Fade2D Documentation pages v1.85
Delaunay Features
ConstraintGraph2 Class Reference

ConstraintGraph2 is a set of Constraint Edges (ConstraintSegment2) More...

#include <ConstraintGraph2.h>

Public Member Functions

void getChildConstraintSegments (std::vector< ConstraintSegment2 * > &vConstraintSegments_) const
 Get child ConstraintSegment2 objects. More...
 
void getDirectChildren (ConstraintSegment2 *pParent, ConstraintSegment2 *&pChild0, ConstraintSegment2 *&pChild1)
 Get direct children. More...
 
Dt2 * getDt2 ()
 
ConstraintInsertionStrategy getInsertionStrategy () const
 Get the constraint insertion strategy. More...
 
void getOriginalConstraintSegments (std::vector< ConstraintSegment2 * > &vConstraintSegments_) const
 Get the original ConstraintSegment2 objects. More...
 
void getPolygonVertices (std::vector< Point2 * > &vVertices_)
 Get the vertices of the constraint segments. More...
 
bool isConstraint (ConstraintSegment2 *pCSeg) const
 Check if a ConstraintSegment2 is a member. More...
 
bool isConstraint (Point2 *p0, Point2 *p1) const
 Check if an edge is a constraint. More...
 
bool isOriented () const
 Are the segments of the constraint graph oriented? More...
 
bool isPolygon () const
 Does the constraint graph form a closed polygon? More...
 
bool isReverse (ConstraintSegment2 *pCSeg) const
 
bool makeDelaunay (double minLength)
 
void show (const char *name)
 Visualization. More...
 
void show (Visualizer2 *pVis, const Color &color)
 Visualization. More...
 

Protected Attributes

bool bIsOriented
 
bool bIsPolygon
 
ConstraintInsertionStrategy cis
 
std::map< ConstraintSegment2 *, bool, func_ltDerefPtr< ConstraintSegment2 * > > mCSegReverse
 
std::map< Point2 *, size_t > mSplitPointNum
 
Dt2 * pDt2
 
GeomTest * pGeomPredicates
 
std::vector< ConstraintSegment2 * > vCSegParents
 

Detailed Description

See also
Fade_2D::createConstraint()

Constrained Delaunay triangulation

Member Function Documentation

◆ getChildConstraintSegments()

void ConstraintGraph2::getChildConstraintSegments ( std::vector< ConstraintSegment2 * > &  vConstraintSegments_) const

Returns the current constraint segments, i.e., the original ones or, if splitted, their child segments.

◆ getDirectChildren()

void ConstraintGraph2::getDirectChildren ( ConstraintSegment2 pParent,
ConstraintSegment2 *&  pChild0,
ConstraintSegment2 *&  pChild1 
)
Parameters
[in]pParentis a ConstraintSegment that may have been splitted
[out]pChild0,pChild1are the direct child segments of pParent. They can be alive or dead (splitted).

The children are returned in the correct order of the present ConstraintGraph2.

◆ getDt2()

Dt2* ConstraintGraph2::getDt2 ( )
Returns
the Delaunay class it belongs to

◆ getInsertionStrategy()

ConstraintInsertionStrategy ConstraintGraph2::getInsertionStrategy ( ) const
Returns
CIS_CONFORMING_DELAUNAY or CIS_CONSTRAINED_DELAUNAY

◆ getOriginalConstraintSegments()

void ConstraintGraph2::getOriginalConstraintSegments ( std::vector< ConstraintSegment2 * > &  vConstraintSegments_) const

Get the original, ConstraintSegment2 objects. They are not subdivided but may be dead and have child segments (which may also be dead and have child segments...)

◆ getPolygonVertices()

void ConstraintGraph2::getPolygonVertices ( std::vector< Point2 * > &  vVertices_)

Use this method to retrieve the vertices of the present ConstraintGraph2. If it forms ONE closed polygon, then the vertices are ordered and oriented in counterclockwise direction, e.g. (a,b,b,c,c,d,d,a). Otherwise they are returned in original order. Be aware that the order is only maintained if the ConstraintGraph2 has been created with Fade_2D::createConstraint(..,..,bOrientedSegments=true).

Note
The segments of the present ConstraintGraph2 may have been splitted. In this case the split points are also contained in the result. If, in the above example, the ConstraintSegment2(a,b) has been subdivided at vertex x then the result is (a,x,x,b,b,c,c,d,d,a).
See also
Do you already know Zone2::getBorderEdges() and edgesToPolygons() ?

◆ isConstraint() [1/2]

bool ConstraintGraph2::isConstraint ( ConstraintSegment2 pCSeg) const

The present ConstraintGraph2 has been created using a set of edges and this method checks if the ConstraintSegment2 pCSeg is one of them. Original edges that have been splitted are not alive anymore and are no members. But their child segments are members.

◆ isConstraint() [2/2]

bool ConstraintGraph2::isConstraint ( Point2 p0,
Point2 p1 
) const

Checks if the edge (p0,p1) is a constraint of the present ConstraintGraph2 object.

◆ isOriented()

bool ConstraintGraph2::isOriented ( ) const
Returns
true if the constraint graph has been created with bOrientedSegments=true or if automatic reorientation was possible which is the case for simple polygons.

◆ isPolygon()

bool ConstraintGraph2::isPolygon ( ) const
Returns
true when the present ConstraintGraph forms a closed polygon.
Note
This method won't check if it is a simple polygon (one without self-intersections).

◆ isReverse()

bool ConstraintGraph2::isReverse ( ConstraintSegment2 pCSeg) const

Get the orientation of a ConstraintSegment2

A ConstraintSegment2 pCSeg is unoriented because it may participate (with different orientations) in more than just one ConstraintGraph2 and thus the vertices returned by pCSeg->getSrc() and pCSeg->getTrg() do not carry any orientation information. However, the orientation of pCSeg is stored in the ConstraintGraph2 objects where pCSeg is a member and this method returns if the source and target vertex must be exchanged to match the present graph's direction.

◆ makeDelaunay()

bool ConstraintGraph2::makeDelaunay ( double  minLength)

Improve the triangle quality (make Delaunay)

Constraint segments can make a triangulation locally non-delaunay i.e., the empty-circumcircle property is not maintained for all triangles. makeDelaunay() subdivides the constraint segments so that they appear naturally as part of the Delaunay triangulation. Use this function to create visually more appealing triangles with better aspect ratios.

Parameters
[in]minLengthspecifies a lower bound. Constraint segments smaller than minLength are not subdivided. This parameter avoids excessive subdivision in narrow settings.
Returns
TRUE when all required somedevisions have been carried out or FALSE when minLength has avoided further subdivision.

◆ show() [1/2]

void ConstraintGraph2::show ( const char *  name)

◆ show() [2/2]

void ConstraintGraph2::show ( Visualizer2 pVis,
const Color color 
)

The documentation for this class was generated from the following file: