QGIS API Documentation 3.40.0-Bratislava (b56115d8743)
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A renderer which draws points as a live heatmap. More...
#include <qgsheatmaprenderer.h>
Public Member Functions | |
QgsHeatmapRenderer () | |
QgsHeatmapRenderer (const QgsHeatmapRenderer &)=delete | |
Direct copies are forbidden. Use clone() instead. | |
~QgsHeatmapRenderer () override | |
bool | accept (QgsStyleEntityVisitorInterface *visitor) const override |
Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer. | |
QgsHeatmapRenderer * | clone () const override |
Create a deep copy of this renderer. | |
QgsColorRamp * | colorRamp () const |
Returns the color ramp used for shading the heatmap. | |
QList< QgsLayerTreeModelLegendNode * > | createLegendNodes (QgsLayerTreeLayer *nodeLayer) const override |
Returns a list of legend nodes to be used for the legend for the renderer. | |
QString | dump () const override |
Returns debug information about this renderer. | |
const QgsColorRampLegendNodeSettings & | legendSettings () const |
Returns the color ramp legend settings. | |
double | maximumValue () const |
Returns the maximum value used for shading the heatmap. | |
void | modifyRequestExtent (QgsRectangle &extent, QgsRenderContext &context) override |
Allows for a renderer to modify the extent of a feature request prior to rendering. | |
QgsHeatmapRenderer & | operator= (const QgsHeatmapRenderer &)=delete |
Direct copies are forbidden. Use clone() instead. | |
double | radius () const |
Returns the radius for the heatmap. | |
const QgsMapUnitScale & | radiusMapUnitScale () const |
Returns the map unit scale used for the heatmap's radius. | |
Qgis::RenderUnit | radiusUnit () const |
Returns the units used for the heatmap's radius. | |
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. | |
double | renderQuality () const |
Returns the render quality used for drawing the heatmap. | |
QDomElement | save (QDomDocument &doc, const QgsReadWriteContext &context) override |
Stores renderer properties to an XML element. | |
void | setColorRamp (QgsColorRamp *ramp) |
Sets the color ramp to use for shading the heatmap. | |
void | setLegendSettings (const QgsColorRampLegendNodeSettings &settings) |
Sets the color ramp legend settings. | |
void | setMaximumValue (const double value) |
Sets the maximum value used for shading the heatmap. | |
void | setRadius (const double radius) |
Sets the radius for the heatmap. | |
void | setRadiusMapUnitScale (const QgsMapUnitScale &scale) |
Sets the map unit scale used for the heatmap's radius. | |
void | setRadiusUnit (const Qgis::RenderUnit unit) |
Sets the units used for the heatmap's radius. | |
void | setRenderQuality (const int quality) |
Sets the render quality used for drawing the heatmap. | |
void | setWeightExpression (const QString &expression) |
Sets the expression used for weighting points when generating the heatmap. | |
void | startRender (QgsRenderContext &context, const QgsFields &fields) override |
Must be called when a new render cycle is started. | |
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 |
QgsSymbolList | symbols (QgsRenderContext &context) const override |
QSet< QString > | usedAttributes (const QgsRenderContext &context) const override |
Returns a list of attributes required by this renderer. | |
QString | weightExpression () const |
Returns the expression used for weighting points when generating the heatmap. | |
Public Member Functions inherited from QgsFeatureRenderer | |
virtual | ~QgsFeatureRenderer () |
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. | |
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. | |
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 QgsSymbol * | originalSymbolForFeature (const QgsFeature &feature, QgsRenderContext &context) const |
Returns symbol for feature. | |
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 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 bool | willRenderFeature (const QgsFeature &feature, QgsRenderContext &context) const |
Returns whether the renderer will render a feature or not. | |
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 QgsHeatmapRenderer * | convertFromRenderer (const QgsFeatureRenderer *renderer) |
static QgsFeatureRenderer * | create (QDomElement &element, const QgsReadWriteContext &context) |
Creates a new heatmap renderer instance from XML. | |
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 |
A renderer which draws points as a live heatmap.
Definition at line 34 of file qgsheatmaprenderer.h.
QgsHeatmapRenderer::QgsHeatmapRenderer | ( | ) |
Definition at line 31 of file qgsheatmaprenderer.cpp.
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override |
Definition at line 39 of file qgsheatmaprenderer.cpp.
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delete |
Direct copies are forbidden. Use clone() instead.
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overridevirtual |
Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer.
Returns true
if the visitor should continue visiting other objects, or false
if visiting should be canceled.
