QGIS API Documentation 3.37.0-Master (fdefdf9c27f)
Public Member Functions | Static Public Member Functions | List of all members
QgsEmbeddedSymbolRenderer Class Reference

A vector feature renderer which uses embedded feature symbology to render per-feature symbols. More...

#include <qgsembeddedsymbolrenderer.h>

Inheritance diagram for QgsEmbeddedSymbolRenderer:
Inheritance graph
[legend]

Public Member Functions

 QgsEmbeddedSymbolRenderer (QgsSymbol *defaultSymbol)
 Constructor for QgsEmbeddedSymbolRenderer. More...
 
 ~QgsEmbeddedSymbolRenderer () override
 
QgsFeatureRenderer::Capabilities capabilities () override
 Returns details about internals of this renderer. More...
 
QgsEmbeddedSymbolRendererclone () const override
 Create a deep copy of this renderer. More...
 
QgsSymboldefaultSymbol () const
 Returns the default symbol which will be rendered for any feature which does not have embedded symbology. More...
 
QgsSymboloriginalSymbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const override
 Returns symbol for feature. More...
 
bool renderFeature (const QgsFeature &feature, QgsRenderContext &context, int layer=-1, bool selected=false, bool drawVertexMarker=false) override
 Render a feature using this renderer in the given context. More...
 
QDomElement save (QDomDocument &doc, const QgsReadWriteContext &context) override
 Stores renderer properties to an XML element. More...
 
void setDefaultSymbol (QgsSymbol *symbol)
 Sets the default symbol which will be rendered for any feature which does not have embedded symbology. More...
 
void startRender (QgsRenderContext &context, const QgsFields &fields) override
 Must be called when a new render cycle is started. More...
 
void stopRender (QgsRenderContext &context) override
 Must be called when a render cycle has finished, to allow the renderer to clean up. More...
 
QgsSymbolsymbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const override
 To be overridden. More...
 
QgsSymbolList symbols (QgsRenderContext &context) const override
 Returns list of symbols used by the renderer. More...
 
QSet< QString > usedAttributes (const QgsRenderContext &context) const override
 Returns a list of attributes required by this renderer. More...
 
bool usesEmbeddedSymbols () const override
 Returns true if the renderer uses embedded symbols for features. More...
 
- Public Member Functions inherited from QgsFeatureRenderer
virtual ~QgsFeatureRenderer ()
 
virtual bool accept (QgsStyleEntityVisitorInterface *visitor) const
 Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer. More...
 
virtual bool canSkipRender ()
 Returns true if the renderer can be entirely skipped, i.e. More...
 
virtual QgsFeatureRenderer::Capabilities capabilities ()
 Returns details about internals of this renderer. More...
 
virtual void checkLegendSymbolItem (const QString &key, bool state=true)
 Sets whether the legend symbology item with the specified ley should be checked. More...
 
virtual QgsFeatureRendererclone () const =0
 Create a deep copy of this renderer. More...
 
void copyRendererData (QgsFeatureRenderer *destRenderer) const
 Clones generic renderer data to another renderer. More...
 
virtual QString dump () const
 Returns debug information about this renderer. More...
 
virtual const QgsFeatureRendererembeddedRenderer () const
 Returns the current embedded renderer (subrenderer) for this feature renderer. More...
 
virtual QString filter (const QgsFields &fields=QgsFields())
 If a renderer does not require all the features this method may be overridden and return an expression used as where clause. More...
 
virtual bool filterNeedsGeometry () const
 Returns true if this renderer requires the geometry to apply the filter. More...
 
bool forceRasterRender () const
 Returns whether the renderer must render as a raster. More...
 
virtual QString legendClassificationAttribute () const
 If supported by the renderer, return classification attribute for the use in legend. More...
 
