Commit 1c47cb6f authored by Tiago Peixoto's avatar Tiago Peixoto
Browse files

Handle foreign cairocffi.Context objects

parent 4b6ba22a
......@@ -1509,6 +1509,10 @@ class GraphArtist(matplotlib.artist.Artist):
raise NotImplementedError("graph plotting is supported only on Cairo backends")
ctx = renderer.gc.ctx
if not isinstance(ctx, cairo.Context):
ctx = _UNSAFE_cairocffi_context_to_pycairo(ctx)
ctx.save()
if self.ax is not None:
......@@ -2083,6 +2087,40 @@ def get_bip_hierachy_pos(state, aspect=1., node_weight=None):
return pos
# Handle cairo contexts from cairocffi
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]
ctypes.pythonapi.PyList_Append.argtypes = 2 * [ctypes.c_void_p]
except ImportError:
pass
def _UNSAFE_cairocffi_context_to_pycairo(cairocffi_context):
# Sanity check. Continuing with another type would probably segfault.
if not isinstance(cairocffi_context, cairocffi.Context):
raise TypeError('Expected a cairocffi.Context, got %r'
% cairocffi_context)
# Create a reference for PycairoContext_FromContext to take ownership of.
cairocffi.cairo.cairo_reference(cairocffi_context._pointer)
# Casting the pointer to uintptr_t (the integer type as wide as a pointer)
# 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(
int(cairocffi.ffi.cast('uintptr_t', cairocffi_context._pointer)),
id(cairo.Context),
None)
assert address
# This trick uses Python’s C API
# to get a reference to a Python object from its address.
temp_list = []
assert ctypes.pythonapi.PyList_Append(id(temp_list), address) == 0
return temp_list[0]
# Bottom imports to avoid circular dependency issues
from .. community import get_hierarchy_tree, NestedBlockState, BlockState, OverlapBlockState
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