hatch.color': ['k', validate_color],
     'hatch.linewidth': [1.0, validate_float],
 
     ## Histogram properties