Merge EllipseSelector example together with RectangleSelector.

anntzer · anntzer · commit feda49775781 · 2021-07-22T21:17:27.000+02:00
The old EllipseSelector example had similar issues as those fixed in f288658 for RectangleSelector. I'm not too happy with the explanation text, but that can be fixed lated.
diff --git a/examples/widgets/rectangle_selector.py b/examples/widgets/rectangle_selector.py
@@ -1,22 +1,21 @@
 """
-==================
-Rectangle Selector
-==================
+===============================
+Rectangle and ellipse selectors
+===============================
 
-Do a mouseclick somewhere, move the mouse to some destination, release
-the button.  This class gives click- and release-events and also draws
-a line or a box from the click-point to the actual mouseposition
-(within the same axes) until the button is released.  Within the
-method ``self.ignore()`` it is checked whether the button from eventpress
-and eventrelease are the same.
+Click somewhere, move the mouse, and release the mouse button.
+`.RectangleSelector` and `.EllipseSelector` draw a rectangle or an ellipse
+from the initial click position to the current mouse position (within the same
+axes) until the button is released.  A connected callback receives the click-
+and release-events.
 """
 
-from matplotlib.widgets import RectangleSelector
+from matplotlib.widgets import EllipseSelector, RectangleSelector
 import numpy as np
 import matplotlib.pyplot as plt
 
 
-def line_select_callback(eclick, erelease):
+def select_callback(eclick, erelease):
     """
     Callback for line selection.
 
@@ -25,36 +24,42 @@ def line_select_callback(eclick, erelease):
     x1, y1 = eclick.xdata, eclick.ydata
     x2, y2 = erelease.xdata, erelease.ydata
     print(f"({x1:3.2f}, {y1:3.2f}) --> ({x2:3.2f}, {y2:3.2f})")
-    print(f" The buttons you used were: {eclick.button} {erelease.button}")
+    print(f"The buttons you used were: {eclick.button} {erelease.button}")
 
 
 def toggle_selector(event):
-    print(' Key pressed.')
+    print('Key pressed.')
     if event.key == 't':
-        if toggle_selector.RS.active:
-            print(' RectangleSelector deactivated.')
-            toggle_selector.RS.set_active(False)
-        else:
-            print(' RectangleSelector activated.')
-            toggle_selector.RS.set_active(True)
+        for selector in selectors:
+            name = type(selector).__name__
+            if selector.active:
+                print(f'{name} deactivated.')
+                selector.set_active(False)
+            else:
+                print(f'{name} activated.')
+                selector.set_active(True)
 
 
-fig, ax = plt.subplots()
+fig = plt.figure(constrained_layout=True)
+axs = fig.subplots(2)
+
 N = 100000  # If N is large one can see improvement by using blitting.
 x = np.linspace(0, 10, N)
 
-ax.plot(x, np.sin(2*np.pi*x))  # plot something
-ax.set_title(
-    "Click and drag to draw a rectangle.\n"
-    "Press 't' to toggle the selector on and off.")
-
-toggle_selector.RS = RectangleSelector(ax, line_select_callback,
-                                       useblit=True,
-                                       button=[1, 3],  # disable middle button
-                                       minspanx=5, minspany=5,
-                                       spancoords='pixels',
-                                       interactive=True)
-fig.canvas.mpl_connect('key_press_event', toggle_selector)
+selectors = []
+for ax, selector_class in zip(axs, [RectangleSelector, EllipseSelector]):
+    ax.plot(x, np.sin(2*np.pi*x))  # plot something
+    ax.set_title(f"Click and drag to draw a {selector_class.__name__}.")
+    selectors.append(selector_class(
+        ax, select_callback,
+        useblit=True,
+        button=[1, 3],  # disable middle button
+        minspanx=5, minspany=5,
+        spancoords='pixels',
+        interactive=True))
+    fig.canvas.mpl_connect('key_press_event', toggle_selector)
+axs[0].set_title("Press 't' to toggle the selectors on and off.\n"
+                 + axs[0].get_title())
 plt.show()
 
 #############################################################################
@@ -65,3 +70,4 @@ def toggle_selector(event):
 #    in this example:
 #
 #    - `matplotlib.widgets.RectangleSelector`
+#    - `matplotlib.widgets.EllipseSelector`
diff --git a/lib/matplotlib/widgets.py b/lib/matplotlib/widgets.py
@@ -3017,31 +3017,7 @@ class EllipseSelector(RectangleSelector):
 
     Examples
     --------
-    >>> import numpy as np
-    >>> import matplotlib.pyplot as plt
-    >>> from matplotlib.widgets import EllipseSelector
-    >>> def onselect(eclick, erelease):
-    ...     "eclick and erelease are matplotlib events at press and release."
-    ...     print(f'startposition: {eclick.xdata}, {eclick.ydata})
-    ...     print(f'endposition  : {erelease.xdata}, {erelease.ydata})
-    ...     print('used button  : ', eclick.button)
-    ...
-    >>> def toggle_selector(event):
-    ...     print(' Key pressed.')
-    ...     if event.key in ['Q', 'q'] and toggle_selector.ES.active:
-    ...         print('EllipseSelector deactivated.')
-    ...         toggle_selector.RS.set_active(False)
-    ...     if event.key in ['A', 'a'] and not toggle_selector.ES.active:
-    ...         print('EllipseSelector activated.')
-    ...         toggle_selector.ES.set_active(True)
-    ...
-    >>> x = np.arange(100.) / 99
-    >>> y = np.sin(x)
-    >>> fig, ax = plt.subplots()
-    >>> ax.plot(x, y)
-    >>> toggle_selector.ES = EllipseSelector(ax, onselect)
-    >>> fig.canvas.mpl_connect('key_press_event', toggle_selector)
-    >>> plt.show()
+    :doc:`/gallery/widgets/rectangle_selector`
     """
 
     _shape_klass = Ellipse
