[Matplotlib-users] How to fix Lasso example bug???

[Leonard J R. <re...@jp...>]

Hello,

What follows is the lasso example code that I am running.  This is the 
example the comes with the matplotlib examples code.  It works fine 
except when one clicks and does not move the mouse.  It seems to hang.
I have traced it down to the self.canvas.widgetlock.locked() call within 
the LassoManager method called onpress.  The onpress method is 
registered as a callback for a button press event.  What I need to know 
is how to determine which widget has the lock and how to release the 
lock before returning from the callback so that everything will continue 
to work.

If anyone knows how to fix this please send example code.

Thanks,

Len


#!/usr/local/bin/python

"""
Simple hacked test case to add fake runs and print out selected point set.

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 and the
inside polygon detection routine.
"""
from matplotlib import widgets
import matplotlib.mlab
from matplotlib import nxutils
from matplotlib import colors
from matplotlib import collections

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

class Datum:
     colorin = colors.colorConverter.to_rgba('red')
     colorout = colors.colorConverter.to_rgba('green')
     def __init__(self, x, y, run=None, include=False):
         self.x = x
         self.y = y
         self.run = run
         if include:
             self.color = self.colorin
         else:
             self.color = self.colorout


class LassoManager:
     def __init__(self, ax, data):
         self.axes = ax
         self.canvas = ax.figure.canvas
         self.data = data

         self.Nxy = len(data)

         self.facecolors = [d.color for d in data]
         self.xys = [(d.x, d.y) for d in data]
         self.facecolors[50] = (0.0,0.0,0.0,1.0)
         self.collection = collections.RegularPolyCollection(
             fig.dpi, 6, sizes=(100,),
             facecolors=self.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):
         ind = numpy.nonzero(nxutils.points_inside_poly(self.xys, verts))[0]
         print "New selection:"
         for i in range(self.Nxy):
             if i in ind:
                 self.facecolors[i] = Datum.colorin
                 print "Index=%d, run=%d, xy = (%f,%f)" % 
(i,self.data[i].run,self.data[i].x,self.data[i].y)
             else:
                 self.facecolors[i] = Datum.colorout

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

     def onpress(self, event):
         print "OK1"
         print self.canvas.widgetlock.locked()
         if self.canvas.widgetlock.locked():
             return
         print "OK2"
         if event.inaxes is None:
             return
         print "OK3"
         self.lasso = widgets.Lasso(event.inaxes, (event.xdata, 
event.ydata), self.callback)
         # acquire a lock on the widget drawing
         self.canvas.widgetlock(self.lasso)
         print "OK4"

data = [Datum(*xy) for xy in rand(100, 2)]
# Fake run data
i = 0
for d in data:
     d.run = i
     i += 1

fig = pyplot.figure()
ax = fig.add_subplot(111, xlim=(0,1), ylim=(0,1), autoscale_on=False)
lman = LassoManager(ax, data)

pyplot.show()

-- 
__________________________________________________
Leonard J. Reder
Jet Propulsion Laboratory
Email: re...@jp...
Phone (Voice): 818-354-3639
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