41 #include <cairo/cairo.h>
int guac_surface_cmp(cairo_surface_t *a, cairo_surface_t *b)
Given two Cairo surfaces, returns zero if the data contained within each is identical, and a positive or negative value if the value of the first is found to be lexically greater or less than the second respectively.
unsigned int guac_hash_surface(cairo_surface_t *surface)
Produces a 24-bit hash value from all pixels of the given surface.