Function ncvisual_geom 

pub unsafe extern "C" fn ncvisual_geom(
    nc: *const notcurses,
    n: *const ncvisual,
    vopts: *const ncvisual_options,
    geom: *mut ncvgeom,
) -> c_int

all-purpose ncvisual geometry solver. one or both of ‘nc’ and ‘n’ must be non-NULL. if ‘nc’ is NULL, only pixy/pixx will be filled in, with the true pixel geometry of ‘n’. if ‘n’ is NULL, only cdimy/cdimx, blitter, scaley/scalex, and maxpixely/maxpixelx are filled in. cdimy/cdimx and maxpixely/maxpixelx are only ever filled in if we know them.