A standard way to do that is the following: If the polygon external ring is composed of n points (P1,P2,...,Pn,P1) and a hole internal ring of m points (H1,H2,...,Hm,H1), try to draw the polygon composed of the single following external ring: (P1,P2,...,Pn,P1,H1,H2,...,Hm,H1,P1). This is equivalent of drawing a fictive imperceptible corridor between the external and internal ring like there:
It can be generalised in case of several holes: (P1,P2,...,Pn,P1, H11,H12,...,H1m1,H21,H11, H21,H22,...,H2m2,H21, ... , P1)