Deprecate SpanSelector.prev attribute

ericpre · ericpre · commit d123ebf85c94 · 2021-06-19T11:58:05.000+01:00
diff --git a/doc/api/next_api_changes/deprecations/20113-EP.rst b/doc/api/next_api_changes/deprecations/20113-EP.rst
@@ -4,6 +4,7 @@ SpanSelector
 Several `~matplotlib.widgets.SpanSelector` class internals have been privatized 
 and deprecated:
 - ``pressv``
+- ``prev``
 - ``rect``
 - ``rectprops``
 - ``active_handle``
diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
@@ -2027,6 +2027,9 @@ def __init__(self, ax, onselect, direction, minspan=0, useblit=False,
         if self._interactive:
             self.artists.extend([line for line in self._edge_handles.artists])
 
+        # prev attritube is deprecated but we still need to maintain it
+        self._prev = (0, 0)
+
     rect = _api.deprecate_privatize_attribute("3.5")
 
     rectprops = _api.deprecate_privatize_attribute("3.5")
@@ -2039,6 +2042,8 @@ def __init__(self, ax, onselect, direction, minspan=0, useblit=False,
         property(lambda self: self._interactive)
         )
 
+    prev = _api.deprecated("3.5")(property(lambda self: self._prev))
+
     def new_axes(self, ax):
         """Set SpanSelector to operate on a new Axes."""
         self.ax = ax
@@ -2075,8 +2080,10 @@ def _press(self, event):
             self.update()
 
         v = event.xdata if self.direction == 'horizontal' else event.ydata
-        # self._pressv is deprecated but we still need to maintain it
+        # self._pressv and self._prev are deprecated but we still need to
+        # maintain them
         self._pressv = v
+        self._prev = self._get_data(event)
 
         if self._active_handle is None:
             # when the press event outside the span, we initially set the
@@ -2120,6 +2127,9 @@ def _release(self, event):
     def _onmove(self, event):
         """Motion notify event handler."""
 
+        # self._prev are deprecated but we still need to maintain it
+        self._prev = self._get_data(event)
+
         v = event.xdata if self.direction == 'horizontal' else event.ydata
         if self.direction == 'horizontal':
             vpress = self.eventpress.xdata
