QGIS API Documentation 3.41.0-Master (181b2f43d8e)
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Null symbol renderer, which draws no symbols for features by default, but allows for labeling and diagrams for the layer. More...
#include <qgsnullsymbolrenderer.h>
Public Member Functions | |
QgsNullSymbolRenderer () | |
~QgsNullSymbolRenderer () | |
QgsFeatureRenderer * | clone () const override |
Create a deep copy of this renderer. | |
QString | dump () const override |
Returns debug information about this renderer. | |
QgsSymbol * | originalSymbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const override |
Returns symbol for feature. | |
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. | |
QDomElement | save (QDomDocument &doc, const QgsReadWriteContext &context) override |
Stores renderer properties to an XML element. | |
void | stopRender (QgsRenderContext &context) override |
Must be called when a render cycle has finished, to allow the renderer to clean up. | |
QgsSymbol * | symbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const override |
To be overridden. | |
QgsSymbolList | symbols (QgsRenderContext &context) const override |
Returns list of symbols used by the renderer. | |
QSet< QString > | usedAttributes (const QgsRenderContext &context) const override |
Returns a list of attributes required by this renderer. | |
bool | willRenderFeature (const QgsFeature &feature, QgsRenderContext &context) const override |
Returns whether the renderer will render a feature or not. | |
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. | |
virtual bool | canSkipRender () |
Returns true if the renderer can be entirely skipped, i.e. | |
virtual QgsFeatureRenderer::Capabilities | capabilities () |
Returns details about internals of this renderer. | |
virtual void | checkLegendSymbolItem (const QString &key, bool state=true) |
Sets whether the legend symbology item with the specified ley should be checked. | |
void | copyRendererData (QgsFeatureRenderer *destRenderer) const |
Clones generic renderer data to another renderer. | |
virtual QList< QgsLayerTreeModelLegendNode * > | createLegendNodes (QgsLayerTreeLayer *nodeLayer) const |
Returns a list of legend nodes to be used for the legend for the renderer. | |
QgsPropertyCollection & | dataDefinedProperties () |
Returns a reference to the renderer's property collection, used for data defined overrides. | |
const QgsPropertyCollection & | dataDefinedProperties () const |
Returns a reference to the renderer's property collection, used for data defined overrides. | |
virtual const QgsFeatureRenderer * | embeddedRenderer () const |
Returns the current embedded renderer (subrenderer) for this feature renderer. | |
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. | |
virtual bool | filterNeedsGeometry () const |
Returns true if this renderer requires the geometry to apply the filter. | |
virtual Qgis::FeatureRendererFlags | flags () const |
Returns flags associated with the renderer. | |
bool | forceRasterRender () const |
Returns whether the renderer must render as a raster. | |
virtual QString | legendClassificationAttribute () const |
If supported by the renderer, return classification attribute for the use in legend. | |
QSet< QString > | legendKeys () const |
Returns the set of all legend keys used by the renderer. | |
virtual QSet< QString > | legendKeysForFeature (const QgsFeature &feature, QgsRenderContext &context) const |
Returns legend keys matching a specified feature. | |
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. | |
virtual bool | legendSymbolItemChecked (const QString &key) |
Returns true if the legend symbology item with the specified key is checked. | |
virtual QgsLegendSymbolList | legendSymbolItems () const |
Returns a list of symbology items for the legend. | |
virtual bool | legendSymbolItemsCheckable () const |
Returns true if symbology items in legend are checkable. | |
virtual void | modifyRequestExtent (QgsRectangle &extent, QgsRenderContext &context) |
Allows for a renderer to modify the extent of a feature request prior to rendering. | |
QgsFeatureRequest::OrderBy | orderBy () const |
Gets the order in which features shall be processed by this renderer. | |
bool | orderByEnabled () const |
Returns whether custom ordering will be applied before features are processed by this renderer. | |
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() | |
QgsPaintEffect * | paintEffect () const |
Returns the current paint effect for the renderer. | |
double | referenceScale () const |
Returns the symbology reference scale. | |
void | setDataDefinedProperties (const QgsPropertyCollection &collection) |
Sets the renderer's property collection, used for data defined overrides. | |
void | setDataDefinedProperty (Property key, const QgsProperty &property) |
Sets a data defined property for the renderer. | |
virtual void | setEmbeddedRenderer (QgsFeatureRenderer *subRenderer) |
Sets an embedded renderer (subrenderer) for this feature renderer. | |
void | setForceRasterRender (bool forceRaster) |
Sets whether the renderer should be rendered to a raster destination. | |
virtual void | setLegendSymbolItem (const QString &key, QgsSymbol *symbol) |
Sets the symbol to be used for a legend symbol item. | |
void | setOrderBy (const QgsFeatureRequest::OrderBy &orderBy) |
Define the order in which features shall be processed by this renderer. | |
void | setOrderByEnabled (bool enabled) |
Sets whether custom ordering should be applied before features are processed by this renderer. | |
void | setPaintEffect (QgsPaintEffect *effect) |
Sets the current paint effect for the renderer. | |
void | setReferenceScale (double scale) |
Sets the symbology reference scale. | |
void | setUsingSymbolLevels (bool usingSymbolLevels) |
void | setVertexMarkerAppearance (Qgis::VertexMarkerType type, double size) |
Sets type and size of editing vertex markers for subsequent rendering. | |
