Re: [Matplotlib-users] Using the lasso tool when file is not main

[Mark B. <mar...@gm...>]

On closer inspection the problem isn't calling it from another file,
it is calling it from wxpython. Not exactly sure how to copy code...

lasso_test.py
-----
from matplotlib.widgets import Lasso
from matplotlib.nxutils import points_inside_poly
from matplotlib.colors import colorConverter
from matplotlib.collections import RegularPolyCollection

from matplotlib.pyplot import figure, show
from numpy import nonzero
from numpy.random import rand
from scipy import linspace, polyval, polyfit, sqrt, stats, randn

class Datum:
    colorin = colorConverter.to_rgba('red')
    colorout = colorConverter.to_rgba('green')
    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:
    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.ind = None

    def callback(self, verts):
        if hasattr(self, 'temp'):
            self.temp.pop(0).remove()

        facecolors = self.collection.get_facecolors()
        ind = nonzero(points_inside_poly(self.xys, verts))[0]
        selected = []
        for i in range(self.Nxy):
            if i in ind:
                facecolors[i] = Datum.colorin
                selected.append(self.xys[i])
            else:
                facecolors[i] = Datum.colorout
        xs = []
        ys = []
        for n in selected:
            xs.append(n[0])
            ys.append(n[1])
        (ar,br) = polyfit(xs,ys,1)
        t = linspace(min(xs),max(xs))
        print('ar=%s br=%s' % (ar,br))
        xr = polyval([ar,br],t)
        self.temp = self.axes.plot(t,xr,'-',c='b')
        self.canvas.draw_idle()
        self.canvas.widgetlock.release(self.lasso)
        del self.lasso
        self.ind = ind
    def onpress(self, event):
        print('clicked')
        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)

class start_lasso():
    def __init__(self):
        data = [Datum(*xy) for xy in rand(100, 2)]

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

--------------------------------
call_lasso.py
----
import wx
import lasso_test

class MyFrame(wx.Frame):
    """ We simply derive a new class of Frame. """
    def __init__(self, parent, title):
        wx.Frame.__init__(self, parent, title=title, size=(200,100))
        button = wx.Button(self, label='Open Lasso')
        self.Bind(wx.EVT_BUTTON, self.open_lasso, button)
        self.Show(True)
    def open_lasso(self, event):
        lasso_test.start_lasso()

app = wx.App(False)
frame = MyFrame(None, 'Small editor')
app.MainLoop()

-----------------------------
Thanks,
Mark


On Wed, Sep 5, 2012 at 5:15 PM, Tony Yu <ts...@gm...> wrote:
>
>
> On Wed, Sep 5, 2012 at 7:19 PM, Mark Budde <mar...@gm...> wrote:
>>
>> Hi,
>> I'm not an expert so please go easy on me. I am using the pyplot lasso
>> demo, and have got it to work how I would like. I am having a problem,
>> however, where I cannot get it to work if my python file is not the
>> main file (where __name__ is not __main__).
>>
>> I took the part at the bottom in the "if __name__ == '__main__':" and
>> put it into a class. Everything works fine if I call the class from
>> within the same file. However, if I call the class from another file,
>> the graph loads fine but the lasso tool does not work. Troubleshooting
>> revealed that LassoManager.onpress is not being called when I click
>> the mouse. Any suggestions are welcome because this is driving me
>> crazy!
>> Thanks,
>> Mark
>>
>
> Hi Mark,
>
> I can't seem to reproduce your issue, but it's a bit difficult without
> seeing how exactly you wrapped up the "main" part of the code. Just
> guessing: maybe the two cases aren't *exactly* the same.
>
> Is it possible that you have ``lman`` (the LassoManager instance) defined in
> the same block of code as ``show`` in one case but not the other? If, for
> example, ``lman`` is defined in a method of your class, but not saved
> anywhere then it'll get discarded after the method finishes. So ``show``
> would need to be called inside that method, or saved as a class attribute.
>
> Like I said, that's just a wild guess. You should paste the class def if
> you're still having problems.
>
> Best
> -Tony
>
> P.S. If you're running matplotlib from Github master, you might be
> interested in an alternative lasso tool  (LassoSelector) that may be simpler
> to use.:
> https://github.com/matplotlib/matplotlib/blob/master/examples/widgets/lasso_selector_demo.py
>