QGIS API Documentation 3.29.0-Master (ade4f0cf0f)
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
25class QgsColorRamp;
26
33class CORE_EXPORT QgsHeatmapRenderer : public QgsFeatureRenderer
34{
35 public:
36
38 ~QgsHeatmapRenderer() override;
39
44
45 //reimplemented methods
46 QgsHeatmapRenderer *clone() const override SIP_FACTORY;
47 void startRender( QgsRenderContext &context, const QgsFields &fields ) override;
48 bool renderFeature( const QgsFeature &feature, QgsRenderContext &context, int layer = -1, bool selected = false, bool drawVertexMarker = false ) override SIP_THROW( QgsCsException );
49 void stopRender( QgsRenderContext &context ) override;
51 QgsSymbol *symbolForFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
53 QgsSymbolList symbols( QgsRenderContext &context ) const override;
54 QString dump() const override;
55 QSet<QString> usedAttributes( const QgsRenderContext &context ) const override;
57 static QgsFeatureRenderer *create( QDomElement &element, const QgsReadWriteContext &context ) SIP_FACTORY;
58 QDomElement save( QDomDocument &doc, const QgsReadWriteContext &context ) override;
59 static QgsHeatmapRenderer *convertFromRenderer( const QgsFeatureRenderer *renderer ) SIP_FACTORY;
60 bool accept( QgsStyleEntityVisitorInterface *visitor ) const override;
61
62 //reimplemented to extent the request so that points up to heatmap's radius distance outside
63 //visible area are included
64 void modifyRequestExtent( QgsRectangle &extent, QgsRenderContext &context ) override;
65
66 //heatmap specific methods
67
73 QgsColorRamp *colorRamp() const { return mGradientRamp; }
74
80 void setColorRamp( QgsColorRamp *ramp SIP_TRANSFER );
81
89 double radius() const { return mRadius; }
90
98 void setRadius( const double radius ) { mRadius = radius; }
99
107 QgsUnitTypes::RenderUnit radiusUnit() const { return mRadiusUnit; }
108
116 void setRadiusUnit( const QgsUnitTypes::RenderUnit unit ) { mRadiusUnit = unit; }
117
125 const QgsMapUnitScale &radiusMapUnitScale() const { return mRadiusMapUnitScale; }
126
134 void setRadiusMapUnitScale( const QgsMapUnitScale &scale ) { mRadiusMapUnitScale = scale; }
135
142 double maximumValue() const { return mExplicitMax; }
143
150 void setMaximumValue( const double value ) { mExplicitMax = value; }
151
158 double renderQuality() const { return mRenderQuality; }
159
166 void setRenderQuality( const int quality ) { mRenderQuality = quality; }
167
173 QString weightExpression() const { return mWeightExpressionString; }
174
180 void setWeightExpression( const QString &expression ) { mWeightExpressionString = expression; }
181
182 private:
183
184 QVector<double> mValues;
185
186 double mCalculatedMaxValue = 0;
187
188 double mRadius = 10;
189 int mRadiusPixels = 0;
190 double mRadiusSquared = 0;
192 QgsMapUnitScale mRadiusMapUnitScale;
193
194 QString mWeightExpressionString;
195 int mWeightAttrNum = -1;
196 std::unique_ptr<QgsExpression> mWeightExpression;
197
198 QgsColorRamp *mGradientRamp = nullptr;
199
200 double mExplicitMax = 0.0;
201 int mRenderQuality = 3;
202
203 int mFeaturesRendered = 0;
204
205 double uniformKernel( double distance, int bandwidth ) const;
206 double quarticKernel( double distance, int bandwidth ) const;
207 double triweightKernel( double distance, int bandwidth ) const;
208 double epanechnikovKernel( double distance, int bandwidth ) const;
209 double triangularKernel( double distance, int bandwidth ) const;
210
211 QgsMultiPointXY convertToMultipoint( const QgsGeometry *geom );
212 void initializeValues( QgsRenderContext &context );
213 void renderImage( QgsRenderContext &context );
214};
215
216
217#endif // QGSHEATMAPRENDERER_H
Abstract base class for color ramps.
Definition: qgscolorramp.h:30
Custom exception class for Coordinate Reference System related exceptions.
Definition: qgsexception.h:66
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:45
A geometry is the spatial representation of a feature.
Definition: qgsgeometry.h:164
A renderer which draws points as a live heatmap.
QString weightExpression() const
Returns the expression used for weighting points when generating the heatmap.
QgsUnitTypes::RenderUnit radiusUnit() const
Returns the units used for the heatmap's radius.
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.
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.
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.
void setRadiusUnit(const QgsUnitTypes::RenderUnit unit)
Sets the units used for the heatmap's radius.
void setRadiusMapUnitScale(const QgsMapUnitScale &scale)
Sets the map unit scale used for the heatmap's radius.
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.
Definition: qgsrectangle.h:42
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:93
RenderUnit
Rendering size units.
Definition: qgsunittypes.h:168
@ RenderMillimeters
Millimeters.
Definition: qgsunittypes.h:169
#define SIP_TRANSFER
Definition: qgis_sip.h:36
#define SIP_FACTORY
Definition: qgis_sip.h:76
#define SIP_THROW(name,...)
Definition: qgis_sip.h:198
QVector< QgsPointXY > QgsMultiPointXY
A collection of QgsPoints that share a common collection of attributes.
Definition: qgsgeometry.h:82
QList< QgsSymbol * > QgsSymbolList
Definition: qgsrenderer.h:44