Merge pull request matplotlib#11105 from anntzer/markerfacecolor-none-alpha

FIX: When drawing markers, don't set the GraphicsContext alpha.

Author: tacaswell

lib/matplotlib/backends/backend_ps.py

@@ -532,7 +532,10 @@ def draw_markers(
         ps_cmd = ['/o {', 'gsave', 'newpath', 'translate'] # don't want the translate to be global
 
         lw = gc.get_linewidth()
-        stroke = lw != 0.0
+        alpha = (gc.get_alpha()
+                 if gc.get_forced_alpha() or len(gc.get_rgb()) == 3
+                 else gc.get_rgb()[3])
+        stroke = lw > 0 and alpha > 0
         if stroke:
             ps_cmd.append('%.1f setlinewidth' % lw)
             jint = gc.get_joinstyle()

lib/matplotlib/lines.py

@@ -757,9 +757,8 @@ def draw(self, renderer):
                 gc = renderer.new_gc()
                 self._set_gc_clip(gc)
 
-                ln_color_rgba = self._get_rgba_ln_color()
-                gc.set_foreground(ln_color_rgba, isRGBA=True)
-                gc.set_alpha(ln_color_rgba[3])
+                lc_rgba = mcolors.to_rgba(self._color, self._alpha)
+                gc.set_foreground(lc_rgba, isRGBA=True)
 
                 gc.set_antialiased(self._antialiased)
                 gc.set_linewidth(self._linewidth)
@@ -783,24 +782,23 @@ def draw(self, renderer):
         if self._marker and self._markersize > 0:
             gc = renderer.new_gc()
             self._set_gc_clip(gc)
-            rgbaFace = self._get_rgba_face()
-            rgbaFaceAlt = self._get_rgba_face(alt=True)
-            edgecolor = self.get_markeredgecolor()
-            if cbook._str_lower_equal(edgecolor, "none"):
-                gc.set_linewidth(0)
-                gc.set_foreground(rgbaFace, isRGBA=True)
-            else:
-                gc.set_foreground(edgecolor)
-                gc.set_linewidth(self._markeredgewidth)
-                mec = self._markeredgecolor
-                if (cbook._str_equal(mec, "auto")
-                        and not cbook._str_lower_equal(
-                            self.get_markerfacecolor(), "none")):
-                    gc.set_alpha(rgbaFace[3])
-                else:
-                    gc.set_alpha(self.get_alpha())
+            gc.set_linewidth(self._markeredgewidth)
             gc.set_antialiased(self._antialiased)
 
+            ec_rgba = mcolors.to_rgba(
+                self.get_markeredgecolor(), self._alpha)
+            fc_rgba = mcolors.to_rgba(
+                self._get_markerfacecolor(), self._alpha)
+            fcalt_rgba = mcolors.to_rgba(
+                self._get_markerfacecolor(alt=True), self._alpha)
+            # If the edgecolor is "auto", it is set according to the *line*
+            # color but inherits the alpha value of the *face* color, if any.
+            if (cbook._str_equal(self._markeredgecolor, "auto")
+                    and not cbook._str_lower_equal(
+                        self.get_markerfacecolor(), "none")):
+                ec_rgba = ec_rgba[:3] + (fc_rgba[3],)
+            gc.set_foreground(ec_rgba, isRGBA=True)
+
             marker = self._marker
             tpath, affine = transf_path.get_transformed_points_and_affine()
             if len(tpath.vertices):
@@ -830,22 +828,15 @@ def draw(self, renderer):
 
                 renderer.draw_markers(gc, marker_path, marker_trans,
                                       subsampled, affine.frozen(),
-                                      rgbaFace)
+                                      fc_rgba)
 
                 alt_marker_path = marker.get_alt_path()
                 if alt_marker_path:
                     alt_marker_trans = marker.get_alt_transform()
                     alt_marker_trans = alt_marker_trans.scale(w)
-                    if (cbook._str_equal(mec, "auto")
-                            and not cbook._str_lower_equal(
-                                self.get_markerfacecoloralt(), "none")):
-                        gc.set_alpha(rgbaFaceAlt[3])
-                    else:
-                        gc.set_alpha(self.get_alpha())
-
                     renderer.draw_markers(
                             gc, alt_marker_path, alt_marker_trans, subsampled,
-                            affine.frozen(), rgbaFaceAlt)
+                            affine.frozen(), fcalt_rgba)
 
             gc.restore()
 
@@ -890,8 +881,7 @@ def _get_markerfacecolor(self, alt=False):
             fc = self._markerfacecoloralt
         else:
             fc = self._markerfacecolor
-
-        if (isinstance(fc, six.string_types) and fc.lower() == 'auto'):
+        if cbook._str_lower_equal(fc, 'auto'):
             if self.get_fillstyle() == 'none':
                 return 'none'
             else:
@@ -1251,9 +1241,6 @@ def update_from(self, other):
     def _get_rgba_face(self, alt=False):
         return mcolors.to_rgba(self._get_markerfacecolor(alt=alt), self._alpha)
 
-    def _get_rgba_ln_color(self, alt=False):
-        return mcolors.to_rgba(self._color, self._alpha)
-
     def set_dash_joinstyle(self, s):
         """
         Set the join style for dashed linestyles