Bug with Gtk and PyPlot

[tbreloff]

I'm not able to use both PyPlot and Gtk at the same time. I get different problems depending on which I import first:

  _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.4.0 (2015-10-08 06:20 UTC)
 _/ |\__'_|_|_|\__'_|  |  
|__/                   |  x86_64-redhat-linux

julia> using Gtk

julia> using PyPlot
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: g_boxed_type_register_static: assertion 'g_type_from_name (name) == 0' failed
  from gtk import _gtk
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: g_type_set_qdata: assertion 'node != NULL' failed
  from gtk import _gtk
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: cannot register existing type 'GtkWidget'
  from gtk import _gtk
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: g_type_add_interface_static: assertion 'G_TYPE_IS_INSTANTIATABLE (instance_type)' failed
  from gtk import _gtk
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: cannot register existing type 'GtkBuildable'
  from gtk import _gtk
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: g_type_interface_add_prerequisite: assertion 'G_TYPE_IS_INTERFACE (interface_type)' failed
  from gtk import _gtk
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: g_once_init_leave: assertion 'result != 0' failed
  from gtk import _gtk
/usr/lib64/python2.7/site-packages/gtk-2.0/gtk/__init__.py:40: Warning: g_type_register_static: assertion 'parent_type > 0' failed
  from gtk import _gtk
^C/usr/lib64/python2.7/site-packages/matplotlib/__init__.py:1005: UserWarning:  This call to matplotlib.use() has no effect
because the the backend has already been chosen;
matplotlib.use() must be called *before* pylab, matplotlib.pyplot,
or matplotlib.backends is imported for the first time.

  warnings.warn(_use_error_msg)
ERROR: InitError: PyError (:PyImport_ImportModule) <type 'exceptions.AttributeError'>
AttributeError("'module' object has no attribute 'gdk'",)
  File "/usr/lib64/python2.7/site-packages/matplotlib/pyplot.py", line 97, in <module>
    _backend_mod, new_figure_manager, draw_if_interactive, _show = pylab_setup()
  File "/usr/lib64/python2.7/site-packages/matplotlib/backends/__init__.py", line 25, in pylab_setup
    globals(),locals(),[backend_name])
  File "/usr/lib64/python2.7/site-packages/matplotlib/backends/backend_gtkagg.py", line 10, in <module>
    from matplotlib.backends.backend_gtk import gtk, FigureManagerGTK, FigureCanvasGTK,\
  File "/usr/lib64/python2.7/site-packages/matplotlib/backends/backend_gtk.py", line 13, in <module>
    import gtk; gdk = gtk.gdk

 [inlined code] from /home/tom/.julia/v0.4/PyCall/src/exception.jl:81
 in pyimport at /home/tom/.julia/v0.4/PyCall/src/PyCall.jl:79
 in __init__ at /home/tom/.julia/v0.4/PyPlot/src/PyPlot.jl:250
 in _require_from_serialized at loading.jl:84
 in _require_from_serialized at ./loading.jl:109
 in require at ./loading.jl:219
during initialization of module PyPlot

julia> 
[tom@tomoffice Plots]$ julia
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.4.0 (2015-10-08 06:20 UTC)
 _/ |\__'_|_|_|\__'_|  |  
|__/                   |  x86_64-redhat-linux

julia> using PyPlot

julia> using Gtk
sys:1: Warning: cannot register existing type 'GdkDisplayManager'
sys:1: Warning: g_once_init_leave: assertion 'result != 0' failed
sys:1: Warning: g_type_register_static: assertion 'parent_type > 0' failed
sys:1: Warning: g_object_new: assertion 'G_TYPE_IS_OBJECT (object_type)' failed


^CERROR: InitError: InterruptException:
 in anonymous at /home/tom/.julia/v0.4/Gtk/src/events.jl:11
 in call at /home/tom/.julia/v0.4/Gtk/src/GLib/gerror.jl:13
 in __init__ at /home/tom/.julia/v0.4/Gtk/src/events.jl:10
 in _require_from_serialized at loading.jl:84
 in _require_from_serialized at ./loading.jl:109
 in require at ./loading.jl:219
during initialization of module Gtk

julia> 

cc: @stevengj

[tbreloff]

FYI: If I rename the gtk-2.0 library that seems to cause problems, I can import both:

[tom@tomoffice site-packages]$ sudo mv gtk-2.0 ignore_gtk-2.0
[sudo] password for tom: 
[tom@tomoffice site-packages]$ cd
[tom@tomoffice ~]$ julia
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "?help" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.4.0 (2015-10-08 06:20 UTC)
 _/ |\__'_|_|_|\__'_|  |  
|__/                   |  x86_64-redhat-linux

julia> using Gtk

julia> using PyPlot

julia> 

but then when later on I get this when building a Gtk window:

**
GLib:ERROR:gmain.c:3017:g_main_dispatch: assertion failed: (source)

signal (6): Aborted
gsignal at /lib64/libc.so.6 (unknown line)
abort at /lib64/libc.so.6 (unknown line)
g_assertion_message at /lib64/libglib-2.0.so.0 (unknown line)
g_assertion_message_expr at /lib64/libglib-2.0.so.0 (unknown line)
g_main_context_dispatch at /lib64/libglib-2.0.so.0 (unknown line)
unknown function (ip: 0x7f7af8bc0ce8)
g_main_context_iteration at /lib64/libglib-2.0.so.0 (unknown line)
gtk_main_iteration at /lib64/libgtk-3.so.0 (unknown line)
ffi_call_unix64 at /lib64/libffi.so.6 (unknown line)
ffi_call at /lib64/libffi.so.6 (unknown line)
g_callable_info_invoke at /lib64/libgirepository-1.0.so.1 (unknown line)
g_function_info_invoke at /lib64/libgirepository-1.0.so.1 (unknown line)
unknown function (ip: 0x7f7af934168f)
PyEval_EvalFrameEx at /usr/lib64/libpython2.7.so.1.0 (unknown line)
PyEval_EvalCodeEx at /usr/lib64/libpython2.7.so.1.0 (unknown line)
unknown function (ip: 0x7f7d24e4d088)
PyObject_Call at /usr/lib64/libpython2.7.so.1.0 (unknown line)
pycall at /home/tom/.julia/v0.4/PyCall/src/exception.jl:78
doevent at /home/tom/.julia/v0.4/PyCall/src/gui.jl:87
jl_apply_generic at /opt/julia/usr/bin/../lib/libjulia.so (unknown line)
anonymous at stream.jl:693
unknown function (ip: 0x7f7d23e8f398)
unknown function (ip: (nil))
Aborted (core dumped)

[vtjnash]

you can't load gtk-2 and gtk-3 into the same memory. either switch matplotlib to using gtk-3 or change the variable in Gtk.jl/deps/ext.jl to use gtk_version = 2.

[stevengj]

(Note that PyCall supports gtk3; you can set your matplotlib backend preference in the matplotlibrc file.)

[ettersi]

I tried switching to gtk-3 for PyPlot, but neither GTK3Cairo nor GTK3Agg solved the problem. WebAgg on the other hand seems to work. So, if you have the same problem, add the line

backend               : WebAgg

to your matplotlibrc file and you should be fine.