Capture pygraphviz image rendering without saving to a file?

2022-06-16

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Question

Does pygraphviz allow for you to render an image to a variable? I would like to serve up dynamic images via a webpage without having to render the graphs to disk.

Answer

I couldn't find a way to do this without a file being involved, so I created this handy function:

import matplotlib.image as mpimg
import matplotlib.pyplot as plt
import networkx as nx
import pygraphviz
def plot_network(G: nx.DiGraph):
  ag = nx.nx_agraph.to_agraph(G)
  ag.layout(prog="dot")
  temp = tempfile.NamedTemporaryFile(delete=False)
  tempname = temp.name + ".png"
  ag.draw(tempname)
  img = mpimg.imread(tempname)
  plt.imshow(img)
  plt.show()
  os.remove(tempname)