CGAL 4.14 - 2D Arrangements
ArrTraits::CompareYNearBoundary_2 Concept Reference

## Operations

A model of this concept must provide:

Comparison_result operator() (const ArrTraits::X_monotone_curve_2 &xcv1, const ArrTraits::X_monotone_curve_2 &xcv2, Arr_curve_end ce)
Given two $$x$$-monotone curves xcv1 and xcv2 and an enumeration ce that specifies either the minimum or the maximum ends of the curves, compares the $$y$$-coordinate of the curves near their respective ends. More...

## ◆ operator()()

 Comparison_result ArrTraits::CompareYNearBoundary_2::operator() ( const ArrTraits::X_monotone_curve_2 & xcv1, const ArrTraits::X_monotone_curve_2 & xcv2, Arr_curve_end ce )

Given two $$x$$-monotone curves xcv1 and xcv2 and an enumeration ce that specifies either the minimum or the maximum ends of the curves, compares the $$y$$-coordinate of the curves near their respective ends.

Returns SMALLER, EQUAL, or LARGER accordingly. More precisely, compares the $$y$$-coordinates of the vertical projection of a point $$p$$ onto predicate Parameter_space_in_x_2 evaluates to ARR_LEFT_BOUNDARY when applied to xcv1 and ce and when applied to xcv2 and ce. In this case $$p$$ is located far to the left, such that the result is invariant under a translation of $$p$$ farther to the left. If ce is evaluates to ARR_RIGHT_BOUNDARY when applied to xcv1 and ce and when applied to xcv2 and ce. In that case $$p$$ is located far to the right in a similar manner.

Precondition
parameter_space_in_x_2(xcv2, ce) = parameter_space_in_x_2(xcv1, ce).
parameter_space_in_x_2(xcv1, ce) $$\neq$$ ARR_INTERIOR.