[cairo] Implementing GUI with Cairo

[Jonathan Roewen]

Hi,

I'm making a hobby OS, and I've successfully got cairo working in my
small kernel, and am now ready to tackle building a GUI based on the
cairo graphics library.

The aim is to have a completely vector-graphics based GUI, and I'm
wondering how to best achieve this with the cairo graphics library.

My current idea is to have a separate cairo_t object for each layer,
all sharing the same surface. However, one of the few problems I'm
having is figuring out how to change properties of graphics already
drawn.

For instance: changing the colours of a button for a depressed state,
and moving a window around.

The other problem is I'm not sure on the proper way to make cairo
redraw [parts of] the image(s).

Any insight would be greatly appreciated.

Jonathan