Segment Fault

[wzpan]

I've found #41 and #24 but none of them seem to be the same issue to mine.

I'm trying to write a wave plotting program kivy app.

In pure Python code it works as expected:

#import the pyplot and wavfile modules 

import matplotlib.pyplot as plot

from scipy.io import wavfile

 
# Read the wav file (mono)

signalData = wavfile.read('test.wav')

# Plot the signal read from wav file

fig, ax = plot.subplots()
ax.plot(signalData[1])

plot.show()

However as I was trying to adapt it into kivy app, I got the following segment fault error:

[INFO   ] [Logger      ] Record log in /Applications/Kivy3.app/Contents/Resources/.kivy/logs/kivy_19-04-01_69.txt
[INFO   ] [Kivy        ] v1.10.1
[INFO   ] [Python      ] v3.6.5 (default, Jun 18 2018, 16:36:13) 
[GCC 4.2.1 Compatible Apple LLVM 9.1.0 (clang-902.0.39.1)]
[INFO   ] [Factory     ] 194 symbols loaded
[INFO   ] [Image       ] Providers: img_tex, img_imageio, img_dds, img_sdl2, img_gif (img_pil, img_ffpyplayer ignored)
[INFO   ] [Text        ] Provider: sdl2
[INFO   ] [Window      ] Provider: sdl2
[INFO   ] [GL          ] Using the "OpenGL ES 2" graphics system
[INFO   ] [GL          ] Backend used <gl>
[INFO   ] [GL          ] OpenGL version <b'2.1 ATI-2.0.36'>
[INFO   ] [GL          ] OpenGL vendor <b'ATI Technologies Inc.'>
[INFO   ] [GL          ] OpenGL renderer <b'AMD Radeon R9 M395 OpenGL Engine'>
[INFO   ] [GL          ] OpenGL parsed version: 2, 1
[INFO   ] [GL          ] Shading version <b'1.20'>
[INFO   ] [GL          ] Texture max size <16384>
[INFO   ] [GL          ] Texture max units <16>
[INFO   ] [Window      ] auto add sdl2 input provider
[INFO   ] [Window      ] virtual keyboard not allowed, single mode, not docked
[INFO   ] [GL          ] NPOT texture support is available
[INFO   ] [Base        ] Start application main loop
Segmentation fault: 11

Here's the whole code:

import matplotlib
matplotlib.use('module://kivy.garden.matplotlib.backend_kivy')
import numpy as np
from scipy.io import wavfile
from kivy.app import App

from kivy.garden.matplotlib.backend_kivyagg import FigureCanvas
from kivy.uix.floatlayout import FloatLayout
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.graphics import Color, Line, Rectangle

import matplotlib.pyplot as plot

signalData = wavfile.read('test.wav')

fig, ax = plot.subplots()
ax.plot(signalData[1])

canvas = fig.canvas

class MatplotlibTest(App):
    title = 'Matplotlib Test'

    def build(self):
        fl = BoxLayout(orientation="vertical")
        fl.add_widget(canvas)
        return fl

if __name__ == '__main__':
    MatplotlibTest().run()

I will be grateful if you could give me a hand.