"""
===================================
Pan/zoom events of overlapping axes
===================================

Example to illustrate how pan/zoom events of overlapping axes are treated.


The default is the following:

- Axes with a visible patch capture pan/zoom events
- Axes with an invisible patch forward pan/zoom events to axes below
- Shared axes always trigger with their parent axes
  (irrespective of the patch visibility)

Note: The visibility of the patch hereby refers to the value of
``ax.patch.get_visible()``. The color and transparency of a
patch have no effect on the treatment of pan/zoom events!


``ax.set_forward_navigation_events(val)`` can be used to override the
default behaviour:

- ``True``:  Forward navigation events to axes below.
- ``False``: Execute navigation events only on this axes.
- ``"auto"``: Use the default behaviour.

To disable pan/zoom events completely, use ``ax.set_navigate(False)``

"""


import matplotlib.pyplot as plt

fig = plt.figure(figsize=(11, 6))
fig.suptitle("Showcase for pan/zoom events on overlapping axes.")

ax = fig.add_axes((.05, .05, .9, .9))
ax.patch.set_color(".75")
ax_twin = ax.twinx()

ax1 = fig.add_subplot(221)
ax1_twin = ax1.twinx()
ax1.text(.5, .5,
         "Visible patch\n\n"
         "Pan/zoom events are NOT\n"
         "forwarded to axes below",
         ha="center", va="center", transform=ax1.transAxes)

ax11 = fig.add_subplot(223, sharex=ax1, sharey=ax1)
ax11.set_forward_navigation_events(True)
ax11.text(.5, .5,
          "Visible patch\n\n"
          "Override capture behavior:\n\n"
          "ax.set_forward_navigation_events(True)",
          ha="center", va="center", transform=ax11.transAxes)

ax2 = fig.add_subplot(222)
ax2_twin = ax2.twinx()
ax2.patch.set_visible(False)
ax2.text(.5, .5,
         "Invisible patch\n\n"
         "Pan/zoom events are\n"
         "forwarded to axes below",
         ha="center", va="center", transform=ax2.transAxes)

ax22 = fig.add_subplot(224, sharex=ax2, sharey=ax2)
ax22.patch.set_visible(False)
ax22.set_forward_navigation_events(False)
ax22.text(.5, .5,
          "Invisible patch\n\n"
          "Override capture behavior:\n\n"
          "ax.set_forward_navigation_events(False)",
          ha="center", va="center", transform=ax22.transAxes)