@asdatapel:
A theme can be made/applied in two ways: Either you set the properties manually in code (like victorlevasseur mentioned) or you load a theme from file, where binary's theme loader will kick in (it's not yet applied to master, so you won't see it right now).
Yes, I am using windows in the screenshot. It's the default theme of BREW (Basic Rendering Engine for Widgets), which utilizes shapes only.
For clarification:
SFGUI does not force you to use any fixed rendering for the widgets. Instead it oursources that functionality into so called "rendering engines". They simply get the widget's pointer and construct sf::Drawables.
SFGUI's reference implementation of a rendering engine is BREW, which -- like said before -- uses shapes. You can change colors, line widths etc., but the overall style won't change.
Themes are only properties that get loaded into the engine, so you're again able to modify colors, line widths etc., but not the overall style. This also means that images are not possible with BREW.
However another guy is currently developing the rendering engine "Bob" (
http://en.wikipedia.org/wiki/Blitter_object) that uses textures (and therefore images) for rendering widgets.
If you've used Gnome before, it's just like that. You have all those rendering engines (Murrine, Aurora etc. pp.) that give a rather fixed overall look, but you can still change some properties here and there (colors, rounded edges etc.). If you like Windows, it's comparible to the oldschool design and the new shiny one.
@victorlevasseur:
You can leave out the template parameter, like:
sfg.:Context.:Get().GetEngine().SetProperty( "sel", "prop", 12345 );
With sfg::Desktop it's even easier:
desktop.SetProperty( "sel", "prop", 12345 );
@thePyro_13:
Correct, I took the colors from a Stream screenshot I found on Google.