QGIS API Documentation  3.3.0-Master (c515a66)
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QgsSnappingUtils Class Reference

This class has all the configuration of snapping and can return answers to snapping queries. More...

#include <qgssnappingutils.h>

Inheritance diagram for QgsSnappingUtils:
Inheritance graph
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Classes

struct  LayerConfig
 Configures how a certain layer should be handled in a snapping operation. More...
 

Public Types

enum  IndexingStrategy { IndexAlwaysFull, IndexNeverFull, IndexHybrid, IndexExtent }
 

Public Slots

void setConfig (const QgsSnappingConfig &snappingConfig)
 The snapping configuration controls the behavior of this object. More...
 
void toggleEnabled ()
 Toggles the state of snapping. More...
 

Signals

void configChanged (const QgsSnappingConfig &snappingConfig)
 Emitted when the snapping settings object changes. More...
 

Public Member Functions

 QgsSnappingUtils (QObject *parent=nullptr, bool enableSnappingForInvisibleFeature=true)
 Constructor for QgsSnappingUtils. More...
 
 ~QgsSnappingUtils () override
 
QgsSnappingConfig config () const
 The snapping configuration controls the behavior of this object. More...
 
QgsVectorLayercurrentLayer () const
 The current layer used if mode is SnapCurrentLayer. More...
 
QString dump ()
 Gets extra information about the instance. More...
 
IndexingStrategy indexingStrategy () const
 Find out which strategy is used for indexing - by default hybrid indexing is used. More...
 
QList< QgsSnappingUtils::LayerConfiglayers () const
 Query layers used for snapping. More...
 
QgsPointLocatorlocatorForLayer (QgsVectorLayer *vl)
 Gets a point locator for the given layer. If such locator does not exist, it will be created. More...
 
QgsMapSettings mapSettings () const
 
void setCurrentLayer (QgsVectorLayer *layer)
 Sets current layer so that if mode is SnapCurrentLayer we know which layer to use. More...
 
void setEnableSnappingForInvisibleFeature (bool enable)
 Set if invisible features must be snapped or not. More...
 
void setIndexingStrategy (IndexingStrategy strategy)
 Sets a strategy for indexing geometry data - determines how fast and memory consuming the data structures will be. More...
 
void setMapSettings (const QgsMapSettings &settings)
 Assign current map settings to the utils - used for conversion between screen coords to map coords. More...
 
QgsPointLocator::Match snapToCurrentLayer (QPoint point, QgsPointLocator::Types type, QgsPointLocator::MatchFilter *filter=nullptr)
 Snap to current layer. More...
 
QgsPointLocator::Match snapToMap (QPoint point, QgsPointLocator::MatchFilter *filter=nullptr)
 Snap to map according to the current configuration. Optional filter allows discarding unwanted matches. More...
 
QgsPointLocator::Match snapToMap (const QgsPointXY &pointMap, QgsPointLocator::MatchFilter *filter=nullptr)
 

Protected Member Functions

void clearAllLocators ()
 Deletes all existing locators (e.g. when destination CRS has changed and we need to reindex) More...
 
virtual void prepareIndexProgress (int index)
 Called when finished indexing a layer. When index == count the indexing is complete. More...
 
virtual void prepareIndexStarting (int count)
 Called when starting to index - can be overridden and e.g. progress dialog can be provided. More...
 

Properties

QgsSnappingConfig config
 

Detailed Description

This class has all the configuration of snapping and can return answers to snapping queries.

Internally, it keeps a cache of QgsPointLocator instances for multiple layers.

Currently it supports the following queries:

Indexing strategy determines how fast the queries will be and how much memory will be used.

When working with map canvas, it may be useful to use derived class QgsMapCanvasSnappingUtils which keeps the configuration in sync with map canvas (e.g. current view, active layer).

Since
QGIS 2.8

Definition at line 47 of file qgssnappingutils.h.

Member Enumeration Documentation

◆ IndexingStrategy

Enumerator
IndexAlwaysFull 

For all layers build index of full extent. Uses more memory, but queries are faster.

IndexNeverFull 

For all layers only create temporary indexes of small extent. Low memory usage, slower queries.

IndexHybrid 

For "big" layers using IndexNeverFull, for the rest IndexAlwaysFull. Compromise between speed and memory usage.

IndexExtent 

For all layer build index of extent given in map settings.

Definition at line 86 of file qgssnappingutils.h.

Constructor & Destructor Documentation

◆ QgsSnappingUtils()

QgsSnappingUtils::QgsSnappingUtils ( QObject *  parent = nullptr,
bool  enableSnappingForInvisibleFeature = true 
)

Constructor for QgsSnappingUtils.

Definition at line 24 of file qgssnappingutils.cpp.

◆ ~QgsSnappingUtils()

QgsSnappingUtils::~QgsSnappingUtils ( )
override

Definition at line 31 of file qgssnappingutils.cpp.

