Utility class that construct a planar graph from the input vector layers and provides shortest path search for tracing of existing features. More...

#include <qgstracer.h>

Inheritance diagram for QgsTracer:

[legend]

Public Types
enum	PathError { ErrNone, ErrTooManyFeatures, ErrPoint1, ErrPoint2, ErrNoPath }
	Possible errors that may happen when calling findShortestPath() More...

Public Member Functions
	QgsTracer ()

	~QgsTracer ()

QgsCoordinateReferenceSystem	destinationCrs () const
	Get CRS used for tracing. More...

QgsRectangle	extent () const
	Get extent to which graph's features will be limited (empty extent means no limit) More...

QVector< QgsPoint >	findShortestPath (const QgsPoint &p1, const QgsPoint &p2, PathError *error=nullptr)
	Given two points, find the shortest path and return points on the way. More...

bool	hasCrsTransformEnabled () const
	Return true if reprojection to destination CRS is enabled. More...

bool	hasTopologyProblem () const
	Whether there was an error during graph creation due to noding exception, indicating some input data topology problems. More...

bool	init ()
	Build the internal data structures. More...

bool	isInitialized () const
	Whether the internal data structures have been initialized. More...

bool	isPointSnapped (const QgsPoint &pt)
	Find out whether the point is snapped to a vertex or edge (i.e. it can be used for tracing start/stop) More...

QList< QgsVectorLayer * >	layers () const
	Get layers used for tracing. More...

int	maxFeatureCount () const
	Get maximum possible number of features in graph. If the number is exceeded, graph is not created. More...

void	setCrsTransformEnabled (bool enabled)
	Set whether to do reprojection to destination CRS. More...

void	setDestinationCrs (const QgsCoordinateReferenceSystem &crs)
	Set CRS used for tracing. More...

void	setExtent (const QgsRectangle &extent)
	Set extent to which graph's features will be limited (empty extent means no limit) More...

void	setLayers (const QList< QgsVectorLayer *> &layers)
	Set layers used for tracing. More...

void	setMaxFeatureCount (int count)
	Get maximum possible number of features in graph. If the number is exceeded, graph is not created. More...

Public Member Functions inherited from QObject
	QObject (QObject *parent)

	QObject (QObject parent, const char name)

virtual	~QObject ()

bool	blockSignals (bool block)

QObject *	child (const char objName, const char inheritsClass, bool recursiveSearch) const

const QObjectList &	children () const

const char *	className () const

bool	connect (const QObject sender, const char signal, const char *method, Qt::ConnectionType type) const

void	deleteLater ()

void	destroyed (QObject *obj)

bool	disconnect (const QObject receiver, const char method)

bool	disconnect (const char signal, const QObject receiver, const char *method)

void	dumpObjectInfo ()

void	dumpObjectTree ()

QList< QByteArray >	dynamicPropertyNames () const

virtual bool	event (QEvent *e)

virtual bool	eventFilter (QObject watched, QEvent event)

T	findChild (const QString &name) const

QList< T >	findChildren (const QRegExp &regExp) const

QList< T >	findChildren (const QString &name) const

bool	inherits (const char *className) const

void	insertChild (QObject *object)

void	installEventFilter (QObject *filterObj)

bool	isA (const char *className) const

bool	isWidgetType () const

void	killTimer (int id)

virtual const QMetaObject *	metaObject () const

void	moveToThread (QThread *targetThread)

const char *	name () const

const char *	name (const char *defaultName) const

QString	objectName () const

QObject *	parent () const

QVariant	property (const char *name) const

void	removeChild (QObject *object)

void	removeEventFilter (QObject *obj)

void	setName (const char *name)

void	setObjectName (const QString &name)

void	setParent (QObject *parent)

bool	setProperty (const char *name, const QVariant &value)

bool	signalsBlocked () const

int	startTimer (int interval)

QThread *	thread () const

Protected Slots
void	invalidateGraph ()
	Destroy the existing graph structure if any (de-initialize) More...

Protected Member Functions
virtual void	configure ()
	Allows derived classes to setup the settings just before the tracer is initialized. More...

Protected Member Functions inherited from QObject
bool	checkConnectArgs (const char signal, const QObject object, const char *method)

virtual void	childEvent (QChildEvent *event)

virtual void	connectNotify (const char *signal)

virtual void	customEvent (QEvent *event)

virtual void	disconnectNotify (const char *signal)

int	receivers (const char *signal) const

QObject *	sender () const

int	senderSignalIndex () const

virtual void	timerEvent (QTimerEvent *event)

Additional Inherited Members
Static Public Member Functions inherited from QObject
bool	connect (const QObject sender, const char signal, const QObject receiver, const char method, Qt::ConnectionType type)

bool	connect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method, Qt::ConnectionType type)

bool	disconnect (const QObject sender, const char signal, const QObject receiver, const char method)

bool	disconnect (const QObject sender, const QMetaMethod &signal, const QObject receiver, const QMetaMethod &method)

QString	tr (const char sourceText, const char disambiguation, int n)

QString	trUtf8 (const char sourceText, const char disambiguation, int n)

Static Protected Member Functions inherited from QObject
QByteArray	normalizeSignalSlot (const char *signalSlot)

Properties inherited from QObject
	objectName

Detailed Description

Utility class that construct a planar graph from the input vector layers and provides shortest path search for tracing of existing features.

Note: added in QGIS 2.14

Definition at line 38 of file qgstracer.h.

