Contains information about the context of a rendering operation. More...

#include <qgsrendercontext.h>

Public Types
enum	Flag { DrawEditingInfo = 0x01, ForceVectorOutput = 0x02, UseAdvancedEffects = 0x04, UseRenderingOptimization = 0x08, DrawSelection = 0x10, DrawSymbolBounds = 0x20, RenderMapTile = 0x40, Antialiasing = 0x80, RenderPartialOutput = 0x100, RenderPreviewJob = 0x200, RenderBlocking = 0x400 }
	Enumeration of flags that affect rendering operations. More...

enum	TextRenderFormat { TextFormatAlwaysOutlines, TextFormatAlwaysText }
	Options for rendering text. More...

Public Member Functions
	QgsRenderContext ()

	QgsRenderContext (const QgsRenderContext &rh)

void	clearCustomRenderingFlag (const QString &flag)
	Clears the specified custom rendering flag. More...

double	convertFromMapUnits (double sizeInMapUnits, QgsUnitTypes::RenderUnit outputUnit) const
	Converts a size from map units to the specified units. More...

double	convertMetersToMapUnits (double meters) const
	Convert meter distances to active MapUnit values for QgsUnitTypes::RenderMetersInMapUnits. More...

double	convertToMapUnits (double size, QgsUnitTypes::RenderUnit unit, const QgsMapUnitScale &scale=QgsMapUnitScale()) const
	Converts a size from the specified units to map units. More...

double	convertToPainterUnits (double size, QgsUnitTypes::RenderUnit unit, const QgsMapUnitScale &scale=QgsMapUnitScale()) const
	Converts a size from the specified units to painter units (pixels). More...

QgsCoordinateTransform	coordinateTransform () const
	Returns the current coordinate transform for the context. More...

int	currentMaskId () const
	Returns the current mask id, which can be used with maskPainter() More...

QVariantMap	customRenderingFlags () const
	Gets custom rendering flags. More...

QSet< const QgsSymbolLayer * >	disabledSymbolLayers () const
	When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled. More...

const QgsDistanceArea &	distanceArea () const
	A general purpose distance and area calculator, capable of performing ellipsoid based calculations. More...

bool	drawEditingInformation () const
	Returns `true` if edit markers should be drawn during the render operation. More...

QgsExpressionContext &	expressionContext ()
	Gets the expression context. More...

const QgsExpressionContext &	expressionContext () const
	Gets the expression context (const version). More...

const QgsRectangle &	extent () const
	When rendering a map layer, calling this method returns the "clipping" extent for the layer (in the layer's CRS). More...

const QgsFeatureFilterProvider *	featureFilterProvider () const
	Gets the filter feature provider used for additional filtering of rendered features. More...

Flags	flags () const
	Returns combination of flags used for rendering. More...

bool	forceVectorOutput () const
	Returns `true` if rendering operations should use vector operations instead of any faster raster shortcuts. More...

const QgsAbstractGeometry *	geometry () const
	Returns pointer to the unsegmentized geometry. More...

bool	hasRenderedFeatureHandlers () const
	Returns `true` if the context has any rendered feature handlers. More...

bool	isGuiPreview () const
	Returns the Gui preview mode. More...

bool	isSymbolLayerEnabled (const QgsSymbolLayer *layer) const
	When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled. More...

QgsLabelingEngine *	labelingEngine () const
	Gets access to new labeling engine (may be `nullptr`) More...

QgsRectangle	mapExtent () const
	Returns the original extent of the map being rendered. More...

const QgsMapToPixel &	mapToPixel () const
	Returns the context's map to pixel transform, which transforms between map coordinates and device coordinates. More...

const QgsMaskIdProvider *	maskIdProvider () const
	Returns the mask id provider attached to the context. More...

QPainter *	maskPainter (int id=0)
	Returns a mask QPainter for the render operation. More...

QgsRenderContext &	operator= (const QgsRenderContext &rh)

QPainter *	painter ()
	Returns the destination QPainter for the render operation. More...

const QPainter *	painter () const
	Returns the const destination QPainter for the render operation. More...

const QgsPathResolver &	pathResolver () const
	Returns the path resolver for conversion between relative and absolute paths during rendering operations, e.g. More...

QList< QgsRenderedFeatureHandlerInterface * >	renderedFeatureHandlers () const
	Returns the list of rendered feature handlers to use while rendering map layers. More...

double	rendererScale () const
	Returns the renderer map scale. More...

bool	renderingStopped () const
	Returns `true` if the rendering operation has been stopped and any ongoing rendering should be canceled immediately. More...

double	scaleFactor () const
	Returns the scaling factor for the render to convert painter units to physical sizes. More...

double	segmentationTolerance () const
	Gets the segmentation tolerance applied when rendering curved geometries. More...

QgsAbstractGeometry::SegmentationToleranceType	segmentationToleranceType () const
	Gets segmentation tolerance type (maximum angle or maximum difference between curve and approximation) More...

