% +------------------------------------------------------------------------+
% | Reference manual page: Bitangent.tex
% +------------------------------------------------------------------------+
% | Last revision: 09.07.2002   
% | Author : Pierre Angelier <Pierre.Angelier@ens.fr>
% | Maintainer: Laurent Rineau <Laurent.Rineau@ens.fr>
% | Package: Visibility_complex
% +------------------------------------------------------------------------+

\ccRefPageBegin

%%RefPage: end of header, begin of main body
% +------------------------------------------------------------------------+

\begin{ccRefConcept}{Bitangent}
\label{pageBitangentRef}
  
% ------------------------------------------------------------------------------
\ccDefinition

The \ccRefName\ concept defines the minimal requirement for the local
\ccc{Bitangent} type of the \ccc{VisibilityComplexTraits} concept.  The
\ccc{Bitangent} type is used as a base class for the concept
VisibilityComplexVertex \ccIndexMainItem[c]{VisibilityComplexVertex}.

A bitangent is a directed line segment tangent to two disks. The relative
positions of these two disks with respect to the supporting line of the
bitangents are coded in the \ccc{Type} information. There are four possible
types: \ccc{RR, LL, RL} and \ccc{LR}.
% ------------------------------------------------------------------------------
  
% ------------------------------------------------------------------------------
\ccTypes
%\ccThree{aaaaaaaaBitangent_2}{aaaaaaaaDisk_handle}{}
%\ccThreeToTwo

\ccNestedType{Disk}{type of disks defining the bitangent. }
\ccGlue
\ccNestedType{Disk_handle}{handle to a \ccc{Disk}. }
\ccGlue
\ccNestedType{Arc}{type following the requirements of the \ccc{Arc} concept 
\ccIndexMainItem[c]{Arc}].}
\ccGlue
\ccNestedType{Arc_handle}{handle to an \ccc{Arc}. }
\ccGlue
\ccNestedType{Type}{enumerated type to specify the type of the bitangent. The
		    possible values are \ccc{LL,RR,RL} or \ccc{LR} respectively 
		    for left-left,right-right,right-left and left-right 
		    bitangents.}{}
% ------------------------------------------------------------------------------

% ------------------------------------------------------------------------------
\ccThree{Disk_handle}{ b.source_object(); }{}
\ccThreeToTwo
\ccCreation
\ccCreationVariable{b}



\ccConstructor{Bitangent();}{default constructor.}
\ccGlue
\ccConstructor{Bitangent(Type t, Disk_handle source, Disk_handle target);}
{ Creates the bitangent with type t directed from source to target. }
\ccGlue
\ccConstructor{Bitangent(Type t, Arc_handle source, Arc_handle target);}
{ Creates the bitangent with type t directed from the arc source to the arc
target. If the two arcs do not have a common bitangent, the constructor is equal
to the default constructor. }

% ------------------------------------------------------------------------------
\ccOperations
\ccTagFullDeclarations

\ccMethod{Type type();}{returns the type of \ccVar.}
\ccGlue
\ccMethod{Disk_handle source_object();}{returns a handle to the source disk.}
\ccGlue
\ccMethod{Disk_handle target_object();}{returns a handle to the target disk.}
% ------------------------------------------------------------------------------

% ------------------------------------------------------------------------------
\ccHasModels
\ccRefIdfierPage{CGAL::Bitangent_2<Disk>}
% ------------------------------------------------------------------------------

% ------------------------------------------------------------------------------
\ccSeeAlso
\ccRefConceptPage{VisibilityComplexVertex}\\
\ccRefConceptPage{VisibilityComplexTraits}
% ------------------------------------------------------------------------------

% +------------------------------------------------------------------------+
\ccTagDefaults
\end{ccRefConcept}
\ccRefPageEnd
% +------------------------------------------------------------------------+