QgsRenderContext Class Reference

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 }
	Enumeration of flags that affect rendering operations. More...

Public Member Functions
	QgsRenderContext ()
	QgsRenderContext (const QgsRenderContext &rh)
	~QgsRenderContext ()
const QPainter *	constPainter () const
const QgsCoordinateTransform *	coordinateTransform () const
bool	drawEditingInformation () const
QgsExpressionContext &	expressionContext ()
	Gets the expression context. More...
const QgsExpressionContext &	expressionContext () const
	Gets the expression context (const version). More...
const QgsRectangle &	extent () const
const QgsFeatureFilterProvider *	featureFilterProvider () const
	Get the filter feature provider used for additional filtering of rendered features. More...
Flags	flags () const
	Return combination of flags used for rendering. More...
bool	forceVectorOutput () const
const QgsAbstractGeometryV2 *	geometry () const
	Returns pointer to the unsegmentized geometry. More...
QgsLabelingEngineInterface *	labelingEngine () const
QgsLabelingEngineV2 *	labelingEngineV2 () const
	Get access to new labeling engine (may be nullptr) More...
const QgsMapToPixel &	mapToPixel () const
QgsRenderContext &	operator= (const QgsRenderContext &rh)
QPainter *	painter ()
double	rasterScaleFactor () const
double	rendererScale () const
bool	renderingStopped () const
double	scaleFactor () const
double	segmentationTolerance () const
	Gets the segmentation tolerance applied when rendering curved geometries. More...
QgsAbstractGeometryV2::SegmentationToleranceType	segmentationToleranceType () const
	Gets segmentation tolerance type (maximum angle or maximum difference between curve and approximation) More...
QColor	selectionColor () const
void	setCoordinateTransform (const QgsCoordinateTransform *t)
	Sets coordinate transformation. More...
void	setDrawEditingInformation (bool b)
void	setExpressionContext (const QgsExpressionContext &context)
	Sets the expression context. More...
void	setExtent (const QgsRectangle &extent)
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 (const QgsRenderContext::Flags &flags)
	Set combination of flags that will be used for rendering. More...
void	setForceVectorOutput (bool force)
void	setGeometry (const QgsAbstractGeometryV2 *geometry)
	Sets pointer to original (unsegmentized) geometry. More...
void	setLabelingEngine (QgsLabelingEngineInterface *iface)
void	setLabelingEngineV2 (QgsLabelingEngineV2 *engine2)
	Assign new labeling engine. More...
void	setMapToPixel (const QgsMapToPixel &mtp)
void	setPainter (QPainter *p)
void	setRasterScaleFactor (double factor)
void	setRendererScale (double scale)
void	setRenderingStopped (bool stopped)
void	setScaleFactor (double factor)
void	setSegmentationTolerance (double tolerance)
	Sets the segmentation tolerance applied when rendering curved geometries. More...
void	setSegmentationToleranceType (QgsAbstractGeometryV2::SegmentationToleranceType type)
	Sets segmentation tolerance type (maximum angle or maximum difference between curve and approximation) More...
void	setSelectionColor (const QColor &color)
void	setShowSelection (const bool showSelection)
	Sets whether vector selections should be shown in the rendered map. More...
void	setUseAdvancedEffects (bool enabled)
	Used to enable or disable advanced effects such as blend modes. More...
void	setUseRenderingOptimization (bool enabled)
void	setVectorSimplifyMethod (const QgsVectorSimplifyMethod &simplifyMethod)
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...
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
	Added in QGIS v2.4. More...

Static Public Member Functions
static QgsRenderContext	fromMapSettings (const QgsMapSettings &mapSettings)
	create initialized QgsRenderContext instance from given QgsMapSettings 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 / bounding box to be rendered etc.

Definition at line 45 of file qgsrendercontext.h.

Member Enumeration Documentation

Flag

enum QgsRenderContext::Flag

Enumeration of flags that affect rendering operations.

Note

added in 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 transparency 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 2.18.

Definition at line 58 of file qgsrendercontext.h.

Constructor & Destructor Documentation

QgsRenderContext() [1/2]

QgsRenderContext::QgsRenderContext

(

)

Definition at line 26 of file qgsrendercontext.cpp.

QgsRenderContext() [2/2]

QgsRenderContext::QgsRenderContext

(

const QgsRenderContext &

rh

)

Definition at line 44 of file qgsrendercontext.cpp.

