Identifies intersections between a collection of line segments. More...

#include <SegmentChecker.h>

Public Member Functions
	SegmentChecker ()

	SegmentChecker (const std::vector< Segment2 * > &vSegments_)
	Constructor to initialize the SegmentChecker with a collection of segments. More...

	~SegmentChecker ()

ClipResult	clipSegment (Segment2 &seg)
	Clips a segment to the intersection with a bounding box. More...

void	getIllegalSegments (bool bAlsoEndPointIntersections, std::vector< Segment2 * > &vIllegalSegmentsOut) const

int	getIndex (Segment2 *pSeg) const
	Retrieves the index of a given segment. More...

void	getIntersectionPoint (SegmentIntersectionType typ, const Segment2 &seg0, const Segment2 &seg1, Point2 &ispOut) const

void	getIntersectionSegment (const Segment2 &seg0, const Segment2 &seg1, Segment2 &issOut) const

SegmentIntersectionType	getIntersectionType (const Segment2 pSeg1, const Segment2 pSeg2) const
	Determines the intersection type of two segments. More...

void	getIntersectors (Segment2 pTestSegment, bool bAlsoEndPointIntersections, std::vector< std::pair< Segment2 , SegmentIntersectionType > > &vIntersectorsOut) const
	Gets all segments intersecting a specified segment. More...

Bbox2	getLimit () const
	Retrieves the current bounding box used for clipping. More...

size_t	getNumberOfSegments () const
	Returns the total number of segments in this SegmentChecker object. More...

Segment2 *	getSegment (size_t i) const
	Gets the segment at the specified index. More...

void	setLimit (const Bbox2 &bbx)
	Sets the bounding box for segment clipping. More...

void	showIllegalSegments (bool bAlsoEndPointIntersections, const char *name) const
	Visualizes only the intersecting segments. More...

void	showSegments (const char *name) const
	Visualizes all segments, both intersecting and non-intersecting. More...

void	subscribe (MsgType msgType, MsgBase *pMsg)
	Subscribes a message handler to receive progress updates. More...

void	unsubscribe (MsgType msgType, MsgBase *pMsg)
	Unsubscribes a message handler from receiving updates. More...

Static Public Member Functions
static const char *	getIntersectionTypeString (SegmentIntersectionType sit)

Detailed Description

Polylines: Intersecting segments are automatically found

This class is used to check a collection of line segments for intersections. The class provides efficient spatial search algorithms, making it suitable for very large inputs.

See also: C++ Example: Segment Checker

Constructor & Destructor Documentation

◆ SegmentChecker() [1/2]

GEOM_FADE2D::SegmentChecker::SegmentChecker ( const std::vector< Segment2 * > & vSegments_ )

explicit

This constructor processes the input segments and prepares an internal data structure that allows for efficient spatial searches.

Parameters

vSegments_ The collection of segments to be checked for intersections.

◆ SegmentChecker() [2/2]

GEOM_FADE2D::SegmentChecker::SegmentChecker ( )

Default constructor for SegmentChecker.

◆ ~SegmentChecker()

GEOM_FADE2D::SegmentChecker::~SegmentChecker ( )

Destructor

Member Function Documentation

◆ clipSegment()

ClipResult GEOM_FADE2D::SegmentChecker::clipSegment ( Segment2 & seg )

This method clips a segment to its intersection with a predefined bounding box.

Parameters

[in,out] seg The segment to be clipped.

Returns: A ClipResult indicating the status of the clipping operation. The segment can be clipped into the same segment, a subsegment, become degenerate, or be completely outside the box.

Note: Ensure that setLimit() has been called with a valid bounding box before using this method, otherwise the method returns CR_INVALID.

◆ getIllegalSegments()

void GEOM_FADE2D::SegmentChecker::getIllegalSegments	(	bool	bAlsoEndPointIntersections,
		std::vector< Segment2 * > &	vIllegalSegmentsOut
	)		const

Get illegal segments

This method returns the segments involved in intersections. Intersections at endpoints are reported only when bAlsoEndPointIntersections is set to true. The result is provided in the output vector vIllegalSegmentsOut.

Types of segment intersections: (1) Non-collinear, (2) collinear, (3) duplicate segments, (4) endpoint intersection

Parameters

	bAlsoEndPointIntersections	If true, intersections at endpoints will also be detected.
[out]	vIllegalSegmentsOut	Output vector to hold the segments involved in intersections.

◆ getIndex()

int GEOM_FADE2D::SegmentChecker::getIndex ( Segment2 * pSeg ) const

This method returns the index of the provided segment in the internal collection.

Parameters

pSeg	The segment whose index is to be returned.

Returns: The index of the segment, or -1 if not found.

◆ getIntersectionPoint()

void GEOM_FADE2D::SegmentChecker::getIntersectionPoint	(	SegmentIntersectionType	typ,
		const Segment2 &	seg0,
		const Segment2 &	seg1,
		Point2 &	ispOut
	)		const

Compute the intersection point of two segments

This method computes the intersection point of two segments. Use getIntersectionType() to determine the segment intersection type sit before calling this function. Call this function only if sit is SIT_POINT or SIT_ENDPOINT.

Parameters

	typ	The intersection type (`SIT_POINT` or `SIT_ENDPOINT`).
	seg0,seg1	The intersecting segments.
[out]	ispOut	The output intersection point.