QSet< QString > legendKeys () const
 Returns the set of all legend keys used by the renderer. More...
 
virtual QSet< QString > legendKeysForFeature (const QgsFeature &feature, QgsRenderContext &context) const
 Returns legend keys matching a specified feature. More...
 
virtual QString legendKeyToExpression (const QString &key, QgsVectorLayer *layer, bool &ok) const
 Attempts to convert the specified legend rule key to a QGIS expression matching the features displayed using that key. More...
 
virtual bool legendSymbolItemChecked (const QString &key)
 Returns true if the legend symbology item with the specified key is checked. More...
 
virtual QgsLegendSymbolList legendSymbolItems () const
 Returns a list of symbology items for the legend. More...
 
virtual bool legendSymbolItemsCheckable () const
 Returns true if symbology items in legend are checkable. More...
 
virtual void modifyRequestExtent (QgsRectangle &extent, QgsRenderContext &context)
 Allows for a renderer to modify the extent of a feature request prior to rendering. More...
 
QgsFeatureRequest::OrderBy orderBy () const
 Gets the order in which features shall be processed by this renderer. More...
 
bool orderByEnabled () const
 Returns whether custom ordering will be applied before features are processed by this renderer. More...
 
virtual QgsSymboloriginalSymbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const
 Returns symbol for feature. More...
 
virtual QgsSymbolList originalSymbolsForFeature (const QgsFeature &feature, QgsRenderContext &context) const
 Equivalent of originalSymbolsForFeature() call extended to support renderers that may use more symbols per feature - similar to symbolsForFeature() More...
 
QgsPaintEffectpaintEffect () const
 Returns the current paint effect for the renderer. More...
 
double referenceScale () const
 Returns the symbology reference scale. More...
 
virtual bool renderFeature (const QgsFeature &feature, QgsRenderContext &context, int layer=-1, bool selected=false, bool drawVertexMarker=false)
 Render a feature using this renderer in the given context. More...
 
virtual QDomElement save (QDomDocument &doc, const QgsReadWriteContext &context)
 Stores renderer properties to an XML element. More...
 
virtual void setEmbeddedRenderer (QgsFeatureRenderer *subRenderer)
 Sets an embedded renderer (subrenderer) for this feature renderer. More...
 
void setForceRasterRender (bool forceRaster)
 Sets whether the renderer should be rendered to a raster destination. More...
 
virtual void setLegendSymbolItem (const QString &key, QgsSymbol *symbol)
 Sets the symbol to be used for a legend symbol item. More...
 
void setOrderBy (const QgsFeatureRequest::OrderBy &orderBy)
 Define the order in which features shall be processed by this renderer. More...
 
void setOrderByEnabled (bool enabled)
 Sets whether custom ordering should be applied before features are processed by this renderer. More...
 
void setPaintEffect (QgsPaintEffect *effect)
 Sets the current paint effect for the renderer. More...
 
void setReferenceScale (double scale)
 Sets the symbology reference scale. More...
 
void setUsingSymbolLevels (bool usingSymbolLevels)
 
void setVertexMarkerAppearance (Qgis::VertexMarkerType type, double size)
 Sets type and size of editing vertex markers for subsequent rendering. More...
 
virtual void startRender (QgsRenderContext &context, const QgsFields &fields)
 Must be called when a new render cycle is started. More...
 
virtual void stopRender (QgsRenderContext &context)
 Must be called when a render cycle has finished, to allow the renderer to clean up. More...
 
virtual QgsSymbolsymbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const =0
 To be overridden. More...
 
virtual QgsSymbolList symbols (QgsRenderContext &context) const
 Returns list of symbols used by the renderer. More...
 
virtual QgsSymbolList symbolsForFeature (const QgsFeature &feature, QgsRenderContext &context) const
 Returns list of symbols used for rendering the feature. More...
 
virtual void toSld (QDomDocument &doc, QDomElement &element, const QVariantMap &props=QVariantMap()) const
 used from subclasses to create SLD Rule elements following SLD v1.1 specs More...
 
