QGIS API Documentation  2.18.3-Las Palmas (77b8c3d)
Public Member Functions | Static Public Member Functions | List of all members
QgsHeatmapRenderer Class Reference

A renderer which draws points as a live heatmap. More...

#include <qgsheatmaprenderer.h>

Inheritance diagram for QgsHeatmapRenderer:
Inheritance graph
[legend]

Public Member Functions

 QgsHeatmapRenderer ()
 
virtual ~QgsHeatmapRenderer ()
 
virtual QgsHeatmapRendererclone () const override
 
QgsVectorColorRampV2colorRamp () const
 Returns the color ramp used for shading the heatmap. More...
 
virtual QString dump () const override
 for debugging More...
 
bool invertRamp () const
 Returns whether the ramp is inverted. More...
 
double maximumValue () const
 Returns the maximum value used for shading the heatmap. More...
 
virtual void modifyRequestExtent (QgsRectangle &extent, QgsRenderContext &context) override
 Allows for a renderer to modify the extent of a feature request prior to rendering. More...
 
double radius () const
 Returns the radius for the heatmap. More...
 
const QgsMapUnitScaleradiusMapUnitScale () const
 Returns the map unit scale used for the heatmap's radius. More...
 
QgsSymbolV2::OutputUnit radiusUnit () const
 Returns the units used for the heatmap's radius. 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...
 
double renderQuality () const
 Returns the render quality used for drawing the heatmap. More...
 
virtual QDomElement save (QDomDocument &doc) override
 store renderer info to XML element More...
 
void setColorRamp (QgsVectorColorRampV2 *ramp)
 Sets the color ramp to use for shading the heatmap. More...
 
void setInvertRamp (const bool invert)
 Sets whether the ramp is inverted. 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 QgsSymbolV2::OutputUnit 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...
 
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 QgsSymbolV2symbolForFeature (QgsFeature &feature, QgsRenderContext &context) override
 
virtual QgsSymbolV2List symbols (QgsRenderContext &context) override
 
virtual QList< QStringusedAttributes () override
 Returns a set of attributes required for this renderer. More...
 
QString weightExpression () const
 Returns the expression used for weighting points when generating the heatmap. More...
 
- Public Member Functions inherited from QgsFeatureRendererV2
virtual ~QgsFeatureRendererV2 ()
 
virtual int capabilities ()
 returns bitwise OR-ed capabilities of the renderer More...
 
virtual void checkLegendSymbolItem (const QString &key, bool state=true)
 item in symbology was checked More...
 
virtual const QgsFeatureRendererV2embeddedRenderer () 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< QStringlegendKeysForFeature (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 (double scaleDenominator=-1, const QString &rule="")
 return a list of item text / symbol More...
 
virtual bool legendSymbolItemsCheckable () const
 items of symbology items in legend should be checkable More...
 
virtual QgsLegendSymbolListV2 legendSymbolItemsV2 () const
 Return a list of symbology items for the legend. More...
 
virtual QgsLegendSymbologyList legendSymbologyItems (QSize iconSize)
 return a list of symbology items for the legend 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 Q_DECL_DEPRECATED QgsSymbolV2originalSymbolForFeature (QgsFeature &feature)
 Return symbol for feature. More...
 
virtual QgsSymbolV2originalSymbolForFeature (QgsFeature &feature, QgsRenderContext &context)
 Return symbol for feature. More...
 
virtual Q_DECL_DEPRECATED QgsSymbolV2List originalSymbolsForFeature (QgsFeature &feat)
 Equivalent of originalSymbolsForFeature() call extended to support renderers that may use more symbols per feature - similar to symbolsForFeature() More...
 
virtual QgsSymbolV2List 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 Q_DECL_DEPRECATED QString rotationField () const
 return rotation field name (or empty string if not set or not supported by renderer) More...
 
virtual void setEmbeddedRenderer (QgsFeatureRendererV2 *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, QgsSymbolV2 *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...
 
