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")

Show plot

When using an IDE such as VSCode, Cairo.jl is required to visualize the plot inside the IDE. When using the REPL, gplothtml will allow displaying the plot on a browser.

Save to figure

using 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))
# alternate way of saving to svg without loading Compose
saveplot(gplot(g, plot_size = (16cm, 16cm)), "karate.svg")

Graphs.jl integration

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

Arguments

• G Graph to draw
• locs_x, locs_y Locations of the nodes (will be normalized and centered). If not specified, will be obtained from layout kwarg.

Keyword Arguments

• layout Layout algorithm: random_layout, circular_layout, spring_layout, shell_layout, stressmajorize_layout, spectral_layout. Default: spring_layout
• title Plot title. Default: ""
• title_color Plot title color. Default: colorant"black"
• title_size Plot title size. Default: 4.0
• font_family Font family for all text. Default: "Helvetica"
• NODESIZE Max size for the nodes. Default: 3.0/sqrt(N)
• nodesize Relative size for the nodes, can be a Vector. Default: 1.0
• nodelabel Labels for the vertices, a Vector or nothing. Default: nothing
• nodelabelc Color for the node labels, can be a Vector. Default: colorant"black"
• nodelabeldist Distances for the node labels from center of nodes. Default: 0.0
• nodelabelangleoffset Angle offset for the node labels. Default: π/4.0
• NODELABELSIZE Largest fontsize for the vertice labels. Default: 4.0
• nodelabelsize Relative fontsize for the vertice labels, can be a Vector. Default: 1.0
• nodefillc Color to fill the nodes with, can be a Vector. Default: colorant"turquoise"
• nodestrokec Color for the nodes stroke, can be a Vector. Default: nothing
• nodestrokelw Line width for the nodes stroke, can be a Vector. Default: 0.0
• edgelabel Labels for the edges, a Vector or nothing. Default: []
• edgelabelc Color for the edge labels, can be a Vector. Default: colorant"black"
• edgelabeldistx, edgelabeldisty Distance for the edge label from center of edge. Default: 0.0
• EDGELABELSIZE Largest fontsize for the edge labels. Default: 4.0
• edgelabelsize Relative fontsize for the edge labels, can be a Vector. Default: 1.0
• EDGELINEWIDTH Max line width for the edges. Default: 0.25/sqrt(N)
• edgelinewidth Relative line width for the edges, can be a Vector. Default: 1.0
• edgestrokec Color for the edge strokes, can be a Vector. Default: colorant"lightgray"
• arrowlengthfrac Fraction of line length to use for arrows. Equal to 0 for undirected graphs. Default: 0.1 for the directed graphs
• arrowangleoffset Angular width in radians for the arrows. Default: π/9 (20 degrees)
• linetype Type of line used for edges ("straight", "curve"). Default: "straight"
• outangle Angular width in radians for the edges (only used if linetype = "curve). Default: π/5 (36 degrees)
• background_color Color for the plot background. Default: nothing
• plot_size Tuple of measures for width x height of plot area. Default: (10cm, 10cm)
• leftpad, rightpad, toppad, bottompad Padding for the plot margins. Default: 0mm
• pad Padding for plot margins (overrides individual padding if given). Default: nothing

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.