QColor	selectionColor () const
	Returns the color to use when rendering selected features. More...

void	setCoordinateTransform (const QgsCoordinateTransform &t)
	Sets the current coordinate transform for the context. More...

void	setCurrentMaskId (int id)
	Stores a mask id as the "current" one. More...

void	setCustomRenderingFlag (const QString &flag, const QVariant &value)
	Sets a custom rendering flag. More...

void	setDisabledSymbolLayers (const QSet< const QgsSymbolLayer *> &symbolLayers)
	When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled. More...

void	setDistanceArea (const QgsDistanceArea &distanceArea)
	A general purpose distance and area calculator, capable of performing ellipsoid based calculations. More...

void	setDrawEditingInformation (bool b)
	Sets whether edit markers should be drawn during the render operation. More...

void	setExpressionContext (const QgsExpressionContext &context)
	Sets the expression context. More...

void	setExtent (const QgsRectangle &extent)
	When rendering a map layer, calling this method sets the "clipping" extent for the layer (in the layer's CRS). More...

void	setFeatureFilterProvider (const QgsFeatureFilterProvider *ffp)
	Set a filter feature provider used for additional filtering of rendered features. More...

void	setFlag (Flag flag, bool on=true)
	Enable or disable a particular flag (other flags are not affected) More...

void	setFlags (QgsRenderContext::Flags flags)
	Set combination of flags that will be used for rendering. More...

void	setForceVectorOutput (bool force)
	Sets whether rendering operations should use vector operations instead of any faster raster shortcuts. More...

void	setGeometry (const QgsAbstractGeometry *geometry)
	Sets pointer to original (unsegmentized) geometry. More...

void	setIsGuiPreview (bool preview)
	Sets GUI preview mode. More...

void	setLabelingEngine (QgsLabelingEngine *engine)
	Assign new labeling engine. More...

void	setMapExtent (const QgsRectangle &extent)
	Sets the original extent of the map being rendered. More...

void	setMapToPixel (const QgsMapToPixel &mtp)
	Sets the context's map to pixel transform, which transforms between map coordinates and device coordinates. More...

void	setMaskIdProvider (QgsMaskIdProvider *provider)
	Attaches a mask id provider to the context. More...

void	setMaskPainter (QPainter *p, int id=0)
	Sets a mask QPainter for the render operation. More...

void	setPainter (QPainter *p)
	Sets the destination QPainter for the render operation. More...

void	setPathResolver (const QgsPathResolver &resolver)
	Sets the path resolver for conversion between relative and absolute paths during rendering operations, e.g. More...

void	setRendererScale (double scale)
	Sets the renderer map scale. More...

void	setRenderingStopped (bool stopped)
	Sets whether the rendering operation has been stopped and any ongoing rendering should be canceled immediately. More...

void	setScaleFactor (double factor)
	Sets the scaling factor for the render to convert painter units to physical sizes. More...

void	setSegmentationTolerance (double tolerance)
	Sets the segmentation tolerance applied when rendering curved geometries. More...

void	setSegmentationToleranceType (QgsAbstractGeometry::SegmentationToleranceType type)
	Sets segmentation tolerance type (maximum angle or maximum difference between curve and approximation) More...

void	setSelectionColor (const QColor &color)
	Sets the color to use when rendering selected features. More...

void	setShowSelection (bool showSelection)
	Sets whether vector selections should be shown in the rendered map. More...

void	setTextRenderFormat (TextRenderFormat format)
	Sets the text render format, which dictates how text is rendered (e.g. More...

void	setTransformContext (const QgsCoordinateTransformContext &context)
	Sets the context's coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system. More...

void	setUseAdvancedEffects (bool enabled)
	Used to enable or disable advanced effects such as blend modes. More...

void	setUseRenderingOptimization (bool enabled)
	Sets whether the rendering optimization (geometry simplification) should be executed. More...

void	setVectorSimplifyMethod (const QgsVectorSimplifyMethod &simplifyMethod)
	Sets the simplification setting to use when rendering vector layers. More...

bool	showSelection () const
	Returns `true` if vector selections should be shown in the rendered map. More...

bool	testFlag (Flag flag) const
	Check whether a particular flag is enabled. More...

TextRenderFormat	textRenderFormat () const
	Returns the text render format, which dictates how text is rendered (e.g. More...

QgsCoordinateTransformContext	transformContext () const
	Returns the context's coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system. More...

bool	useAdvancedEffects () const
	Returns `true` if advanced effects such as blend modes such be used. More...

bool	useRenderingOptimization () const
	Returns `true` if the rendering optimization (geometry simplification) can be executed. More...

const QgsVectorSimplifyMethod &	vectorSimplifyMethod () const
	Returns the simplification settings to use when rendering vector layers. More...

Static Public Member Functions
static QgsRenderContext	fromMapSettings (const QgsMapSettings &mapSettings)
	create initialized QgsRenderContext instance from given QgsMapSettings More...

static QgsRenderContext	fromQPainter (QPainter *painter)
	Creates a default render context given a pixel based QPainter destination. More...

Detailed Description

Contains information about the context of a rendering operation.

The context of a rendering operation defines properties such as the conversion ratio between screen and map units, the extents to be rendered etc.

Definition at line 55 of file qgsrendercontext.h.

Member Enumeration Documentation

◆ Flag

enum QgsRenderContext::Flag

Enumeration of flags that affect rendering operations.

