QGIS API Documentation
3.0.2-Girona (307d082)
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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. More... | |
~QgsHeatmapRenderer () override | |
QgsHeatmapRenderer * | clone () const override |
Create a deep copy of this renderer. More... | |
QgsColorRamp * | colorRamp () const |
Returns the color ramp used for shading the heatmap. More... | |
QString | dump () const override |
Returns debug information about this renderer. More... | |
double | maximumValue () const |
Returns the maximum value used for shading the heatmap. More... | |
void | modifyRequestExtent (QgsRectangle &extent, QgsRenderContext &context) override |
Allows for a renderer to modify the extent of a feature request prior to rendering. More... | |
QgsHeatmapRenderer & | operator= (const QgsHeatmapRenderer &)=delete |
Direct copies are forbidden. Use clone() instead. More... | |
double | radius () const |
Returns the radius for the heatmap. More... | |
const QgsMapUnitScale & | radiusMapUnitScale () const |
Returns the map unit scale used for the heatmap's radius. More... | |
QgsUnitTypes::RenderUnit | radiusUnit () const |
Returns the units used for the heatmap's radius. More... | |
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... | |
double | renderQuality () const |
Returns the render quality used for drawing the heatmap. More... | |
QDomElement | save (QDomDocument &doc, const QgsReadWriteContext &context) override |
store renderer info to XML element More... | |
void | setColorRamp (QgsColorRamp *ramp) |
Sets the color ramp to use for shading the heatmap. More... | |
void | setMaximumValue (const double value) |
Sets the maximum value used for shading the heatmap. More... | |
void | setRadius (const double radius) |
Sets the radius for the heatmap. More... | |
void | setRadiusMapUnitScale (const QgsMapUnitScale &scale) |
Sets the map unit scale used for the heatmap's radius. More... | |
void | setRadiusUnit (const QgsUnitTypes::RenderUnit unit) |
Sets the units used for the heatmap's radius. More... | |
void | setRenderQuality (const int quality) |
Sets the render quality used for drawing the heatmap. More... | |
void | setWeightExpression (const QString &expression) |
Sets the expression used for weighting points when generating the heatmap. 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... | |
QgsSymbol * | symbolForFeature (QgsFeature &feature, QgsRenderContext &context) override |
QgsSymbolList | symbols (QgsRenderContext &context) override |
QSet< QString > | usedAttributes (const QgsRenderContext &context) const override |
Return a list of attributes required by this renderer. More... | |
QString | weightExpression () const |
Returns the expression used for weighting points when generating the heatmap. 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 QgsFeatureRenderer * | embeddedRenderer () 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... | |
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 QgsSymbol * | originalSymbolForFeature (QgsFeature &feature, QgsRenderContext &context) |
Return symbol for feature. 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... | |
QgsPaintEffect * | paintEffect () 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 bool | willRenderFeature (QgsFeature &feat, QgsRenderContext &context) |
Returns whether the renderer will render a feature or not. More... | |
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 QgsHeatmapRenderer * | convertFromRenderer (const QgsFeatureRenderer *renderer) |
static QgsFeatureRenderer * | create (QDomElement &element, const QgsReadWriteContext &context) |
Creates a new heatmap renderer instance from XML. More... | |
Static Public Member Functions inherited from QgsFeatureRenderer | |
static QgsFeatureRenderer * | defaultRenderer (QgsWkbTypes::GeometryType geomType) |
return a new renderer - used by default in vector layers More... | |
static QgsFeatureRenderer * | load (QDomElement &symbologyElem, const QgsReadWriteContext &context) |
create a renderer from XML element More... | |
static QgsFeatureRenderer * | loadSld (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 |
QgsPaintEffect * | mPaintEffect = nullptr |
QString | mType |
bool | mUsingSymbolLevels |
A renderer which draws points as a live heatmap.
Definition at line 33 of file qgsheatmaprenderer.h.
QgsHeatmapRenderer::QgsHeatmapRenderer | ( | ) |
Definition at line 34 of file qgsheatmaprenderer.cpp.
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override |
Definition at line 40 of file qgsheatmaprenderer.cpp.
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delete |
Direct copies are forbidden. Use clone() instead.
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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 272 of file qgsheatmaprenderer.cpp.
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Returns the color ramp used for shading the heatmap.
Definition at line 72 of file qgsheatmaprenderer.h.
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static |
Definition at line 380 of file qgsheatmaprenderer.cpp.
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Creates a new heatmap renderer instance from XML.
Definition at line 301 of file qgsheatmaprenderer.cpp.
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overridevirtual |
Returns debug information about this renderer.
Reimplemented from QgsFeatureRenderer.
Definition at line 267 of file qgsheatmaprenderer.cpp.
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Returns the maximum value used for shading the heatmap.
Definition at line 141 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 290 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 88 of file qgsheatmaprenderer.h.
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Returns the map unit scale used for the heatmap's radius.
Definition at line 124 of file qgsheatmaprenderer.h.
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Returns the units used for the heatmap's radius.
Definition at line 106 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 particula layer from symbols (in order to support symbol level rendering).
Reimplemented from QgsFeatureRenderer.
Definition at line 90 of file qgsheatmaprenderer.cpp.
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Returns the render quality used for drawing the heatmap.
Definition at line 157 of file qgsheatmaprenderer.h.
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overridevirtual |
store renderer info to XML element
Reimplemented from QgsFeatureRenderer.
Definition at line 320 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 392 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 149 of file qgsheatmaprenderer.h.
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Sets the radius for the heatmap.
radius | heatmap radius |
Definition at line 97 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 133 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 115 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 165 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 179 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 55 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 214 of file qgsheatmaprenderer.cpp.
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overridevirtual |
Implements QgsFeatureRenderer.
Definition at line 352 of file qgsheatmaprenderer.cpp.
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overridevirtual |
Reimplemented from QgsFeatureRenderer.
Definition at line 358 of file qgsheatmaprenderer.cpp.
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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.
Implements QgsFeatureRenderer.
Definition at line 363 of file qgsheatmaprenderer.cpp.
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inline |
Returns the expression used for weighting points when generating the heatmap.
Definition at line 172 of file qgsheatmaprenderer.h.