pytrainer doesnt start on 18.04: ImportError: No module named _backend_gdk

[Achim Behrens]

pytrainer doesnt start on 18.04.
output from terminal is:
> running pytrainer from egg installation
> data_path: /usr/share/pytrainer/
> gettext_path: /usr/share/locale
> site_path: /usr/lib/python2.7/site-packages
> Traceback (most recent call last):
> File "/usr/bin/pytr", line 97, in <module>
> main()
> File "/usr/bin/pytr", line 93, in main
> from pytrainer.main import pyTrainer
> File "/usr/lib/python2.7/dist-packages/pytrainer/main.py", line 40, in <module>
> from gui.windowmain import Main
> File "/usr/lib/python2.7/dist-packages/pytrainer/gui/windowmain.py", line 38, in <module>
> from pytrainer.recordgraph import RecordGraph
> File "/usr/lib/python2.7/dist-packages/pytrainer/recordgraph.py", line 20, in <module>
> from gui.drawArea import DrawArea
> File "/usr/lib/python2.7/dist-packages/pytrainer/gui/drawArea.py", line 22, in <module>
> from matplotlib.backends.backend_gtkagg import FigureCanvasGTKAgg as FigureCanvasGTK
> File "/usr/lib/python2.7/dist-packages/matplotlib/backends/backend_gtkagg.py", line 14, in <module>
> from matplotlib.backends.backend_gtk import (
> File "/usr/lib/python2.7/dist-packages/matplotlib/backends/backend_gtk.py", line 35, in <module>
> from matplotlib.backends.backend_gdk import RendererGDK, FigureCanvasGDK
> File "/usr/lib/python2.7/dist-packages/matplotlib/backends/backend_gdk.py", line 33, in <module>
> from matplotlib.backends._backend_gdk import pixbuf_get_pixels_array
> ImportError: No module named _backend_gdk

according to https://github.com/pytrainer/pytrainer/issues/114 this is an issue with matplotlib not having GTK 2 support compiled in anymore.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: pytrainer 1.11.0-1
ProcVersionSignature: Ubuntu 4.15.0-12.13-generic 4.15.7
Uname: Linux 4.15.0-12-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
CurrentDesktop: Unity:Unity7:ubuntu
Date: Mon Mar 26 03:00:03 2018
InstallationDate: Installed on 2013-09-28 (1639 days ago)
InstallationMedia: Ubuntu 13.10 "Saucy Salamander" - Beta amd64 (20130925.1)
PackageArchitecture: all
SourcePackage: pytrainer
UpgradeStatus: Upgraded to bionic on 2018-01-12 (72 days ago)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Martin Bøgelund (mbogelund)]

pytrainer still doesn't work in Ubuntu 18.10.