View Full Version : GraphViz and Ruby in Eclipse

January 6th, 2009, 06:26 PM
Hi All,

for school i have to output a tree within a ruby application. I found out that graphviz is a suited toolkit for this task.


I've installed Eclipse (with ruby), GraphViz, libgraphviz4 and libgv-ruby. When I use
require 'graphviz' the console shows:
no such file to load -- graphviz (LoadError)
I think i need to add the graphviz library to my project, but i can't figure out how to add the graphviz library to a ruby project.
Can someone help me out?

January 9th, 2009, 12:03 PM
I found the answer myself. After installing the graphviz package go to

http://rockit.sourceforge.net/subprojects/graphr/ and download the tarball package

1. unpack tarball (if you haven't already)
2. Run tests: ruby -I./lib tests/runtests.rb (OPTIONAL)
3. Install: ruby install.rb

Drag the 'graph' folder into the eclipse project.

# Lets crank out a simple graph...
require 'graph/graphviz_dot'

# We create a DotGraphPrinter from some links.
# In this simple example we don't even have a "real" graph
# just an Array with the links. The optional third
# element of a link is link information. The nodes in this graph
# are implicit in the links. If we had additional nodes that were
# not linked we would supply them in an array as 2nd parameter to new.
links = [[:start, 1, "*"], [1, 1, "a"], [1, 2, "~a"], [2, :stop, "*"]]
dgp = DotGraphPrinter.new(links)

# We specialize the printer to change the shape of nodes
# based on their names.
dgp.node_shaper = proc{|n|
["start", "stop"].include?(n.to_s) ? "doublecircle" : "box"

# We can also set the attributes on individual nodes and edges.
# These settings override the default shapers and labelers.
dgp.set_node_attributes(2, :shape => "diamond")

# Add URL link from node (this only work in some output formats?)
# Note the extra quotes needed!
dgp.set_node_attributes(2, :URL => '"node2.html"')

# And now output to files
dgp.write_to_file("public/img/g.png", "png") # Generate png file

<img src="/img/g.png" />

The output is a png image.