Contains utilities for working with QgsExpressionContext objects, including methods for creating scopes for specific uses (eg project scopes, layer scopes). More...

#include <qgsexpressioncontext.h>

Static Public Member Functions
static QgsExpressionContextScope *	atlasScope (const QgsAtlasComposition *atlas)
	Creates a new scope which contains variables and functions relating to a QgsAtlasComposition. More...

static QgsExpressionContextScope *	composerItemScope (const QgsComposerItem *composerItem)
	Creates a new scope which contains variables and functions relating to a QgsComposerItem. More...

static QgsExpressionContextScope *	compositionScope (const QgsComposition *composition)
	Creates a new scope which contains variables and functions relating to a QgsComposition. More...

static QgsExpressionContext	createFeatureBasedContext (const QgsFeature &feature, const QgsFields &fields)
	Helper function for creating an expression context which contains just a feature and fields collection. More...

static QgsExpressionContextScope *	globalScope ()
	Creates a new scope which contains variables and functions relating to the global QGIS context. More...

static QgsExpressionContextScope *	layerScope (const QgsMapLayer *layer)
	Creates a new scope which contains variables and functions relating to a QgsMapLayer. More...

static QgsExpressionContextScope *	mapSettingsScope (const QgsMapSettings &mapSettings)
	Creates a new scope which contains variables and functions relating to a QgsMapSettings object. More...

static QgsExpressionContextScope *	projectScope ()
	Creates a new scope which contains variables and functions relating to the current QGIS project. More...

static void	registerContextFunctions ()
	Registers all known core functions provided by QgsExpressionContextScope objects. More...

static void	setComposerItemVariable (QgsComposerItem *composerItem, const QString &name, const QVariant &value)
	Sets a composer item context variable. More...

static void	setComposerItemVariables (QgsComposerItem *composerItem, const QgsStringMap &variables)
	Sets all composition context variables. More...

static void	setCompositionVariable (QgsComposition *composition, const QString &name, const QVariant &value)
	Sets a composition context variable. More...

static void	setCompositionVariables (QgsComposition *composition, const QgsStringMap &variables)
	Sets all composition context variables. More...

static void	setGlobalVariable (const QString &name, const QVariant &value)
	Sets a global context variable. More...

static void	setGlobalVariables (const QgsStringMap &variables)
	Sets all global context variables. More...

static void	setLayerVariable (QgsMapLayer *layer, const QString &name, const QVariant &value)
	Sets a layer context variable. More...

static void	setLayerVariables (QgsMapLayer *layer, const QgsStringMap &variables)
	Sets all layer context variables. More...

static void	setProjectVariable (const QString &name, const QVariant &value)
	Sets a project context variable. More...

static void	setProjectVariables (const QgsStringMap &variables)
	Sets all project context variables. More...

static QgsExpressionContextScope *	updateSymbolScope (const QgsSymbolV2 symbol, QgsExpressionContextScope symbolScope=nullptr)
	Updates a symbol scope related to a QgsSymbolV2 to an expression context. More...

Detailed Description

Contains utilities for working with QgsExpressionContext objects, including methods for creating scopes for specific uses (eg project scopes, layer scopes).

Note: added in QGIS 2.12

Definition at line 463 of file qgsexpressioncontext.h.

Member Function Documentation

◆ atlasScope()

QgsExpressionContextScope * QgsExpressionContextUtils::atlasScope ( const QgsAtlasComposition * atlas )

static

Creates a new scope which contains variables and functions relating to a QgsAtlasComposition.

For instance, current page name and number.

Parameters

atlas source atlas. If null, a set of default atlas variables will be added to the scope.

Definition at line 832 of file qgsexpressioncontext.cpp.

◆ composerItemScope()

QgsExpressionContextScope * QgsExpressionContextUtils::composerItemScope ( const QgsComposerItem * composerItem )

static

Creates a new scope which contains variables and functions relating to a QgsComposerItem.

For instance, item size and position.