Since: QGIS 2.14

Enumerator
DrawEditingInfo	Enable drawing of vertex markers for layers in editing mode.
ForceVectorOutput	Vector graphics should not be cached and drawn as raster images.
UseAdvancedEffects	Enable layer opacity and blending effects.
UseRenderingOptimization	Enable vector simplification and other rendering optimizations.
DrawSelection	Whether vector selections should be shown in the rendered map.
DrawSymbolBounds	Draw bounds of symbols (for debugging/testing)
RenderMapTile	Draw map such that there are no problems between adjacent tiles.
Antialiasing	Use antialiasing while drawing.
RenderPartialOutput	Whether to make extra effort to update map image with partially rendered layers (better for interactive map canvas). Added in QGIS 3.0.
RenderPreviewJob	Render is a 'canvas preview' render, and shortcuts should be taken to ensure fast rendering.
RenderBlocking	Render and load remote sources in the same thread to ensure rendering remote sources (svg and images). WARNING: this flag must NEVER be used from GUI based applications (like the main QGIS application) or crashes will result. Only for use in external scripts or QGIS server.

Definition at line 67 of file qgsrendercontext.h.

◆ TextRenderFormat

enum QgsRenderContext::TextRenderFormat

Options for rendering text.

Since: QGIS 3.4.3

Enumerator

TextFormatAlwaysOutlines

Always render text using path objects (AKA outlines/curves).

This setting guarantees the best quality rendering, even when using a raster paint surface (where sub-pixel path based text rendering is superior to sub-pixel text-based rendering). The downside is that text is converted to paths only, so users cannot open created vector outputs for post-processing in other applications and retain text editability.

This setting also guarantees complete compatibility with the full range of formatting options available through QgsTextRenderer and QgsTextFormat, some of which may not be possible to reproduce when using a vector-based paint surface and TextFormatAlwaysText mode.

A final benefit to this setting is that vector exports created using text as outlines do not require all users to have the original fonts installed in order to display the text in its original style.

TextFormatAlwaysText

Always render text as text objects.

While this mode preserves text objects as text for post-processing in external vector editing applications, it can result in rendering artifacts or poor quality rendering, depending on the text format settings.

Even with raster based paint devices, TextFormatAlwaysText can result in inferior rendering quality to TextFormatAlwaysOutlines.

When rendering using TextFormatAlwaysText to a vector based device (e.g. PDF or SVG), care must be taken to ensure that the required fonts are available to users when opening the created files, or default fallback fonts will be used to display the output instead. (Although PDF exports MAY automatically embed some fonts when possible, depending on the user's platform).

Definition at line 87 of file qgsrendercontext.h.

Constructor & Destructor Documentation

◆ QgsRenderContext() [1/2]

QgsRenderContext::QgsRenderContext ( )

Definition at line 31 of file qgsrendercontext.cpp.

◆ QgsRenderContext() [2/2]

QgsRenderContext::QgsRenderContext ( const QgsRenderContext & rh )

Definition at line 40 of file qgsrendercontext.cpp.

Member Function Documentation

◆ clearCustomRenderingFlag()

void QgsRenderContext::clearCustomRenderingFlag ( const QString & flag )

inline

Clears the specified custom rendering flag.

Parameters

flag	the flag name

See also: setCustomRenderingFlag()

Since: QGIS 3.12

Definition at line 784 of file qgsrendercontext.h.

◆ convertFromMapUnits()

double QgsRenderContext::convertFromMapUnits	(	double	sizeInMapUnits,
		QgsUnitTypes::RenderUnit	outputUnit
	)		const

Converts a size from map units to the specified units.

See also: convertToMapUnits()

Since: QGIS 3.0

Definition at line 405 of file qgsrendercontext.cpp.

◆ convertMetersToMapUnits()

double QgsRenderContext::convertMetersToMapUnits ( double meters ) const

Convert meter distances to active MapUnit values for QgsUnitTypes::RenderMetersInMapUnits.

Note: When the sourceCrs() is geographic, the center of the Extent will be used

Since: QGIS 3.0

Definition at line 444 of file qgsrendercontext.cpp.

◆ convertToMapUnits()

double QgsRenderContext::convertToMapUnits	(	double	size,
		QgsUnitTypes::RenderUnit	unit,
		const QgsMapUnitScale &	scale = `QgsMapUnitScale()`
	)		const

Converts a size from the specified units to map units.

The conversion respects the limits specified by the optional scale parameter.

See also: convertToPainterUnits()

Since: QGIS 3.0

Definition at line 341 of file qgsrendercontext.cpp.

◆ convertToPainterUnits()

double QgsRenderContext::convertToPainterUnits	(	double	size,
		QgsUnitTypes::RenderUnit	unit,
		const QgsMapUnitScale &	scale = `QgsMapUnitScale()`
	)		const

Converts a size from the specified units to painter units (pixels).

The conversion respects the limits specified by the optional scale parameter.

See also: convertToMapUnits()

Since: QGIS 3.0

Definition at line 279 of file qgsrendercontext.cpp.

◆ coordinateTransform()

QgsCoordinateTransform QgsRenderContext::coordinateTransform ( ) const

inline

Returns the current coordinate transform for the context.

This represents the coordinate transform required to transform a layer which is being rendered back to the CRS of the rendered map. If no coordinate transformation is required, or the render context is not associated with a map layer render, then an invalid coordinate transformation is returned.