QString type () const
 
virtual QSet< QString > usedAttributes (const QgsRenderContext &context) const =0
 Returns a list of attributes required by this renderer. More...
 
virtual bool usesEmbeddedSymbols () const
 Returns true if the renderer uses embedded symbols for features. More...
 
bool usingSymbolLevels () const
 
virtual bool willRenderFeature (const QgsFeature &feature, QgsRenderContext &context) const
 Returns whether the renderer will render a feature or not. More...
 
virtual QDomElement writeSld (QDomDocument &doc, const QString &styleName, const QVariantMap &props=QVariantMap()) const
 create the SLD UserStyle element following the SLD v1.1 specs with the given name More...
 

Static Public Member Functions

static QgsEmbeddedSymbolRendererconvertFromRenderer (const QgsFeatureRenderer *renderer)
 Creates a QgsEmbeddedSymbolRenderer from an existing renderer. More...
 
static QgsFeatureRenderercreate (QDomElement &element, const QgsReadWriteContext &context)
 Creates a new embedded symbol renderer from an XML element, using the supplied read/write context. More...
 
- Static Public Member Functions inherited from QgsFeatureRenderer
static QgsFeatureRendererdefaultRenderer (Qgis::GeometryType geomType)
 Returns a new renderer - used by default in vector layers. More...
 
static QgsFeatureRendererload (QDomElement &symbologyElem, const QgsReadWriteContext &context)
 create a renderer from XML element More...
 
static QgsFeatureRendererloadSld (const QDomNode &node, Qgis::GeometryType geomType, QString &errorMessage)
 Create a new renderer according to the information contained in the UserStyle element of a SLD style document. More...
 

Additional Inherited Members

- Public Types inherited from QgsFeatureRenderer
typedef QFlags< CapabilityCapabilities
 
enum  Capability { SymbolLevels = 1 , MoreSymbolsPerFeature = 1 << 2 , Filter = 1 << 3 , ScaleDependent = 1 << 4 }
 Used to specify details about a renderer. More...
 
- Protected Member Functions inherited from QgsFeatureRenderer
 QgsFeatureRenderer (const QString &type)
 
void renderFeatureWithSymbol (const QgsFeature &feature, QgsSymbol *symbol, QgsRenderContext &context, int layer, bool selected, bool drawVertexMarker)
 Render the feature with the symbol using context. More...
 
void renderVertexMarker (QPointF pt, QgsRenderContext &context)
 render editing vertex marker at specified point More...
 
void renderVertexMarkerPolygon (QPolygonF &pts, QList< QPolygonF > *rings, QgsRenderContext &context)
 render editing vertex marker for a polygon More...
 
void renderVertexMarkerPolyline (QPolygonF &pts, QgsRenderContext &context)
 render editing vertex marker for a polyline More...
 
void saveRendererData (QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context)
 Saves generic renderer data into the specified element. More...
 
- Static Protected Member Functions inherited from QgsFeatureRenderer
static QPointF _getPoint (QgsRenderContext &context, const QgsPoint &point)
 Creates a point in screen coordinates from a wkb string in map coordinates. More...
 
static void convertSymbolRotation (QgsSymbol *symbol, const QString &field)
 
static void convertSymbolSizeScale (QgsSymbol *symbol, Qgis::ScaleMethod method, const QString &field)
 
- Protected Attributes inherited from QgsFeatureRenderer
double mCurrentVertexMarkerSize = 2
 The current size of editing marker. More...
 
Qgis::VertexMarkerType mCurrentVertexMarkerType = Qgis::VertexMarkerType::Cross
 The current type of editing marker. More...
 
bool mForceRaster = false
 
QgsFeatureRequest::OrderBy mOrderBy
 
bool mOrderByEnabled = false
 
QgsPaintEffectmPaintEffect = nullptr
 
double mReferenceScale = -1.0
 
QString mType
 
bool mUsingSymbolLevels = false
 

Detailed Description

A vector feature renderer which uses embedded feature symbology to render per-feature symbols.

