QGIS API Documentation 3.37.0-Master (614ebf5f6b2)
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qgsheatmaprenderer.h
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1/***************************************************************************
2 qgsheatmaprenderer.h
3 ---------------------
4 begin : November 2014
5 copyright : (C) 2014 Nyall Dawson
6 email : nyall dot dawson at gmail dot com
7 ***************************************************************************
8 * *
9 * This program is free software; you can redistribute it and/or modify *
10 * it under the terms of the GNU General Public License as published by *
11 * the Free Software Foundation; either version 2 of the License, or *
12 * (at your option) any later version. *
13 * *
14 ***************************************************************************/
15#ifndef QGSHEATMAPRENDERER_H
16#define QGSHEATMAPRENDERER_H
17
18#include "qgis_core.h"
19#include "qgis_sip.h"
20#include "qgsrenderer.h"
21#include "qgsexpression.h"
22#include "qgsgeometry.h"
23#include "qgsmapunitscale.h"
24#include "qgis.h"
26
27class QgsColorRamp;
28
34class CORE_EXPORT QgsHeatmapRenderer : public QgsFeatureRenderer
35{
36 public:
37
39 ~QgsHeatmapRenderer() override;
40
45
46 //reimplemented methods
47 QgsHeatmapRenderer *clone() const override SIP_FACTORY;
48 void startRender( QgsRenderContext &context, const QgsFields &fields ) override;
49 bool renderFeature( const QgsFeature &feature, QgsRenderContext &context, int layer = -1, bool selected = false, bool drawVertexMarker = false ) override SIP_THROW( QgsCsException );
50 void stopRender( QgsRenderContext &context ) override;
52 QgsSymbol *symbolForFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
54 QgsSymbolList symbols( QgsRenderContext &context ) const override;
55 QString dump() const override;
56 QSet<QString> usedAttributes( const QgsRenderContext &context ) const override;
58 static QgsFeatureRenderer *create( QDomElement &element, const QgsReadWriteContext &context ) SIP_FACTORY;
59 QDomElement save( QDomDocument &doc, const QgsReadWriteContext &context ) override;
60 static QgsHeatmapRenderer *convertFromRenderer( const QgsFeatureRenderer *renderer ) SIP_FACTORY;
61 bool accept( QgsStyleEntityVisitorInterface *visitor ) const override;
62 QList<QgsLayerTreeModelLegendNode *> createLegendNodes( QgsLayerTreeLayer *nodeLayer ) const override SIP_FACTORY;
63
64 //reimplemented to extent the request so that points up to heatmap's radius distance outside
65 //visible area are included
66 void modifyRequestExtent( QgsRectangle &extent, QgsRenderContext &context ) override;
67
68 //heatmap specific methods
69
75 QgsColorRamp *colorRamp() const { return mGradientRamp; }
76
82 void setColorRamp( QgsColorRamp *ramp SIP_TRANSFER );
83
90 const QgsColorRampLegendNodeSettings &legendSettings() const { return mLegendSettings; }
91
98 void setLegendSettings( const QgsColorRampLegendNodeSettings &settings );
99
107 double radius() const { return mRadius; }
108
116 void setRadius( const double radius ) { mRadius = radius; }
117
125 Qgis::RenderUnit radiusUnit() const { return mRadiusUnit; }
126
134 void setRadiusUnit( const Qgis::RenderUnit unit ) { mRadiusUnit = unit; }
135
143 const QgsMapUnitScale &radiusMapUnitScale() const { return mRadiusMapUnitScale; }
144
152 void setRadiusMapUnitScale( const QgsMapUnitScale &scale ) { mRadiusMapUnitScale = scale; }
153
160 double maximumValue() const { return mExplicitMax; }
161
168 void setMaximumValue( const double value ) { mExplicitMax = value; }
169
176 double renderQuality() const { return mRenderQuality; }
177
184 void setRenderQuality( const int quality ) { mRenderQuality = quality; }
185
191 QString weightExpression() const { return mWeightExpressionString; }
192
198 void setWeightExpression( const QString &expression ) { mWeightExpressionString = expression; }
199
200 private:
201
202 QVector<double> mValues;
203
204 double mCalculatedMaxValue = 0;
205
