matplotlib
diff --git a/‎lib/matplotlib/_enums.py
Copy file name to clipboardExpand all lines: lib/matplotlib/_enums.py
+86-48Lines changed: 86 additions & 48 deletions b/‎lib/matplotlib/_enums.py
Copy file name to clipboardExpand all lines: lib/matplotlib/_enums.py
+86-48Lines changed: 86 additions & 48 deletions
@@ -10,6 +10,7 @@
 they define.
 """
 
+from collections import namedtuple
 from enum import Enum, auto
 from numbers import Number
 
@@ -19,6 +20,20 @@
 class _AutoStringNameEnum(Enum):
     """Automate the ``name = 'name'`` part of making a (str, Enum)."""
 
+    def __new__(cls, str_value, *value_aliases):
+        """
+        Override Enum.__new__ to allow aliases.
+
+        For more details on strategies for allowing multiple names per enum
+        instance, see the discussion at
+        https://stackoverflow.com/questions/24105268/is-it-possible-to-override-new-in-an-enum-to-parse-strings-to-an-instance
+        """
+        obj = cls.__new__(str_value)
+        obj._value_ = str_value
+        for alias in value_aliases:
+            cls._value2member_map_[alias] = obj
+        return obj
+
     def _generate_next_value_(name, start, count, last_values):
         return name
 
@@ -224,7 +239,7 @@ def demo():
 }
 
 
-class NamedLineStyle(str, _AutoStringNameEnum):
+class LineStyle():
     """
     Describe if the line is solid or dashed, and the dash pattern, if any.
 
@@ -258,9 +273,9 @@ class NamedLineStyle(str, _AutoStringNameEnum):
     Setting ``onoffseq`` to ``None`` results in a solid *LineStyle*.
 
     The default dashing patterns described in the table above are themselves
-    all described in this notation, and can therefore be customized by editing
-    the appropriate ``lines.*_pattern`` *rc* parameter, as described in
-    :doc:`/tutorials/introductory/customizing`.
+    defined under the hood using an offset and an onoffseq, and can therefore
+    be customized by editing the appropriate ``lines.*_pattern`` *rc*
+    parameter, as described in :doc:`/tutorials/introductory/customizing`.
 
     .. plot::
         :alt: Demo of possible LineStyle's.
@@ -271,22 +286,17 @@ class NamedLineStyle(str, _AutoStringNameEnum):
     .. note::
 
         In addition to directly taking a ``linestyle`` argument,
-        `~.lines.Line2D` exposes a ``~.lines.Line2D.set_dashes`` method that
-        can be used to create a new *LineStyle* by providing just the
-        ``onoffseq``, but does not let you customize the offset. This method is
-        called when using the keyword *dashes* to the cycler , as shown in
-        :doc:`property_cycle </tutorials/intermediate/color_cycle>`.
+        `~.lines.Line2D` exposes a ``~.lines.Line2D.set_dashes`` method (and
+        the :doc:`property_cycle </tutorials/intermediate/color_cycle>` has a
+        *dashes* keyword) that can be used to create a new *LineStyle* by
+        providing just the ``onoffseq``, but does not let you customize the
+        offset. This method simply sets the underlying linestyle, and is only
+        kept for backwards compatibility.
     """
-    solid = auto()
-    dashed = auto()
-    dotted = auto()
-    dashdot = auto()
-    none = auto()
-    custom = auto()
 
-class LineStyle(str):
 
-    def __init__(self, ls, scale=1):
+
+    def __init__(self, ls, offset=None, scale=None):
         """
         Parameters
         ----------
@@ -301,56 +311,57 @@ def __init__(self, ls, scale=1):
         """
 