See also: setCoordinateTransform()

Definition at line 226 of file qgsrendercontext.h.

◆ currentMaskId()

int QgsRenderContext::currentMaskId ( ) const

inline

Returns the current mask id, which can be used with maskPainter()

See also: setCurrentMaskId(); maskPainter()

Since: QGIS 3.12

Definition at line 736 of file qgsrendercontext.h.

◆ customRenderingFlags()

QVariantMap QgsRenderContext::customRenderingFlags ( ) const

inline

Gets custom rendering flags.

Layers might honour these to alter their rendering.

Returns: a map of custom flags

See also: setCustomRenderingFlag()

Since: QGIS 3.12

Definition at line 767 of file qgsrendercontext.h.

◆ disabledSymbolLayers()

QSet<const QgsSymbolLayer *> QgsRenderContext::disabledSymbolLayers ( ) const

inline

When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.

Returns the list of disabled symbol layers.

See also: setDisabledSymbolLayers(); isSymbolLayerEnabled()

Since: QGIS 3.12

Definition at line 203 of file qgsrendercontext.h.

◆ distanceArea()

const QgsDistanceArea& QgsRenderContext::distanceArea ( ) const

inline

A general purpose distance and area calculator, capable of performing ellipsoid based calculations.

Since: QGIS 3.0

Definition at line 232 of file qgsrendercontext.h.

◆ drawEditingInformation()

bool QgsRenderContext::drawEditingInformation ( ) const

Returns true if edit markers should be drawn during the render operation.

See also: setDrawEditingInformation()

Definition at line 222 of file qgsrendercontext.cpp.

◆ expressionContext() [1/2]

QgsExpressionContext& QgsRenderContext::expressionContext ( )

inline

Gets the expression context.

This context should be used for all expression evaluation associated with this render context.

See also: setExpressionContext()

Since: QGIS 2.12

Definition at line 577 of file qgsrendercontext.h.

◆ expressionContext() [2/2]

const QgsExpressionContext& QgsRenderContext::expressionContext ( ) const

inline

Gets the expression context (const version).

This context should be used for all expression evaluation associated with this render context.

See also: setExpressionContext()

Note: not available in Python bindings

Since: QGIS 2.12

Definition at line 586 of file qgsrendercontext.h.

◆ extent()

const QgsRectangle& QgsRenderContext::extent ( ) const

inline

When rendering a map layer, calling this method returns the "clipping" extent for the layer (in the layer's CRS).

This extent is a "worst-case" scenario, which is guaranteed to cover the complete visible portion of the layer when it is rendered to a map. It is often larger than the actual visible portion of that layer.

Warning: For some layers, depending on the visible extent and the coordinate transforms involved, this extent will represent the entire globe. This method should never be used to determine the actual visible extent of a map render.

See also: setExtent(); mapExtent()

Definition at line 287 of file qgsrendercontext.h.

◆ featureFilterProvider()

const QgsFeatureFilterProvider * QgsRenderContext::featureFilterProvider ( ) const

Gets the filter feature provider used for additional filtering of rendered features.

Returns: the filter feature provider

See also: setFeatureFilterProvider()

Since: QGIS 2.14

Definition at line 274 of file qgsrendercontext.cpp.

◆ flags()

QgsRenderContext::Flags QgsRenderContext::flags ( ) const

Returns combination of flags used for rendering.

Since: QGIS 2.14

Definition at line 155 of file qgsrendercontext.cpp.

◆ forceVectorOutput()

bool QgsRenderContext::forceVectorOutput ( ) const

Returns true if rendering operations should use vector operations instead of any faster raster shortcuts.

See also: setForceVectorOutput()

Definition at line 207 of file qgsrendercontext.cpp.

◆ fromMapSettings()

QgsRenderContext QgsRenderContext::fromMapSettings ( const QgsMapSettings & mapSettings )

static

create initialized QgsRenderContext instance from given QgsMapSettings

Since: QGIS 2.4

Definition at line 165 of file qgsrendercontext.cpp.

◆ fromQPainter()

QgsRenderContext QgsRenderContext::fromQPainter ( QPainter * painter )

static

Creates a default render context given a pixel based QPainter destination.

If no painter is specified or the painter has no device, then a default DPI of 88 will be assumed.

Since: QGIS 3.0

Definition at line 106 of file qgsrendercontext.cpp.

◆ geometry()

const QgsAbstractGeometry* QgsRenderContext::geometry ( ) const

inline

Returns pointer to the unsegmentized geometry.

Definition at line 589 of file qgsrendercontext.h.

◆ hasRenderedFeatureHandlers()

bool QgsRenderContext::hasRenderedFeatureHandlers ( ) const

inline

Returns true if the context has any rendered feature handlers.

See also: renderedFeatureHandlers()

Since: QGIS 3.10

Definition at line 704 of file qgsrendercontext.h.

◆ isGuiPreview()

bool QgsRenderContext::isGuiPreview ( ) const

inline

Returns the Gui preview mode.

GUI preview mode is used to change the behavior of some renderings when they are done to preview of symbology in the GUI. This is especially used to display mask symbol layers rather than painting them in a mask painter, which is not meant to be visible, by definition.

