On Fri, May 2, 2014 at 8:56 PM, Tom Rondeau <address@hidden> wrote:
On Fri, May 2, 2014 at 8:49 AM, Marcus Müller <address@hidden> wrote:
MarcusGreetings,The easiest solution nowadays should be that you generate a QT flow graph in GRC, use PyQT to generate your GUI, register a message handler and integrate matplotlib (there are examples out there, just don't have one at my fingertips right now), and use the message passing interface to get data out of your flow graph into your GUI.Hi Activecat,typical GUI problem; background is that X applications are inherently hard to multithread, which basically requires graphical toolkits to run in a main loop. This conflicts with every block being run in its own thread.
Tim's written a number of blocks like this:Tom
The examples (https://github.com/osh/gr-pyqt) are using Qt and Qwt to plot graphs, not matplotlib.
(When all the "import pylab" are removed, everything still work as usual, except for pylab.fftshift ).
In order to stick to matplotlib, I created a custom block, register a message handler, and use the message passing interface to get data out from the flowgraph into the custom block. (Everything is as described by Marcus as above, except I do not use QT.) For this flowgraph, Generate-Option="No GUI"
ERROR: handler caught exception: main thread is not in main loop
Question:
How to get rid of this error?
How to get rid of this error?
Or, does this mean plotting using matplotlib is not an option ..?
My objective is to plot graphs in realtime using matplotlib.
I try to stick to Matplotlib because it is the tool I that I am using for numerical analysis.
The custom block is coded as:
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import numpy
from gnuradio import gr
import pmt
from matplotlib import pyplot
class matplotlib4(gr.sync_block):
def __init__(self):
gr.sync_block.__init__(self,
name="matplotlib4",
in_sig=None,
out_sig=None)
pyplot.ion()
self.fig1 = pyplot.figure()
self.ax1 = self.fig1.add_subplot(2,1,1)
self.ax1.set_ylabel('Real')
self.ax1.set_xlabel('time')
self.ax1.set_ylim(-1.2, 1.2)
self.ax1.grid(True)
self.line1, = self.ax1.plot( [0.3]*1000 )
self.line2, = self.ax1.plot( [0.3]*1000 )
self.axes1 = pyplot.gca()
pyplot.draw() # no error of "main thread is not in main loop"
pyplot.show() # no error of "main thread is not in main loop"
self.message_port_register_in( pmt.intern("cpdus"))
self.set_msg_handler(pmt.intern("cpdus"), self.handler4)
def handler4( self, msg ):
samples = pmt.cdr(msg)
data = "" pmt.c32vector_elements(samples), dtype=numpy.complex64 )
self.line1.set_ydata( data.real )
self.line2.set_ydata( data.imag )
#self.fig1.canvas.draw() # handler caught exception: main thread is not in main loop
#pyplot.draw() # handler caught exception: main thread is not in main loop
#self.axes1.figure.canvas.draw() # handler caught exception: main thread is not in main loop
print "handler4(): x.size={}".format( data.size )
def work(self, input_items, output_items):
print "matplotlib4.work(): *** This should not be invoked*** "
return len(input_items[0])
Flowgraph being used for this test:
