nimgraphviz's Introduction

nimgraphviz

The nimgraphviz module is a library for making graphs using GraphViz based on PyGraphviz.

To use it, add

requires "nimgraphviz >= 0.3.0"

to your .nimble file.

To export images, you must have GraphViz installed. Download it here: https://graphviz.gitlab.io/download.

Read the docs here.

Here is an example of creating a simple graph:

# create a directed graph
let graph = newGraph[Arrow]()

# You can add subgraphs to it:
let sub = newGraph(graph)
# You can nest subgraphs indefinitely :
# let subsub = newGraph(sub)

# The subgraph is automatically included in the main graph
# when you export it. It can also work standalone.
# Note that some layout engines behave differently when a subgraph
# name begins with "cluster". Please refer to the official GraphViz
# documentation for details.

# set some attributes of the graph:
graph["fontsize"] = "32"
graph["label"] = "Test Graph"
# (You can also access nodes and edges attributes this way :)
# graph["a", "bgcolor"] = "red"
# graph["a"->"b", "arrowhead"] = "diamond"

# add edges:
# (if a node does not exist already it will be created automatically)
graph.addEdge("a"->"b", ("label", "A to B"))
graph.addEdge("c"->"b", ("style", "dotted"))
graph.addEdge("b"->"a")
sub.addEdge("x"->"y")

graph.addNode("c", ("color", "blue"), ("shape", "box"),
                    ("style", "filled"), ("fontcolor", "white"))
graph.addNode("d", ("label", "node 'd'"))

# if you want to export the graph in the DOT language,
# you can do it like this:
# echo graph.exportDot()

# Export graph as PNG:
graph.exportImage("test_graph.png")

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