QGIS API Documentation  2.99.0-Master (9fdd060)
Public Member Functions | Static Public Member Functions | List of all members
QgsNullSymbolRenderer Class Reference

Null symbol renderer. More...

#include <qgsnullsymbolrenderer.h>

Inheritance diagram for QgsNullSymbolRenderer:
Inheritance graph
[legend]

Public Member Functions

 QgsNullSymbolRenderer ()
 
virtual QgsFeatureRendererclone () const override
 Create a deep copy of this renderer. More...
 
virtual QString dump () const override
 Returns debug information about this renderer. More...
 
virtual QgsSymboloriginalSymbolForFeature (QgsFeature &feature, QgsRenderContext &context) override
 Return symbol for feature. More...
 
virtual bool renderFeature (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...
 
virtual QDomElement save (QDomDocument &doc, const QgsReadWriteContext &context) override
 store renderer info to XML element More...
 
virtual void startRender (QgsRenderContext &context, const QgsFields &fields) override
 Needs to be called when a new render cycle is started. More...
 
virtual void stopRender (QgsRenderContext &context) override
 Needs to be called when a render cycle has finished to clean up. More...
 
virtual QgsSymbolsymbolForFeature (QgsFeature &feature, QgsRenderContext &context) override
 To be overridden. More...
 
virtual QgsSymbolList symbols (QgsRenderContext &context) override
 Returns list of symbols used by the renderer. More...
 
virtual QSet< QString > usedAttributes (const QgsRenderContext &context) const override
 Return a list of attributes required by this renderer. More...
 
virtual bool willRenderFeature (QgsFeature &feat, QgsRenderContext &context) override
 Returns whether the renderer will render a feature or not. More...
 
- Public Member Functions inherited from QgsFeatureRenderer
virtual ~QgsFeatureRenderer ()
 
virtual QgsFeatureRenderer::Capabilities capabilities ()
 Returns details about internals of this renderer. More...
 
virtual void checkLegendSymbolItem (const QString &key, bool state=true)
 item in symbology was checked 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...
 
virtual QSet< QString > legendKeysForFeature (QgsFeature &feature, QgsRenderContext &context)
 Return legend keys matching a specified feature. More...
 
virtual bool legendSymbolItemChecked (const QString &key)
 items of symbology items in legend is checked More...
 
virtual QgsLegendSymbolList legendSymbolItems () const
 Returns a list of symbology items for the legend. More...
 
virtual bool legendSymbolItemsCheckable () const
 items of symbology items in legend should be 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
 Get 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 QgsSymbolList originalSymbolsForFeature (QgsFeature &feat, QgsRenderContext &context)
 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...
 
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 setUsingSymbolLevels (bool usingSymbolLevels)
 
void setVertexMarkerAppearance (int type, int size)
 set type and size of editing vertex markers for subsequent rendering More...
 
virtual QgsSymbolList symbolsForFeature (QgsFeature &feat, QgsRenderContext &context)
 Returns list of symbols used for rendering the feature. More...
 
virtual void toSld (QDomDocument &doc, QDomElement &element, const QgsStringMap &props=QgsStringMap()) const
 used from subclasses to create SLD Rule elements following SLD v1.1 specs More...
 
QString type () const
 
bool usingSymbolLevels () const
 
virtual QDomElement writeSld (QDomDocument &doc, const QString &styleName, const QgsStringMap &props=QgsStringMap()) const
 create the SLD UserStyle element following the SLD v1.1 specs with the given name More...
 

Static Public Member Functions

static QgsNullSymbolRendererconvertFromRenderer (const QgsFeatureRenderer *renderer)
 Creates a QgsNullSymbolRenderer from an existing renderer. More...
 
static QgsFeatureRenderercreate (QDomElement &element, const QgsReadWriteContext &context)
 Creates a null renderer from XML element. More...
 
- Static Public Member Functions inherited from QgsFeatureRenderer
static QgsFeatureRendererdefaultRenderer (QgsWkbTypes::GeometryType geomType)
 return 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, QgsWkbTypes::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
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 copyRendererData (QgsFeatureRenderer *destRenderer) const
 Clones generic renderer data to another renderer. More...
 
void renderFeatureWithSymbol (QgsFeature &feature, QgsSymbol *symbol, QgsRenderContext &context, int layer, bool selected, bool drawVertexMarker)
 
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...
 