~QgsRenderContext()

QgsRenderContext::~QgsRenderContext

(

)

Definition at line 89 of file qgsrendercontext.cpp.

Member Function Documentation

constPainter()

const QPainter* QgsRenderContext::constPainter ( ) const

inline

Definition at line 99 of file qgsrendercontext.h.

coordinateTransform()

const QgsCoordinateTransform* QgsRenderContext::coordinateTransform ( ) const

inline

Definition at line 101 of file qgsrendercontext.h.

drawEditingInformation()

bool QgsRenderContext::drawEditingInformation

(

)

const

Definition at line 163 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()

Note

added in QGIS 2.12

Definition at line 196 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

added in QGIS 2.12

not available in Python bindings

Definition at line 204 of file qgsrendercontext.h.

extent()

const QgsRectangle& QgsRenderContext::extent ( ) const

inline

Definition at line 103 of file qgsrendercontext.h.

featureFilterProvider()

const QgsFeatureFilterProvider* QgsRenderContext::featureFilterProvider ( ) const

inline

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

Returns

the filter feature provider

Note

added in QGIS 2.14

See also

setFeatureFilterProvider()

Definition at line 223 of file qgsrendercontext.h.

flags()

QgsRenderContext::Flags QgsRenderContext::flags

(

)

const

Return combination of flags used for rendering.

Note

added in QGIS 2.14

Definition at line 108 of file qgsrendercontext.cpp.

forceVectorOutput()

bool QgsRenderContext::forceVectorOutput

(

)

const

Definition at line 148 of file qgsrendercontext.cpp.

fromMapSettings()

QgsRenderContext QgsRenderContext::fromMapSettings ( const QgsMapSettings &  mapSettings )

static

create initialized QgsRenderContext instance from given QgsMapSettings

Note

added in 2.4

Definition at line 118 of file qgsrendercontext.cpp.

geometry()

const QgsAbstractGeometryV2* QgsRenderContext::geometry ( ) const

inline

Returns pointer to the unsegmentized geometry.

Definition at line 207 of file qgsrendercontext.h.

labelingEngine()

QgsLabelingEngineInterface* QgsRenderContext::labelingEngine ( ) const

inline

Definition at line 127 of file qgsrendercontext.h.

labelingEngineV2()

QgsLabelingEngineV2* QgsRenderContext::labelingEngineV2 ( ) const

inline

Get access to new labeling engine (may be nullptr)

Note

not available in Python bindings

Definition at line 131 of file qgsrendercontext.h.

mapToPixel()

const QgsMapToPixel& QgsRenderContext::mapToPixel ( ) const

inline

Definition at line 105 of file qgsrendercontext.h.

operator=()

QgsRenderContext & QgsRenderContext::operator=

(

const QgsRenderContext &

rh

)

Definition at line 66 of file qgsrendercontext.cpp.

painter()

QPainter* QgsRenderContext::painter ( )

inline

Definition at line 98 of file qgsrendercontext.h.

rasterScaleFactor()

double QgsRenderContext::rasterScaleFactor ( ) const

inline

Definition at line 109 of file qgsrendercontext.h.

rendererScale()

double QgsRenderContext::rendererScale ( ) const

inline

Definition at line 125 of file qgsrendercontext.h.

renderingStopped()

bool QgsRenderContext::renderingStopped ( ) const

inline

Definition at line 111 of file qgsrendercontext.h.

scaleFactor()

double QgsRenderContext::scaleFactor ( ) const

inline

Definition at line 107 of file qgsrendercontext.h.

segmentationTolerance()

double QgsRenderContext::segmentationTolerance ( ) const

inline

Gets the segmentation tolerance applied when rendering curved geometries.

Definition at line 229 of file qgsrendercontext.h.

segmentationToleranceType()

QgsAbstractGeometryV2::SegmentationToleranceType QgsRenderContext::segmentationToleranceType ( ) const

inline

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

Definition at line 235 of file qgsrendercontext.h.

selectionColor()

QColor QgsRenderContext::selectionColor ( ) const

inline

Definition at line 133 of file qgsrendercontext.h.

setCoordinateTransform()

void QgsRenderContext::setCoordinateTransform

(

const QgsCoordinateTransform *

t

)

Sets coordinate transformation.

