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       1                 :            : /***************************************************************************
       2                 :            :   qgssnappingutils.h
       3                 :            :   --------------------------------------
       4                 :            :   Date                 : November 2014
       5                 :            :   Copyright            : (C) 2014 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 QGSSNAPPINGUTILS_H
      17                 :            : #define QGSSNAPPINGUTILS_H
      18                 :            : 
      19                 :            : 
      20                 :            : #include "qgis_core.h"
      21                 :            : #include "qgis_sip.h"
      22                 :            : #include "qgsmapsettings.h"
      23                 :            : #include "qgstolerance.h"
      24                 :            : #include "qgspointlocator.h"
      25                 :            : #include "qgssnappingconfig.h"
      26                 :            : 
      27                 :            : class QgsSnappingConfig;
      28                 :            : 
      29                 :            : /**
      30                 :            :  * \ingroup core
      31                 :            :  * \brief This class has all the configuration of snapping and can return answers to snapping queries.
      32                 :            :  *
      33                 :            :  * Internally, it keeps a cache of QgsPointLocator instances for multiple layers.
      34                 :            :  *
      35                 :            :  * Currently it supports the following queries:
      36                 :            :  *
      37                 :            :  * - snapToMap() - has multiple modes of operation
      38                 :            :  * - snapToCurrentLayer()
      39                 :            :  *
      40                 :            :  * For more complex queries it is possible to use locatorForLayer() method that returns
      41                 :            :  * point locator instance with layer's indexed data.
      42                 :            :  *
      43                 :            :  * Indexing strategy determines how fast the queries will be and how much memory will be used.
      44                 :            :  *
      45                 :            :  * When working with map canvas, it may be useful to use derived class QgsMapCanvasSnappingUtils
      46                 :            :  * which keeps the configuration in sync with map canvas (e.g. current view, active layer).
      47                 :            :  *
      48                 :            :  * \since QGIS 2.8
      49                 :            :  */
      50                 :            : class CORE_EXPORT QgsSnappingUtils : public QObject
      51                 :            : {
      52                 :            :     Q_OBJECT
      53                 :            : 
      54                 :            :     Q_PROPERTY( QgsSnappingConfig config READ config WRITE setConfig NOTIFY configChanged )
      55                 :            : 
      56                 :            :   public:
      57                 :            : 
      58                 :            :     /**
      59                 :            :      * Constructor for QgsSnappingUtils
      60                 :            :      * \param parent parent object
      61                 :            :      * \param enableSnappingForInvisibleFeature TRUE if we want to snap feature even if there are not visible
      62                 :            :      */
      63                 :            :     QgsSnappingUtils( QObject *parent SIP_TRANSFERTHIS = nullptr, bool enableSnappingForInvisibleFeature = true );
      64                 :            :     ~QgsSnappingUtils() override;
      65                 :            : 
      66                 :            :     // main actions
      67                 :            : 
      68                 :            :     /**
      69                 :            :      * Gets a point locator for the given layer. If such locator does not exist, it will be created
      70                 :            :      * \param vl the vector layer
      71                 :            :      */
      72                 :            :     QgsPointLocator *locatorForLayer( QgsVectorLayer *vl );
      73                 :            : 
      74                 :            :     /**
      75                 :            :      * Snap to map according to the current configuration.
      76                 :            :      * \param point point in canvas coordinates
      77                 :            :      * \param filter allows discarding unwanted matches.
      78                 :            :      * \param relaxed TRUE if this method is non blocking and the matching result can be invalid while indexing
      79                 :            :      */
      80                 :            :     QgsPointLocator::Match snapToMap( QPoint point, QgsPointLocator::MatchFilter *filter = nullptr, bool relaxed = false );
      81                 :            : 
      82                 :            :     /**
      83                 :            :      * Snap to map according to the current configuration.
      84                 :            :      * \param pointMap point in map coordinates
      85                 :            :      * \param filter allows discarding unwanted matches.
