CGAL 6.1 - 2D Conforming Triangulations and Meshes

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CGAL::Triangulation_conformer_2< CDT > Class Template Reference
Reference Manual

`#include <CGAL/Triangulation_conformer_2.h>`

## Definition

template<typename CDT>
class CGAL::Triangulation_conformer_2< CDT >

The class `Triangulation_conformer_2` is an auxiliary class of `Delaunay_mesher_2<CDT>`.

It permits to refine a constrained Delaunay triangulation into a conforming Delaunay or conforming Gabriel triangulation. For standard needs, consider using the global functions `make_conforming_Gabriel_2()` and `make_conforming_Delaunay_2()`.

Template Parameters

  CDT | must be a 2D constrained Delaunay triangulation and its geometric traits class must be a model of the concept `ConformingDelaunayTriangulationTraits_2`.

Using This Class

The constructor of the class `Triangulation_conformer_2` takes a reference to a `CDT` as an argument. A call to the method `make_conforming_Delaunay()` or `make_conforming_Gabriel()` will refine this constrained Delaunay triangulation into a conforming Delaunay or conforming Gabriel triangulation. Note that if, during the life time of the `Triangulation_conformer_2` object, the triangulation is externally modified, any further call to its member methods may lead to undefined behavior. Consider reconstructing a new `Triangulation_conformer_2` object if the triangulation has been modified.

The conforming methods insert points into constrained edges, thereby splitting them into several sub-constraints. You have access to the initial inserted constraints if you instantiate the template parameter by a `Constrained_triangulation_plus_2<CDT>`.

## Creation
| Triangulation_conformer_2 (CDT &t)
| Create a new conforming maker, working on `t`.

## Conforming methods
void | make_conforming_Delaunay ()
| Refines the triangulation into a conforming Delaunay triangulation.
void | make_conforming_Gabriel ()
| Refines the triangulation into a conforming Gabriel triangulation.

## Checking
The following methods verify that the constrained triangulation is conforming Delaunay or conforming Gabriel. These methods scan the whole triangulation and their complexity is proportional to the number of edges.
bool | is_conforming_Delaunay ()
| Returns `true` iff all triangles fulfill the Delaunay property.
bool | is_conforming_Gabriel ()
| Returns `true` iff all constrained edges have the Gabriel property: their circumsphere is empty.

## Step by Step Operations
The `Triangulation_conformer_2` class allows, for debugging or demos, to play the conforming algorithm step by step, using the following methods. They exist in two versions, depending on whether you want the triangulation to be conforming Delaunay or conforming Gabriel, respectively. Any call to a `step_by_step_conforming_XX` function requires a previous call to the corresponding function `init_XX` and Gabriel and Delaunay methods can not be mixed between two calls of `init_XX`.
void | init_Delaunay ()
| The method must be called after all points and constrained segments are inserted and before any call to the following methods.
bool | step_by_step_conforming_Delaunay ()
| Applies one step of the algorithm, by inserting one point, if the algorithm is not done.
void | init_Gabriel ()
| Analog to `init_Delaunay` for Gabriel conforming.
bool | step_by_step_conforming_Gabriel ()
| Analog to `step_by_step_conforming_Delaunay()` for Gabriel conforming.
bool | is_conforming_done ()
| Tests if the step by step conforming algorithm is done.

## Member Function Documentation

## ◆ init_Delaunay()

template<typename CDT >

void CGAL::Triangulation_conformer_2< CDT >::init_Delaunay | ( |  | ) |

The method must be called after all points and constrained segments are inserted and before any call to the following methods.

If some points or segments are then inserted in the triangulation, this method must be called again.

## ◆ is_conforming_done()

template<typename CDT >

bool CGAL::Triangulation_conformer_2< CDT >::is_conforming_done | ( |  | ) |

Tests if the step by step conforming algorithm is done.

If it returns `true`, the following calls to `step_by_step_conforming_XX` will not insert any points, until some new constrained segments or points are inserted in the triangulation and `init_XX` is called again.

## ◆ make_conforming_Delaunay()

template<typename CDT >

void CGAL::Triangulation_conformer_2< CDT >::make_conforming_Delaunay | ( |  | ) |

Refines the triangulation into a conforming Delaunay triangulation.

After a call to this method, all triangles fulfill the Delaunay property, that is the empty circle property.

## ◆ make_conforming_Gabriel()

template<typename CDT >

void CGAL::Triangulation_conformer_2< CDT >::make_conforming_Gabriel | ( |  | ) |

Refines the triangulation into a conforming Gabriel triangulation.

After a call to this method, all constrained edges \( e\) have the Gabriel property: the circle with diameter \( e\) does not contain any vertex of the triangulation.

## ◆ step_by_step_conforming_Delaunay()

template<typename CDT >

bool CGAL::Triangulation_conformer_2< CDT >::step_by_step_conforming_Delaunay | ( |  | ) |

Applies one step of the algorithm, by inserting one point, if the algorithm is not done.

Returns `false` iff no point has been inserted because the algorithm is done.