The GUI framework is the software library which allows
applications to put pixels onto the LCD. It handles contention
between applications, deals with windows and usually provides an
abstraction away from pixel-by-pixel drawing through widget
libraries. On a desktop system, this is separated into several
components: An X-server which allows client applications to
connect and draw things in the client's window. Then there are
the widget toolkits, where you generally have a choice between
Motif, GTK+, QT or Enlightenment (there are many others, but
these are the more common ones). On an embedded system, this
separation is not always as clear cut. - LinuxDevices has a more
detailed guide to embedded graphics here, although this is quite
old now. - Thomas Petazzoni gave a conference giving general
information about the various graphical libraries available for
embedded Linux devices, at Embedded Linux Conference Europe
2008. Slides and video are available. Frame buffer (FBDev) Most
Linux systems on embedded devic