Improve documentation and syntax

Author: ericpre

doc/api/next_api_changes/deprecations/20839-EP.rst

@@ -1,4 +1,4 @@
 Selector widget state internals
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-*state_modifier_keys* are immutable now. They can be set when creating the
-widget, but cannot be changed afterwards anymore.
+The *state_modifier_keys* attribute have been privatized and the modifier keys
+needs to be set when creating the widget.

doc/users/next_whats_new/rectangle_patch_rotation.rst

@@ -0,0 +1,5 @@
+Rectangle patch rotation point
+------------------------------
+
+The rotation point of the `~matplotlib.patches.Rectangle` can now be set to 'xy',
+'center' or a 2-tuple of numbers.

doc/users/next_whats_new/selector_improvement.rst

@@ -2,8 +2,9 @@ Selectors improvement: rotation, aspect ratio correction and add/remove state
 -----------------------------------------------------------------------------
 
 The `~matplotlib.widgets.RectangleSelector` and
-`~matplotlib.widgets.EllipseSelector` can now be rotated interactively.
-The rotation is enabled or disable by striking the *r* key
+`~matplotlib.widgets.EllipseSelector` can now be rotated interactively between
+-45° and 45°. The range limits are currently dictated by the implementation.
+The rotation is enabled or disabled by striking the *r* key
 ('r' is the default key mapped to 'rotate' in *state_modifier_keys*) or by calling
 ``selector.add_state('rotate')``.
 

lib/matplotlib/widgets.py

@@ -1835,7 +1835,7 @@ def __init__(self, ax, onselect, useblit=False, button=None,
     eventpress = _api.deprecate_privatize_attribute("3.5")
     eventrelease = _api.deprecate_privatize_attribute("3.5")
     state = _api.deprecate_privatize_attribute("3.5")
-    state_modifier_keys = _api.deprecate_privatize_attribute("3.5")
+    state_modifier_keys = _api.deprecate_privatize_attribute("3.6")
 
     def set_active(self, active):
         super().set_active(active)
@@ -2803,7 +2803,8 @@ def onselect(eclick: MouseEvent, erelease: MouseEvent)
         - "clear": Clear the current shape, default: "escape".
         - "square": Make the shape square, default: "shift".
         - "center": change the shape around its center, default: "ctrl".
-        - "rotate": Rotate the shape around its center, default: "r".
+        - "rotate": Rotate the shape around its center between -45° and 45°,
+          default: "r".
 
         "square" and "center" can be combined. The square shape can be defined
         in data or figure coordinates as determined by the
@@ -3061,7 +3062,8 @@ def _onmove(self, event):
         eventpress = self._eventpress
         # The calculations are done for rotation at zero: we apply inverse
         # transformation to events except when we rotate and move
-        if not (self._active_handle == 'C' or rotate):
+        move = self._active_handle == 'C'
+        if not move and not rotate:
             inv_tr = self._get_rotation_transform().inverted()
             event.xdata, event.ydata = inv_tr.transform(
                 [event.xdata, event.ydata])
@@ -3078,8 +3080,8 @@ def _onmove(self, event):
             refx, refy = dx, dy
         else:
             # Add 1e-6 to avoid divided by zero error
-            refx = event.xdata / (eventpress.xdata + 1e-6)
-            refy = event.ydata / (eventpress.ydata + 1e-6)
+            refx = event.xdata / (eventpress.xdata or 1E-6)
+            refy = event.ydata / (eventpress.ydata or 1E-6)
 
         x0, x1, y0, y1 = self._extents_on_press
         # rotate an existing shape
@@ -3099,6 +3101,7 @@ def _onmove(self, event):
 
             # Keeping the center fixed
             if 'center' in state:
+                # hh, hw are half-height and half-width
                 if 'square' in state:
                     # when using a corner, find which reference to use
                     if self._active_handle in self._corner_order:
@@ -3277,14 +3280,17 @@ def extents(self, extents):
 
     @property
     def rotation(self):
-        """Rotation in degree in interval [0, 45]."""
+        """
+        Rotation in degree in interval [-45°, 45°]. The rotation is limited in
+        range to keep the implementation simple.
+        """
         return np.rad2deg(self._rotation)
 
     @rotation.setter
     def rotation(self, value):
-        # Restrict to a limited range of rotation [0, 45] to avoid changing
+        # Restrict to a limited range of rotation [-45°, 45°] to avoid changing
         # order of handles
-        if 0 <= value and value <= 45:
+        if -45 <= value and value <= 45:
             self._rotation = np.deg2rad(value)
             # call extents setter to draw shape and update handles positions
             self.extents = self.extents