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       1                 :            : /***************************************************************************
       2                 :            :   qgsvectorlayerlabelprovider.h
       3                 :            :   --------------------------------------
       4                 :            :   Date                 : September 2015
       5                 :            :   Copyright            : (C) 2015 by Martin Dobias
       6                 :            :   Email                : wonder dot sk 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                 :            : 
      16                 :            : #ifndef QGSVECTORLAYERLABELPROVIDER_H
      17                 :            : #define QGSVECTORLAYERLABELPROVIDER_H
      18                 :            : 
      19                 :            : #define SIP_NO_FILE
      20                 :            : 
      21                 :            : #include "qgis_core.h"
      22                 :            : #include "qgslabelingengine.h"
      23                 :            : #include "qgsrenderer.h"
      24                 :            : #include "qgstextrenderer.h"
      25                 :            : 
      26                 :            : class QgsAbstractFeatureSource;
      27                 :            : class QgsFeatureRenderer;
      28                 :            : class QgsSymbol;
      29                 :            : 
      30                 :            : /**
      31                 :            :  * \ingroup core
      32                 :            :  * \brief The QgsVectorLayerLabelProvider class implements a label provider
      33                 :            :  * for vector layers. Parameters for the labeling are taken from the layer's
      34                 :            :  * custom properties or from the given settings.
      35                 :            :  *
      36                 :            :  * \note this class is not a part of public API yet. See notes in QgsLabelingEngine
      37                 :            :  * \note not available in Python bindings
      38                 :            :  * \since QGIS 2.12
      39                 :            :  */
      40                 :            : class CORE_EXPORT QgsVectorLayerLabelProvider : public QgsAbstractLabelProvider
      41                 :            : {
      42                 :            :   public:
      43                 :            : 
      44                 :            :     //! Convenience constructor to initialize the provider from given vector layer
      45                 :            :     explicit QgsVectorLayerLabelProvider( QgsVectorLayer *layer,
      46                 :            :                                           const QString &providerId,
      47                 :            :                                           bool withFeatureLoop,
      48                 :            :                                           const QgsPalLayerSettings *settings,
      49                 :            :                                           const QString &layerName = QString() );
      50                 :            : 
      51                 :            :     //! Constructor to initialize the provider from any map layer (e.g. vector tile layer)
      52                 :            :     explicit QgsVectorLayerLabelProvider( QgsWkbTypes::GeometryType geometryType,
      53                 :            :                                           const QgsFields &fields,
      54                 :            :                                           const QgsCoordinateReferenceSystem &crs,
      55                 :            :                                           const QString &providerId,
      56                 :            :                                           const QgsPalLayerSettings *settings,
      57                 :            :                                           QgsMapLayer *layer,
      58                 :            :                                           const QString &layerName = QString() );
      59                 :            : 
      60                 :            :     ~QgsVectorLayerLabelProvider() override;
      61                 :            : 
      62                 :            :     QList<QgsLabelFeature *> labelFeatures( QgsRenderContext &context ) override;
      63                 :            : 
      64                 :            :     void drawLabelBackground( QgsRenderContext &context, pal::LabelPosition *label ) const override;
      65                 :            :     void drawLabel( QgsRenderContext &context, pal::LabelPosition *label ) const override;
      66                 :            :     void drawUnplacedLabel( QgsRenderContext &context, pal::LabelPosition *label ) const override;
      67                 :            :     void startRender( QgsRenderContext &context ) override;
      68                 :            :     void stopRender( QgsRenderContext &context ) override;
      69                 :            : 
      70                 :            :     // new virtual methods
      71                 :            : 
      72                 :            :     /**
      73                 :            :      * Prepare for registration of features. Must be called after provider has been added to engine (uses its map settings)
      74                 :            :      * \param context render context.
      75                 :            :      * \param attributeNames list of attribute names to which additional required attributes shall be added
      76                 :            :      * \returns Whether the preparation was successful - if not, the provider shall not be used
      77                 :            :      */
      78                 :            :     virtual bool prepare( QgsRenderContext &context, QSet<QString> &attributeNames );
      79                 :            : 
      80                 :            :     /**
      81                 :            :      * Register a feature for labeling as one or more QgsLabelFeature objects stored into mLabels
      82                 :            :      *
      83                 :            :      * \param feature feature to label
      84                 :            :      * \param context render context. The QgsExpressionContext contained within the render context
      85                 :            :      * must have already had the feature and fields sets prior to calling this method.