Parameters

composerItem source composer item

Definition at line 869 of file qgsexpressioncontext.cpp.

◆ compositionScope()

QgsExpressionContextScope * QgsExpressionContextUtils::compositionScope ( const QgsComposition * composition )

static

Creates a new scope which contains variables and functions relating to a QgsComposition.

For instance, number of pages and page sizes.

Parameters

composition source composition

Definition at line 765 of file qgsexpressioncontext.cpp.

◆ createFeatureBasedContext()

QgsExpressionContext QgsExpressionContextUtils::createFeatureBasedContext	(	const QgsFeature &	feature,
		const QgsFields &	fields
	)

static

Helper function for creating an expression context which contains just a feature and fields collection.

Generally this method should not be used as the created context does not include standard scopes such as the global and project scopes.

Definition at line 935 of file qgsexpressioncontext.cpp.

◆ globalScope()

QgsExpressionContextScope * QgsExpressionContextUtils::globalScope ( )

static

Creates a new scope which contains variables and functions relating to the global QGIS context.

For instance, QGIS version numbers and variables specified through QGIS options.

See also: setGlobalVariable()

Definition at line 458 of file qgsexpressioncontext.cpp.

◆ layerScope()

QgsExpressionContextScope * QgsExpressionContextUtils::layerScope ( const QgsMapLayer * layer )

static

Creates a new scope which contains variables and functions relating to a QgsMapLayer.

For instance, layer name, id and fields.

Definition at line 652 of file qgsexpressioncontext.cpp.

◆ mapSettingsScope()

QgsExpressionContextScope * QgsExpressionContextUtils::mapSettingsScope ( const QgsMapSettings & mapSettings )

static

Creates a new scope which contains variables and functions relating to a QgsMapSettings object.

For instance, map scale and rotation.

Definition at line 727 of file qgsexpressioncontext.cpp.

◆ projectScope()

QgsExpressionContextScope * QgsExpressionContextUtils::projectScope ( )

static

Creates a new scope which contains variables and functions relating to the current QGIS project.

For instance, project path and title, and variables specified through the project properties.

See also: setProjectVariable()

Definition at line 585 of file qgsexpressioncontext.cpp.

◆ registerContextFunctions()

void QgsExpressionContextUtils::registerContextFunctions ( )

static

Registers all known core functions provided by QgsExpressionContextScope objects.

Definition at line 943 of file qgsexpressioncontext.cpp.

◆ setComposerItemVariable()

void QgsExpressionContextUtils::setComposerItemVariable	(	QgsComposerItem *	composerItem,
		const QString &	name,
		const QVariant &	value
	)

static

Sets a composer item context variable.

This variable will be contained within scopes retrieved via composerItemScope().

Parameters

composerItem	target composer item
name	variable name
value	variable value

See also: setComposerItemVariables(); composerItemScope()

Definition at line 900 of file qgsexpressioncontext.cpp.

◆ setComposerItemVariables()

void QgsExpressionContextUtils::setComposerItemVariables	(	QgsComposerItem *	composerItem,
		const QgsStringMap &	variables
	)

static

Sets all composition context variables.

Existing compositoin variables will be removed and replaced with the variables specified.

Parameters

composerItem	target composer item
variables	new set of layer variables

See also: setComposerItemVariable(); composerItemScope()

Definition at line 916 of file qgsexpressioncontext.cpp.

◆ setCompositionVariable()

void QgsExpressionContextUtils::setCompositionVariable	(	QgsComposition *	composition,
		const QString &	name,
		const QVariant &	value
	)

static

Sets a composition context variable.

This variable will be contained within scopes retrieved via compositionScope().

Parameters

composition	target composition
name	variable name
value	variable value

See also: setCompositionVariables(); compositionScope()

Definition at line 797 of file qgsexpressioncontext.cpp.

◆ setCompositionVariables()

void QgsExpressionContextUtils::setCompositionVariables	(	QgsComposition *	composition,
		const QgsStringMap &	variables
	)

static

Sets all composition context variables.

