.. 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_lasso_demo.py: ========== Lasso Demo ========== Show how to use a lasso to select a set of points and get the indices of the selected points. A callback is used to change the color of the selected points This is currently a proof-of-concept implementation (though it is usable as is). There will be some refinement of the API. .. image:: /gallery/event_handling/images/sphx_glr_lasso_demo_001.png :class: sphx-glr-single-img .. code-block:: default from matplotlib import colors as mcolors, path from matplotlib.collections import RegularPolyCollection import matplotlib.pyplot as plt from matplotlib.widgets import Lasso import numpy as np class Datum(object): colorin = mcolors.to_rgba("red") colorout = mcolors.to_rgba("blue") def __init__(self, x, y, include=False): self.x = x self.y = y if include: self.color = self.colorin else: self.color = self.colorout class LassoManager(object): def __init__(self, ax, data): self.axes = ax self.canvas = ax.figure.canvas self.data = data self.Nxy = len(data) facecolors = [d.color for d in data] self.xys = [(d.x, d.y) for d in data] self.collection = RegularPolyCollection( 6, sizes=(100,), facecolors=facecolors, offsets=self.xys, transOffset=ax.transData) ax.add_collection(self.collection) self.cid = self.canvas.mpl_connect('button_press_event', self.onpress) def callback(self, verts): facecolors = self.collection.get_facecolors() p = path.Path(verts) ind = p.contains_points(self.xys) for i in range(len(self.xys)): if ind[i]: facecolors[i] = Datum.colorin else: facecolors[i] = Datum.colorout self.canvas.draw_idle() self.canvas.widgetlock.release(self.lasso) del self.lasso def onpress(self, event): if self.canvas.widgetlock.locked(): return if event.inaxes is None: return self.lasso = Lasso(event.inaxes, (event.xdata, event.ydata), self.callback) # acquire a lock on the widget drawing self.canvas.widgetlock(self.lasso) if __name__ == '__main__': np.random.seed(19680801) data = [Datum(*xy) for xy in np.random.rand(100, 2)] ax = plt.axes(xlim=(0, 1), ylim=(0, 1), autoscale_on=False) ax.set_title('Lasso points using left mouse button') lman = LassoManager(ax, data) plt.show() .. _sphx_glr_download_gallery_event_handling_lasso_demo.py: .. only :: html .. container:: sphx-glr-footer :class: sphx-glr-footer-example .. container:: sphx-glr-download :download:`Download Python source code: lasso_demo.py ` .. container:: sphx-glr-download :download:`Download Jupyter notebook: lasso_demo.ipynb ` .. only:: html .. rst-class:: sphx-glr-signature Keywords: matplotlib code example, codex, python plot, pyplot `Gallery generated by Sphinx-Gallery `_