      86                 :            :      * \param obstacleGeometry optional obstacle geometry, if a different geometry to the feature's geometry
      87                 :            :      * should be used as an obstacle for labels (e.g., if the feature has been rendered with an offset point
      88                 :            :      * symbol, the obstacle geometry should represent the bounds of the offset symbol). If not set,
      89                 :            :      * the feature's original geometry will be used as an obstacle for labels.
      90                 :            :      * \param symbol feature symbol to label (ownership is not transferred - the symbol must exist until after labeling is complete)
      91                 :            :      */
      92                 :            :     virtual void registerFeature( const QgsFeature &feature, QgsRenderContext &context, const QgsGeometry &obstacleGeometry = QgsGeometry(), const QgsSymbol *symbol = nullptr );
      93                 :            : 
      94                 :            :     /**
      95                 :            :      * Returns the geometry for a point feature which should be used as an obstacle for labels. This
      96                 :            :      * obstacle geometry will respect the dimensions and offsets of the symbol used to render the
      97                 :            :      * point, and ensures that labels will not overlap large or offset points.
      98                 :            :      * \param fet point feature
      99                 :            :      * \param context render context
     100                 :            :      * \param symbols symbols rendered for point feature
     101                 :            :      * \since QGIS 2.14
     102                 :            :      */
     103                 :            :     static QgsGeometry getPointObstacleGeometry( QgsFeature &fet, QgsRenderContext &context, const QgsSymbolList &symbols );
     104                 :            : 
     105                 :            :     /**
     106                 :            :      * Returns the layer's settings.
     107                 :            :      * \since QGIS 3.10
     108                 :            :      */
     109                 :            :     const QgsPalLayerSettings &settings() const;
     110                 :            : 
     111                 :            :     /**
     112                 :            :      * Sets fields of this label provider. Normally this is not needed, but when used for vector tiles,
     113                 :            :      * fields are not known at the time of creation of label providers. It should be called before
     114                 :            :      * a call to prepare() which uses the list of fields.
     115                 :            :      * \since QGIS 3.14
     116                 :            :      */
     117                 :          0 :     void setFields( const QgsFields &fields ) { mFields = fields; }
     118                 :            : 
     119                 :            :   protected:
     120                 :            :     //! initialization method - called from constructors
     121                 :            :     void init();
     122                 :            :     //! Internal label drawing method
     123                 :            :     void drawLabelPrivate( pal::LabelPosition *label, QgsRenderContext &context, QgsPalLayerSettings &tmpLyr, QgsTextRenderer::TextPart drawType, double dpiRatio = 1.0 ) const;
     124                 :            : 
     125                 :            :   protected:
     126                 :            :     //! Layer's labeling configuration
     127                 :            :     QgsPalLayerSettings mSettings;
     128                 :            :     //! Geometry type of layer
     129                 :            :     QgsWkbTypes::GeometryType mLayerGeometryType;
     130                 :            : 
     131                 :            :     QgsFeatureRenderer *mRenderer = nullptr;
     132                 :            : 
     133                 :            :     // these are needed only if using own renderer loop
     134                 :            : 
     135                 :            :     //! Layer's fields
     136                 :            :     QgsFields mFields;
     137                 :            :     //! Layer's CRS
     138                 :            :     QgsCoordinateReferenceSystem mCrs;
     139                 :            :     //! Layer's feature source
     140                 :            :     std::unique_ptr<QgsAbstractFeatureSource> mSource;
     141                 :            : 
     142                 :            :     //! List of generated
     143                 :            :     QList<QgsLabelFeature *> mLabels;
     144                 :            : 
     145                 :            :   private:
     146                 :            : 
     147                 :            :     friend class TestQgsLabelingEngine;
     148                 :            :     void drawCallout( QgsRenderContext &context, pal::LabelPosition *label ) const;
     149                 :            : };
     150                 :            : 
     151                 :            : #endif // QGSVECTORLAYERLABELPROVIDER_H