Source code for automaton.converters.pydot

#    Copyright (C) 2015 Yahoo! Inc. All Rights Reserved.
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

    import pydot
except ImportError:

[docs]def convert(machine, graph_name, graph_attrs=None, node_attrs_cb=None, edge_attrs_cb=None, add_start_state=True, name_translations=None): """Translates the state machine into a pydot graph. :param machine: state machine to convert :type machine: FiniteMachine :param graph_name: name of the graph to be created :type graph_name: string :param graph_attrs: any initial graph attributes to set (see for what these can be) :type graph_attrs: dict :param node_attrs_cb: a callback that takes one argument ``state`` and is expected to return a dict of node attributes (see for what these can be) :type node_attrs_cb: callback :param edge_attrs_cb: a callback that takes three arguments ``start_state, event, end_state`` and is expected to return a dict of edge attributes (see for what these can be) :type edge_attrs_cb: callback :param add_start_state: when enabled this creates a *private* start state with the name ``__start__`` that will be a point node that will have a dotted edge to the ``default_start_state`` that your machine may have defined (if your machine has no actively defined ``default_start_state`` then this does nothing, even if enabled) :type add_start_state: bool :param name_translations: a dict that provides alternative ``state`` string names for each state :type name_translations: dict """ if not PYDOT_AVAILABLE: raise RuntimeError("pydot (or pydot2 or equivalent) is required" " to convert a state machine into a pydot" " graph") if not name_translations: name_translations = {} graph_kwargs = { 'rankdir': 'LR', 'nodesep': '0.25', 'overlap': 'false', 'ranksep': '0.5', 'size': "11x8.5", 'splines': 'true', 'ordering': 'in', } if graph_attrs is not None: graph_kwargs.update(graph_attrs) graph_kwargs['graph_name'] = graph_name g = pydot.Dot(**graph_kwargs) node_attrs = { 'fontsize': '11', } nodes = {} for (start_state, event, end_state) in machine: if start_state not in nodes: start_node_attrs = node_attrs.copy() if node_attrs_cb is not None: start_node_attrs.update(node_attrs_cb(start_state)) pretty_start_state = name_translations.get(start_state, start_state) nodes[start_state] = pydot.Node(pretty_start_state, **start_node_attrs) g.add_node(nodes[start_state]) if end_state not in nodes: end_node_attrs = node_attrs.copy() if node_attrs_cb is not None: end_node_attrs.update(node_attrs_cb(end_state)) pretty_end_state = name_translations.get(end_state, end_state) nodes[end_state] = pydot.Node(pretty_end_state, **end_node_attrs) g.add_node(nodes[end_state]) edge_attrs = {} if edge_attrs_cb is not None: edge_attrs.update(edge_attrs_cb(start_state, event, end_state)) g.add_edge(pydot.Edge(nodes[start_state], nodes[end_state], **edge_attrs)) if add_start_state and machine.default_start_state: start = pydot.Node("__start__", shape="point", width="0.1", xlabel='start', fontcolor='green', **node_attrs) g.add_node(start) g.add_edge(pydot.Edge(start, nodes[machine.default_start_state], style='dotted')) return g