Cairo is a software library used to provide a vector graphics-based, device-independent API for software developers.
GTK+ is a toolkit for creating graphical user interfaces (GUIs) with cross platform compatibility and an easy to use API.
"With gtk it s more common to use cairo already mentioned by jeff foster"
from question "Looking for a Java Graphics alternative"
"The problem is that the canvas drawn by cairo is larger than the area of gtk s scrolled_window"
from question "GtkDrawingArea with Cairo - how to make it scrollable"