- 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, QgsSymbol::ScaleMethod method, const QString &field)
 
- Protected Attributes inherited from QgsFeatureRenderer
int mCurrentVertexMarkerSize
 The current size of editing marker. More...
 
int mCurrentVertexMarkerType
 The current type of editing marker. More...
 
bool mForceRaster
 
QgsFeatureRequest::OrderBy mOrderBy
 
bool mOrderByEnabled
 
QgsPaintEffectmPaintEffect = nullptr
 
QString mType
 
bool mUsingSymbolLevels
 

Detailed Description

Null symbol renderer.

Renderer which draws no symbols for features by default, but allows for labeling and diagrams for the layer. Selected features will also be drawn with a default symbol.

Since
QGIS 2.16

Definition at line 31 of file qgsnullsymbolrenderer.h.

Constructor & Destructor Documentation

◆ QgsNullSymbolRenderer()

QgsNullSymbolRenderer::QgsNullSymbolRenderer ( )

Definition at line 23 of file qgsnullsymbolrenderer.cpp.

Member Function Documentation

◆ clone()

QgsFeatureRenderer * QgsNullSymbolRenderer::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 93 of file qgsnullsymbolrenderer.cpp.

◆ convertFromRenderer()

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

Creates a QgsNullSymbolRenderer from an existing renderer.

Parameters
rendererrenderer to convert from
Returns
a new renderer if the conversion was possible, otherwise nullptr.

Definition at line 120 of file qgsnullsymbolrenderer.cpp.

◆ create()

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

Creates a null renderer from XML element.

Parameters
elementDOM element
contextreading context
Returns
new null symbol renderer

Definition at line 104 of file qgsnullsymbolrenderer.cpp.

◆ dump()

QString QgsNullSymbolRenderer::dump ( ) const
overridevirtual

Returns debug information about this renderer.

Reimplemented from QgsFeatureRenderer.

Definition at line 88 of file qgsnullsymbolrenderer.cpp.

◆ originalSymbolForFeature()

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

Return 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.

Since
QGIS 2.12

Reimplemented from QgsFeatureRenderer.

Definition at line 33 of file qgsnullsymbolrenderer.cpp.

◆ renderFeature()

bool QgsNullSymbolRenderer::renderFeature ( 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 particula layer from symbols (in order to support symbol level rendering).

Reimplemented from QgsFeatureRenderer.

Definition at line 38 of file qgsnullsymbolrenderer.cpp.

◆ save()

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

store renderer info to XML element

Reimplemented from QgsFeatureRenderer.

Definition at line 112 of file qgsnullsymbolrenderer.cpp.

◆ startRender()

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

Needs to be called when a new render cycle is started.

Parameters
contextAdditional information passed to the renderer about the job which will be rendered
fieldsThe fields available for rendering
Returns
Information passed back from the renderer that can e.g. be used to reduce the amount of requested features

Implements QgsFeatureRenderer.

Definition at line 63 of file qgsnullsymbolrenderer.cpp.

◆ stopRender()

void QgsNullSymbolRenderer::stopRender ( QgsRenderContext context)
overridevirtual

Needs to be called when a render cycle has finished to clean up.

Implements QgsFeatureRenderer.

Definition at line 69 of file qgsnullsymbolrenderer.cpp.

◆ symbolForFeature()

QgsSymbol * QgsNullSymbolRenderer::symbolForFeature ( QgsFeature feature,
QgsRenderContext context 
)
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
Since
QGIS 2.12

Implements QgsFeatureRenderer.

Definition at line 28 of file qgsnullsymbolrenderer.cpp.

◆ symbols()

QgsSymbolList QgsNullSymbolRenderer::symbols ( QgsRenderContext context)
overridevirtual

Returns list of symbols used by the renderer.

Parameters
contextrender context
Since
QGIS 2.12

Reimplemented from QgsFeatureRenderer.

Definition at line 99 of file qgsnullsymbolrenderer.cpp.

◆ usedAttributes()

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

Return 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 83 of file qgsnullsymbolrenderer.cpp.

◆ willRenderFeature()

bool QgsNullSymbolRenderer::willRenderFeature ( QgsFeature feat,
QgsRenderContext context 
)
overridevirtual

Returns whether the renderer will render a feature or not.

Must be called between startRender() and stopRender() calls. Default implementation uses symbolForFeature().

Since
QGIS 2.12

Reimplemented from QgsFeatureRenderer.

Definition at line 77 of file qgsnullsymbolrenderer.cpp.


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