qgsvectorlayerlabelprovider.h

Go to the documentation of this file.

/***************************************************************************
  qgsvectorlayerlabelprovider.h
  --------------------------------------
  Date                 : September 2015
  Copyright            : (C) 2015 by Martin Dobias
  Email                : wonder dot sk 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 QGSVECTORLAYERLABELPROVIDER_H
#define QGSVECTORLAYERLABELPROVIDER_H
 
 
#include "qgis_core.h"
#include "qgslabelingengine.h"
#include "qgspallabeling.h"
#include "qgsrenderer.h"
 
#define SIP_NO_FILE
 
class QgsAbstractFeatureSource;
class QgsFeatureRenderer;
class QgsSymbol;

class CORE_EXPORT QgsVectorLayerLabelProvider : public QgsAbstractLabelProvider
{
  public:

    explicit QgsVectorLayerLabelProvider( QgsVectorLayer *layer,
                                          const QString &providerId,
                                          bool withFeatureLoop,
                                          const QgsPalLayerSettings *settings,
                                          const QString &layerName = QString() );

    explicit QgsVectorLayerLabelProvider( Qgis::GeometryType geometryType,
                                          const QgsFields &fields,
                                          const QgsCoordinateReferenceSystem &crs,
                                          const QString &providerId,
                                          const QgsPalLayerSettings *settings,
                                          QgsMapLayer *layer,
                                          const QString &layerName = QString() );
 
    ~QgsVectorLayerLabelProvider() override;
 
    QList<QgsLabelFeature *> labelFeatures( QgsRenderContext &context ) override;
 
    void drawLabelBackground( QgsRenderContext &context, pal::LabelPosition *label ) const override;
    void drawLabel( QgsRenderContext &context, pal::LabelPosition *label ) const override;
    void drawUnplacedLabel( QgsRenderContext &context, pal::LabelPosition *label ) const override;
    void startRender( QgsRenderContext &context ) override;
    void stopRender( QgsRenderContext &context ) override;
 
    // new virtual methods

    virtual bool prepare( QgsRenderContext &context, QSet<QString> &attributeNames );

    virtual QList< QgsLabelFeature * > registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry(), const QgsSymbol *symbol = nullptr );

    static QgsGeometry getPointObstacleGeometry( QgsFeature &fet, QgsRenderContext &context, const QgsSymbolList &symbols );

    const QgsPalLayerSettings &settings() const;

    void setFields( const QgsFields &fields );
 
  protected:
    void init();
    void drawLabelPrivate( pal::LabelPosition *label, QgsRenderContext &context, QgsPalLayerSettings &tmpLyr, Qgis::TextComponent drawType, double dpiRatio = 1.0 ) const;
 
  protected:
    QgsPalLayerSettings mSettings;
    Qgis::GeometryType mLayerGeometryType;
 
    QgsFeatureRenderer *mRenderer = nullptr;
 
    // these are needed only if using own renderer loop

    QgsFields mFields;
    QgsCoordinateReferenceSystem mCrs;
    std::unique_ptr<QgsAbstractFeatureSource> mSource;

    QList<QgsLabelFeature *> mLabels;
 
  private:
 
    friend class TestQgsLabelingEngine;
    friend class QgsVectorTileBasicLabelProvider;
 
    void drawCallout( QgsRenderContext &context, pal::LabelPosition *label ) const;
};
 
#endif // QGSVECTORLAYERLABELPROVIDER_H