27#include <QDomDocument>
43 mValues.resize( context.
painter()->device()->width() * context.
painter()->device()->height() / ( mRenderQuality * mRenderQuality ) );
45 mCalculatedMaxValue = 0;
46 mFeaturesRendered = 0;
47 mRadiusPixels = std::round( context.
convertToPainterUnits( mRadius, mRadiusUnit, mRadiusMapUnitScale ) / mRenderQuality );
48 mRadiusSquared = mRadiusPixels * mRadiusPixels;
61 mWeightAttrNum = fields.
lookupField( mWeightExpressionString );
62 if ( mWeightAttrNum == -1 )
64 mWeightExpression.reset(
new QgsExpression( mWeightExpressionString ) );
68 initializeValues( context );
90 Q_UNUSED( drawVertexMarker )
104 if ( !mWeightExpressionString.isEmpty() )
107 if ( mWeightAttrNum == -1 )
109 Q_ASSERT( mWeightExpression.get() );
115 value = attrs.value( mWeightAttrNum );
118 const double evalWeight = value.toDouble( &ok );
125 const int width = context.
painter()->device()->width() / mRenderQuality;
126 const int height = context.
painter()->device()->height() / mRenderQuality;
140 for ( QgsMultiPointXY::const_iterator pointIt = multiPoint.constBegin(); pointIt != multiPoint.constEnd(); ++pointIt )
143 const int pointX = pixel.
x() / mRenderQuality;
144 const int pointY = pixel.
y() / mRenderQuality;
145 for (
int x = std::max( pointX - mRadiusPixels, 0 ); x < std::min( pointX + mRadiusPixels, width ); ++x )
150 for (
int y = std::max( pointY - mRadiusPixels, 0 ); y < std::min( pointY + mRadiusPixels, height ); ++y )
152 const int index = y * width + x;
153 if ( index >= mValues.count() )
157 const double distanceSquared = std::pow( pointX - x, 2.0 ) + std::pow( pointY - y, 2.0 );
158 if ( distanceSquared > mRadiusSquared )
163 const double score = weight * quarticKernel( std::sqrt( distanceSquared ), mRadiusPixels );
164 const double value = mValues.at( index ) + score;
165 if ( value > mCalculatedMaxValue )
167 mCalculatedMaxValue = value;
169 mValues[ index ] = value;
177 if ( mFeaturesRendered % 200 == 0 )
179 renderImage( context );
186double QgsHeatmapRenderer::uniformKernel(
const double distance,
const int bandwidth )
const
189 Q_UNUSED( bandwidth )
193double QgsHeatmapRenderer::quarticKernel(
const double distance,
const int bandwidth )
const
195 return std::pow( 1. - std::pow( distance /
static_cast< double >( bandwidth ), 2 ), 2 );
198double QgsHeatmapRenderer::triweightKernel(
const double distance,
const int bandwidth )
const
200 return std::pow( 1. - std::pow( distance /
static_cast< double >( bandwidth ), 2 ), 3 );
203double QgsHeatmapRenderer::epanechnikovKernel(
const double distance,
const int bandwidth )
const
205 return ( 1. - std::pow( distance /
static_cast< double >( bandwidth ), 2 ) );
208double QgsHeatmapRenderer::triangularKernel(
const double distance,
const int bandwidth )
const
210 return ( 1. - ( distance /
static_cast< double >( bandwidth ) ) );
217 renderImage( context );
218 mWeightExpression.reset();
228 QImage image( context.
painter()->device()->width() / mRenderQuality,
229 context.
painter()->device()->height() / mRenderQuality,
230 QImage::Format_ARGB32 );
231 image.fill( Qt::transparent );
233 const double scaleMax = mExplicitMax > 0 ? mExplicitMax : mCalculatedMaxValue;
238 for (
int heightIndex = 0; heightIndex < image.height(); ++heightIndex )
243 QRgb *scanLine =
reinterpret_cast< QRgb *
>( image.scanLine( heightIndex ) );
244 for (
int widthIndex = 0; widthIndex < image.width(); ++widthIndex )
247 pixVal = mValues.at( idx ) > 0 ? std::min( ( mValues.at( idx ) / scaleMax ), 1.0 ) : 0;
250 pixColor = mGradientRamp->
color( pixVal );
252 scanLine[widthIndex] = pixColor.rgba();
257 if ( mRenderQuality > 1 )
259 const QImage resized = image.scaled( context.