See also: isGuiPreview; setIsGuiPreview

Since: QGIS 3.12

Definition at line 759 of file qgsrendercontext.h.

◆ isSymbolLayerEnabled()

bool QgsRenderContext::isSymbolLayerEnabled ( const QgsSymbolLayer * layer ) const

inline

When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.

Checks whether a given symbol layer has been disabled for the current pass.

See also: setDisabledSymbolLayers(); disabledSymbolLayers()

Since: QGIS 3.12

Definition at line 214 of file qgsrendercontext.h.

◆ labelingEngine()

QgsLabelingEngine* QgsRenderContext::labelingEngine ( ) const

inline

Gets access to new labeling engine (may be nullptr)

Note: not available in Python bindings

Definition at line 364 of file qgsrendercontext.h.

◆ mapExtent()

QgsRectangle QgsRenderContext::mapExtent ( ) const

inline

Returns the original extent of the map being rendered.

Unlike extent(), this extent is always in the final destination CRS for the map render and represents the exact bounds of the map being rendered.

See also: extent(); setMapExtent()

Since: QGIS 3.4.8

Definition at line 299 of file qgsrendercontext.h.

◆ mapToPixel()

const QgsMapToPixel& QgsRenderContext::mapToPixel ( ) const

inline

Returns the context's map to pixel transform, which transforms between map coordinates and device coordinates.

See also: setMapToPixel()

Definition at line 306 of file qgsrendercontext.h.

◆ maskIdProvider()

const QgsMaskIdProvider* QgsRenderContext::maskIdProvider ( ) const

inline

Returns the mask id provider attached to the context.

See also: setMaskIdProvider()

Since: QGIS 3.12

Definition at line 721 of file qgsrendercontext.h.

◆ maskPainter()

QPainter* QgsRenderContext::maskPainter ( int id = 0 )

inline

Returns a mask QPainter for the render operation.

Multiple mask painters can be defined, each with a unique identifier. nullptr is returned if a mask painter with the given identifier does not exist. This is currently used to implement selective masking.

See also: setMaskPainter(); currentMaskId()

Since: QGIS 3.12

Definition at line 192 of file qgsrendercontext.h.

◆ operator=()

QgsRenderContext & QgsRenderContext::operator= ( const QgsRenderContext & rh )

Definition at line 72 of file qgsrendercontext.cpp.

◆ painter() [1/2]

QPainter* QgsRenderContext::painter ( )

inline

Returns the destination QPainter for the render operation.

See also: setPainter()

Definition at line 171 of file qgsrendercontext.h.

◆ painter() [2/2]

const QPainter* QgsRenderContext::painter ( ) const

inline

Returns the const destination QPainter for the render operation.

See also: setPainter()

Since: QGIS 3.12

Definition at line 180 of file qgsrendercontext.h.

◆ pathResolver()

const QgsPathResolver& QgsRenderContext::pathResolver ( ) const

inline

Returns the path resolver for conversion between relative and absolute paths during rendering operations, e.g.

for resolving relative symbol paths.

See also: setPathResolver()

Since: QGIS 3.0

Definition at line 261 of file qgsrendercontext.h.

◆ renderedFeatureHandlers()

QList< QgsRenderedFeatureHandlerInterface * > QgsRenderContext::renderedFeatureHandlers ( ) const

Returns the list of rendered feature handlers to use while rendering map layers.

See also: hasRenderedFeatureHandlers()

Since: QGIS 3.10

Definition at line 475 of file qgsrendercontext.cpp.

◆ rendererScale()

double QgsRenderContext::rendererScale ( ) const

inline

Returns the renderer map scale.

This will match the desired scale denominator for the rendered map, eg 1000.0 for a 1:1000 map render.

See also: setRendererScale()

Definition at line 358 of file qgsrendercontext.h.

◆ renderingStopped()

bool QgsRenderContext::renderingStopped ( ) const

inline

Returns true if the rendering operation has been stopped and any ongoing rendering should be canceled immediately.

See also: setRenderingStopped()

Definition at line 322 of file qgsrendercontext.h.

◆ scaleFactor()

double QgsRenderContext::scaleFactor ( ) const

inline

Returns the scaling factor for the render to convert painter units to physical sizes.

This is usually equal to the number of pixels per millimeter.

See also: setScaleFactor()

Definition at line 314 of file qgsrendercontext.h.

◆ segmentationTolerance()

double QgsRenderContext::segmentationTolerance ( ) const

inline

Gets the segmentation tolerance applied when rendering curved geometries.

See also: setSegmentationTolerance()

Definition at line 621 of file qgsrendercontext.h.

◆ segmentationToleranceType()

QgsAbstractGeometry::SegmentationToleranceType QgsRenderContext::segmentationToleranceType ( ) const

inline

Gets segmentation tolerance type (maximum angle or maximum difference between curve and approximation)

See also: setSegmentationToleranceType()

Definition at line 635 of file qgsrendercontext.h.

◆ selectionColor()

QColor QgsRenderContext::selectionColor ( ) const

inline

Returns the color to use when rendering selected features.

See also: setSelectionColor()

Definition at line 371 of file qgsrendercontext.h.

◆ setCoordinateTransform()

void QgsRenderContext::setCoordinateTransform ( const QgsCoordinateTransform & t )

Sets the current coordinate transform for the context.

