Add draft implementation of the get_window_extent method

lib/matplotlib/text.py

@@ -2086,5 +2086,39 @@ def draw(self, renderer):
 
         Text.draw(self, renderer)
 
+    def get_window_extent(self, renderer=None):
+        '''
+        Return a :class:`~matplotlib.transforms.Bbox` object bounding
+        the text and arrow annotation, in display units.
+
+        *renderer* defaults to the _renderer attribute of the text
+        object.  This is not assigned until the first execution of
+        :meth:`draw`, so you must use this kwarg if you want
+        to call :meth:`get_window_extent` prior to the first
+        :meth:`draw`.  For getting web page regions, it is
+        simpler to call the method after saving the figure. The
+        *dpi* used defaults to self.figure.dpi; the renderer dpi is
+        irrelevant.
+
+        '''
+        arrow = self.arrow
+        arrow_patch = self.arrow_patch
+
+        text_bbox = Text.get_window_extent(self, renderer=renderer)
+        if text_bbox.width == 0.0 and text_bbox.height == 0.0:
+            bboxes = []
+        else:
+            bboxes = [text_bbox]
+
+        if self.arrow is not None:
+            bboxes.append(arrow.get_window_extent(renderer=renderer))
+        elif self.arrow_patch is not None:
+            bboxes.append(arrow_patch.get_window_extent(renderer=renderer))
+
+        if len(bboxes) == 0:
+            return Bbox.from_bounds(self._x, self._y, 0.0, 0.0)
+        else:
+            return Bbox.union(bboxes)
+
 
 docstring.interpd.update(Annotation=Annotation.__init__.__doc__)