.. only:: html
.. note::
:class: sphx-glr-download-link-note
Click :ref:`here ` to download the full example code
.. rst-class:: sphx-glr-example-title
.. _sphx_glr_gallery_event_handling_trifinder_event_demo.py:
====================
Trifinder Event Demo
====================
Example showing the use of a TriFinder object. As the mouse is moved over the
triangulation, the triangle under the cursor is highlighted and the index of
the triangle is displayed in the plot title.
.. image:: /gallery/event_handling/images/sphx_glr_trifinder_event_demo_001.png
:alt: trifinder event demo
:class: sphx-glr-single-img
.. code-block:: default
import matplotlib.pyplot as plt
from matplotlib.tri import Triangulation
from matplotlib.patches import Polygon
import numpy as np
def update_polygon(tri):
if tri == -1:
points = [0, 0, 0]
else:
points = triang.triangles[tri]
xs = triang.x[points]
ys = triang.y[points]
polygon.set_xy(np.column_stack([xs, ys]))
def on_mouse_move(event):
if event.inaxes is None:
tri = -1
else:
tri = trifinder(event.xdata, event.ydata)
update_polygon(tri)
plt.title('In triangle %i' % tri)
event.canvas.draw()
# Create a Triangulation.
n_angles = 16
n_radii = 5
min_radius = 0.25
radii = np.linspace(min_radius, 0.95, n_radii)
angles = np.linspace(0, 2 * np.pi, n_angles, endpoint=False)
angles = np.repeat(angles[..., np.newaxis], n_radii, axis=1)
angles[:, 1::2] += np.pi / n_angles
x = (radii*np.cos(angles)).flatten()
y = (radii*np.sin(angles)).flatten()
triang = Triangulation(x, y)
triang.set_mask(np.hypot(x[triang.triangles].mean(axis=1),
y[triang.triangles].mean(axis=1))
< min_radius)
# Use the triangulation's default TriFinder object.
trifinder = triang.get_trifinder()
# Setup plot and callbacks.
plt.subplot(111, aspect='equal')
plt.triplot(triang, 'bo-')
polygon = Polygon([[0, 0], [0, 0]], facecolor='y') # dummy data for (xs, ys)
update_polygon(-1)
plt.gca().add_patch(polygon)
plt.gcf().canvas.mpl_connect('motion_notify_event', on_mouse_move)
plt.show()
.. _sphx_glr_download_gallery_event_handling_trifinder_event_demo.py:
.. only :: html
.. container:: sphx-glr-footer
:class: sphx-glr-footer-example
.. container:: sphx-glr-download sphx-glr-download-python
:download:`Download Python source code: trifinder_event_demo.py `
.. container:: sphx-glr-download sphx-glr-download-jupyter
:download:`Download Jupyter notebook: trifinder_event_demo.ipynb `
.. only:: html
.. rst-class:: sphx-glr-signature
Keywords: matplotlib code example, codex, python plot, pyplot
`Gallery generated by Sphinx-Gallery
`_