Hi Tiago,

I installed graph-tool on a mac machine. After struggling a lot to import graph_tool without any error in python, I was running an example with plotting and I was getting following error 

>>> from graph_tool import all

/Users/zahra/anaconda3/lib/python3.6/site-packages/graph_tool/draw/cairo_draw.py:1494: RuntimeWarning: Error importing Gtk module: No module named 'gi'; GTK+ drawing will not work.

  warnings.warn(msg, RuntimeWarning)

>>> from graph_tool.all import *

>>> g=Graph()

>>> v1 = g.add_vertex(

... )

>>> v2 = g.add_vertex()

>>> e=g.add_edge(v1,v2)

>>> graph_draw(g, vertex_text=g.vertex_index, vertex_font_size=18,output_size=(200, 200), output="../two-nodes.png")

Traceback (most recent call last):

  File "<stdin>", line 1, in <module>

  File "/Users/zahra/anaconda3/lib/python3.6/site-packages/graph_tool/draw/cairo_draw.py", line 1185, in graph_draw

    nodesfirst, fit_view=fit_view, **kwargs)

  File "/Users/zahra/anaconda3/lib/python3.6/site-packages/graph_tool/draw/cairo_draw.py", line 707, in cairo_draw

    max_render_time, cr)

MemoryError

>>> quit()