The concept ConstrainedTriangulationTraits_2 defines the requirements for the geometric traits class of a constrained triangulation ( Constrained_Triangulation_2<Traits,Tds,Itag>) that supports intersections of input constraints (i. e. when the template parameter Itag is instantiated by one of the tag classes Exact_intersections_tag or Exact_predicates_tag). This concept refines the concept TriangulationTraits_2, adding requirements for function objects to compute the intersection points of two constraints. When Exact_predicates_tag is used, the traits class is also required to provide additional types to compute the squared distance between a point and a line
 
A function object whose operator()
computes the intersection of two segments : Object_2 operator()(Segment_2 s1, Segment_2 s2); Returns the intersection of s1 and s2.

When the constrained triangulation is instantiated with the intersection tag Exact_predicates_tag, the used algorithm needs to be able to compare some distances between points and lines and the following types are further required.
 
A number type supporting the comparison operator
<.
 
 
The line type.
 
 
A function object whose operator()
constructs a line from two points : Line_2 operator()(Point_2 p1, Point_2 p2).
 
 
A function object with an
operator() designed to compute the squared distance between
a line and a point :
RT operator()(Point_2 p1, Line_2); Return the squared distance
between p and l.