painter()->device()->width(),
260 context.
painter()->device()->height() );
261 context.
painter()->drawImage( 0, 0, resized );
265 context.
painter()->drawImage( 0, 0, image );
271 return QStringLiteral(
"[HEATMAP]" );
296 const double extension = context.
convertToMapUnits( mRadius, mRadiusUnit, mRadiusMapUnitScale );
307 r->
setRadius( element.attribute( QStringLiteral(
"radius" ), QStringLiteral(
"50.0" ) ).toFloat() );
310 r->
setMaximumValue( element.attribute( QStringLiteral(
"max_value" ), QStringLiteral(
"0.0" ) ).toFloat() );
311 r->
setRenderQuality( element.attribute( QStringLiteral(
"quality" ), QStringLiteral(
"0" ) ).toInt() );
314 QDomElement sourceColorRampElem = element.firstChildElement( QStringLiteral(
"colorramp" ) );
315 if ( !sourceColorRampElem.isNull() && sourceColorRampElem.attribute( QStringLiteral(
"name" ) ) == QLatin1String(
"[source]" ) )
326 rendererElem.setAttribute( QStringLiteral(
"type" ), QStringLiteral(
"heatmapRenderer" ) );
327 rendererElem.setAttribute( QStringLiteral(
"radius" ), QString::number( mRadius ) );
328 rendererElem.setAttribute( QStringLiteral(
"radius_unit" ), QString::number(
static_cast< int >( mRadiusUnit ) ) );
330 rendererElem.setAttribute( QStringLiteral(
"max_value" ), QString::number( mExplicitMax ) );
331 rendererElem.setAttribute( QStringLiteral(
"quality" ), QString::number( mRenderQuality ) );
332 rendererElem.setAttribute( QStringLiteral(
"weight_expression" ), mWeightExpressionString );
337 rendererElem.appendChild( colorRampElem );
358 QSet<QString> attributes;
364 attributes << mWeightExpressionString;
375 if ( renderer->
type() == QLatin1String(
"heatmapRenderer" ) )
381 std::unique_ptr< QgsHeatmapRenderer > res = std::make_unique< QgsHeatmapRenderer >();
383 return res.release();
400 delete mGradientRamp;
401 mGradientRamp = ramp;
RenderUnit
Rendering size units.
Abstract base class for color ramps.
virtual QColor color(double value) const =0
Returns the color corresponding to a specified value.
virtual QgsColorRamp * clone() const =0
Creates a clone of the color ramp.
Class for parsing and evaluation of expressions (formerly called "search strings").
bool hasParserError() const
Returns true if an error occurred when parsing the input expression.
QSet< QString > referencedColumns() const
Gets list of columns referenced by the expression.
virtual void stopRender(QgsRenderContext &context)
Must be called when a render cycle has finished, to allow the renderer to clean up.
void copyRendererData(QgsFeatureRenderer *destRenderer) const
Clones generic renderer data to another renderer.
void saveRendererData(QDomDocument &doc, QDomElement &element, const QgsReadWriteContext &context)
Saves generic renderer data into the specified element.
virtual void startRender(QgsRenderContext &context, const QgsFields &fields)
Must be called when a new render cycle is started.
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...
bool hasGeometry() const
Returns true if the feature has an associated geometry.
Container of fields for a vector layer.
int lookupField(const QString &fieldName) const
Looks up field's index from the field name.
A geometry is the spatial representation of a feature.
Qgis::GeometryOperationResult transform(const QgsCoordinateTransform &ct, Qgis::TransformDirection direction=Qgis::TransformDirection::Forward, bool transformZ=false)
Transforms this geometry as described by the coordinate transform ct.
QgsMultiPointXY asMultiPoint() const
Returns the contents of the geometry as a multi-point.
QgsPointXY asPoint() const
Returns the contents of the geometry as a 2-dimensional point.
bool isMultipart() const
Returns true if WKB of the geometry is of WKBMulti* type.
Gradient color ramp, which smoothly interpolates between two colors and also supports optional extra ...
A renderer which draws points as a live heatmap.
void setColorRamp(QgsColorRamp *ramp)
Sets the color ramp to use for shading the heatmap.
