使Matplotlib和GTK3在python3窗口上运行

Question

I'm trying to make GTK3 and Python3 work under windows to my project.

I have an continuum anaconda setup with a 32-bit python 3.4 and Matplotib via conda install matplotlib.

I've installed PyGobject( https://sourceforge.net/projects/pygobjectwin32/ ) and installed GTK+ / Glade via the installer.

The basic exemple from the GTK3 tutorial works well (empty screen)

import gi
gi.require_version('Gtk', '3.0')
from gi.repository import Gtk

win = Gtk.Window()
win.connect("delete-event", Gtk.main_quit)
win.show_all()
Gtk.main()

I want now to embed matplotlib in gtk, I got the example from matplotlib ( http://matplotlib.org/examples/user_interfaces/embedding_in_gtk3.html )

I saw then that I needed cairocffi because some incompabilities. (PyCairo has no support for a matplotlib function)

I got the windows binaries for cffi from Gohlke

And finnaly did a

pip install cairocffi

And now I just get a python.exe stopped working.

Tried with GTK3agg and GTK3Cairo backends and I have the same result

Looking around I found that maybe the cairo version is outdated for the functions used by matplotlib, but I dont know how to proceed.

Cairocffi works if I try running something else.

More information (from the comment below):

I still got an unhandled win32 error. I managed to open the error and it says:

Unhandled exception at 0x08CF6D58 (libcairo-2.dll) in python.exe:
0xC0000005: Access violation reading location 0x000000A8.
If there is a handler for this exception, the program may be safely continued. 

It just crashes...

Answer 1

I've had my share of problems using matplotlib in Python3 + Gtk3 . I found this cookbook page with working examples. Try to run the examples in the cookbook - particularly the simplest one:

#!/usr/bin/python3

from gi.repository import Gtk

from matplotlib.figure import Figure
from numpy import arange, pi, random, linspace
import matplotlib.cm as cm
#Possibly this rendering backend is broken currently
#from matplotlib.backends.backend_gtk3agg import FigureCanvasGTK3Agg as FigureCanvas
from matplotlib.backends.backend_gtk3cairo import FigureCanvasGTK3Cairo as FigureCanvas

myfirstwindow = Gtk.Window()
myfirstwindow.connect("delete-event", Gtk.main_quit)
myfirstwindow.set_default_size(400, 400)

fig = Figure(figsize=(5,5), dpi=100)
ax = fig.add_subplot(111, projection='polar')

N = 20
theta = linspace(0.0, 2 * pi, N, endpoint=False)
radii = 10 * random.rand(N)
width = pi / 4 * random.rand(N)

bars = ax.bar(theta, radii, width=width, bottom=0.0)

for r, bar in zip(radii, bars):
    bar.set_facecolor(cm.jet(r / 10.))
    bar.set_alpha(0.5)

ax.plot()

sw = Gtk.ScrolledWindow()
myfirstwindow.add(sw) 

canvas = FigureCanvas(fig)
canvas.set_size_request(400,400)
sw.add_with_viewport(canvas)

myfirstwindow.show_all()
Gtk.main()

Also, not that you need a fairly recent version of matplotlib to make things work on Python3 .

If you still have problems, please show us the complete error message.

Note: I tested this on Linux (don't have Windows), but, from you description of problems, the issue is (was) a common one.

Answer 2

I have the same issue on Windows since years. The documentation of matplotlib 2.0.0 realease states that Gtk3 backend is not supported on Windows . Recently, I had an issue running the Gtk3Agg backend under Linux (Ubuntu). In both cases, it is always related to Cairo.

Thus, I wrote my own implementation of this backend, you can find it here . import the FigureCanvasGtk3Agg from my module and use it the same way as the official one. It lacks some features, but, if you just want to display a plot, it'll do the job.

You can try the module by running it, it should display a simple colorful graph in a window. I tried it under both Linux and Windows and had no issue.

How does it works:

The trick is to avoid importing Cairo in Python3 as it usually doesn't work (to my experience). It is done by using a GdkPixbuf .

Then Gdk.cairo_set_source_pixbuf does the rest of the job along with calling two methods of the cairo context provided by Gtk in the 'draw-event' callback. Cairo is never imported in the module.