Installing PyGtk in virtualenv

Question

So I am trying to run a simple matplotlib example in my virtualenv (in the console). Here's the code:

import matplotlib
matplotlib.use('GTKAgg')
import matplotlib.pyplot as plt
radius = [1.0, 2.0, 3.0, 4.0, 5.0, 6.0]
area = [3.14159, 12.56636, 28.27431, 50.26544, 78.53975, 113.09724]
plt.plot(radius, area)
plt.show()

However, when I run this I get:

ImportError: Gtk* backend requires pygtk to be installed.

And now the fun starts. I tried to pip install pygtk but it throws:

********************************************************************
* Building PyGTK using distutils is only supported on windows. *
* To build PyGTK in a supported way, read the INSTALL file.    *
********************************************************************
Complete output from command python setup.py egg_info:
********************************************************************

I have checked the INSTALL file and says to try ./configfure; make; make install. However. I am not quite sure how to do this within virtualenv. Where do I unpack the sources for pygtk in order to be installed within virtualenv.

Answer 1

The trick is to manually set the correct paths and then run configure inside the virtualenv. This is quite basic, but it worked for me.

Install python-config in the virtual env and link it to python2.7-config:

pip install config
ln -s /home/PATH/TO/VIRT/bin/python-config /home/PATH/TO/VIRT/bin/python2.7-config

Install cairo in the virtual env:

wget http://cairographics.org/releases/py2cairo-1.10.0.tar.bz2
tar -xf py2cairo-1.10.0.tar.bz2
cd py2cairo-1.10.0
./waf configure --prefix=/home/PATH/TO/VIRT/
./waf build
./waf install

Install PyGTK

wget http://pypi.python.org/packages/source/P/PyGTK/pygtk-2.24.0.tar.bz2
tar -xf pygtk-2.24.0.tar.bz2
cd pygtk-2.24.0
export PKG_CONFIG_PATH=/home/PATH/TO/VIRT/lib/pkgconfig
./configure --prefix=/home/PATH/TO/VIRT/
make 
make install

And that should do it. Just replace PATH/TO/VIRT/ with your own path. I'm sure someone could assist on adding the path to virtualenvwrapper?

Answer 2

I did this

sudo apt-get install python-gtk2

I found that it was already installed upon some investigation, i found out that when I create a virtual environment, it was missing some links so I came across this post: Virtualenv on Ubuntu with no site-packages.

I read it and tailored the commands provided to my setup as follows:

1. First I changed into my virtualenv and activated it by

   source bin/activate
   

2. Then I changed into the lib/python2.7 folder inside my virtualenv:

   cd lib/python2.7
   

3. I then executed the following commands.

   $ ln -s /usr/lib/python2.7/dist-packages/cairo/
   $ ln -s /usr/lib/python2.7/dist-packages/pygtk.py
   $ ln -s /usr/lib/python2.7/dist-packages/pygtk.pth
   $ ln -s /usr/lib/python2.7/dist-packages/gtk-2.0/
   

4. Finally, to check I typed 'python', and executed:

   >>> import pygtk
   

   It gave me no error, and therefore I knew its now available in my virtual env.

I'm using Ubuntu 14.04 (64-bit) on an intel Core i5.

Answer 3

pygtk cannot be installed in your virtualenv from PyPI, so

pip install pygtk

will download but not install. You can go through the hoops of downloading the tar files and compiling and installing those, but if it is OK to make links to the relevant packages installed in the system then activating your virtualenv and installing ruamel.venvgtk is enough:

pip install ruamel.venvgtk

This is a shameless plug for my own work, none of the other solutions here worked well with repeated virtualenv creation as is e.g. done by tox.

In the setup.py of the packages the following happens:

try:
    import gtk
except ImportError:
    print('--------------')
    import subprocess
    instdir = subprocess.check_output([
        '/usr/bin/python',
        '-c',
        'import os, pygtk; print os.path.dirname(pygtk.__file__)',
    ]).strip()
    for dst_base in sys.path:
        if dst_base.strip():
            break
    for d in [
        'pygtk.pth',
        'pygtk.py',
        'gtk-2.0',
        'gobject',
        'glib',
        'cairo',
        ]:
        src = os.path.join(instdir, d)
        dst = os.path.join(dst_base, d)
        if os.path.exists(src) and not os.path.exists(dst):
            print('linking', d, 'to', dst_base)
            os.symlink(src, dst)

i.e the system's python is asked where pygtk is installed (on Linux Mint 17.1 this is /usr/lib/python2.7/dist-packages), and then links are set up to the first path (that is non-zero length) for the activated python.

Answer 4

My experience (on Posix systems exclusively) has been that some packages cannot be installed in virtualenv (I think it's because they need to compile themselves, etc). Sometimes they can be installed in the individual package afterwards.

One way you could handle this situation is to compile and install the package somewhere else and then configure the virtualenv to load that package by adding site-packages paths. Check out the documentation for more. (or setup a boostrap script that changes the environment path every time you activate your environment (easy to do with virtualenvwrapper

Answer 5

I fixed the problem by installing the python-gtk2 debian package.