206 double mRadius = 10;
207 int mRadiusPixels = 0;
208 double mRadiusSquared = 0;
210 QgsMapUnitScale mRadiusMapUnitScale;
211
212 QString mWeightExpressionString;
213 int mWeightAttrNum = -1;
214 std::unique_ptr<QgsExpression> mWeightExpression;
215
216 QgsColorRamp *mGradientRamp = nullptr;
217
218 double mExplicitMax = 0.0;
219 int mRenderQuality = 3;
220
221 int mFeaturesRendered = 0;
222
223 QgsColorRampLegendNodeSettings mLegendSettings;
224
225 double uniformKernel( double distance, int bandwidth ) const;
226 double quarticKernel( double distance, int bandwidth ) const;
227 double triweightKernel( double distance, int bandwidth ) const;
228 double epanechnikovKernel( double distance, int bandwidth ) const;
229 double triangularKernel( double distance, int bandwidth ) const;
230
231 QgsMultiPointXY convertToMultipoint( const QgsGeometry *geom );
232 void initializeValues( QgsRenderContext &context );
233 void renderImage( QgsRenderContext &context );
234};
235
236
237#endif // QGSHEATMAPRENDERER_H
RenderUnit
Rendering size units.
Definition qgis.h:4489
@ Millimeters
Millimeters.
Settings for a color ramp legend node.
Abstract base class for color ramps.
Custom exception class for Coordinate Reference System related exceptions.
virtual QgsFeatureRenderer * clone() const =0
Create a deep copy of this renderer.
The feature class encapsulates a single feature including its unique ID, geometry and a list of field...
Definition qgsfeature.h:56
Container of fields for a vector layer.
Definition qgsfields.h:46
A geometry is the spatial representation of a feature.
A renderer which draws points as a live heatmap.
QString weightExpression() const
Returns the expression used for weighting points when generating the heatmap.
QgsHeatmapRenderer & operator=(const QgsHeatmapRenderer &)=delete
Direct copies are forbidden. Use clone() instead.
void setRadius(const double radius)
Sets the radius for the heatmap.
double maximumValue() const
Returns the maximum value used for shading the heatmap.
void setRadiusUnit(const Qgis::RenderUnit unit)
Sets the units used for the heatmap's radius.
double renderQuality() const
Returns the render quality used for drawing the heatmap.
void setRenderQuality(const int quality)
Sets the render quality used for drawing the heatmap.
double radius() const
Returns the radius for the heatmap.
QgsHeatmapRenderer(const QgsHeatmapRenderer &)=delete
Direct copies are forbidden. Use clone() instead.
Qgis::RenderUnit radiusUnit() const
Returns the units used for the heatmap's radius.
void setWeightExpression(const QString &expression)
Sets the expression used for weighting points when generating the heatmap.
void setMaximumValue(const double value)
Sets the maximum value used for shading the heatmap.
const QgsMapUnitScale & radiusMapUnitScale() const
Returns the map unit scale used for the heatmap's radius.
const QgsColorRampLegendNodeSettings & legendSettings() const
Returns the color ramp legend settings.
void setRadiusMapUnitScale(const QgsMapUnitScale &scale)
Sets the map unit scale used for the heatmap's radius.
Layer tree node points to a map layer.
The QgsLegendRendererItem class is abstract interface for legend items returned from QgsMapLayerLegen...
Struct for storing maximum and minimum scales for measurements in map units.
The class is used as a container of context for various read/write operations on other objects.
A rectangle specified with double values.
Contains information about the context of a rendering operation.
An interface for classes which can visit style entity (e.g.
Abstract base class for all rendered symbols.
Definition qgssymbol.h:94
#define SIP_TRANSFER
Definition qgis_sip.h:36
#define SIP_FACTORY
Definition qgis_sip.h:76
#define SIP_THROW(name,...)
Definition qgis_sip.h:203
QVector< QgsPointXY > QgsMultiPointXY
A collection of QgsPoints that share a common collection of attributes.
Definition qgsgeometry.h:80
QList< QgsSymbol * > QgsSymbolList
Definition qgsrenderer.h:47