Collection of PtList type
PtLists
is the type used to store a collection of PtList objects.
Such objects are returned from shape analysis functions, such as findContours for example, which returns several lists of points, each of one for each detected contour.
PtList
supports the extraction operator (n:step:m)
, returning a single or a list of PtList
, depending on the size of the interval.
PtList
supports also the size
function, returning the size of the list.