.. 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_misc_cursor_demo_sgskip.py:
===========
Cursor Demo
===========
This example shows how to use Matplotlib to provide a data cursor. It uses
Matplotlib to draw the cursor and may be a slow since this requires redrawing
the figure with every mouse move.
Faster cursoring is possible using native GUI drawing, as in
:doc:`/gallery/user_interfaces/wxcursor_demo_sgskip`.
The mpldatacursor__ and mplcursors__ third-party packages can be used to
achieve a similar effect.
__ https://github.com/joferkington/mpldatacursor
__ https://github.com/anntzer/mplcursors
.. code-block:: default
import matplotlib.pyplot as plt
import numpy as np
class Cursor:
def __init__(self, ax):
self.ax = ax
self.lx = ax.axhline(color='k') # the horiz line
self.ly = ax.axvline(color='k') # the vert line
# text location in axes coords
self.txt = ax.text(0.7, 0.9, '', transform=ax.transAxes)
def mouse_move(self, event):
if not event.inaxes:
return
x, y = event.xdata, event.ydata
# update the line positions
self.lx.set_ydata(y)
self.ly.set_xdata(x)
self.txt.set_text('x=%1.2f, y=%1.2f' % (x, y))
self.ax.figure.canvas.draw()
class SnaptoCursor:
"""
Like Cursor but the crosshair snaps to the nearest x, y point.
For simplicity, this assumes that *x* is sorted.
"""
def __init__(self, ax, x, y):
self.ax = ax
self.lx = ax.axhline(color='k') # the horiz line
self.ly = ax.axvline(color='k') # the vert line
self.x = x
self.y = y
# text location in axes coords
self.txt = ax.text(0.7, 0.9, '', transform=ax.transAxes)
def mouse_move(self, event):
if not event.inaxes:
return
x, y = event.xdata, event.ydata
indx = min(np.searchsorted(self.x, x), len(self.x) - 1)
x = self.x[indx]
y = self.y[indx]
# update the line positions
self.lx.set_ydata(y)
self.ly.set_xdata(x)
self.txt.set_text('x=%1.2f, y=%1.2f' % (x, y))
print('x=%1.2f, y=%1.2f' % (x, y))
self.ax.figure.canvas.draw()
t = np.arange(0.0, 1.0, 0.01)
s = np.sin(2 * 2 * np.pi * t)
fig, ax = plt.subplots()
ax.plot(t, s, 'o')
cursor = Cursor(ax)
fig.canvas.mpl_connect('motion_notify_event', cursor.mouse_move)
fig, ax = plt.subplots()
ax.plot(t, s, 'o')
snap_cursor = SnaptoCursor(ax, t, s)
fig.canvas.mpl_connect('motion_notify_event', snap_cursor.mouse_move)
plt.show()
.. _sphx_glr_download_gallery_misc_cursor_demo_sgskip.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: cursor_demo_sgskip.py `
.. container:: sphx-glr-download sphx-glr-download-jupyter
:download:`Download Jupyter notebook: cursor_demo_sgskip.ipynb `
.. only:: html
.. rst-class:: sphx-glr-signature
Keywords: matplotlib code example, codex, python plot, pyplot
`Gallery generated by Sphinx-Gallery
`_