Main Pal labeling class. More...

#include <pal.h>

Public Types
typedef bool(*	FnIsCanceled) (void *ctx)

Public Member Functions
	Pal ()
	Create an new pal instance. More...

	Pal (const Pal &other)=delete
	Pal cannot be copied. More...

	~Pal ()

Layer *	addLayer (QgsAbstractLabelProvider *provider, const QString &layerName, QgsPalLayerSettings::Placement arrangement, double defaultPriority, bool active, bool toLabel, bool displayAll=false)
	add a new layer More...

std::unique_ptr< Problem >	extractProblem (const QgsRectangle &extent, const QgsGeometry &mapBoundary)
	Extracts the labeling problem for the specified map extent - only features within this extent will be considered. More...

int	getLineP ()
	Returns the number of candidates to generate for line features. More...

int	getPointP ()
	Returns the number of candidates to generate for point features. More...

int	getPolyP ()
	Returns the number of candidates to generate for polygon features. More...

SearchMethod	getSearch ()
	Returns the search method in use. More...

bool	getShowPartial ()
	Returns whether partial labels should be allowed. More...

bool	isCanceled ()
	Check whether the job has been canceled. More...

Pal &	operator= (const Pal &other)=delete
	Pal cannot be copied. More...

void	registerCancelationCallback (FnIsCanceled fnCanceled, void *context)
	Register a function that returns whether this job has been canceled - PAL calls it during the computation. More...

void	removeLayer (Layer *layer)
	remove a layer More...

void	setLineP (int line_p)
	set maximum # candidates to generate for lines features Higher the value is, longer Pal::labeller will spend time More...

void	setPointP (int point_p)
	set # candidates to generate for points features Higher the value is, longer Pal::labeller will spend time More...

void	setPolyP (int poly_p)
	set maximum # candidates to generate for polygon features Higher the value is, longer Pal::labeller will spend time More...

void	setSearch (SearchMethod method)
	Select the search method to use. More...

void	setShowPartial (bool show)
	Set flag show partial label. More...

QList< LabelPosition * >	solveProblem (Problem *prob, bool displayAll)

Friends
class	FeaturePart

class	Layer

class	Problem

Detailed Description

Main Pal labeling class.

A pal object will contains layers and global information such as which search method will be used.

Note: not available in Python bindings

Definition at line 87 of file pal.h.

Member Typedef Documentation

typedef bool( * pal::Pal::FnIsCanceled) (void *ctx)

Definition at line 129 of file pal.h.

Constructor & Destructor Documentation

Pal::Pal ( )

Create an new pal instance.

Definition at line 48 of file pal.cpp.

Pal::~Pal ( )

Definition at line 90 of file pal.cpp.

pal::Pal::Pal ( const Pal & other )

delete

Pal cannot be copied.

Member Function Documentation

Layer * Pal::addLayer	(	QgsAbstractLabelProvider *	provider,
		const QString &	layerName,
		QgsPalLayerSettings::Placement	arrangement,
		double	defaultPriority,
		bool	active,
		bool	toLabel,
		bool	displayAll = `false`
	)

add a new layer

Parameters

provider	Provider associated with the layer
layerName	layer's name
arrangement	Howto place candidates
defaultPriority	layer's prioriry (0 is the best, 1 the worst)
active	is the layer is active (currently displayed)
toLabel	the layer will be labeled only if toLablel is true
displayAll	if true, all features will be labelled even though overlaps occur

Exceptions

PalException::LayerExists

Definition at line 103 of file pal.cpp.

std::unique_ptr< Problem > Pal::extractProblem	(	const QgsRectangle &	extent,
		const QgsGeometry &	mapBoundary
	)

Extracts the labeling problem for the specified map extent - only features within this extent will be considered.

The mapBoundary argument specifies the actual geometry of the map boundary, which will be used to detect whether a label is visible (or partially visible) in the rendered map. This may differ from extent in the case of rotated or non-rectangular maps.

Definition at line 450 of file pal.cpp.

int Pal::getLineP ( )

Returns the number of candidates to generate for line features.

Definition at line 542 of file pal.cpp.

int Pal::getPointP ( )

Returns the number of candidates to generate for point features.

Definition at line 537 of file pal.cpp.

int Pal::getPolyP ( )

Returns the number of candidates to generate for polygon features.

Definition at line 547 of file pal.cpp.

SearchMethod Pal::getSearch ( )

Returns the search method in use.

Definition at line 567 of file pal.cpp.

bool Pal::getShowPartial ( )

Returns whether partial labels should be allowed.

Definition at line 562 of file pal.cpp.

bool pal::Pal::isCanceled ( )

inline

Check whether the job has been canceled.

Definition at line 135 of file pal.h.

Pal& pal::Pal::operator= ( const Pal & other )

delete

Pal cannot be copied.

void Pal::registerCancelationCallback	(	Pal::FnIsCanceled	fnCanceled,
		void *	context
	)

Register a function that returns whether this job has been canceled - PAL calls it during the computation.

Definition at line 444 of file pal.cpp.

void Pal::removeLayer ( Layer * layer )

remove a layer

Parameters

layer layer to remove

Definition at line 76 of file pal.cpp.

void Pal::setLineP ( int line_p )

set maximum # candidates to generate for lines features Higher the value is, longer Pal::labeller will spend time

Parameters

line_p maximum # candidates for a line

Definition at line 486 of file pal.cpp.

void Pal::setPointP ( int point_p )

set # candidates to generate for points features Higher the value is, longer Pal::labeller will spend time

Parameters

point_p # candidates for a point

Definition at line 480 of file pal.cpp.

void Pal::setPolyP ( int poly_p )

set maximum # candidates to generate for polygon features Higher the value is, longer Pal::labeller will spend time

Parameters

poly_p maximum # candidate for a polygon

Definition at line 492 of file pal.cpp.

void Pal::setSearch ( SearchMethod method )

Select the search method to use.

For interactive mapping using CHAIN is a good idea because it is the fastest. Other methods, ordered by speedness, are POPMUSIC_TABU, POPMUSIC_CHAIN and POPMUSIC_TABU_CHAIN, defined in pal::_searchMethod enumeration

Parameters

method the method to use

Definition at line 572 of file pal.cpp.

void Pal::setShowPartial ( bool show )

Set flag show partial label.

Parameters

show	flag value

Definition at line 532 of file pal.cpp.

QList< LabelPosition * > Pal::solveProblem	(	Problem *	prob,
		bool	displayAll
	)

Definition at line 455 of file pal.cpp.

Friends And Related Function Documentation

friend class FeaturePart

friend

Definition at line 90 of file pal.h.

friend class Layer

friend

Definition at line 91 of file pal.h.

friend class Problem

friend

Definition at line 89 of file pal.h.

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

/build/qgis-3.4.15+24xenial/src/core/pal/pal.h
/build/qgis-3.4.15+24xenial/src/core/pal/pal.cpp

Public Types

Public Member Functions

Friends

Detailed Description

Member Typedef Documentation

Constructor & Destructor Documentation

Member Function Documentation

Friends And Related Function Documentation