#include <cairo.h>
#include <cairo-win32.h>

void main()
{
   cairo_surface_t *surface = cairo_win32_surface_create(GetWindowDC(GetDesktopWindow()));
   cairo_t *cairo = cairo_create( surface );
   cairo_surface_t* scaled =
      cairo_surface_create_similar(surface,
                                   CAIRO_CONTENT_COLOR_ALPHA, -20, 20); scaled;
}