.. 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_path_editor.py:
===========
Path Editor
===========
Sharing events across GUIs.
This example demonstrates a cross-GUI application using Matplotlib event
handling to interact with and modify objects on the canvas.
.. image:: /gallery/event_handling/images/sphx_glr_path_editor_001.png
:class: sphx-glr-single-img
.. code-block:: default
import numpy as np
import matplotlib.path as mpath
import matplotlib.patches as mpatches
import matplotlib.pyplot as plt
Path = mpath.Path
fig, ax = plt.subplots()
pathdata = [
(Path.MOVETO, (1.58, -2.57)),
(Path.CURVE4, (0.35, -1.1)),
(Path.CURVE4, (-1.75, 2.0)),
(Path.CURVE4, (0.375, 2.0)),
(Path.LINETO, (0.85, 1.15)),
(Path.CURVE4, (2.2, 3.2)),
(Path.CURVE4, (3, 0.05)),
(Path.CURVE4, (2.0, -0.5)),
(Path.CLOSEPOLY, (1.58, -2.57)),
]
codes, verts = zip(*pathdata)
path = mpath.Path(verts, codes)
patch = mpatches.PathPatch(path, facecolor='green', edgecolor='yellow', alpha=0.5)
ax.add_patch(patch)
class PathInteractor:
"""
An path editor.
Key-bindings
't' toggle vertex markers on and off. When vertex markers are on,
you can move them, delete them
"""
showverts = True
epsilon = 5 # max pixel distance to count as a vertex hit
def __init__(self, pathpatch):
self.ax = pathpatch.axes
canvas = self.ax.figure.canvas
self.pathpatch = pathpatch
self.pathpatch.set_animated(True)
x, y = zip(*self.pathpatch.get_path().vertices)
self.line, = ax.plot(x, y, marker='o', markerfacecolor='r', animated=True)
self._ind = None # the active vert
canvas.mpl_connect('draw_event', self.draw_callback)
canvas.mpl_connect('button_press_event', self.button_press_callback)
canvas.mpl_connect('key_press_event', self.key_press_callback)
canvas.mpl_connect('button_release_event', self.button_release_callback)
canvas.mpl_connect('motion_notify_event', self.motion_notify_callback)
self.canvas = canvas
def draw_callback(self, event):
self.background = self.canvas.copy_from_bbox(self.ax.bbox)
self.ax.draw_artist(self.pathpatch)
self.ax.draw_artist(self.line)
self.canvas.blit(self.ax.bbox)
def pathpatch_changed(self, pathpatch):
"""This method is called whenever the pathpatch object is called."""
# only copy the artist props to the line (except visibility)
vis = self.line.get_visible()
plt.Artist.update_from(self.line, pathpatch)
self.line.set_visible(vis) # don't use the pathpatch visibility state
def get_ind_under_point(self, event):
"""
Return the index of the point closest to the event position or *None*
if no point is within ``self.epsilon`` to the event position.
"""
# display coords
xy = np.asarray(self.pathpatch.get_path().vertices)
xyt = self.pathpatch.get_transform().transform(xy)
xt, yt = xyt[:, 0], xyt[:, 1]
d = np.sqrt((xt - event.x)**2 + (yt - event.y)**2)
ind = d.argmin()
if d[ind] >= self.epsilon:
ind = None
return ind
def button_press_callback(self, event):
"""Callback for mouse button presses."""
if not self.showverts:
return
if event.inaxes is None:
return
if event.button != 1:
return
self._ind = self.get_ind_under_point(event)
def button_release_callback(self, event):
"""Callback for mouse button releases."""
if not self.showverts:
return
if event.button != 1:
return
self._ind = None
def key_press_callback(self, event):
"""Callback for key presses."""
if not event.inaxes:
return
if event.key == 't':
self.showverts = not self.showverts
self.line.set_visible(self.showverts)
if not self.showverts:
self._ind = None
self.canvas.draw()
def motion_notify_callback(self, event):
"""Callback for mouse movements."""
if not self.showverts:
return
if self._ind is None:
return
if event.inaxes is None:
return
if event.button != 1:
return
x, y = event.xdata, event.ydata
vertices = self.pathpatch.get_path().vertices
vertices[self._ind] = x, y
self.line.set_data(zip(*vertices))
self.canvas.restore_region(self.background)
self.ax.draw_artist(self.pathpatch)
self.ax.draw_artist(self.line)
self.canvas.blit(self.ax.bbox)
interactor = PathInteractor(patch)
ax.set_title('drag vertices to update path')
ax.set_xlim(-3, 4)
ax.set_ylim(-3, 4)
plt.show()
.. _sphx_glr_download_gallery_event_handling_path_editor.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: path_editor.py `
.. container:: sphx-glr-download sphx-glr-download-jupyter
:download:`Download Jupyter notebook: path_editor.ipynb `
.. only:: html
.. rst-class:: sphx-glr-signature
Keywords: matplotlib code example, codex, python plot, pyplot
`Gallery generated by Sphinx-Gallery
`_