Closed ulemanstreaming closed 1 month ago
Hello @ulemanstreaming,
the diagrams module supports pygraphviz
and graphviz
backends and get_graph
will return either pygraphviz
or graphviz
graph objects which you can edit to your liking. If you use pygraphviz
(default) you could edit pygraphviz.AGraph
attributes like this:
from transitions.extensions import GraphMachine
states = ["welcome", "industry", "usecase", "load_data"]
transitions = [
["next_step", "welcome", "industry"],
["next_step", "industry", "usecase"],
["next_step", "usecase", "load_data"],
["previous_step", "load_data", "usecase"],
["previous_step", "usecase", "industry"],
["previous_step", "industry", "welcome"],
]
m = GraphMachine(states=states, transitions=transitions, initial='welcome')
graph = m.get_combined_graph()
graph.graph_attr["fontname"] = "arial"
graph.edge_attr["fontname"] = "arial"
graph.node_attr["fontname"] = "arial"
graph.draw('graph_arial.png', prog='dot')
But there is also a mechanism for 'global' graph settings:
The dot/graphviz settings are defined as class members (Graphmachine.machine_attributes
, Graphmachine.style_attributes
). For global changes you can either 'monkey patch' those or use inheritance and create your own configuration. For a start, you can copy the above mentioned configurations.
GraphMachine
uses MarkupMachine
to get a dictionary representation of the current machine configuration (states, transitions, etc.). You could override get_markup_config
to intercept this process and add a capitalised label.
from transitions.extensions import GraphMachine
from copy import deepcopy
states = ["welcome", "industry", "usecase", "load_data"]
transitions = [
["next_step", "welcome", "industry"],
["next_step", "industry", "usecase"],
["next_step", "usecase", "load_data"],
["previous_step", "load_data", "usecase"],
["previous_step", "usecase", "industry"],
["previous_step", "industry", "welcome"],
]
machine_attributes = deepcopy(GraphMachine.machine_attributes)
style_attributes = deepcopy(GraphMachine.style_attributes)
machine_attributes["fontname"] = "arial"
style_attributes["node"]["default"]["fontname"] = "arial"
style_attributes["edge"]["default"]["fontname"] = "arial"
class ArialGraph(GraphMachine):
machine_attributes=machine_attributes
style_attributes=style_attributes
def get_markup_config(self):
config = super(ArialGraph, self).get_markup_config()
for state in config['states']:
state['label'] = state['name'].capitalize()
return config
ag = ArialGraph(states=states, transitions=transitions, initial='welcome')
ag.get_combined_graph().draw('graph_inherited.png', prog='dot')
So this is how you could achieve what you are looking for as of now. However, if you have some ideas about how to streamline this process and make it more user friendly let me know. Adding more parameters to the constructor is something I'd like to avoid since there are already so many of them.
Instead of
graph.graph_attr["fontname"] = "arial"
graph.edge_attr["fontname"] = "arial"
graph.node_attr["fontname"] = "arial"
you could also pass them as arguments to dot:
graph.draw('graph_args.png', prog='dot', args="-Gfontname=Arial -Efontname=Arial -Nfontname=Arial")
Thank you @aleneum . These are very helpful suggestions, and sufficient for my current purposes.
I already subclass GraphMachine (using your suggested Alternative initialization pattern), so there's no need for me to create a separate subclass. I work in a Jupyter notebook, which can readily display a PNG if it's returned by a method named _repr_png_
. So I simply implement that, along with your suggestions for get_markup_config()
and the *_attribute
data members. I also use a smaller font inside the graph and replace underscore with space in the state labels. This leads to:
class Wizard(GraphMachine):
machine_attributes = deepcopy(GraphMachine.machine_attributes)
style_attributes = deepcopy(GraphMachine.style_attributes)
machine_attributes['fontname'] = 'arial'
style_attributes['node']['default']['fontname'] = 'arial'
style_attributes['edge']['default']['fontname'] = 'arial'
style_attributes['node']['default']['fontsize'] = 9
style_attributes['edge']['default']['fontsize'] = 9
def __init(...)
...
def get_markup_config(self):
config = super(Wizard, self).get_markup_config()
for state in config['states']:
state['label'] = state['name'].capitalize().replace('_', ' ')
return config
def _repr_png_(self, **kwargs):
return self.get_graph(title=self._title, **kwargs).draw(None, prog='dot', format='png')
![image](https://user-images.githubusercontent.com/6932205/234097798-fd941173-dc9b-493f-b66b-16afbfb9adbe.png)
So, it works. I have no suggestions for making it easier beyond documenting these tricks, or maybe doing more with the `kwargs` parameter in `get_graph()`. I agree that loading up the constructor with more parameters is not great; if you really wanted to give callers more control, adding one or a few methods to set style attributes might be preferable.
This issue can be closed as far as I'm concerned.
You have an idea for a feature that would make
transitions
more helpful or easier to use? Great! We are looking forward to your suggestion.Is your feature request related to a problem? Please describe. No
Describe the solution you'd like The graphs drawn by GraphMachine are great, but the fixed-pitch font looks a bit clunky and takes more space than it needs to. I tried to pass a keyword argument to
get_graph()
(font=
orfontname=
orfont_name=
) but it's not set up to pass that on todot
and raises aTypeError
.In principle, the **kwargs parameter could allow for a passthrough argument that lets the caller set this kind of layout properties but a general solution might be tricky and a lot of work to implement. Simply picking a nicer font and sticking with it would be an improvement to me and, I hope, to many other users.
Additional context I started playing with FSMs using statemachine but switched to
transitions
because it seems better engineered (and more convenient for my purposes). Both packages produce similar graphs, but I thinkstatemachine
's look better (it uses Arial). (statemachine
also makes nice, capitalized node labels from state names, but the font choice is the main thing for me.)