Capture Pygraphviz Image Rendering Without Saving To A File?

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.

Solution 1:

According to the sources if you call draw method of AGraph object while path parameter is omitted (or set to None) it will return data instead saving to a file. Do not forget to specify format paramater.

Solution 2:

I think is is what you want:

# https://stackoverflow.com/questions/28533111/plotting-networkx-graph-with-node-labels-defaulting-to-node-nameimport dgl
import numpy as np
import torch

import networkx as nx

import matplotlib.pyplot as plt
import matplotlib.image as mpimg

from pathlib import Path

g = dgl.graph(([0, 0, 0, 0, 0], [1, 2, 3, 4, 5]), num_nodes=6)
print(f'{g=}')
print(f'{g.edges()=}')

# Since the actual graph is undirected, we convert it for visualization purpose.
g = g.to_networkx().to_undirected()
print(f'{g=}')

# relabel
int2label = {0: "app", 1: "cons", 2: "with", 3: "app3", 4: "app4", 5: "app5"}
g = nx.relabel_nodes(g, int2label)

# https://networkx.org/documentation/stable/reference/drawing.html#module-networkx.drawing.layout
g = nx.nx_agraph.to_agraph(g)
print(f'{g=}')
print(f'{g.string()=}')

# draw
g.layout()
g.draw("file.png")

# https://stackoverflow.com/questions/20597088/display-a-png-image-from-python-on-mint-15-linux
img = mpimg.imread('file.png')
plt.imshow(img)
plt.show()

# remove file https://stackoverflow.com/questions/6996603/how-to-delete-a-file-or-folder
Path('./file.png').expanduser().unlink()
# import os# os.remove('./file.png')

you basically need to render the graph object explicitly from the file and then delete it (unfortunately idk of a better answer). For more details check out my long discussion on why I think pygraphviz is the way to go (and not networkx) for visualizing: https://stackoverflow.com/a/67439711/1601580