QgsRenderContext does not take ownership

Definition at line 173 of file qgsrendercontext.cpp.

setDrawEditingInformation()

void QgsRenderContext::setDrawEditingInformation

(

bool

b

)

Definition at line 178 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()

Note

added in QGIS 2.12

Definition at line 189 of file qgsrendercontext.h.

setExtent()

void QgsRenderContext::setExtent ( const QgsRectangle &  extent )

inline

Definition at line 148 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

Note

added in QGIS 2.14

See also

featureFilterProvider()

Definition at line 203 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)

Note

added in QGIS 2.14

Definition at line 100 of file qgsrendercontext.cpp.

setFlags()

void QgsRenderContext::setFlags

(

const QgsRenderContext::Flags &

flags

)

Set combination of flags that will be used for rendering.

Note

added in QGIS 2.14

Definition at line 95 of file qgsrendercontext.cpp.

setForceVectorOutput()

void QgsRenderContext::setForceVectorOutput

(

bool

force

)

Definition at line 183 of file qgsrendercontext.cpp.

setGeometry()

void QgsRenderContext::setGeometry ( const QgsAbstractGeometryV2 *  geometry )

inline

Sets pointer to original (unsegmentized) geometry.

Definition at line 209 of file qgsrendercontext.h.

setLabelingEngine()

void QgsRenderContext::setLabelingEngine ( QgsLabelingEngineInterface *  iface )

inline

Definition at line 160 of file qgsrendercontext.h.

setLabelingEngineV2()

void QgsRenderContext::setLabelingEngineV2 ( QgsLabelingEngineV2 *  engine2 )

inline

Assign new labeling engine.

Note

not available in Python bindings

Definition at line 163 of file qgsrendercontext.h.

setMapToPixel()

void QgsRenderContext::setMapToPixel ( const QgsMapToPixel &  mtp )

inline

Definition at line 147 of file qgsrendercontext.h.

setPainter()

void QgsRenderContext::setPainter ( QPainter *  p )

inline

Definition at line 156 of file qgsrendercontext.h.

setRasterScaleFactor()

void QgsRenderContext::setRasterScaleFactor ( double  factor )

inline

Definition at line 154 of file qgsrendercontext.h.

setRendererScale()

void QgsRenderContext::setRendererScale ( double  scale )

inline

Definition at line 155 of file qgsrendercontext.h.

setRenderingStopped()

void QgsRenderContext::setRenderingStopped ( bool  stopped )

inline

Definition at line 152 of file qgsrendercontext.h.

setScaleFactor()

void QgsRenderContext::setScaleFactor ( double  factor )

inline

Definition at line 153 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

Definition at line 227 of file qgsrendercontext.h.

setSegmentationToleranceType()

void QgsRenderContext::setSegmentationToleranceType ( QgsAbstractGeometryV2::SegmentationToleranceType  type )

inline

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

Parameters

type	the segmentation tolerance typename

Definition at line 233 of file qgsrendercontext.h.

setSelectionColor()

void QgsRenderContext::setSelectionColor ( const QColor &  color )

inline

Definition at line 164 of file qgsrendercontext.h.

setShowSelection()

void QgsRenderContext::setShowSelection

(

const 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

Note

Added in QGIS v2.4

Definition at line 188 of file qgsrendercontext.cpp.

setUseAdvancedEffects()

void QgsRenderContext::setUseAdvancedEffects

(

bool

enabled

)

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

Definition at line 158 of file qgsrendercontext.cpp.

setUseRenderingOptimization()

void QgsRenderContext::setUseRenderingOptimization

(

bool

enabled

)

Definition at line 198 of file qgsrendercontext.cpp.

setVectorSimplifyMethod()

void QgsRenderContext::setVectorSimplifyMethod ( const QgsVectorSimplifyMethod &  simplifyMethod )

inline

Definition at line 182 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

Note

Added in QGIS v2.4

Definition at line 168 of file qgsrendercontext.cpp.

testFlag()

bool QgsRenderContext::testFlag

(

QgsRenderContext::Flag

flag

)

const

Check whether a particular flag is enabled.

Note

added in QGIS 2.14

Definition at line 113 of file qgsrendercontext.cpp.

useAdvancedEffects()

bool QgsRenderContext::useAdvancedEffects

(

)

const

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

Definition at line 153 of file qgsrendercontext.cpp.

useRenderingOptimization()

bool QgsRenderContext::useRenderingOptimization

(

)

const

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

Definition at line 193 of file qgsrendercontext.cpp.

vectorSimplifyMethod()

const QgsVectorSimplifyMethod& QgsRenderContext::vectorSimplifyMethod ( ) const

inline

Added in QGIS v2.4.

Definition at line 181 of file qgsrendercontext.h.

---

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

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