GUI libraries

[Danni Coy]

AFAIK the linux situation looks like this.

GTK is the current native toolkit for the Gnome based environments and
descendants including Unity.
Canonical are trying to move towards Qt for Unity.
Qt is the standard toolkit for KDE.

However Qt can treat GTK as a native toolkit and will render native
GTK widgets in Gnome as it does render native windows widgets on
windows and native Mac widgets on mac. It does take a bit of work and
testing with margin sizes etc to get a Qt App to look exactly like a
GTK App. Conversely the KDE devs have come up with a fairly nice GTK
theme (oxygen)  that matches the native KDE apps quite closely when
using the default theme (except for the far shitier file dialogs I
guess).