virtual void | startRender (QgsRenderContext &context, const QgsFields &fields) |
Must be called when a new render cycle is started. | |
virtual QgsSymbolList | symbolsForFeature (const QgsFeature &feature, QgsRenderContext &context) const |
Returns list of symbols used for rendering the feature. | |
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 | |
QString | type () const |
virtual bool | usesEmbeddedSymbols () const |
Returns true if the renderer uses embedded symbols for features. | |
bool | usingSymbolLevels () const |
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 | |
Static Public Member Functions | |
static QgsNullSymbolRenderer * | convertFromRenderer (const QgsFeatureRenderer *renderer) |
Creates a QgsNullSymbolRenderer from an existing renderer. | |
static QgsFeatureRenderer * | create (QDomElement &element, const QgsReadWriteContext &context) |
Creates a null renderer from XML element. | |
Static Public Member Functions inherited from QgsFeatureRenderer | |
static QgsFeatureRenderer * | defaultRenderer (Qgis::GeometryType geomType) |
Returns a new renderer - used by default in vector layers. | |
static QgsFeatureRenderer * | load (QDomElement &symbologyElem, const QgsReadWriteContext &context) |
create a renderer from XML element | |
static QgsFeatureRenderer * | loadSld (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. | |
static const QgsPropertiesDefinition & | propertyDefinitions () |
Returns the symbol property definitions. | |
Additional Inherited Members | |
Public Types inherited from QgsFeatureRenderer | |
typedef QFlags< Capability > | Capabilities |
enum | Capability { SymbolLevels = 1 , MoreSymbolsPerFeature = 1 << 2 , Filter = 1 << 3 , ScaleDependent = 1 << 4 } |
Used to specify details about a renderer. More... | |
enum class | Property : int { HeatmapRadius , HeatmapMaximum } |
Data definable properties for renderers. 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. | |
void | renderVertexMarker (QPointF pt, QgsRenderContext &context) |
render editing vertex marker at specified point | |
void | renderVertexMarkerPolygon (QPolygonF &pts, QList< QPolygonF > *rings, QgsRenderContext &context) |
render editing vertex marker for a polygon | |
void | renderVertexMarkerPolyline (QPolygonF &pts, QgsRenderContext &context) |
render editing vertex marker for a polyline | |
void | saveRendererData (QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context) |
Saves generic renderer data into the specified element. | |
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. | |
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. | |
Qgis::VertexMarkerType | mCurrentVertexMarkerType = Qgis::VertexMarkerType::Cross |
The current type of editing marker. | |
bool | mForceRaster = false |
QgsFeatureRequest::OrderBy | mOrderBy |
bool | mOrderByEnabled = false |
QgsPaintEffect * | mPaintEffect = nullptr |
double | mReferenceScale = -1.0 |
QString | mType |
bool | mUsingSymbolLevels = false |
Null symbol 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.
Definition at line 32 of file qgsnullsymbolrenderer.h.
QgsNullSymbolRenderer::QgsNullSymbolRenderer | ( | ) |
Definition at line 23 of file qgsnullsymbolrenderer.cpp.
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default |
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overridevirtual |
Create a deep copy of this renderer.
Should be implemented by all subclasses and generate a proper subclass.
Implements QgsFeatureRenderer.
Definition at line 91 of file qgsnullsymbolrenderer.cpp.
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static |
Creates a QgsNullSymbolRenderer from an existing renderer.
renderer | renderer to convert from |
nullptr
. Definition at line 122 of file qgsnullsymbolrenderer.cpp.
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static |
Creates a null renderer from XML element.
element | DOM element |
context | reading context |
Definition at line 103 of file qgsnullsymbolrenderer.cpp.
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overridevirtual |
Returns debug information about this renderer.
Reimplemented from QgsFeatureRenderer.
Definition at line 86 of file qgsnullsymbolrenderer.cpp.
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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 35 of file qgsnullsymbolrenderer.cpp.
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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).
Reimplemented from QgsFeatureRenderer.
Definition at line 40 of file qgsnullsymbolrenderer.cpp.
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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 111 of file qgsnullsymbolrenderer.cpp.
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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().
Reimplemented from QgsFeatureRenderer.
Definition at line 65 of file qgsnullsymbolrenderer.cpp.
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overridevirtual |
To be overridden.
Must be called between startRender() and stopRender() calls.
feature | feature |
context | render context |
Implements QgsFeatureRenderer.
Definition at line 30 of file qgsnullsymbolrenderer.cpp.
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overridevirtual |
Returns list of symbols used by the renderer.
context | render context |
Reimplemented from QgsFeatureRenderer.
Definition at line 98 of file qgsnullsymbolrenderer.cpp.
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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.
Implements QgsFeatureRenderer.
Definition at line 81 of file qgsnullsymbolrenderer.cpp.
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overridevirtual |
Returns whether the renderer will render a feature or not.
Must be called between startRender() and stopRender() calls. Default implementation uses symbolForFeature().
Reimplemented from QgsFeatureRenderer.
Definition at line 75 of file qgsnullsymbolrenderer.cpp.