I just want to use matplotlib to visualize some data when debugging. Follow this page: Analyzing C/C++ matrix in the gdb debugger with Python and Numpy - CodeProject, it works OK unless the matplotlib GUI just block the GDB's command line. Which means if I leave the GUI window open, the GDB's command line is freezed, and I can't enter anything in the GDB command until I close the pyplot window.
To solve this, I just try to run the plotting code in another thread, to simplify the test case, I just create a simple python source code named "test-pyplot.py" with the contents below
import numpy as np
from matplotlib import pyplot as plt
from threading import Thread
class MyThread (Thread):
def __init__(self, thread_id):
Thread.__init__(self)
self.thread_id = thread_id
def run(self):
x = np.arange(0, 5, 0.1);
y = np.sin(x)
plt.plot(x, y)
plt.show(block = True) #this cause the mainloop
thread1 = MyThread(1)
thread1.start()
Now, under the GDB command line, I simply type: source test-pyplot.py, and a non blocking GUI will open and it looks good, that GDB's command line can still accept command, so far so good.
But the problem happens when I close the plot window, then I run the source test-pyplot.py again, this time, GDB just hangs.
I'm using python 2.7.6 under Windows, and I see that matplotlib was default to use the tkAgg as the drawing back end, so I try to see whether this will happen for a normal tk GUI window. Here is another test python file named "test-tk.py", which has contents below:
from Tkinter import *
from threading import Thread
class App():
def __init__(self):
self.g=Tk()
self.th=Thread(target=self.g.mainloop)
self.th.start()
def destroy(self):
self.g.destroy()
a1 = App()
If I run the command source test-tk.py under GDB prompt, a tk window will show up, GDB is still alive(not freezed), and I can close the tk window, and type the command source test-tk.py again, and every thing works fine, GDB does not hang. I can even run the command source test-tk.py twice without close the first tk window, then there will be two tk window shown.
Question: how to correctly show matplotlib pyplot figure in non-blocking mode, which don't hang GDB? Thanks.
Normally, plt.show will internally call the mainloop function of the Tkinter package, which is a event loop.
matplotlib do have an option named interactive mode, which can be enabled by calling the `plt.ion()', but it don't solve my problem.