QgsSymbol * symbolForFeature(const QgsFeature &feature, QgsRenderContext &context) const override
void modifyRequestExtent(QgsRectangle &extent, QgsRenderContext &context) override
Allows for a renderer to modify the extent of a feature request prior to rendering.
void startRender(QgsRenderContext &context, const QgsFields &fields) override
Must be called when a new render cycle is started.
QSet< QString > usedAttributes(const QgsRenderContext &context) const override
Returns a list of attributes required by this renderer.
void setRadius(const double radius)
Sets the radius for the heatmap.
void setRadiusUnit(const Qgis::RenderUnit unit)
Sets the units used for the heatmap's radius.
static QgsFeatureRenderer * create(QDomElement &element, const QgsReadWriteContext &context)
Creates a new heatmap renderer instance from XML.
void setRenderQuality(const int quality)
Sets the render quality used for drawing the heatmap.
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.
~QgsHeatmapRenderer() override
static QgsHeatmapRenderer * convertFromRenderer(const QgsFeatureRenderer *renderer)
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.
void stopRender(QgsRenderContext &context) override
Must be called when a render cycle has finished, to allow the renderer to clean up.
QString dump() const override
Returns debug information about this renderer.
QDomElement save(QDomDocument &doc, const QgsReadWriteContext &context) override
Stores renderer properties to an XML element.
QgsHeatmapRenderer * clone() const override
Create a deep copy of this renderer.
bool accept(QgsStyleEntityVisitorInterface *visitor) const override
Accepts the specified symbology visitor, causing it to visit all symbols associated with the renderer...
void setRadiusMapUnitScale(const QgsMapUnitScale &scale)
Sets the map unit scale used for the heatmap's radius.
QgsSymbolList symbols(QgsRenderContext &context) const override
QgsPointXY transform(const QgsPointXY &p) const
Transforms a point p from map (world) coordinates to device coordinates.
A class to represent a 2D point.
The class is used as a container of context for various read/write operations on other objects.
A rectangle specified with double values.
double xMinimum() const
Returns the x minimum value (left side of rectangle).
void setYMinimum(double y)
Set the minimum y value.
double yMinimum() const
Returns the y minimum value (bottom side of rectangle).
void setXMinimum(double x)
Set the minimum x value.
double xMaximum() const
Returns the x maximum value (right side of rectangle).
double yMaximum() const
Returns the y maximum value (top side of rectangle).
void setYMaximum(double y)
Set the maximum y value.
void setXMaximum(double x)
Set the maximum x value.
Contains information about the context of a rendering operation.
double convertToMapUnits(double size, Qgis::RenderUnit unit, const QgsMapUnitScale &scale=QgsMapUnitScale()) const
Converts a size from the specified units to map units.
double convertToPainterUnits(double size, Qgis::RenderUnit unit, const QgsMapUnitScale &scale=QgsMapUnitScale(), Qgis::RenderSubcomponentProperty property=Qgis::RenderSubcomponentProperty::Generic) const
Converts a size from the specified units to painter units (pixels).
QPainter * painter()
Returns the destination QPainter for the render operation.
QgsExpressionContext & expressionContext()
Gets the expression context.
const QgsMapToPixel & mapToPixel() const
Returns the context's map to pixel transform, which transforms between map coordinates and device coo...
bool renderingStopped() const
Returns true if the rendering operation has been stopped and any ongoing rendering should be canceled...
QgsCoordinateTransform coordinateTransform() const
Returns the current coordinate transform for the context.
A color ramp entity for QgsStyle databases.
An interface for classes which can visit style entity (e.g.
virtual bool visit(const QgsStyleEntityVisitorInterface::StyleLeaf &entity)
Called when the visitor will visit a style entity.
static QString encodeMapUnitScale(const QgsMapUnitScale &mapUnitScale)
static QgsColorRamp * loadColorRamp(QDomElement &element)
Creates a color ramp from the settings encoded in an XML element.
static QgsMapUnitScale decodeMapUnitScale(const QString &str)
static QDomElement saveColorRamp(const QString &name, QgsColorRamp *ramp, QDomDocument &doc)
Encodes a color ramp's settings to an XML element.
Abstract base class for all rendered symbols.
QVector< QgsPointXY > QgsMultiPointXY
A collection of QgsPoints that share a common collection of attributes.
#define RENDERER_TAG_NAME
QList< QgsSymbol * > QgsSymbolList
Contains information relating to the style entity currently being visited.