geos::operation::overlayng::MaximalEdgeRing Class Reference

#include <MaximalEdgeRing.h>

Collaboration diagram for geos::operation::overlayng::MaximalEdgeRing:

Public Member Functions
	MaximalEdgeRing (OverlayEdge *e)
std::vector< std::unique_ptr< OverlayEdgeRing > >	buildMinimalRings (const GeometryFactory *geometryFactory)

Static Public Member Functions
static void	linkResultAreaMaxRingAtNode (OverlayEdge *nodeEdge)

Private Member Functions
void	attachEdges (OverlayEdge *startEdge)
void	linkMinimalRings ()

Static Private Member Functions
static void	linkMinRingEdgesAtNode (OverlayEdge *nodeEdge, MaximalEdgeRing *maxRing)
static bool	isAlreadyLinked (OverlayEdge *edge, MaximalEdgeRing *maxRing)
static OverlayEdge *	selectMaxOutEdge (OverlayEdge *currOut, MaximalEdgeRing *maxEdgeRing)
static OverlayEdge *	linkMaxInEdge (OverlayEdge *currOut, OverlayEdge *currMaxRingOut, MaximalEdgeRing *maxEdgeRing)

Private Attributes
OverlayEdge *	startEdge

Static Private Attributes
static constexpr int	STATE_FIND_INCOMING = 1
static constexpr int	STATE_LINK_OUTGOING = 2

Friends
std::ostream &	operator<< (std::ostream &os, const MaximalEdgeRing &mer)

Detailed Description

Definition at line 44 of file g/MaximalEdgeRing.h.

Constructor & Destructor Documentation

geos::operation::overlayng::MaximalEdgeRing::MaximalEdgeRing ( OverlayEdge *  e )

inline

Definition at line 92 of file g/MaximalEdgeRing.h.

References geos::geom::operator<<().

Here is the call graph for this function:

Member Function Documentation

void geos::operation::overlayng::MaximalEdgeRing::attachEdges ( OverlayEdge *  startEdge )

private

std::vector<std::unique_ptr<OverlayEdgeRing> > geos::operation::overlayng::MaximalEdgeRing::buildMinimalRings

(

const GeometryFactory *

geometryFactory

)

static bool geos::operation::overlayng::MaximalEdgeRing::isAlreadyLinked ( OverlayEdge *  edge, MaximalEdgeRing *  maxRing  )

staticprivate

Tests if an edge of the maximal edge ring is already linked into a minimal OverlayEdgeRing. If so, this node has already been processed earlier in the maximal edgering linking scan.

Parameters

edge	an edge of a maximal edgering
maxRing	the maximal edgering

Returns

true if the edge has already been linked into a minimal edgering.

static OverlayEdge* geos::operation::overlayng::MaximalEdgeRing::linkMaxInEdge ( OverlayEdge *  currOut, OverlayEdge *  currMaxRingOut, MaximalEdgeRing *  maxEdgeRing  )

staticprivate

void geos::operation::overlayng::MaximalEdgeRing::linkMinimalRings ( )

private

static void geos::operation::overlayng::MaximalEdgeRing::linkMinRingEdgesAtNode ( OverlayEdge *  nodeEdge, MaximalEdgeRing *  maxRing  )

staticprivate

Links the edges of a MaximalEdgeRing around this node into minimal edge rings (OverlayEdgeRings). Minimal ring edges are linked in the opposite orientation (CW) to the maximal ring. This changes self-touching rings into a two or more separate rings, as per the OGC SFS polygon topology semantics. This relinking must be done to each max ring separately, rather than all the node result edges, since there may be more than one max ring incident at the node.

Parameters

nodeEdge	an edge originating at this node
maxRing	the maximal ring to link

static void geos::operation::overlayng::MaximalEdgeRing::linkResultAreaMaxRingAtNode ( OverlayEdge *  nodeEdge )

static

Traverses the star of edges originating at a node and links consecutive result edges together into maximal edge rings. To link two edges the resultNextMax< pointer for an incoming< result edge is set to the next outgoing result edge.

Edges are linked when:

• they belong to an area (i.e. they have sides)
• they are marked as being in the result

Edges are linked in CCW order (which is the order they are linked in the underlying graph). This means that rings have their face on the Right (in other words, the topological location of the face is given by the RHS label of the DirectedEdge). This produces rings with CW orientation.

PRECONDITIONS:

• This edge is in the result
• This edge is not yet linked
• The edge and its sym are NOT both marked as being in the result

static OverlayEdge* geos::operation::overlayng::MaximalEdgeRing::selectMaxOutEdge ( OverlayEdge *  currOut, MaximalEdgeRing *  maxEdgeRing  )

staticprivate

Friends And Related Function Documentation

std::ostream& operator<< ( std::ostream &  os, const MaximalEdgeRing &  mer  )

friend

Member Data Documentation

OverlayEdge* geos::operation::overlayng::MaximalEdgeRing::startEdge

private

Definition at line 53 of file g/MaximalEdgeRing.h.

constexpr int geos::operation::overlayng::MaximalEdgeRing::STATE_FIND_INCOMING = 1

staticprivate

Definition at line 49 of file g/MaximalEdgeRing.h.

constexpr int geos::operation::overlayng::MaximalEdgeRing::STATE_LINK_OUTGOING = 2

staticprivate

Definition at line 50 of file g/MaximalEdgeRing.h.

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

• g/MaximalEdgeRing.h