When comparing Dia vs Diagramo, the Slant community recommends Dia for most people. In the question“What are the best flowchart / diagram softwares?” Dia is ranked 10th while Diagramo is ranked 24th. The most important reason people chose Dia is:
Has flowcharts, uml, chemical engineering, electronics, and dozens of other complete sets, built in.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Tons of icon sets
Has flowcharts, uml, chemical engineering, electronics, and dozens of other complete sets, built in.
Pro Free and open source
Pro Custom gzipped XML format
Pro Free
Free and open source.
Pro Export to PNG, JPG, GIF or SVG
Cons
Con Unmaintained
Dia has not been updated since 2009. It's already a very complete piece of software, but still sad.
Con UX is a joke
UX is not good enough. For example, to edit element text you must double-click it, then click text box, and then you can start typing text.
Con Save not working
Online saving does not seem to work, tested with Chrome browser.
Con Website is not secure
No https website.