virtual Q_DECL_DEPRECATED void setRotationField (const QString &fieldName)
 sets rotation field of renderer (if supported by 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 Q_DECL_DEPRECATED void startRender (QgsRenderContext &context, const QgsVectorLayer *vlayer)
 
virtual Q_DECL_DEPRECATED QgsSymbolV2symbolForFeature (QgsFeature &feature)
 To be overridden. More...
 
virtual Q_DECL_DEPRECATED QgsSymbolV2List symbols ()
 For symbol levels. More...
 
virtual Q_DECL_DEPRECATED QgsSymbolV2List symbolsForFeature (QgsFeature &feat)
 Returns list of symbols used for rendering the feature. More...
 
virtual QgsSymbolV2List symbolsForFeature (QgsFeature &feat, QgsRenderContext &context)
 Returns list of symbols used for rendering the feature. More...
 
virtual void toSld (QDomDocument &doc, QDomElement &element) const
 used from subclasses to create SLD Rule elements following SLD v1.1 specs More...
 
virtual void toSld (QDomDocument &doc, QDomElement &element, const QgsStringMap &props) const
 used from subclasses to create SLD Rule elements following SLD v1.1 specs More...
 
QString type () const
 
bool usingSymbolLevels () const
 
virtual Q_DECL_DEPRECATED bool willRenderFeature (QgsFeature &feat)
 Returns whether the renderer will render a feature or not. More...
 
virtual bool willRenderFeature (QgsFeature &feat, QgsRenderContext &context)
 Returns whether the renderer will render a feature or not. More...
 
virtual Q_DECL_DEPRECATED QDomElement writeSld (QDomDocument &doc, const QgsVectorLayer &layer) const
 create the SLD UserStyle element following the SLD v1.1 specs More...
 
virtual QDomElement writeSld (QDomDocument &doc, const QString &styleName) const
 create the SLD UserStyle element following the SLD v1.1 specs with the given name More...
 
virtual QDomElement writeSld (QDomDocument &doc, const QString &styleName, const QgsStringMap &props) const
 create the SLD UserStyle element following the SLD v1.1 specs with the given name More...
 

Static Public Member Functions

static QgsHeatmapRendererconvertFromRenderer (const QgsFeatureRendererV2 *renderer)
 
static QgsFeatureRendererV2create (QDomElement &element)
 
- Static Public Member Functions inherited from QgsFeatureRendererV2
static QgsFeatureRendererV2defaultRenderer (QGis::GeometryType geomType)
 return a new renderer - used by default in vector layers More...
 
static QgsFeatureRendererV2load (QDomElement &symbologyElem)
 create a renderer from XML element More...
 
static QgsFeatureRendererV2loadSld (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 QgsFeatureRendererV2
enum  Capabilities {
  SymbolLevels = 1, RotationField = 1 << 1, MoreSymbolsPerFeature = 1 << 2, Filter = 1 << 3,
  ScaleDependent = 1 << 4
}
 
- Protected Member Functions inherited from QgsFeatureRendererV2
 QgsFeatureRendererV2 (const QString &type)
 
Q_DECL_DEPRECATED void copyPaintEffect (QgsFeatureRendererV2 *destRenderer) const
 Copies paint effect of this renderer to another renderer. More...
 
void copyRendererData (QgsFeatureRendererV2 *destRenderer) const
 Clones generic renderer data to another renderer. More...
 
void renderFeatureWithSymbol (QgsFeature &feature, QgsSymbolV2 *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...
 
void setScaleMethodToSymbol (QgsSymbolV2 *symbol, int scaleMethod)
 
- Static Protected Member Functions inherited from QgsFeatureRendererV2
static QgsConstWkbPtr _getLineString (QPolygonF &pts, QgsRenderContext &context, QgsConstWkbPtr &wkb, bool clipToExtent=true)
 Creates a line string in screen coordinates from a wkb string in map coordinates. More...
 
static QgsConstWkbPtr _getPoint (QPointF &pt, QgsRenderContext &context, QgsConstWkbPtr &wkb)
 Creates a point in screen coordinates from a wkb string in map coordinates. More...
 
static QgsConstWkbPtr _getPolygon (QPolygonF &pts, QList< QPolygonF > &holes, QgsRenderContext &context, QgsConstWkbPtr &wkb, bool clipToExtent=true)
 Creates a polygon in screen coordinates from a wkb string in map coordinates. More...
 
static void convertSymbolRotation (QgsSymbolV2 *symbol, const QString &field)
 
static void convertSymbolSizeScale (QgsSymbolV2 *symbol, QgsSymbolV2::ScaleMethod method, const QString &field)
 
- Protected Attributes inherited from QgsFeatureRendererV2
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
 
QString mType
 
bool mUsingSymbolLevels
 

Detailed Description

A renderer which draws points as a live heatmap.

