Function sdl2_sys::SDL_UpperBlit

pub unsafe extern "C" fn SDL_UpperBlit(
    src: *mut SDL_Surface,
    srcrect: *const SDL_Rect,
    dst: *mut SDL_Surface,
    dstrect: *mut SDL_Rect
) -> c_int

This is the public blit function, SDL_BlitSurface(), and it performs rectangle validation and clipping before passing it to SDL_LowerBlit()