Member Enumeration Documentation

◆ PathError

enum QgsTracer::PathError

Possible errors that may happen when calling findShortestPath()

Enumerator
ErrNone	No error.
ErrTooManyFeatures	Max feature count threshold was reached while reading features.
ErrPoint1	Start point cannot be joined to the graph.
ErrPoint2	End point cannot be joined to the graph.
ErrNoPath	Points are not connected in the graph.

Definition at line 85 of file qgstracer.h.

Constructor & Destructor Documentation

◆ QgsTracer()

QgsTracer::QgsTracer ( )

Definition at line 455 of file qgstracer.cpp.

◆ ~QgsTracer()

QgsTracer::~QgsTracer ( )

Definition at line 572 of file qgstracer.cpp.

Member Function Documentation

◆ configure()

virtual void QgsTracer::configure ( )

inlineprotectedvirtual

Allows derived classes to setup the settings just before the tracer is initialized.

This allows the configuration to be set in a lazy way only when it is really necessary. Default implementation does nothing.

Reimplemented in QgsMapCanvasTracer.

Definition at line 106 of file qgstracer.h.

◆ destinationCrs()

QgsCoordinateReferenceSystem QgsTracer::destinationCrs ( ) const

inline

Get CRS used for tracing.

Definition at line 56 of file qgstracer.h.

◆ extent()

QgsRectangle QgsTracer::extent ( ) const

inline

Get extent to which graph's features will be limited (empty extent means no limit)

Definition at line 61 of file qgstracer.h.

◆ findShortestPath()

QVector< QgsPoint > QgsTracer::findShortestPath	(	const QgsPoint &	p1,
		const QgsPoint &	p2,
		PathError *	error = `nullptr`
	)

Given two points, find the shortest path and return points on the way.

The optional "error" argument may receive error code (PathError enum) if it is not null

Returns: array of points - trace of linestrings of other features (empty array one error)

Definition at line 674 of file qgstracer.cpp.

◆ hasCrsTransformEnabled()

bool QgsTracer::hasCrsTransformEnabled ( ) const

inline

Return true if reprojection to destination CRS is enabled.

Definition at line 51 of file qgstracer.h.

◆ hasTopologyProblem()

bool QgsTracer::hasTopologyProblem ( ) const

inline

Whether there was an error during graph creation due to noding exception, indicating some input data topology problems.

Note: added in QGIS 2.16

Definition at line 82 of file qgstracer.h.

◆ init()

bool QgsTracer::init ( )

Build the internal data structures.

This may take some time depending on how big the input layers are. It is not necessary to call this method explicitly - it will be called by findShortestPath() if necessary.

Definition at line 630 of file qgstracer.cpp.

◆ invalidateGraph

void QgsTracer::invalidateGraph ( )

protectedslot

Destroy the existing graph structure if any (de-initialize)

Definition at line 642 of file qgstracer.cpp.

◆ isInitialized()

bool QgsTracer::isInitialized ( ) const

inline

Whether the internal data structures have been initialized.

Definition at line 77 of file qgstracer.h.

◆ isPointSnapped()

bool QgsTracer::isPointSnapped ( const QgsPoint & pt )

Find out whether the point is snapped to a vertex or edge (i.e. it can be used for tracing start/stop)

Definition at line 717 of file qgstracer.cpp.

◆ layers()

QList<QgsVectorLayer*> QgsTracer::layers ( ) const

inline

Get layers used for tracing.

Definition at line 46 of file qgstracer.h.

◆ maxFeatureCount()

int QgsTracer::maxFeatureCount ( ) const

inline

Get maximum possible number of features in graph. If the number is exceeded, graph is not created.

Definition at line 66 of file qgstracer.h.

◆ setCrsTransformEnabled()

void QgsTracer::setCrsTransformEnabled ( bool enabled )

Set whether to do reprojection to destination CRS.

Definition at line 603 of file qgstracer.cpp.

◆ setDestinationCrs()

void QgsTracer::setDestinationCrs ( const QgsCoordinateReferenceSystem & crs )

Set CRS used for tracing.

Definition at line 612 of file qgstracer.cpp.

◆ setExtent()

void QgsTracer::setExtent ( const QgsRectangle & extent )

Set extent to which graph's features will be limited (empty extent means no limit)

Definition at line 621 of file qgstracer.cpp.

◆ setLayers()

void QgsTracer::setLayers ( const QList< QgsVectorLayer *> & layers )

Set layers used for tracing.

Definition at line 577 of file qgstracer.cpp.

◆ setMaxFeatureCount()

void QgsTracer::setMaxFeatureCount ( int count )

inline

Get maximum possible number of features in graph. If the number is exceeded, graph is not created.

Definition at line 68 of file qgstracer.h.

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

/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgstracer.h
/tmp/buildd/qgis-2.18.21+99unstable/src/core/qgstracer.cpp

Public Types

Public Member Functions

Protected Slots

Protected Member Functions

Additional Inherited Members

Detailed Description

Member Enumeration Documentation

◆ PathError

Constructor & Destructor Documentation

◆ QgsTracer()

◆ ~QgsTracer()

Member Function Documentation

◆ configure()

◆ destinationCrs()

◆ extent()

◆ findShortestPath()

◆ hasCrsTransformEnabled()

◆ hasTopologyProblem()

◆ init()

◆ invalidateGraph

◆ isInitialized()

◆ isPointSnapped()

◆ layers()

◆ maxFeatureCount()

◆ setCrsTransformEnabled()

◆ setDestinationCrs()

◆ setExtent()

◆ setLayers()

◆ setMaxFeatureCount()