wxSystemSettings::GetMetric(wxSYS_SCREEN_X);
wxSystemSettings::GetMetric(wxSYS_SCREEN_Y);
wxSystemSettings::GetMetric(wxSYS_SCREEN_Y);
::wxDisplaySize(&width, &height);
also the functions that can be of interest are:
wxSystemSettings::GetScreenType();
wxDisplay::GetGeometry();
wxDisplay::GetClientArea();
wxDisplay::GetGeometry();
wxDisplay::GetClientArea();