import easygraph as eg
__all__ = [
"from_pyGraphviz_agraph",
"to_pyGraphviz_agraph",
]
[docs]def from_pyGraphviz_agraph(A, create_using=None):
"""Returns a EasyGraph Graph or DiGraph from a PyGraphviz graph.
Parameters
----------
A : PyGraphviz AGraph
A graph created with PyGraphviz
create_using : EasyGraph graph constructor, optional (default=None)
Graph type to create. If graph instance, then cleared before populated.
If `None`, then the appropriate Graph type is inferred from `A`.
Examples
--------
>>> K5 = eg.complete_graph(5)
>>> A = eg.to_pyGraphviz_agraph(K5)
>>> G = eg.from_pyGraphviz_agraph(A)
Notes
-----
The Graph G will have a dictionary G.graph_attr containing
the default graphviz attributes for graphs, nodes and edges.
Default node attributes will be in the dictionary G.node_attr
which is keyed by node.
Edge attributes will be returned as edge data in G. With
edge_attr=False the edge data will be the Graphviz edge weight
attribute or the value 1 if no edge weight attribute is found.
"""
if create_using is None:
if A.is_directed():
if A.is_strict():
create_using = eg.DiGraph
else:
create_using = eg.MultiDiGraph
else:
if A.is_strict():
create_using = eg.Graph
else:
create_using = eg.MultiGraph
# assign defaults
N = eg.empty_graph(0, create_using)
if A.name is not None:
N.name = A.name
# add graph attributes
N.graph.update(A.graph_attr)
# add nodes, attributes to N.node_attr
for n in A.nodes():
str_attr = {str(k): v for k, v in n.attr.items()}
N.add_node(str(n), **str_attr)
# add edges, assign edge data as dictionary of attributes
for e in A.edges():
u, v = str(e[0]), str(e[1])
attr = dict(e.attr)
str_attr = {str(k): v for k, v in attr.items()}
if not N.is_multigraph():
if e.name is not None:
str_attr["key"] = e.name
N.add_edge(u, v, **str_attr)
else:
N.add_edge(u, v, key=e.name, **str_attr)
# add default attributes for graph, nodes, and edges
# hang them on N.graph_attr
N.graph["graph"] = dict(A.graph_attr)
N.graph["node"] = dict(A.node_attr)
N.graph["edge"] = dict(A.edge_attr)
return N
[docs]def to_pyGraphviz_agraph(N):
"""Returns a pygraphviz graph from a EasyGraph graph N.
Parameters
----------
N : EasyGraph graph
A graph created with EasyGraph
Examples
--------
>>> K5 = eg.complete_graph(5)
>>> A = eg.to_pyGraphviz_agraph(K5)
Notes
-----
If N has an dict N.graph_attr an attempt will be made first
to copy properties attached to the graph (see from_agraph)
and then updated with the calling arguments if any.
"""
try:
import pygraphviz
except ImportError as err:
raise ImportError("requires pygraphviz http://pygraphviz.github.io/") from err
directed = N.is_directed()
strict = eg.number_of_selfloops(N) == 0 and not N.is_multigraph()
A = pygraphviz.AGraph(name=N.name, strict=strict, directed=directed)
# default graph attributes
A.graph_attr.update(N.graph.get("graph", {}))
A.node_attr.update(N.graph.get("node", {}))
A.edge_attr.update(N.graph.get("edge", {}))
A.graph_attr.update(
(k, v) for k, v in N.graph.items() if k not in ("graph", "node", "edge")
)
# add nodes
for n, nodedata in N.nodes(data=True):
A.add_node(n)
# Add node data
a = A.get_node(n)
a.attr.update({k: str(v) for k, v in nodedata.items()})
# loop over edges
if N.is_multigraph():
for u, v, key, edgedata in N.edges(data=True, keys=True):
str_edgedata = {k: str(v) for k, v in edgedata.items() if k != "key"}
A.add_edge(u, v, key=str(key))
# Add edge data
a = A.get_edge(u, v)
a.attr.update(str_edgedata)
else:
for u, v, edgedata in N.edges(data=True):
str_edgedata = {k: str(v) for k, v in edgedata.items()}
A.add_edge(u, v)
# Add edge data
a = A.get_edge(u, v)
a.attr.update(str_edgedata)
return A