>I think the GDI solution is faster and more universal, because the GDI+ has default support only in XP/2K/2003 Windows versions.
>
>http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/linecurv_2d2q.asp

Thank you, Anatoliy, for your quick answer.

I think the Windows GDI API set is exactly what my friend is needing for his CAD application.

Many types of applications use lines and curves to draw graphics output on raster devices. Computer-aided design (CAD) and drawing applications use lines and curves to outline objects, specify the centers of objects, the dimensions of objects, and so on.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/gdi/linecurv_1ar7.asp

I will be passing this on to him.

Thanks again.

Peter