         self._linestyle_spec = ls
+        # if isinstance(ls, str):
+        #     if ls in [' ', '', 'None']:
+        #         ls = 'none'
+        #     if ls in _ls_mapper:
+        #         ls = _ls_mapper[ls]
+        #     Enum.__init__(self)
+        #     offset, onoffseq = None, None
+        # else:
+        #     try:
+        #         offset, onoffseq = ls
+        #     except ValueError:  # not enough/too many values to unpack
+        #         raise ValueError('LineStyle should be a string or a 2-tuple, '
+        #                          'instead received: ' + str(ls))
         if isinstance(ls, str):
-            if ls in [' ', '', 'None']:
-                ls = 'none'
-            if ls in _ls_mapper:
-                ls = _ls_mapper[ls]
-            Enum.__init__(self)
-            offset, onoffseq = None, None
-        else:
-            try:
-                offset, onoffseq = ls
-            except ValueError:  # not enough/too many values to unpack
-                raise ValueError('LineStyle should be a string or a 2-tuple, '
-                                 'instead received: ' + str(ls))
+            return
+        offset, onoffseq = ls
         if offset is None:
             _api.warn_deprecated(
                 "3.3", message="Passing the dash offset as None is deprecated "
                 "since %(since)s and support for it will be removed "
                 "%(removal)s; pass it as zero instead.")
             offset = 0
-
-        if onoffseq is not None:
-            # normalize offset to be positive and shorter than the dash cycle
-            dsum = sum(onoffseq)
-            if dsum:
-                offset %= dsum
-            if len(onoffseq) % 2 != 0:
-                raise ValueError('LineStyle onoffseq must be of even length.')
-            if not all(isinstance(elem, Number) for elem in onoffseq):
-                raise ValueError('LineStyle onoffseq must be list of floats.')
-        self._us_offset = offset
-        self._us_onoffseq = onoffseq
+        # force 0 <= offset < dash cycle length
+        self._us_offset, self._us_onoffseq = \
+                LineStyle._normalize_offset(offset, onoffseq)
 
     def __hash__(self):
         if self == LineStyle.custom:
             return (self._us_offset, tuple(self._us_onoffseq)).__hash__()
         return _AutoStringNameEnum.__hash__(self)
 
+    @staticmethod
+    def _normalize_offset(offset, onoffseq):
+        """Normalize offset to be positive and shorter than the dash cycle."""
+        dsum = sum(onoffseq)
+        if dsum:
+            offset %= dsum
 
     def get_dashes(self, lw=1):
         """
         Get the (scaled) dash sequence for this `.LineStyle`.
         """
-        # defer lookup until draw time
+        # named linestyle lookup happens at draw time (here)
         if self._us_offset is None or self._us_onoffseq is None:
-            self._us_offset, self._us_onoffseq = \
-                    LineStyle._get_dash_pattern(self.name)
-            # normalize offset to be positive and shorter than the dash cycle
-            dsum = sum(self._us_onoffseq)
-            self._us_offset %= dsum
-        return self._scale_dashes(self._us_offset, self._us_onoffseq, lw)
+            offset, onoffseq = LineStyle._get_dash_pattern(self.name)
+        else:
+            offset, onoff_seq = self._us_offset, self._us_onoffseq
+        # normalize offset to be positive and shorter than the dash cycle
+        dsum = sum(onoffseq)
+        offset %= dsum
+        return self._scale_dashes(offset, onoffseq, lw)
 
     @staticmethod
     def _scale_dashes(offset, dashes, lw):
@@ -462,6 +473,33 @@ def plot_linestyles(ax, linestyles, title):
         plt.tight_layout()
         plt.show()
 
+def _LineStyle_new(cls, ls, offset=None, scale=None):
+    if cls is NamedLineStyle or isinstance(ls, NamedLineStyle):
+        return cls(ls)
+    elif isinstance(ls, LineStyle):
+        scale = scale if scale is not None else ls.scale
+        offset = offset if offset is not None else ls.offset
+        onoffseq = ls.onoffseq
+        return LineStyle.__new__(onoffseq, offset=offset, scale=scale)
+    elif isinstance(ls, str):
+        return cls(ls)
+    else:
+        return super(LineStyle, cls).__new__(cls, ls, offset=offset,
+                                                scale=scale)
+        # if len(onoffseq) % 2 != 0:
+        #     raise ValueError('LineStyle onoffseq must be of even length.')
+        # if not all(isinstance(elem, Number) for elem in onoffseq):
+        #     raise ValueError('LineStyle onoffseq must be list of floats.')
+
+
+class NamedLineStyle(LineStyle, _AutoStringNameEnum):
+    """There is only one instance of each named LineStyle ever."""
+    solid = 'solid', '-'
+    dashed = 'dashed', '--'
+    dotted = 'dotted', ':'
+    dashdot = 'dashdot', '-.'
+    none = 'none', 'None', ' '
+
 
 LineStyle._ls_mapper = _ls_mapper
 LineStyle._deprecated_lineStyles = _deprecated_lineStyles