Existing composition variables will be removed and replaced with the variables specified.

Parameters

composition	target composition
variables	new set of layer variables

See also: setCompositionVariable(); compositionScope()

Definition at line 813 of file qgsexpressioncontext.cpp.

◆ setGlobalVariable()

void QgsExpressionContextUtils::setGlobalVariable	(	const QString &	name,
		const QVariant &	value
	)

static

Sets a global context variable.

This variable will be contained within scopes retrieved via globalScope().

Parameters

name	variable name
value	variable value

See also: setGlobalVariable(); globalScope()

Definition at line 499 of file qgsexpressioncontext.cpp.

◆ setGlobalVariables()

void QgsExpressionContextUtils::setGlobalVariables ( const QgsStringMap & variables )

static

Sets all global context variables.

Existing global variables will be removed and replaced with the variables specified.

Parameters

variables new set of global variables

See also: setGlobalVariable(); globalScope()

Definition at line 514 of file qgsexpressioncontext.cpp.

◆ setLayerVariable()

void QgsExpressionContextUtils::setLayerVariable	(	QgsMapLayer *	layer,
		const QString &	name,
		const QVariant &	value
	)

static

Sets a layer context variable.

This variable will be contained within scopes retrieved via layerScope().

Parameters

layer	map layer
name	variable name
value	variable value

See also: setLayerVariables(); layerScope()

Definition at line 692 of file qgsexpressioncontext.cpp.

◆ setLayerVariables()

void QgsExpressionContextUtils::setLayerVariables	(	QgsMapLayer *	layer,
		const QgsStringMap &	variables
	)

static

Sets all layer context variables.

Existing layer variables will be removed and replaced with the variables specified.

Parameters

layer	map layer
variables	new set of layer variables

See also: setLayerVariable(); layerScope()

Definition at line 708 of file qgsexpressioncontext.cpp.

◆ setProjectVariable()

void QgsExpressionContextUtils::setProjectVariable	(	const QString &	name,
		const QVariant &	value
	)

static

Sets a project context variable.

This variable will be contained within scopes retrieved via projectScope().

Parameters

name	variable name
value	variable value

See also: setProjectVariables(); projectScope()

Definition at line 618 of file qgsexpressioncontext.cpp.

◆ setProjectVariables()

void QgsExpressionContextUtils::setProjectVariables ( const QgsStringMap & variables )

static

Sets all project context variables.

Existing project variables will be removed and replaced with the variables specified.

Parameters

variables new set of project variables

See also: setProjectVariable(); projectScope()

Definition at line 633 of file qgsexpressioncontext.cpp.

◆ updateSymbolScope()

QgsExpressionContextScope * QgsExpressionContextUtils::updateSymbolScope	(	const QgsSymbolV2 *	symbol,
		QgsExpressionContextScope *	symbolScope = `nullptr`
	)

static

Updates a symbol scope related to a QgsSymbolV2 to an expression context.

Parameters

symbol	symbol to extract properties from
symbolScope	pointer to an existing scope to update

Note: added in QGIS 2.14

Definition at line 747 of file qgsexpressioncontext.cpp.

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

/build/qgis-2.14.11+dfsg/src/core/qgsexpressioncontext.h
/build/qgis-2.14.11+dfsg/src/core/qgsexpressioncontext.cpp

Static Public Member Functions

Detailed Description

Member Function Documentation

◆ atlasScope()

◆ composerItemScope()

◆ compositionScope()

◆ createFeatureBasedContext()

◆ globalScope()

◆ layerScope()

◆ mapSettingsScope()

◆ projectScope()

◆ registerContextFunctions()

◆ setComposerItemVariable()

◆ setComposerItemVariables()

◆ setCompositionVariable()

◆ setCompositionVariables()

◆ setGlobalVariable()

◆ setGlobalVariables()

◆ setLayerVariable()

◆ setLayerVariables()

◆ setProjectVariable()

◆ setProjectVariables()

◆ updateSymbolScope()