What, in detail, the GDK do?

[frederico schardong <frede sch gmail com>]

Hi,

I have looked at wikipedia the explication about GDK and would like to
know more about this sentence: "GDK (GIMP Drawing Kit) is a computer
graphics library that acts as a wrapper around the low-level drawing
and windowing functions provided by the underlying graphics system."

So how low level GDK goes? It renders the widgets according the OS?
Where GTK+ ends and GDK starts? Where GDK ends and GLib starts?

-- 
Thanks,
Frederico Schardong,
SOLIS - Open source solutions
www.solis.coop.br
Linux registered user #500582