Well there are a couple of ways you can do this.
Download the gtk+ source from here
http://www.gtk.org/download/
and in they example folder you can look at "scribble-simple, pixmap, wheelbarrow"
and then theres the demos folder you can look at the "pixbuf-demo" and then in the /demos/gtk-demo/ folder there is gtk-demo click that file and look at the images demo.
Here is a list of gtk+ tutorials
Gnome2 Developers Guide
http://home.cs.tum.edu/~siegel/files/tog2dg.pdf
Gtk+ 2.0 Tutorial
http://www.gtk.org/tutorial/
Gtk+ 2.0 Tree View tutorial
http://scentric.net/tutorial/treeview-tutorial.html
http://scentric.net/tutorial/treeview-tutorial.pdf
The Glib Object system
http://le-hacker.org/papers/gobject/index.html
http://le-hacker.org/papers/gobject/gobject-book-a4.pdf
Gtk+ 2.0 Text View tutorial
http://www.bravegnu.org/gtktext/
The Pango connection:
Part1:
http://www.ibm.com/developerworks/library/l-u-pango1/
Part 2:
http://www.ibm.com/developerworks/library/l-u-pango2/
GNOMEnclature: The wonders of GLib
Part 1:
http://www.ibm.com/developerworks/linux ... -glib.html
Part 2:
http://www.ibm.com/developerworks/linux ... glib2.html
And study these tutorials as thay show you how to use the cairo vector graphics engine.
Writing a Widget Using Cairo and GTK+
Part1:
http://www.gnomejournal.org/article/34/ ... -and-gtk28
Part2:
http://www.gnomejournal.org/article/36/ ... k28-part-2
Here are some cairo c examples on how to draw etc.
http://cairographics.org/samples/
Look here also.
http://cairographics.org/documentation/
There is also
Clutter
http://clutter-project.org/
Hope that helps