Zoltán Komáromy: Not obligatory, but recommended, if the programmer is skilled in the world of graphical softwares. Programming is the engineering task, requires precision, mathematical logics. This is required for making graphical softwares, but not enough. Because artistic creativity is needed, and also ideas that can arise only from the mind of a user who actually uses those softwares, even for years. For me it was fortunate to have both, I am a programmer by qualification and also been a graphic artist for years at a commercial television company. I have learned several softwares, saw their weaknesses and strengths. I have developed serious extensions for those, but never a standalone graphical software. Besides this, of course, a lot of perseverance and luck is also good to have. Most of the help I got from programmers on mailing lists and communities of open source developers. I am thankful for that!