Note
Added in version 2.7

Definition at line 33 of file qgsheatmaprenderer.h.

Constructor & Destructor Documentation

QgsHeatmapRenderer::QgsHeatmapRenderer ( )

Definition at line 34 of file qgsheatmaprenderer.cpp.

QgsHeatmapRenderer::~QgsHeatmapRenderer ( )
virtual

Definition at line 52 of file qgsheatmaprenderer.cpp.

Member Function Documentation

QgsHeatmapRenderer * QgsHeatmapRenderer::clone ( ) const
overridevirtual

Implements QgsFeatureRendererV2.

Definition at line 286 of file qgsheatmaprenderer.cpp.

QgsVectorColorRampV2* QgsHeatmapRenderer::colorRamp ( ) const
inline

Returns the color ramp used for shading the heatmap.

Returns
color ramp for heatmap
See also
setColorRamp

Definition at line 65 of file qgsheatmaprenderer.h.

QgsHeatmapRenderer * QgsHeatmapRenderer::convertFromRenderer ( const QgsFeatureRendererV2 renderer)
static

Definition at line 408 of file qgsheatmaprenderer.cpp.

QgsFeatureRendererV2 * QgsHeatmapRenderer::create ( QDomElement element)
static

Definition at line 329 of file qgsheatmaprenderer.cpp.

QString QgsHeatmapRenderer::dump ( ) const
overridevirtual

for debugging

Reimplemented from QgsFeatureRendererV2.

Definition at line 281 of file qgsheatmaprenderer.cpp.

bool QgsHeatmapRenderer::invertRamp ( ) const
inline

Returns whether the ramp is inverted.

Returns
true if color ramp is inverted
See also
setInvertRamp
colorRamp

Definition at line 77 of file qgsheatmaprenderer.h.

double QgsHeatmapRenderer::maximumValue ( ) const
inline

Returns the maximum value used for shading the heatmap.

Returns
maximum value for heatmap shading. If 0, then maximum value will be automatically calculated.
See also
setMaximumValue

Definition at line 136 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::modifyRequestExtent ( QgsRectangle extent,
QgsRenderContext context 
)
overridevirtual

Allows for a renderer to modify the extent of a feature request prior to rendering.

Parameters
extentreference to request's filter extent. Modify extent to change the extent of feature request
contextrender context
Note
added in QGIS 2.7

Reimplemented from QgsFeatureRendererV2.

Definition at line 305 of file qgsheatmaprenderer.cpp.

double QgsHeatmapRenderer::radius ( ) const
inline

Returns the radius for the heatmap.

Returns
heatmap radius
See also
setRadius
radiusUnit
radiusMapUnitScale

Definition at line 92 of file qgsheatmaprenderer.h.

const QgsMapUnitScale& QgsHeatmapRenderer::radiusMapUnitScale ( ) const
inline

Returns the map unit scale used for the heatmap's radius.

Returns
map unit scale for heatmap's radius
See also
radius
radiusUnit
setRadiusMapUnitScale

Definition at line 122 of file qgsheatmaprenderer.h.

QgsSymbolV2::OutputUnit QgsHeatmapRenderer::radiusUnit ( ) const
inline

Returns the units used for the heatmap's radius.

Returns
units for heatmap radius
See also
radius
setRadiusUnit
radiusMapUnitScale

Definition at line 107 of file qgsheatmaprenderer.h.

bool QgsHeatmapRenderer::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 QgsFeatureRendererV2.

Definition at line 102 of file qgsheatmaprenderer.cpp.

double QgsHeatmapRenderer::renderQuality ( ) const
inline

Returns the render quality used for drawing the heatmap.

