We will install the toolkits by installing each toolkit configuration utility.
GTK 2 and 3
If you are going to use GTK2 themes run:
# pkg install gtkchtheme # pkg install gtk-engines2 # pkg install ubuntulooks # pkg install gtk-murrine-engine # pkg install gtk-aurora-engine # pkg install gtk-equinox-engine # pkg install gnome-icon-theme # pkg install gnome-icon-theme-extras
Note: Equinox theme engine will also install Faenza icon set.
Run gtk-chtheme to setup GTK 2 theme. In order to change GTK3 theme edit ~/.config/gtk-3.0/settings.ini file.
Qt 4 and 5
If you are going to use Qt themes run:
# pkg install qt4-qtconfig # pkg install gstreamer1-plugins-all # pkg install gtk-oxygen-engine gtk3-oxygen-engine qtcurve qt5ct
Run /usr/local/lib/qt4/bin/qtconfig to setup Qt 4 theme. If you use KDE then you can change its appearance in System Settings.
Run Qt5 configuration utility like this:
$ env QT_QPA_PLATFORMTHEME=qt5ct qt5ct
Make the toolkits look the same
If you use KDE you can try making GTK use qtcurve just like your KDE does (using KDE settings manager).
Going the opposite way and making Qt look like GTK is a bit tough at the moment. First add this to /etc/make.conf:
# portmaster qt4-gui
And your qtconfig utility will receive another option: GTK+ - enable it and Qt4 will use GTK2 color theme.
The same should be possible with Qt5 but it is not at the moment.