planning the GUI before starting to program

Does anybody know if there's a free aplication which I can use to plan my application GUI?

I'd like to draw it (like in paint), before I start programming it.

t开发者_开发技巧hanks :)

Paper. It's simple, cheap, easy to modify, full-compatible with all toolkits and doesn't have a long learning curve.

There are plenty of options. I usually use paper and a pencil, then WPF (typing XAML gets me pretty far fairly quickly, when only needing standard controls) and then actually implement it (which was in Swing the last time, hence the WPF prototype which took only an hour, not a week).

There is the Powerpoint Prototyping toolkit which lets you create prototypes, even halfway functional ones, easily.

Use netbean's UI designer and capture the screen.