MNT: normalize line/draw style in Line2D.__init__

tacaswell · tacaswell · commit 42654d0a5616 · 2016-05-16T15:44:26.000-04:00
Because the drawstyle can be set via both the drawstyle and via
linestyle do some checking / normalize in the init.

Pulled the code that is shared between the `__init__` and
`set_linestyle` into a new private method.

Reverts minor change to order of operations
diff --git a/lib/matplotlib/lines.py b/lib/matplotlib/lines.py
@@ -314,6 +314,18 @@ def __init__(self, xdata, ydata,
         if solid_joinstyle is None:
             solid_joinstyle = rcParams['lines.solid_joinstyle']
 
+        if is_string_like(linestyle):
+            ds, ls = self._split_drawstyle_linestyle(linestyle)
+            if ds is not None and drawstyle is not None and ds != drawstyle:
+                raise ValueError("Inconsistent drawstyle ({0!r}) and "
+                                 "linestyle ({1!r})".format(drawstyle,
+                                                            linestyle)
+                                 )
+            linestyle = ls
+
+            if ds is not None:
+                drawstyle = ds
+
         if drawstyle is None:
             drawstyle = 'default'
 
@@ -332,8 +344,8 @@ def __init__(self, xdata, ydata,
 
         self._dashSeq = None
 
-        self.set_drawstyle(drawstyle)
         self.set_linestyle(linestyle)
+        self.set_drawstyle(drawstyle)
         self.set_linewidth(linewidth)
 
         self._color = None
@@ -979,6 +991,38 @@ def set_linewidth(self, w):
             self.stale = True
         self._linewidth = w
 
+    def _split_drawstyle_linestyle(self, ls):
+        '''Split drawstyle from linestyle string
+
+        If `ls` is only a drawstyle default to returning a linestyle
+        of '-'.
+
+        Parameters
+        ----------
+        ls : str
+            The linestyle to be processed
+
+        Returns
+        -------
+        ret_ds : str or None
+            If the linestyle string does not contain a drawstyle prefix
+            return None, otherwise return it.
+
+        ls : str
+            The linestyle with the drawstyle (if any) stripped.
+        '''
+        ret_ds = None
+        for ds in self.drawStyleKeys:  # long names are first in the list
+            if ls.startswith(ds):
+                ret_ds = ds
+                if len(ls) > len(ds):
+                    ls = ls[len(ds):]
+                else:
+                    ls = '-'
+                break
+
+        return ret_ds, ls
+
     def set_linestyle(self, ls):
         """
         Set the linestyle of the line (also accepts drawstyles,
@@ -1030,15 +1074,9 @@ def set_linestyle(self, ls):
             self.set_dashes(ls[1])
             self._linestyle = "--"
             return
-
-        for ds in self.drawStyleKeys:  # long names are first in the list
-            if ls.startswith(ds):
-                self.set_drawstyle(ds)
-                if len(ls) > len(ds):
-                    ls = ls[len(ds):]
-                else:
-                    ls = '-'
-                break
+        ds, ls = self._split_drawstyle_linestyle(ls)
+        if ds is not None:
+            self.set_drawstyle(ds)
 
         if ls in [' ', '', 'none']:
             ls = 'None'
diff --git a/lib/matplotlib/tests/test_axes.py b/lib/matplotlib/tests/test_axes.py
@@ -4250,6 +4250,12 @@ def test_ls_ds_conflict():
                   linestyle='steps-pre:', drawstyle='steps-post')
 
 
+@cleanup
+def test_ls_ds_conflict():
+    assert_raises(ValueError, plt.plot, range(32),
+                  linestyle='steps-pre:', drawstyle='steps-post')
+
+
 @image_comparison(baseline_images=['date_timezone_x'], extensions=['png'])
 def test_date_timezone_x():
     # Tests issue 5575
