internal static extern double cvContourArea(CVHandle contour, SeqSlice slice, int oriented);
internal static extern double cvArcLength(CVHandle curve, SeqSlice slice, int is_closed);
internal static extern void cvSeqRemoveSlice(Seq seq, SeqSlice slice);
internal static extern Seq cvSeqSlice(Seq seq, SeqSlice slice, MemStorage storage, int copy_data);
internal static extern IntPtr cvCvtSeqToArray(Seq seq, IntPtr elements, SeqSlice slice);
internal static extern int cvSliceLength(SeqSlice slice, Seq seq);