Edge Colormap

In this example we draw a graph with matplotlib using the circular layout. We also use vertex degree to color some edges. You must have matplotlib installed for this to work.

Start by importing the package

import jgrapht
import jgrapht.drawing.draw_matplotlib as drawing
import matplotlib.pyplot as plt
import numpy as np

Creating a graph

g = jgrapht.create_graph(directed=False, weighted=True,)

Add some vertices

for i in range(0, 10):
    g.add_vertex()

and some edges

e1 = g.add_edge(0, 1)
e2 = g.add_edge(0, 2)
e3 = g.add_edge(0, 3)
e4 = g.add_edge(0, 4)
e5 = g.add_edge(0, 5)
e6 = g.add_edge(0, 6)
e7 = g.add_edge(0, 7)
e8 = g.add_edge(0, 8)
e9 = g.add_edge(0, 9)

Compute the position of the vertices

positions = drawing.layout(g, name="circular")

Draw the graph using the node labels and the edge line width and edge colormap

drawing.draw_jgrapht(
    g,
    positions=positions,
    edge_linewidth=6,
    edge_cmap=plt.cm.Blues(np.linspace(0.1, 1, len(g.edges))),
    axis=False,
)
plt.show()