Ubuntu Diagram Editor:
Diagram Software for the rest of us!
With Gliffy online diagram software, you can easily create professional-quality flowcharts, diagrams, floor plans, technical drawings, and more.
Our online diagram editor makes it easier than ever to create great looking drawings.
1). Can edit diagram files suffixs with .dia
2). Can export dia file as a png file
3). Can draw UML diagram.
sudo apt-get install dia