Reimplemented from QgsFeatureRenderer.
Definition at line 405 of file qgsheatmaprenderer.cpp.
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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 286 of file qgsheatmaprenderer.cpp.
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Returns the color ramp used for shading the heatmap.
Definition at line 75 of file qgsheatmaprenderer.h.
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static |
Definition at line 391 of file qgsheatmaprenderer.cpp.
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static |
Creates a new heatmap renderer instance from XML.
Definition at line 316 of file qgsheatmaprenderer.cpp.
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overridevirtual |
Returns a list of legend nodes to be used for the legend for the renderer.
Ownership is transferred to the caller.
The default implementation creates a legend node for each symbol item returned by legendSymbolItems()
Reimplemented from QgsFeatureRenderer.
Definition at line 416 of file qgsheatmaprenderer.cpp.
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overridevirtual |
Returns debug information about this renderer.
Reimplemented from QgsFeatureRenderer.
Definition at line 281 of file qgsheatmaprenderer.cpp.
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Returns the color ramp legend settings.
Definition at line 90 of file qgsheatmaprenderer.h.
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Returns the maximum value used for shading the heatmap.
Definition at line 160 of file qgsheatmaprenderer.h.
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overridevirtual |
Allows for a renderer to modify the extent of a feature request prior to rendering.
extent | reference to request's filter extent. Modify extent to change the extent of feature request |
context | render context |
Reimplemented from QgsFeatureRenderer.
Definition at line 305 of file qgsheatmaprenderer.cpp.
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delete |
Direct copies are forbidden. Use clone() instead.
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inline |
Returns the radius for the heatmap.
Definition at line 107 of file qgsheatmaprenderer.h.
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Returns the map unit scale used for the heatmap's radius.
Definition at line 143 of file qgsheatmaprenderer.h.
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Returns the units used for the heatmap's radius.
Definition at line 125 of file qgsheatmaprenderer.h.
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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 98 of file qgsheatmaprenderer.cpp.
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inline |
Returns the render quality used for drawing the heatmap.
Definition at line 176 of file qgsheatmaprenderer.h.
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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 340 of file qgsheatmaprenderer.cpp.
void QgsHeatmapRenderer::setColorRamp | ( | QgsColorRamp * | ramp | ) |
Sets the color ramp to use for shading the heatmap.
ramp | color ramp for heatmap. Ownership of ramp is transferred to the renderer. |
Definition at line 428 of file qgsheatmaprenderer.cpp.
void QgsHeatmapRenderer::setLegendSettings | ( | const QgsColorRampLegendNodeSettings & | settings | ) |
Sets the color ramp legend settings.
Definition at line 434 of file qgsheatmaprenderer.cpp.
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Sets the maximum value used for shading the heatmap.
value | maximum value for heatmap shading. Set to 0 for automatic calculation of maximum value. |
Definition at line 168 of file qgsheatmaprenderer.h.
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Sets the radius for the heatmap.
radius | heatmap radius |
Definition at line 116 of file qgsheatmaprenderer.h.
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Sets the map unit scale used for the heatmap's radius.
scale | map unit scale for heatmap's radius |
Definition at line 152 of file qgsheatmaprenderer.h.
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Sets the units used for the heatmap's radius.
unit | units for heatmap radius |
Definition at line 134 of file qgsheatmaprenderer.h.
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Sets the render quality used for drawing the heatmap.
quality | render quality. A value of 1 indicates maximum quality, and increasing the value will result in faster drawing but lower quality rendering. |
Definition at line 184 of file qgsheatmaprenderer.h.
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Sets the expression used for weighting points when generating the heatmap.
expression | point weight expression. If set to empty, all points are equally weighted. |
Definition at line 198 of file qgsheatmaprenderer.h.
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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.
context | Additional information passed to the renderer about the job which will be rendered |
fields | The fields available for rendering |
Reimplemented from QgsFeatureRenderer.
Definition at line 54 of file qgsheatmaprenderer.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 225 of file qgsheatmaprenderer.cpp.
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overridevirtual |
Implements QgsFeatureRenderer.
Definition at line 363 of file qgsheatmaprenderer.cpp.
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overridevirtual |
Reimplemented from QgsFeatureRenderer.
Definition at line 369 of file qgsheatmaprenderer.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 374 of file qgsheatmaprenderer.cpp.
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inline |
Returns the expression used for weighting points when generating the heatmap.
Definition at line 191 of file qgsheatmaprenderer.h.