[cairo] Cairo, GtkDrawingArea, and buffer

[Xi Yang]

Hi, everyone!
I want to have a customized widget, and I decided to use GtkDrawingArea and Cairo together. 


However, each time the GtkDrawingArea is resized or uncovered, it needs to be redrawed. I don't want to perform the Cairo drawing at each exposure_event, as my drawing procedure is pretty complicated.


I need a buffer which the cairo_t would build on. At each exposure_event, I just need to copy the buffer to the GtkDrawingArea. So how can I achieve that? Which classes should I use?

Thanks!