Details

seg0 and seg1 can be any arbitrary Segment2 objects. They do not need to be part of the segment set used to initialize the SegmentChecker.

◆ getIntersectionSegment()

void GEOM_FADE2D::SegmentChecker::getIntersectionSegment	(	const Segment2 &	seg0,
		const Segment2 &	seg1,
		Segment2 &	issOut
	)		const

Computes the intersection segment of two collinear intersecting segments

This method computes the intersection segment of two collinear segments that intersect. This function should only be used when the intersection type is SIT_SEGMENT.

Parameters

	seg0,seg1	The intersecting segments, where their SegmentIntersectionType is SIT_SEGMENT.
[out]	issOut	The computed intersection segment of `seg0` and `seg1`.

Details

seg0 and seg1 can be any arbitrary Segment2 objects. They do not need to be part of the segment set initialized in the SegmentChecker.

◆ getIntersectionType()

SegmentIntersectionType GEOM_FADE2D::SegmentChecker::getIntersectionType	(	const Segment2 *	pSeg1,
		const Segment2 *	pSeg2
	)		const

This method computes the type of intersection between two segments, such as no intersection, endpoint intersection, or collinear intersection.

Parameters

pSeg1,pSeg2 The segments to be checked for intersection.

Returns: The intersection type (e.g., SIT_NONE, SIT_SEGMENT, SIT_POINT, or SIT_ENDPOINT).

Note: pSeg1 and pSeg2 are pointers to arbitrary Segment2 objects. They do not need to be included in the set that has been used to initialize the SegmentChecker.

◆ getIntersectionTypeString()

static const char* GEOM_FADE2D::SegmentChecker::getIntersectionTypeString ( SegmentIntersectionType sit )

static

Return the intersection type as a human-readable string.

This method converts the given intersection type sit to a human-readable string.

Parameters

sit	The intersection type to be converted to a string.

Returns: A string representation of the intersection type.

◆ getIntersectors()

void GEOM_FADE2D::SegmentChecker::getIntersectors	(	Segment2 *	pTestSegment,
		bool	bAlsoEndPointIntersections,
		std::vector< std::pair< Segment2 *, SegmentIntersectionType > > &	vIntersectorsOut
	)		const

This method returns all segments that intersect a given segment along with the type of their intersection.

Parameters

	pTestSegment	The segment to check for intersections.
	bAlsoEndPointIntersections	Flag to include endpoint intersections.
[out]	vIntersectorsOut	The output vector holding the intersecting segments and their intersection types.

◆ getLimit()

Bbox2 GEOM_FADE2D::SegmentChecker::getLimit ( ) const

Retrieves the current bounding box used for clipSegment().

Returns: The currently set bounding box.

◆ getNumberOfSegments()

size_t GEOM_FADE2D::SegmentChecker::getNumberOfSegments ( ) const

Returns: The number of segments in the current object.

◆ getSegment()

Segment2* GEOM_FADE2D::SegmentChecker::getSegment ( size_t i ) const

This method returns the Segment2 at index i from the internal collection of segments.

Parameters

i	The index of the segment to be returned.

Returns: The segment at the specified index.

◆ setLimit()

void GEOM_FADE2D::SegmentChecker::setLimit ( const Bbox2 & bbx )

This method defines the bounding box that will be used by clipSegment().

Parameters

bbx	The bounding box to be set.

◆ showIllegalSegments()

void GEOM_FADE2D::SegmentChecker::showIllegalSegments	(	bool	bAlsoEndPointIntersections,
		const char *	name
	)		const

Visualization of polyline intersections

This method highlights the intersecting segments in a PDF or postscript file.

Parameters

bAlsoEndPointIntersections	Flag to include or exclude endpoint intersections as illegal.
name	he filename, use .pdf or .ps as file extension.

◆ showSegments()

void GEOM_FADE2D::SegmentChecker::showSegments ( const char * name ) const

Line segments written to a postscript file

This method generates a PDF or PostScript file showing all the segments.

Parameters

name	The filename, use .pdf or .ps as file extension.

◆ subscribe()

void GEOM_FADE2D::SegmentChecker::subscribe	(	MsgType	msgType,
		MsgBase *	pMsg
	)

This method allows a custom progress bar or message handler to be registered to receive progress updates during the intersection check. This is optional and is primarily used for larger datasets.

Parameters

msgType	The type of message (e.g., MSG_PROGRESS).
pMsg	A user-defined progress bar or message handler derived from MsgBase.

◆ unsubscribe()

void GEOM_FADE2D::SegmentChecker::unsubscribe	(	MsgType	msgType,
		MsgBase *	pMsg
	)

This method removes a previously registered message handler.

Parameters

msgType	The type of message to unsubscribe from.
pMsg	The message handler to unsubscribe.

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

SegmentChecker.h

Public Member Functions

Static Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ SegmentChecker() [1/2]

◆ SegmentChecker() [2/2]

◆ ~SegmentChecker()

Member Function Documentation

◆ clipSegment()

◆ getIllegalSegments()

◆ getIndex()

◆ getIntersectionPoint()

◆ getIntersectionSegment()

◆ getIntersectionType()

◆ getIntersectionTypeString()

◆ getIntersectors()

◆ getLimit()

◆ getNumberOfSegments()

◆ getSegment()

◆ setLimit()

◆ showIllegalSegments()

◆ showSegments()

◆ subscribe()

◆ unsubscribe()