没有模块 'gi' 和 ImportError：GTK3 后端需要 PyGObject 错误

Question

I am trying to run some code on an AWS ec2 (ubuntu). When I comment out the portion that displays graphs from matplotlib, it runs fine. However, I want to view graphs.

When running the code, I get this error:

Traceback (most recent call last):
  File "/home/ubuntu/anaconda3/envs/pytorch_p36/lib/python3.6/site-packages/matplotlib/backends/backend_gtk3.py", line 18, in <module>
    import gi
ModuleNotFoundError: No module named 'gi'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "run.py", line 8, in <module>
    from process_mask import ProcessMasks
  File "/home/ubuntu/rPPG/process_mask.py", line 10, in <module>
    matplotlib.use('GTK3Agg')
  File "/home/ubuntu/anaconda3/envs/pytorch_p36/lib/python3.6/site-packages/matplotlib/cbook/deprecation.py", line 307, in wrapper
    return func(*args, **kwargs)
  File "/home/ubuntu/anaconda3/envs/pytorch_p36/lib/python3.6/site-packages/matplotlib/__init__.py", line 1307, in use
    switch_backend(name)
  File "/home/ubuntu/anaconda3/envs/pytorch_p36/lib/python3.6/site-packages/matplotlib/pyplot.py", line 221, in switch_backend
    backend_mod = importlib.import_module(backend_name)
  File "/home/ubuntu/anaconda3/envs/pytorch_p36/lib/python3.6/importlib/__init__.py", line 126, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "/home/ubuntu/anaconda3/envs/pytorch_p36/lib/python3.6/site-packages/matplotlib/backends/backend_gtk3agg.py", line 4, in <module>
    from . import backend_agg, backend_cairo, backend_gtk3
  File "/home/ubuntu/anaconda3/envs/pytorch_p36/lib/python3.6/site-packages/matplotlib/backends/backend_gtk3.py", line 20, in <module>
    raise ImportError("The GTK3 backends require PyGObject")
ImportError: The GTK3 backends require PyGObject

I've been searching SO and other sources and have tried a lot of things including:

sudo apt-get install python3-gi

pip install vext
pip install vext.gi

sudo apt install python3-gi

pip3 install --user pgi

Also, this works:

$ /usr/bin/python3
Python 3.4.0 (default, Apr 11 2014, 13:05:11) 
[GCC 4.8.2] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import gi
>>> 

but my actual code is in a virtual env with a bunch of dependencies, so this doesn't work with my actual code ( /usr/bin/python run.py ).

Answer 1

I ran into exact same issue, but after much efforts I managed to make TkAgg working (which was giving the import error for _tkagg). Little late, but someone might find it useful.

FWIW I resolved the issue as follows (to use TkAgg):

◉ Installed tk-dev from package manager

◉ Reinstalled python3-tk from package manager

◉ Rebuilt and reinstalled matplotlib from source

◉ (and of course setting TkAgg in matplotrc)

If you think you have tk-dev and python3-tk installed correctly, you need to rebuild and reinstall matplotlib, so that it generates _tkagg.py in your backends directory.

I'm using Python3.3 (numpy 1.7) on LM14. But I think it should work on Ubuntu/Python3.2

Thanks