GraphPlot

Graph layout and visualization algorithms based on Compose.jl and inspired by GraphLayout.jl.

The spring_layout and stressmajorize_layout function are copy from IainNZ's GraphLayout.jl.

Other layout algorithms are wrapped from NetworkX.

gadfly.js is copied from Gadfly.jl

Getting Started

From the Julia REPL the latest version can be installed with

Pkg.add("GraphPlot")

GraphPlot is then loaded with

using GraphPlot

Usage

karate network

using Graphs: smallgraph
g = smallgraph(:karate)
gplot(g)

Add node label

using Graphs
nodelabel = 1:nv(g)
gplot(g, nodelabel=nodelabel)

Adjust node labels

gplot(g, nodelabel=nodelabel, nodelabeldist=1.5, nodelabelangleoffset=π/4)

Control the node size

# nodes size proportional to their degree
nodesize = [Graphs.outdegree(g, v) for v in Graphs.vertices(g)]
gplot(g, nodesize=nodesize)

Control the node color

Feed the keyword argument nodefillc a color array, ensure each node has a color. length(nodefillc) must be equal |V|.

using Colors

# Generate n maximally distinguishable colors in LCHab space.
nodefillc = distinguishable_colors(nv(g), colorant"blue")
gplot(g, nodefillc=nodefillc, nodelabel=nodelabel, nodelabeldist=1.8, nodelabelangleoffset=π/4)

Transparent

# stick out large degree nodes
alphas = nodesize/maximum(nodesize)
nodefillc = [RGBA(0.0,0.8,0.8,i) for i in alphas]
gplot(g, nodefillc=nodefillc)

Control the node label size

nodelabelsize = nodesize
gplot(g, nodelabelsize=nodelabelsize, nodesize=nodesize, nodelabel=nodelabel)

Draw edge labels

edgelabel = 1:Graphs.ne(g)
gplot(g, edgelabel=edgelabel, nodelabel=nodelabel)

Adjust edge labels

edgelabel = 1:Graphs.ne(g)
gplot(g, edgelabel=edgelabel, nodelabel=nodelabel, edgelabeldistx=0.5, edgelabeldisty=0.5)

Color the graph

# nodes membership
membership = [1,1,1,1,1,1,1,1,2,1,1,1,1,1,2,2,1,1,2,1,2,1,2,2,2,2,2,2,2,2,2,2,2,2]
nodecolor = [colorant"lightseagreen", colorant"orange"]
# membership color
nodefillc = nodecolor[membership]
gplot(g, nodefillc=nodefillc)

Different layout

spring layout (default)

This is the defaut layout and will be chosen if no layout is specified. The default parameters to the spring layout algorithm can be changed by supplying an anonymous function, e.g., if nodes appear clustered too tightly together, try

layout=(args...)->spring_layout(args...; C=20)
gplot(g, layout=layout, nodelabel=nodelabel)

where C influences the desired distance between nodes.

random layout

gplot(g, layout=random_layout, nodelabel=nodelabel)

circular layout

gplot(g, layout=circular_layout, nodelabel=nodelabel)

spectral layout

gplot(g, layout=spectral_layout)

shell layout

nlist = Vector{Vector{Int}}(undef, 2) # two shells
nlist[1] = 1:5 # first shell
nlist[2] = 6:nv(g) # second shell
locs_x, locs_y = shell_layout(g, nlist)
gplot(g, locs_x, locs_y, nodelabel=nodelabel)

Curve edge

gplot(g, linetype="curve")

Save to figure

using Cairo, Compose
# save to pdf
draw(PDF("karate.pdf", 16cm, 16cm), gplot(g))
# save to png
draw(PNG("karate.png", 16cm, 16cm), gplot(g))
# save to svg
draw(SVG("karate.svg", 16cm, 16cm), gplot(g))

Graphs.jl integration

using Graphs
h = watts_strogatz(50, 6, 0.3)
gplot(h)

Arguments

• G graph to plot
• layout Optional. layout algorithm. Currently can choose from [random_layout, circular_layout, spring_layout, stressmajorize_layout, shell_layout, spectral_layout]. Default: spring_layout
• nodelabel Optional. Labels for the vertices. Default: nothing
• nodefillc Optional. Color to fill the nodes with. Default: colorant"turquoise"
• nodestrokec Color for the node stroke. Default: nothing
• arrowlengthfrac Fraction of line length to use for arrows. Set to 0 for no arrows. Default: 0 for undirected graph and 0.1 for directed graph
• arrowangleoffset angular width in radians for the arrows. Default: π/9 (20 degrees)

Reporting Bugs

Filing an issue to report a bug, counterintuitive behavior, or even to request a feature is extremely valuable in helping me prioritize what to work on, so don't hestitate.