qgsmergedfeaturerenderer.h

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/***************************************************************************
    qgsmergedfeaturerenderer.h
    ---------------------
    begin                : December 2020
    copyright            : (C) 2020 by Nyall Dawson
    email                : nyall dot dawson at gmail dot com
 ***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/
#ifndef QGSMERGEDFEATURERENDERER_H
#define QGSMERGEDFEATURERENDERER_H
 
#include "qgis.h"
#include "qgis_core.h"
#include "qgis_sip.h"
#include "qgsexpression.h"
#include "qgsfeature.h"
#include "qgsgeometry.h"
#include "qgsrendercontext.h"
#include "qgsrenderer.h"

class CORE_EXPORT QgsMergedFeatureRenderer : public QgsFeatureRenderer
{
  public:
    QgsMergedFeatureRenderer( QgsFeatureRenderer *embeddedRenderer SIP_TRANSFER );

    QgsMergedFeatureRenderer( const QgsMergedFeatureRenderer & ) = delete;
    QgsMergedFeatureRenderer &operator=( const QgsMergedFeatureRenderer & ) = delete;

    static std::unique_ptr<QgsFeatureRenderer> create( QDomElement &element, const QgsReadWriteContext &context );
 
    QgsMergedFeatureRenderer *clone() const override SIP_FACTORY;
    void startRender( QgsRenderContext &context, const QgsFields &fields ) override;
    Qgis::FeatureRendererFlags flags() const override;

    bool renderFeature( const QgsFeature &feature, QgsRenderContext &context, int layer = -1, bool selected = false, bool drawVertexMarker = false ) override SIP_THROW( QgsCsException );

    void stopRender( QgsRenderContext &context ) override;
 
    QString dump() const override;
    QSet<QString> usedAttributes( const QgsRenderContext &context ) const override;
    bool filterNeedsGeometry() const override;
    QgsFeatureRenderer::Capabilities capabilities() override;
    QgsSymbolList symbols( QgsRenderContext &context ) const override;
    QgsSymbol *symbolForFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
    QgsSymbol *originalSymbolForFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
    QgsSymbolList symbolsForFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
    QgsSymbolList originalSymbolsForFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
    QSet< QString > legendKeysForFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
    QString legendKeyToExpression( const QString &key, QgsVectorLayer *layer, bool &ok ) const override;
    QgsLegendSymbolList legendSymbolItems() const override;
    bool willRenderFeature( const QgsFeature &feature, QgsRenderContext &context ) const override;
    QDomElement save( QDomDocument &doc, const QgsReadWriteContext &context ) override;
    void setEmbeddedRenderer( QgsFeatureRenderer *subRenderer SIP_TRANSFER ) override;
    const QgsFeatureRenderer *embeddedRenderer() const override;
    void setLegendSymbolItem( const QString &key, QgsSymbol *symbol ) override;
    bool legendSymbolItemsCheckable() const override;
    bool legendSymbolItemChecked( const QString &key ) override;
    void checkLegendSymbolItem( const QString &key, bool state = true ) override;
    bool accept( QgsStyleEntityVisitorInterface *visitor ) const override;

    static std::unique_ptr<QgsMergedFeatureRenderer> convertFromRenderer( const QgsFeatureRenderer *renderer );
 
  protected:
    QgsMergedFeatureRenderer( const QString &type, QgsFeatureRenderer *embeddedRenderer SIP_TRANSFER );

    enum GeometryOperation
    {
      Merge,          
      InvertOnly,     
      MergeAndInvert, 
    };

    GeometryOperation mOperation = Merge;

    std::unique_ptr<QgsFeatureRenderer> mSubRenderer;
 
  private:
    struct CombinedFeature
    {
        QVector<QgsGeometry> geometries; //< list of geometries
        QgsFeature feature;              //< one feature (for attriute-based rendering)
    };
    typedef QVector<CombinedFeature> FeatureCategoryVector;
    FeatureCategoryVector mFeaturesCategories;

    QMap<QByteArray, int> mSymbolCategories;

    QgsPolygonXY mExtentPolygon;

    QgsRenderContext mContext;

    QgsFields mFields;

    struct FeatureDecoration
    {
        QgsFeature feature;
        bool selected;
        bool drawMarkers;
        int layer;
        FeatureDecoration( const QgsFeature &a_feature, bool a_selected, bool a_drawMarkers, int a_layer )
          : feature( a_feature )
          , selected( a_selected )
          , drawMarkers( a_drawMarkers )
          , layer( a_layer )
        {}
    };
    QList<FeatureDecoration> mFeatureDecorations;
};
 
 
#endif // QGSMERGEDFEATURERENDERER_H