This renderer can be used for vector layers with a data provider which supports the QgsVectorDataProvider::FeatureSymbology capability, where the dataset has embedded information on how each feature should be rendered.

Since
QGIS 3.20

Definition at line 35 of file qgsembeddedsymbolrenderer.h.

Constructor & Destructor Documentation

◆ QgsEmbeddedSymbolRenderer()

QgsEmbeddedSymbolRenderer::QgsEmbeddedSymbolRenderer ( QgsSymbol defaultSymbol)

Constructor for QgsEmbeddedSymbolRenderer.

The defaultSymbol will be used to render any feature without embedded symbology. Ownership of defaultSymbol is transferred to the renderer.

Definition at line 23 of file qgsembeddedsymbolrenderer.cpp.

◆ ~QgsEmbeddedSymbolRenderer()

QgsEmbeddedSymbolRenderer::~QgsEmbeddedSymbolRenderer ( )
overridedefault

Member Function Documentation

◆ capabilities()

QgsFeatureRenderer::Capabilities QgsEmbeddedSymbolRenderer::capabilities ( )
overridevirtual

Returns details about internals of this renderer.

E.g. if you only want to deal with visible features:

if not renderer.capabilities().testFlag(QgsFeatureRenderer.Filter) or renderer.willRenderFeature(feature, context):
deal_with_my_feature()
else:
skip_the_curren_feature()

Reimplemented from QgsFeatureRenderer.

Definition at line 99 of file qgsembeddedsymbolrenderer.cpp.

◆ clone()

QgsEmbeddedSymbolRenderer * QgsEmbeddedSymbolRenderer::clone ( ) const
overridevirtual

Create a deep copy of this renderer.

Should be implemented by all subclasses and generate a proper subclass.

Returns
A copy of this renderer

Implements QgsFeatureRenderer.

Definition at line 92 of file qgsembeddedsymbolrenderer.cpp.

◆ convertFromRenderer()

QgsEmbeddedSymbolRenderer * QgsEmbeddedSymbolRenderer::convertFromRenderer ( const QgsFeatureRenderer renderer)
static

Creates a QgsEmbeddedSymbolRenderer from an existing renderer.

Returns
a new renderer if the conversion was possible, otherwise nullptr.

Definition at line 119 of file qgsembeddedsymbolrenderer.cpp.

◆ create()

QgsFeatureRenderer * QgsEmbeddedSymbolRenderer::create ( QDomElement &  element,
const QgsReadWriteContext context 
)
static

Creates a new embedded symbol renderer from an XML element, using the supplied read/write context.

The caller takes ownership of the returned renderer.

Definition at line 104 of file qgsembeddedsymbolrenderer.cpp.

◆ defaultSymbol()

QgsSymbol * QgsEmbeddedSymbolRenderer::defaultSymbol ( ) const

Returns the default symbol which will be rendered for any feature which does not have embedded symbology.

See also
setDefaultSymbol()

Definition at line 160 of file qgsembeddedsymbolrenderer.cpp.

◆ originalSymbolForFeature()

QgsSymbol * QgsEmbeddedSymbolRenderer::originalSymbolForFeature ( const QgsFeature feature,
QgsRenderContext context 
) const
overridevirtual

Returns symbol for feature.

The difference compared to symbolForFeature() is that it returns original symbol which can be used as an identifier for renderer's rule - the former may return a temporary replacement of a symbol for use in rendering.

Reimplemented from QgsFeatureRenderer.

Definition at line 40 of file qgsembeddedsymbolrenderer.cpp.

◆ renderFeature()

bool QgsEmbeddedSymbolRenderer::renderFeature ( const QgsFeature feature,
QgsRenderContext context,
int  layer = -1,
bool  selected = false,
bool  drawVertexMarker = false 
)
overridevirtual

Render a feature using this renderer in the given context.

Must be called between startRender() and stopRender() calls. Default implementation renders a symbol as determined by symbolForFeature() call. Returns true if the feature has been returned (this is used for example to determine whether the feature may be labelled).

