Fix problem with recent pycairo

src/graph/draw/Makefile.am

@@ -19,3 +19,18 @@ libgraph_tool_draw_la_SOURCES = \
     graph_tree_cts.cc
 
 libgraph_tool_draw_la_include_HEADERS = 
+
+gt_pycairo_auxdir = $(MOD_DIR)/draw
+
+gt_pycairo_aux_LTLIBRARIES = gt_pycairo_aux.la
+
+gt_pycairo_aux_la_includedir = $(MOD_DIR)/include/draw
+
+gt_pycairo_aux_la_LIBADD = $(MOD_LIBADD)
+
+gt_pycairo_aux_la_LDFLAGS = $(MOD_LDFLAGS) $(CAIROMM_LIBS)
+
+gt_pycairo_aux_la_SOURCES = \
+    pycairo_aux.cc
+
+gt_pycairo_aux_la_include_HEADERS = 

src/graph/draw/pycairo_aux.cc

+// graph-tool -- a general graph modification and manipulation thingy
+//
+// Copyright (C) 2006-2018 Tiago de Paula Peixoto <tiago@skewed.de>
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 3
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+#include "graph.hh"
+
+#include PYCAIRO_HEADER
+
+extern "C"
+PyObject* gt_PycairoContext_FromContext(cairo_t *ctx, PyTypeObject *type,
+                                        PyObject *base)
+{
+    return PycairoContext_FromContext(ctx, type, base);
+}

src/graph_tool/draw/cairo_draw.py

@@ -2173,9 +2173,9 @@ def get_bip_hierachy_pos(state, aspect=1., node_weight=None):
 try:
     import cairocffi
     import ctypes
-    pycairo = ctypes.PyDLL(cairo._cairo.__file__)
-    pycairo.PycairoContext_FromContext.restype = ctypes.c_void_p
-    pycairo.PycairoContext_FromContext.argtypes = 3 * [ctypes.c_void_p]
+    pycairo_aux = ctypes.PyDLL(os.path.dirname(os.path.abspath(__file__)) + "/gt_pycairo_aux.so")
+    pycairo_aux.gt_PycairoContext_FromContext.restype = ctypes.c_void_p
+    pycairo_aux.gt_PycairoContext_FromContext.argtypes = 3 * [ctypes.c_void_p]
     ctypes.pythonapi.PyList_Append.argtypes = 2 * [ctypes.c_void_p]
 except ImportError:
     pass
@@ -2192,7 +2192,7 @@ def _UNSAFE_cairocffi_context_to_pycairo(cairocffi_context):
     # gets the context’s integer address.
     # On CPython id(cairo.Context) gives the address to the Context type,
     # as expected by PycairoContext_FromContext.
-    address = pycairo.PycairoContext_FromContext(
+    address = pycairo_aux.gt_PycairoContext_FromContext(
         int(cairocffi.ffi.cast('uintptr_t', cairocffi_context._pointer)),
         id(cairo.Context),
         None)