Resolve 'text ignores rotational part of transformation' bug (#698)

immaxchen · immaxchen · commit b59d8a329995 · 2020-06-20T00:04:42.000+08:00
Considering the text rotation don't get transformed may by a desired behavior
(such as text for annotation to some data point). Here made it as an option to
control whether or not the text rotation get transformed.
diff --git a/lib/matplotlib/text.py b/lib/matplotlib/text.py
@@ -136,6 +136,7 @@ def __init__(self,
                  rotation_mode=None,
                  usetex=None,          # defaults to rcParams['text.usetex']
                  wrap=False,
+                 rotation_transformed=False,
                  **kwargs
                  ):
         """
@@ -157,6 +158,7 @@ def __init__(self,
         self.set_horizontalalignment(horizontalalignment)
         self._multialignment = multialignment
         self._rotation = rotation
+        self._rotation_transformed = rotation_transformed
         self._bbox_patch = None  # a FancyBboxPatch instance
         self._renderer = None
         if linespacing is None:
@@ -228,7 +230,16 @@ def _get_multialignment(self):
 
     def get_rotation(self):
         """Return the text angle in degrees between 0 and 360."""
-        return get_rotation(self._rotation)  # string_or_number -> number
+        if self.get_rotation_transformed():
+            angle = get_rotation(self._rotation)
+            x, y = self.get_unitless_position()
+            return self.get_transform().transform_angles([angle, ], [[x, y]])
+        else:
+            return get_rotation(self._rotation)  # string_or_number -> number
+
+    def get_rotation_transformed(self):
+        """Return if the text rotation get transformed or not."""
+        return self._rotation_transformed
 
     def set_rotation_mode(self, m):
         """
@@ -259,6 +270,7 @@ def update_from(self, other):
         self._fontproperties = other._fontproperties.copy()
         self._usetex = other._usetex
         self._rotation = other._rotation
+        self._rotation_transformed = other._rotation_transformed
         self._picker = other._picker
         self._linespacing = other._linespacing
         self.stale = True
@@ -843,6 +855,7 @@ def get_prop_tup(self, renderer=None):
                 self._verticalalignment, self._horizontalalignment,
                 hash(self._fontproperties),
                 self._rotation, self._rotation_mode,
+                self._rotation_transformed,
                 self.figure.dpi, weakref.ref(renderer),
                 self._linespacing
                 )
@@ -1132,6 +1145,17 @@ def set_rotation(self, s):
         self._rotation = s
         self.stale = True
 
+    def set_rotation_transformed(self, t):
+        """
+        Set if the text rotation get transformed or not.
+
+        Parameters
+        ----------
+        t : bool
+        """
+        self._rotation_transformed = t
+        self.stale = True
+
     def set_verticalalignment(self, align):
         """
         Set the vertical alignment.
