Dia
From WhyNotWiki
Welcome to Dia's new homepage. Dia is a GTK+ based diagram creation program for Linux, Unix and Windows released under the GPL license.
Dia is roughly inspired by the commercial Windows program 'Visio', though more geared towards informal diagrams for casual use. It can be used to draw many different kinds of diagrams. It currently has special objects to help draw entity relationship diagrams, UML diagrams, flowcharts, network diagrams, and many other diagrams. It is also possible to add support for new shapes by writing simple XML files, using a subset of SVG to draw the shape.
It can load and save diagrams to a custom XML format (gzipped by default, to save space), can export diagrams to a number of formats, including EPS, SVG, XFIG, WMF and PNG, and can print diagrams (including ones that span multiple pages).
http://www.gnome.org/projects/dia/
[edit] How to export a .dia file to another format (like .png) from the command line
Why I want to do this: So that I can upload a .dia file to a wiki and have it automatically generate a version that can be displayed on the web (.png). Sort of like MediaWiki can handle .svg files and automatically convert them to .png as needed...
Command Line Options (http://www.togaware.com/linux/survivor/Reference_Command.html).
dia --export survey-chart.png survey-chart.diagenerates a Portable Network Graphics image.
Re: Command line flags to allow exporting DIA diagram in any format? (http://www.mail-archive.com/dia-list@lysator.liu.se/msg03821.html).
> Is it possible to have command line flags to DIA to allow export of a > diagram, without firing up the GUI, in any format (including SVG?).--export (autodetects the extension), if you compile with --enable-gnome (or install the dia-gnome flavour of the package, on some distributions). However, it still depends on X libraries, and still requires a live X connection (alas).
When I tried to run dia from the command line (without X running, because this is on a server, which doesn't have X):
> dia (dia:23037): Gtk-WARNING **: cannot open display:
Too bad.
