Some advanced hardware devices can draw paths containing Bezier curves (cubic splines), which are general-purpose curve primitives. If so, the driver can include support for these curves in the DrvStrokePath function.
When GDI must draw a Bezier curve path on a device-managed surface, it will test the GCAPS_BEZIERS flag (in the DEVINFO structure) to determine if it should call DrvStrokePath. If called, this function either performs the requested operation or decides not to handle it, just as it does for geometric wide lines. In the latter case, GDI breaks the request down into simpler operations, for example, by converting curves to line approximations.