[cairo] Need small help

[Ravindra]

Hi,
I'm new to Cairo. I would appreciate if someone could answer my
following two questions,

1. How to draw an existing image on a new image that I would be creating
using cairo_t? Existing image could be in a file.
2. Is it possible to have two cairo_t structures in my program and
create an image using one struct and later draw this image on the other
cairo_t struct (also destroying the first struct)?

My guess is to use cairo_set_pattern (cairo_surface_t), but I'm not very
sure of its proper usage. Please provide some pointers in the right
direction. In the meantime, I would be looking at cairo-demo samples.

Thanks in advance,
Ravindra