opencv/imgproc.go
func ContourArea(contour *Seq, slice Slice, oriented int) float64 {
	return float64(C.cvContourArea(
		unsafe.Pointer(contour),
		(C.CvSlice)(slice),
		C.int(oriented)))
}
func ContourArea(contour *Seq, slice Slice, oriented int) float64 {
	return float64(C.cvContourArea(
		unsafe.Pointer(contour),
		(C.CvSlice)(slice),
		C.int(oriented)))
}
// double cvContourArea(const CvArr* contour, CvSlice slice=CV_WHOLE_SEQ, int oriented=0 )