If layer is not -1, the renderer should draw only a particular layer from symbols (in order to support symbol level rendering).

See also
startRender()
stopRender()

Reimplemented from QgsFeatureRenderer.

Definition at line 56 of file qgsembeddedsymbolrenderer.cpp.

◆ save()

QDomElement QgsEmbeddedSymbolRenderer::save ( QDomDocument &  doc,
const QgsReadWriteContext context 
)
overridevirtual

Stores renderer properties to an XML element.

Subclasses which override this method should call saveRendererData() as part of their implementation in order to store all common base class properties in the returned DOM element.

Reimplemented from QgsFeatureRenderer.

Definition at line 137 of file qgsembeddedsymbolrenderer.cpp.

◆ setDefaultSymbol()

void QgsEmbeddedSymbolRenderer::setDefaultSymbol ( QgsSymbol symbol)

Sets the default symbol which will be rendered for any feature which does not have embedded symbology.

Ownership of symbol is transferred to the renderer.

See also
defaultSymbol()

Definition at line 165 of file qgsembeddedsymbolrenderer.cpp.

◆ startRender()

void QgsEmbeddedSymbolRenderer::startRender ( QgsRenderContext context,
const QgsFields fields 
)
overridevirtual

Must be called when a new render cycle is started.

A call to startRender() must always be followed by a corresponding call to stopRender() after all features have been rendered.

Parameters
contextAdditional information passed to the renderer about the job which will be rendered
fieldsThe fields available for rendering
See also
stopRender()
Warning
This method is not thread safe. Before calling startRender() in a non-main thread, the renderer should instead be cloned and startRender()/stopRender() called on the clone.

Reimplemented from QgsFeatureRenderer.

Definition at line 49 of file qgsembeddedsymbolrenderer.cpp.

◆ stopRender()

void QgsEmbeddedSymbolRenderer::stopRender ( QgsRenderContext context)
overridevirtual

Must be called when a render cycle has finished, to allow the renderer to clean up.

Calls to stopRender() must always be preceded by a call to startRender().

Warning
This method is not thread safe. Before calling startRender() in a non-main thread, the renderer should instead be cloned and startRender()/stopRender() called on the clone.
See also
startRender()

Reimplemented from QgsFeatureRenderer.

Definition at line 73 of file qgsembeddedsymbolrenderer.cpp.

◆ symbolForFeature()

QgsSymbol * QgsEmbeddedSymbolRenderer::symbolForFeature ( const QgsFeature feature,
QgsRenderContext context 
) const
overridevirtual

To be overridden.

Must be called between startRender() and stopRender() calls.

Parameters
featurefeature
contextrender context
Returns
returns pointer to symbol or 0 if symbol was not found

Implements QgsFeatureRenderer.

Definition at line 32 of file qgsembeddedsymbolrenderer.cpp.

◆ symbols()

QgsSymbolList QgsEmbeddedSymbolRenderer::symbols ( QgsRenderContext context) const
overridevirtual

Returns list of symbols used by the renderer.

Parameters
contextrender context

Reimplemented from QgsFeatureRenderer.

Definition at line 152 of file qgsembeddedsymbolrenderer.cpp.

◆ usedAttributes()

QSet< QString > QgsEmbeddedSymbolRenderer::usedAttributes ( const QgsRenderContext context) const
overridevirtual

Returns a list of attributes required by this renderer.

Attributes not listed in here may not have been requested from the provider at rendering time.

Returns
A set of attributes

Implements QgsFeatureRenderer.

Definition at line 79 of file qgsembeddedsymbolrenderer.cpp.

◆ usesEmbeddedSymbols()

bool QgsEmbeddedSymbolRenderer::usesEmbeddedSymbols ( ) const
overridevirtual

Returns true if the renderer uses embedded symbols for features.

The default implementation returns false.

Since
QGIS 3.20

Reimplemented from QgsFeatureRenderer.

Definition at line 87 of file qgsembeddedsymbolrenderer.cpp.


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