This represents the coordinate transform required to transform the layer which is being rendered back to the CRS of the rendered map.

Set to an invalid QgsCoordinateTransform to indicate that no transformation is required.

See also: coordinateTransform()

Definition at line 232 of file qgsrendercontext.cpp.

◆ setCurrentMaskId()

void QgsRenderContext::setCurrentMaskId ( int id )

inline

Stores a mask id as the "current" one.

See also: currentMaskId()

Since: QGIS 3.12

Definition at line 728 of file qgsrendercontext.h.

◆ setCustomRenderingFlag()

void QgsRenderContext::setCustomRenderingFlag	(	const QString &	flag,
		const QVariant &	value
	)

inline

Sets a custom rendering flag.

Layers might honour these to alter their rendering.

Parameters

flag	the flag name
value	the flag value

See also: customRenderingFlags()

Since: QGIS 3.12

Definition at line 776 of file qgsrendercontext.h.

◆ setDisabledSymbolLayers()

void QgsRenderContext::setDisabledSymbolLayers ( const QSet< const QgsSymbolLayer *> & symbolLayers )

inline

When rendering a map layer in a second pass (for selective masking), some symbol layers may be disabled.

Sets the list of disabled symbol layers.

See also: disabledSymbolLayers(); isSymbolLayerEnabled()

Since: QGIS 3.12

Definition at line 492 of file qgsrendercontext.h.

◆ setDistanceArea()

void QgsRenderContext::setDistanceArea ( const QgsDistanceArea & distanceArea )

inline

A general purpose distance and area calculator, capable of performing ellipsoid based calculations.

Will be used to convert meter distances to active MapUnit values for QgsUnitTypes::RenderMetersInMapUnits

Since: QGIS 3.0

Definition at line 449 of file qgsrendercontext.h.

◆ setDrawEditingInformation()

void QgsRenderContext::setDrawEditingInformation ( bool b )

Sets whether edit markers should be drawn during the render operation.

See also: drawEditingInformation()

Definition at line 237 of file qgsrendercontext.cpp.

◆ setExpressionContext()

void QgsRenderContext::setExpressionContext ( const QgsExpressionContext & context )

inline

Sets the expression context.

This context is used for all expression evaluation associated with this render context.

See also: expressionContext()

Since: QGIS 2.12

Definition at line 569 of file qgsrendercontext.h.

◆ setExtent()

void QgsRenderContext::setExtent ( const QgsRectangle & extent )

inline

When rendering a map layer, calling this method sets the "clipping" extent for the layer (in the layer's CRS).

This extent should be a "worst-case" scenario, which is guaranteed to completely cover the entire visible portion of the layer when it is rendered to the map. It may be larger than the actual visible area, but MUST contain at least the entire visible area.

See also: setExtent(); setMapExtent()

Definition at line 415 of file qgsrendercontext.h.

◆ setFeatureFilterProvider()

void QgsRenderContext::setFeatureFilterProvider ( const QgsFeatureFilterProvider * ffp )

Set a filter feature provider used for additional filtering of rendered features.

Parameters

ffp	the filter feature provider

See also: featureFilterProvider()

Since: QGIS 2.14

Definition at line 262 of file qgsrendercontext.cpp.

◆ setFlag()

void QgsRenderContext::setFlag	(	QgsRenderContext::Flag	flag,
		bool	on = `true`
	)

Enable or disable a particular flag (other flags are not affected)

Since: QGIS 2.14

Definition at line 147 of file qgsrendercontext.cpp.

◆ setFlags()

void QgsRenderContext::setFlags ( QgsRenderContext::Flags flags )

Set combination of flags that will be used for rendering.

Since: QGIS 2.14

Definition at line 142 of file qgsrendercontext.cpp.

◆ setForceVectorOutput()

void QgsRenderContext::setForceVectorOutput ( bool force )

Sets whether rendering operations should use vector operations instead of any faster raster shortcuts.

See also: forceVectorOutput()

Definition at line 242 of file qgsrendercontext.cpp.

◆ setGeometry()

void QgsRenderContext::setGeometry ( const QgsAbstractGeometry * geometry )

inline

Sets pointer to original (unsegmentized) geometry.

Definition at line 591 of file qgsrendercontext.h.

◆ setIsGuiPreview()

void QgsRenderContext::setIsGuiPreview ( bool preview )

inline

Sets GUI preview mode.

GUI preview mode is used to change the behavior of some renderings when they are done to preview of symbology in the GUI. This is especially used to display mask symbol layers rather than painting them in a mask painter, which is not meant to be visible, by definition.

See also: isGuiPreview

Since: QGIS 3.12

Definition at line 747 of file qgsrendercontext.h.

◆ setLabelingEngine()

void QgsRenderContext::setLabelingEngine ( QgsLabelingEngine * engine )

inline

Assign new labeling engine.

Note: not available in Python bindings

Definition at line 506 of file qgsrendercontext.h.

◆ setMapExtent()

void QgsRenderContext::setMapExtent ( const QgsRectangle & extent )

inline

Sets the original extent of the map being rendered.

Unlike setExtent(), this extent is always in the final destination CRS for the map render and represents the exact bounds of the map being rendered.