Member Function Documentation

◆ clearAllLocators()

void QgsSnappingUtils::clearAllLocators ( )
protected

Deletes all existing locators (e.g. when destination CRS has changed and we need to reindex)

Definition at line 50 of file qgssnappingutils.cpp.

◆ config()

QgsSnappingConfig QgsSnappingUtils::config ( ) const

The snapping configuration controls the behavior of this object.

◆ configChanged

void QgsSnappingUtils::configChanged ( const QgsSnappingConfig snappingConfig)
signal

Emitted when the snapping settings object changes.

◆ currentLayer()

QgsVectorLayer* QgsSnappingUtils::currentLayer ( ) const
inline

The current layer used if mode is SnapCurrentLayer.

Definition at line 82 of file qgssnappingutils.h.

◆ dump()

QString QgsSnappingUtils::dump ( )

Gets extra information about the instance.

Since
QGIS 2.14

Definition at line 495 of file qgssnappingutils.cpp.

◆ indexingStrategy()

IndexingStrategy QgsSnappingUtils::indexingStrategy ( ) const
inline

Find out which strategy is used for indexing - by default hybrid indexing is used.

Definition at line 97 of file qgssnappingutils.h.

◆ layers()

QList<QgsSnappingUtils::LayerConfig> QgsSnappingUtils::layers ( ) const
inline

Query layers used for snapping.

Definition at line 149 of file qgssnappingutils.h.

◆ locatorForLayer()

QgsPointLocator * QgsSnappingUtils::locatorForLayer ( QgsVectorLayer vl)

Gets a point locator for the given layer. If such locator does not exist, it will be created.

Definition at line 37 of file qgssnappingutils.cpp.

◆ mapSettings()

QgsMapSettings QgsSnappingUtils::mapSettings ( ) const
inline

Definition at line 77 of file qgssnappingutils.h.

◆ prepareIndexProgress()

virtual void QgsSnappingUtils::prepareIndexProgress ( int  index)
inlineprotectedvirtual

Called when finished indexing a layer. When index == count the indexing is complete.

Reimplemented in QgsMapCanvasSnappingUtils.

Definition at line 196 of file qgssnappingutils.h.

◆ prepareIndexStarting()

virtual void QgsSnappingUtils::prepareIndexStarting ( int  count)
inlineprotectedvirtual

Called when starting to index - can be overridden and e.g. progress dialog can be provided.

Reimplemented in QgsMapCanvasSnappingUtils.

Definition at line 194 of file qgssnappingutils.h.

◆ setConfig

void QgsSnappingUtils::setConfig ( const QgsSnappingConfig snappingConfig)
slot

The snapping configuration controls the behavior of this object.

Definition at line 444 of file qgssnappingutils.cpp.

◆ setCurrentLayer()

void QgsSnappingUtils::setCurrentLayer ( QgsVectorLayer layer)

Sets current layer so that if mode is SnapCurrentLayer we know which layer to use.

Definition at line 490 of file qgssnappingutils.cpp.

◆ setEnableSnappingForInvisibleFeature()

void QgsSnappingUtils::setEnableSnappingForInvisibleFeature ( bool  enable)

Set if invisible features must be snapped or not.

Parameters
enableEnable or not this feature
Since
QGIS 3.2

Definition at line 439 of file qgssnappingutils.cpp.

◆ setIndexingStrategy()

void QgsSnappingUtils::setIndexingStrategy ( IndexingStrategy  strategy)
inline

Sets a strategy for indexing geometry data - determines how fast and memory consuming the data structures will be.

Definition at line 95 of file qgssnappingutils.h.

◆ setMapSettings()

void QgsSnappingUtils::setMapSettings ( const QgsMapSettings settings)

Assign current map settings to the utils - used for conversion between screen coords to map coords.

Definition at line 480 of file qgssnappingutils.cpp.

◆ snapToCurrentLayer()

QgsPointLocator::Match QgsSnappingUtils::snapToCurrentLayer ( QPoint  point,
QgsPointLocator::Types  type,
QgsPointLocator::MatchFilter filter = nullptr 
)

Snap to current layer.

Snap to current layer

Definition at line 463 of file qgssnappingutils.cpp.

◆ snapToMap() [1/2]

QgsPointLocator::Match QgsSnappingUtils::snapToMap ( QPoint  point,
QgsPointLocator::MatchFilter filter = nullptr 
)

Snap to map according to the current configuration. Optional filter allows discarding unwanted matches.

Definition at line 215 of file qgssnappingutils.cpp.

◆ snapToMap() [2/2]

QgsPointLocator::Match QgsSnappingUtils::snapToMap ( const QgsPointXY pointMap,
QgsPointLocator::MatchFilter filter = nullptr 
)

Definition at line 226 of file qgssnappingutils.cpp.

◆ toggleEnabled

void QgsSnappingUtils::toggleEnabled ( )
slot

Toggles the state of snapping.

Since
QGIS 3.0

Definition at line 457 of file qgssnappingutils.cpp.

Property Documentation

◆ config

QgsSnappingConfig QgsSnappingUtils::config
readwrite

Definition at line 51 of file qgssnappingutils.h.


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