Function vips_sys::im_fastlineuser

pub unsafe extern "C" fn im_fastlineuser(
    im: *mut VipsImage, 
    x1: c_int, 
    y1: c_int, 
    x2: c_int, 
    y2: c_int, 
    fn_: VipsPlotFn, 
    client1: *mut c_void, 
    client2: *mut c_void, 
    client3: *mut c_void
) -> c_int