See also: mapExtent(); setExtent()

Since: QGIS 3.4.8

Definition at line 427 of file qgsrendercontext.h.

◆ setMapToPixel()

void QgsRenderContext::setMapToPixel ( const QgsMapToPixel & mtp )

inline

Sets the context's map to pixel transform, which transforms between map coordinates and device coordinates.

See also: mapToPixel()

Definition at line 401 of file qgsrendercontext.h.

◆ setMaskIdProvider()

void QgsRenderContext::setMaskIdProvider ( QgsMaskIdProvider * provider )

inline

Attaches a mask id provider to the context.

It will allow some rendering operations to set the current mask id based on the context (label layer names and label rules for instance).

See also: QgsMaskIdProvider; setCurrentMaskId(); maskIdProvider()

Since: QGIS 3.12

Definition at line 714 of file qgsrendercontext.h.

◆ setMaskPainter()

void QgsRenderContext::setMaskPainter	(	QPainter *	p,
		int	id = `0`
	)

inline

Sets a mask QPainter for the render operation.

Ownership of the painter is not transferred and the QPainter must stay alive for the duration of any rendering operations. Multiple mask painters can be defined and the second parameter gives a unique identifier to each one.

See also: maskPainter()

Definition at line 481 of file qgsrendercontext.h.

◆ setPainter()

void QgsRenderContext::setPainter ( QPainter * p )

inline

Sets the destination QPainter for the render operation.

Ownership of the painter is not transferred and the QPainter destination must stay alive for the duration of any rendering operations.

See also: painter()

Definition at line 472 of file qgsrendercontext.h.

◆ setPathResolver()

void QgsRenderContext::setPathResolver ( const QgsPathResolver & resolver )

inline

Sets the path resolver for conversion between relative and absolute paths during rendering operations, e.g.

for resolving relative symbol paths.

See also: pathResolver()

Since: QGIS 3.0

Definition at line 270 of file qgsrendercontext.h.

◆ setRendererScale()

void QgsRenderContext::setRendererScale ( double scale )

inline

Sets the renderer map scale.

This should match the desired scale denominator for the rendered map, eg 1000.0 for a 1:1000 map render.

See also: rendererScale()

Definition at line 464 of file qgsrendercontext.h.

◆ setRenderingStopped()

void QgsRenderContext::setRenderingStopped ( bool stopped )

inline

Sets whether the rendering operation has been stopped and any ongoing rendering should be canceled immediately.

See also: renderingStopped()

Definition at line 442 of file qgsrendercontext.h.

◆ setScaleFactor()

void QgsRenderContext::setScaleFactor ( double factor )

inline

Sets the scaling factor for the render to convert painter units to physical sizes.

This should usually be equal to the number of pixels per millimeter.

See also: scaleFactor()

Definition at line 457 of file qgsrendercontext.h.

◆ setSegmentationTolerance()

void QgsRenderContext::setSegmentationTolerance ( double tolerance )

inline

Sets the segmentation tolerance applied when rendering curved geometries.

Parameters

tolerance the segmentation tolerance

See also: segmentationTolerance(); segmentationToleranceType()

Definition at line 615 of file qgsrendercontext.h.

◆ setSegmentationToleranceType()

void QgsRenderContext::setSegmentationToleranceType ( QgsAbstractGeometry::SegmentationToleranceType type )

inline

Sets segmentation tolerance type (maximum angle or maximum difference between curve and approximation)

Parameters

type	the segmentation tolerance typename

See also: segmentationToleranceType(); segmentationTolerance()

Definition at line 629 of file qgsrendercontext.h.

◆ setSelectionColor()

void QgsRenderContext::setSelectionColor ( const QColor & color )

inline

Sets the color to use when rendering selected features.

See also: selectionColor()

Definition at line 513 of file qgsrendercontext.h.

◆ setShowSelection()

void QgsRenderContext::setShowSelection ( bool showSelection )

Sets whether vector selections should be shown in the rendered map.

Parameters

showSelection set to true if selections should be shown

See also: showSelection; setSelectionColor

Since: QGIS v2.4

Definition at line 247 of file qgsrendercontext.cpp.

◆ setTextRenderFormat()

void QgsRenderContext::setTextRenderFormat ( TextRenderFormat format )

inline

Sets the text render format, which dictates how text is rendered (e.g.

as paths or real text objects).

See also: textRenderFormat()

Since: QGIS 3.4.3

Definition at line 687 of file qgsrendercontext.h.

◆ setTransformContext()

void QgsRenderContext::setTransformContext ( const QgsCoordinateTransformContext & context )

Sets the context's coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.

See also: transformContext()

Since: QGIS 3.0

Definition at line 134 of file qgsrendercontext.cpp.

◆ setUseAdvancedEffects()

void QgsRenderContext::setUseAdvancedEffects ( bool enabled )

Used to enable or disable advanced effects such as blend modes.

See also: useAdvancedEffects()

Definition at line 217 of file qgsrendercontext.cpp.

◆ setUseRenderingOptimization()

void QgsRenderContext::setUseRenderingOptimization ( bool enabled )

Sets whether the rendering optimization (geometry simplification) should be executed.

See also: useRenderingOptimization()

Definition at line 257 of file qgsrendercontext.cpp.

