Combine Key And Mouse Button Events In Wxpython Panel Using Matplotlib

In a wxPython panel I want to use matplotlib's Lasso widget. In my implementation Lasso is used in three different functionalities. Nevertheless, in order to accomplish these funct

Solution 1:

I'm not entirely sure what you're doing wrong because your code looks incomplete. I think your general idea was correct, but you seem to have been mixing up classes and trying to access the property shift_is_held from the wrong class or something.

I wrote this simple example using the lasso_example.py code from matplotlib examples. I did run into some complications trying to use the control key. When I try to drag with the mouse using the control key, the Lasso manager becomes unresponsive (including in the original code from matplotlib). I could not figure out why, so I used the shift and alt keys as modifiers in the present code.

You'll see that the logic of what action to perform depending on which key is held down at the moment when you release the lasso is performed in LassoManager.callback()

import logging
import matplotlib
from matplotlib.widgets import Lasso
from matplotlib.colors import colorConverter
from matplotlib.collections import RegularPolyCollection
from matplotlib import path

import matplotlib.pyplot as plt
from numpy.random import rand

logger = logging.getLogger()
logger.setLevel(logging.DEBUG)


classDatum(object):
    colorin = colorConverter.to_rgba('red')
    colorShift = colorConverter.to_rgba('cyan')
    colorCtrl = colorConverter.to_rgba('pink')
    colorout = colorConverter.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


classLassoManager(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]
        fig = ax.figure
        self.collection = RegularPolyCollection(
            fig.dpi, 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)
        self.keyPress = self.canvas.mpl_connect('key_press_event', self.onKeyPress)
        self.keyRelease = self.canvas.mpl_connect('key_release_event', self.onKeyRelease)
        self.lasso = None
        self.shiftKey = False
        self.ctrlKey = Falsedefcallback(self, verts):
        logging.debug('in LassoManager.callback(). Shift: %s, Ctrl: %s' % (self.shiftKey, self.ctrlKey))
        facecolors = self.collection.get_facecolors()
        p = path.Path(verts)
        ind = p.contains_points(self.xys)
        for i inrange(len(self.xys)):
            if ind[i]:
                if self.shiftKey:
                    facecolors[i] = Datum.colorShift
                elif self.ctrlKey:
                    facecolors[i] = Datum.colorCtrl
                else:
                    facecolors[i] = Datum.colorin
            else:
                facecolors[i] = Datum.colorout

        self.canvas.draw_idle()
        self.canvas.widgetlock.release(self.lasso)
        del self.lasso

    defonpress(self, event):
        if self.canvas.widgetlock.locked():
            returnif event.inaxes isNone:
            return
        self.lasso = Lasso(event.inaxes, (event.xdata, event.ydata), self.callback)
        # acquire a lock on the widget drawing
        self.canvas.widgetlock(self.lasso)

    defonKeyPress(self, event):
        logging.debug('in LassoManager.onKeyPress(). Event received: %s (key: %s)' % (event, event.key))
        if event.key == 'alt+alt':
            self.ctrlKey = Trueif event.key == 'shift':
            self.shiftKey = TruedefonKeyRelease(self, event):
        logging.debug('in LassoManager.onKeyRelease(). Event received: %s (key: %s)' % (event, event.key))
        if event.key == 'alt':
            self.ctrlKey = Falseif event.key == 'shift':
            self.shiftKey = Falseif __name__ == '__main__':

    data = [Datum(*xy) for xy in rand(100, 2)]

    ax = plt.axes(xlim=(0,1), ylim=(0,1), autoscale_on=False)
    lman = LassoManager(ax, data)

    plt.show()