Returns
render quality. A value of 1 indicates maximum quality, and increasing the value will result in faster drawing but lower quality rendering.
See also
setRenderQuality

Definition at line 149 of file qgsheatmaprenderer.h.

QDomElement QgsHeatmapRenderer::save ( QDomDocument doc)
overridevirtual

store renderer info to XML element

Reimplemented from QgsFeatureRendererV2.

Definition at line 348 of file qgsheatmaprenderer.cpp.

void QgsHeatmapRenderer::setColorRamp ( QgsVectorColorRampV2 ramp)

Sets the color ramp to use for shading the heatmap.

Parameters
rampcolor ramp for heatmap. Ownership of ramp is transferred to the renderer.
See also
colorRamp

Definition at line 420 of file qgsheatmaprenderer.cpp.

void QgsHeatmapRenderer::setInvertRamp ( const bool  invert)
inline

Sets whether the ramp is inverted.

Parameters
invertset to true to invert color ramp
See also
invertRamp
setColorRamp

Definition at line 84 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::setMaximumValue ( const double  value)
inline

Sets the maximum value used for shading the heatmap.

Parameters
valuemaximum value for heatmap shading. Set to 0 for automatic calculation of maximum value.
See also
maximumValue

Definition at line 142 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::setRadius ( const double  radius)
inline

Sets the radius for the heatmap.

Parameters
radiusheatmap radius
See also
radius
setRadiusUnit
setRadiusMapUnitScale

Definition at line 99 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::setRadiusMapUnitScale ( const QgsMapUnitScale scale)
inline

Sets the map unit scale used for the heatmap's radius.

Parameters
scalemap unit scale for heatmap's radius
See also
setRadius
setRadiusUnit
radiusMapUnitScale

Definition at line 129 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::setRadiusUnit ( const QgsSymbolV2::OutputUnit  unit)
inline

Sets the units used for the heatmap's radius.

Parameters
unitunits for heatmap radius
See also
radiusUnit
setRadius
radiusMapUnitScale

Definition at line 114 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::setRenderQuality ( const int  quality)
inline

Sets the render quality used for drawing the heatmap.

Parameters
qualityrender quality. A value of 1 indicates maximum quality, and increasing the value will result in faster drawing but lower quality rendering.
See also
renderQuality

Definition at line 155 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::setWeightExpression ( const QString expression)
inline

Sets the expression used for weighting points when generating the heatmap.

Parameters
expressionpoint weight expression. If set to empty, all points are equally weighted.
See also
weightExpression

Definition at line 167 of file qgsheatmaprenderer.h.

void QgsHeatmapRenderer::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 QgsFeatureRendererV2.

Definition at line 67 of file qgsheatmaprenderer.cpp.

void QgsHeatmapRenderer::stopRender ( QgsRenderContext context)
overridevirtual

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

Implements QgsFeatureRendererV2.

Definition at line 230 of file qgsheatmaprenderer.cpp.

QgsSymbolV2 * QgsHeatmapRenderer::symbolForFeature ( QgsFeature feature,
QgsRenderContext context 
)
overridevirtual
Note
symbolForFeature2 in python bindings

Reimplemented from QgsFeatureRendererV2.

Definition at line 380 of file qgsheatmaprenderer.cpp.

QgsSymbolV2List QgsHeatmapRenderer::symbols ( QgsRenderContext context)
overridevirtual
Note
symbol2 in python bindings

Reimplemented from QgsFeatureRendererV2.

Definition at line 386 of file qgsheatmaprenderer.cpp.

QList< QString > QgsHeatmapRenderer::usedAttributes ( )
overridevirtual

Returns a set of attributes required for this renderer.

TODO QGIS3: Change QList to QSet

Implements QgsFeatureRendererV2.

Definition at line 391 of file qgsheatmaprenderer.cpp.

QString QgsHeatmapRenderer::weightExpression ( ) const
inline

Returns the expression used for weighting points when generating the heatmap.

Returns
point weight expression. If empty, all points are equally weighted.
See also
setWeightExpression

Definition at line 161 of file qgsheatmaprenderer.h.


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