◆ setVectorSimplifyMethod()

void QgsRenderContext::setVectorSimplifyMethod ( const QgsVectorSimplifyMethod & simplifyMethod )

inline

Sets the simplification setting to use when rendering vector layers.

This can be used to specify simplification methods to apply during map exports and renders, e.g. to allow vector layers to be simplified to an appropriate maximum level of detail during PDF exports or to speed up layer rendering

The default is to use no simplification.

See also: vectorSimplifyMethod()

Since: QGIS 2.4

Definition at line 561 of file qgsrendercontext.h.

◆ showSelection()

bool QgsRenderContext::showSelection ( ) const

Returns true if vector selections should be shown in the rendered map.

Returns: true if selections should be shown

See also: setShowSelection; selectionColor

Since: QGIS v2.4

Definition at line 227 of file qgsrendercontext.cpp.

◆ testFlag()

bool QgsRenderContext::testFlag ( QgsRenderContext::Flag flag ) const

Check whether a particular flag is enabled.

Since: QGIS 2.14

Definition at line 160 of file qgsrendercontext.cpp.

◆ textRenderFormat()

TextRenderFormat QgsRenderContext::textRenderFormat ( ) const

inline

Returns the text render format, which dictates how text is rendered (e.g.

as paths or real text objects).

See also: setTextRenderFormat()

Since: QGIS 3.4.3

Definition at line 676 of file qgsrendercontext.h.

◆ transformContext()

QgsCoordinateTransformContext QgsRenderContext::transformContext ( ) const

Returns the context's coordinate transform context, which stores various information regarding which datum transforms should be used when transforming points from a source to destination coordinate reference system.

See also: setTransformContext()

Since: QGIS 3.0

Definition at line 125 of file qgsrendercontext.cpp.

◆ useAdvancedEffects()

bool QgsRenderContext::useAdvancedEffects ( ) const

Returns true if advanced effects such as blend modes such be used.

See also: setUseAdvancedEffects()

Definition at line 212 of file qgsrendercontext.cpp.

◆ useRenderingOptimization()

bool QgsRenderContext::useRenderingOptimization ( ) const

Returns true if the rendering optimization (geometry simplification) can be executed.

See also: setUseRenderingOptimization()

Definition at line 252 of file qgsrendercontext.cpp.

◆ vectorSimplifyMethod()

const QgsVectorSimplifyMethod& QgsRenderContext::vectorSimplifyMethod ( ) const

inline

Returns the simplification settings to use when rendering vector layers.

The default is to use no simplification.

See also: setVectorSimplifyMethod()

Since: QGIS 2.4

Definition at line 546 of file qgsrendercontext.h.

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

/build/qgis-3.12.1+28bionic/src/core/qgsrendercontext.h
/build/qgis-3.12.1+28bionic/src/core/qgsrendercontext.cpp

Public Types

Public Member Functions

Static Public Member Functions

Detailed Description

Member Enumeration Documentation

◆ Flag

◆ TextRenderFormat

Constructor & Destructor Documentation

◆ QgsRenderContext() [1/2]

◆ QgsRenderContext() [2/2]

Member Function Documentation

◆ clearCustomRenderingFlag()

◆ convertFromMapUnits()

◆ convertMetersToMapUnits()

◆ convertToMapUnits()

◆ convertToPainterUnits()

◆ coordinateTransform()

◆ currentMaskId()

◆ customRenderingFlags()

◆ disabledSymbolLayers()

◆ distanceArea()

◆ drawEditingInformation()

◆ expressionContext() [1/2]

◆ expressionContext() [2/2]

◆ extent()

◆ featureFilterProvider()

◆ flags()

◆ forceVectorOutput()

◆ fromMapSettings()

◆ fromQPainter()

◆ geometry()

◆ hasRenderedFeatureHandlers()

◆ isGuiPreview()

◆ isSymbolLayerEnabled()

◆ labelingEngine()

◆ mapExtent()

◆ mapToPixel()

◆ maskIdProvider()

◆ maskPainter()

◆ operator=()

◆ painter() [1/2]

◆ painter() [2/2]

◆ pathResolver()

◆ renderedFeatureHandlers()

◆ rendererScale()

◆ renderingStopped()

◆ scaleFactor()

◆ segmentationTolerance()

◆ segmentationToleranceType()

◆ selectionColor()

◆ setCoordinateTransform()

◆ setCurrentMaskId()

◆ setCustomRenderingFlag()

◆ setDisabledSymbolLayers()

◆ setDistanceArea()

◆ setDrawEditingInformation()

◆ setExpressionContext()

◆ setExtent()

◆ setFeatureFilterProvider()

◆ setFlag()

◆ setFlags()

◆ setForceVectorOutput()

◆ setGeometry()

◆ setIsGuiPreview()

◆ setLabelingEngine()

◆ setMapExtent()

◆ setMapToPixel()

◆ setMaskIdProvider()

◆ setMaskPainter()

◆ setPainter()

◆ setPathResolver()

◆ setRendererScale()

◆ setRenderingStopped()

◆ setScaleFactor()

◆ setSegmentationTolerance()

◆ setSegmentationToleranceType()

◆ setSelectionColor()

◆ setShowSelection()

◆ setTextRenderFormat()

◆ setTransformContext()