Address review comments.

anntzer · anntzer · commit cd979de13665 · 2018-07-28T19:54:53.000+02:00
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -481,13 +481,14 @@ def get_hatch(self):
         return self._hatch
 
     @contextlib.contextmanager
-    def _prepare_path_drawer(self, renderer):
+    def _bind_draw_path_function(self, renderer):
         """
         ``draw()`` helper factored out for sharing with `FancyArrowPatch`.
 
-        Yields a callable that can be called as a bound ``draw_path`` method
-        except that the first argument (the ``GraphicsContext``) has already
-        been suitably filled in.
+        Yields a callable ``dp`` such that calling ``dp(*args, **kwargs)`` is
+        equivalent to calling ``renderer1.draw_path(gc, *args, **kwargs)``
+        where ``renderer1`` and ``gc`` have been suitably set from ``renderer``
+        and the artist's properties.
         """
 
         renderer.open_group('patch', self.get_gid())
@@ -499,7 +500,7 @@ def _prepare_path_drawer(self, renderer):
         if self._edgecolor[3] == 0:
             lw = 0
         gc.set_linewidth(lw)
-        gc.set_dashes(0, self._dashes)
+        gc.set_dashes(self._dashoffset, self._dashes)
         gc.set_capstyle(self._capstyle)
         gc.set_joinstyle(self._joinstyle)
 
@@ -530,7 +531,7 @@ def _prepare_path_drawer(self, renderer):
             from matplotlib.patheffects import PathEffectRenderer
             renderer = PathEffectRenderer(self.get_path_effects(), renderer)
 
-        # In `with _prepare_path_drawer(renderer) as draw_path: draw_path(...)`
+        # In `with _bind_draw_path_function(renderer) as draw_path: ...`
         # (in the implementations of `draw()` below), calls to `draw_path(...)`
         # will occur as if they took place here with `gc` inserted as
         # additional first argument.
@@ -546,7 +547,10 @@ def draw(self, renderer):
         if not self.get_visible():
             return
 
-        with self._prepare_path_drawer(renderer) as draw_path:
+
+        # Patch has traditionally ignored the dashoffset.
+        with cbook._setattr_cm(self, _dashoffset=0), \
+                self._bind_draw_path_function(renderer) as draw_path:
             path = self.get_path()
             transform = self.get_transform()
             tpath = transform.transform_path_non_affine(path)
@@ -4277,9 +4281,9 @@ def draw(self, renderer):
         if not self.get_visible():
             return
 
-        # FancyArrowPatch have traditionally forced the capstyle and joinstyle.
+        # FancyArrowPatch has traditionally forced the capstyle and joinstyle.
         with cbook._setattr_cm(self, _capstyle='round', _joinstyle='round'), \
-                self._prepare_path_drawer(renderer) as draw_path:
+                self._bind_draw_path_function(renderer) as draw_path:
 
             # FIXME : dpi_cor is for the dpi-dependecy of the linewidth. There
             # could be room for improvement.
@@ -4293,7 +4297,9 @@ def draw(self, renderer):
             affine = transforms.IdentityTransform()
 
             for p, f in zip(path, fillable):
-                draw_path(p, affine, self._facecolor if f else None)
+                draw_path(
+                    p, affine,
+                    self._facecolor if f and self._facecolor[3] else None)
 
 
 class ConnectionPatch(FancyArrowPatch):