      86                 :            :      * \param relaxed TRUE if this method is non blocking and the matching result can be invalid while indexing
      87                 :            :      */
      88                 :            :     QgsPointLocator::Match snapToMap( const QgsPointXY &pointMap, QgsPointLocator::MatchFilter *filter = nullptr, bool relaxed = false );
      89                 :            : 
      90                 :            :     //! Snap to current layer
      91                 :            :     QgsPointLocator::Match snapToCurrentLayer( QPoint point, QgsPointLocator::Types type, QgsPointLocator::MatchFilter *filter = nullptr );
      92                 :            : 
      93                 :            :     // environment setup
      94                 :            : 
      95                 :            :     //! Assign current map settings to the utils - used for conversion between screen coords to map coords
      96                 :            :     void setMapSettings( const QgsMapSettings &settings );
      97                 :            :     QgsMapSettings mapSettings() const { return mMapSettings; }
      98                 :            : 
      99                 :            :     //! Sets current layer so that if mode is SnapCurrentLayer we know which layer to use
     100                 :            :     void setCurrentLayer( QgsVectorLayer *layer );
     101                 :            :     //! The current layer used if mode is SnapCurrentLayer
     102                 :            :     QgsVectorLayer *currentLayer() const { return mCurrentLayer; }
     103                 :            : 
     104                 :            :     // configuration
     105                 :            : 
     106                 :            :     enum IndexingStrategy
     107                 :            :     {
     108                 :            :       IndexAlwaysFull,    //!< For all layers build index of full extent. Uses more memory, but queries are faster.
     109                 :            :       IndexNeverFull,     //!< For all layers only create temporary indexes of small extent. Low memory usage, slower queries.
     110                 :            :       IndexHybrid,        //!< For "big" layers using IndexNeverFull, for the rest IndexAlwaysFull. Compromise between speed and memory usage.
     111                 :            :       IndexExtent         //!< For all layer build index of extent given in map settings
     112                 :            :     };
     113                 :            : 
     114                 :            :     //! Sets a strategy for indexing geometry data - determines how fast and memory consuming the data structures will be
     115                 :            :     void setIndexingStrategy( IndexingStrategy strategy ) { mStrategy = strategy; }
     116                 :            :     //! Find out which strategy is used for indexing - by default hybrid indexing is used
     117                 :            :     IndexingStrategy indexingStrategy() const { return mStrategy; }
     118                 :            : 
     119                 :            :     /**
     120                 :            :      * Configures how a certain layer should be handled in a snapping operation
     121                 :            :      */
     122                 :            :     struct LayerConfig
     123                 :            :     {
     124                 :            : 
     125                 :            :       /**
     126                 :            :        * Create a new configuration for a snapping layer.
     127                 :            :        *
     128                 :            :        * \code{.py}
     129                 :            :        * snapper = QgsMapCanvasSnappingUtils(mapCanvas)
     130                 :            :        *
     131                 :            :        * snapping_layer1 = QgsSnappingUtils.LayerConfig(layer1, QgsPointLocator.Vertex, 10, QgsTolerance.Pixels)
     132                 :            :        * snapping_layer2 = QgsSnappingUtils.LayerConfig(layer2, QgsPointLocator.Vertex and QgsPointLocator.Edge, 10, QgsTolerance.Pixels)
     133                 :            :        *
     134                 :            :        * snapper.setLayers([snapping_layer1, snapping_layer2])
     135                 :            :        * \endcode
     136                 :            :        *
     137                 :            :        * \param l   The vector layer for which this configuration is
     138                 :            :        * \param t   Which parts of the geometry should be snappable
     139                 :            :        * \param tol The tolerance radius in which the snapping will trigger
     140                 :            :        * \param u   The unit in which the tolerance is specified
     141                 :            :        */
     142                 :          0 :       LayerConfig( QgsVectorLayer *l, QgsPointLocator::Types t, double tol, QgsTolerance::UnitType u )
     143                 :          0 :         : layer( l )
     144                 :          0 :         , type( t )
     145                 :          0 :         , tolerance( tol )
     146                 :          0 :         , unit( u )
     147                 :          0 :       {}
     148                 :            : 
     149                 :            :       bool operator==( const QgsSnappingUtils::LayerConfig &other ) const
     150                 :            :       {
     151                 :            :         return layer == other.layer && type == other.type && tolerance == other.tolerance && unit == other.unit;
     152                 :            :       }
     153                 :            :       bool operator!=( const QgsSnappingUtils::LayerConfig &other ) const
     154                 :            :       {
     155                 :            :         return !operator==( other );
     156                 :            :       }
     157                 :            : 
     158                 :            :       //! The layer to configure.
     159                 :            :       QgsVectorLayer *layer = nullptr;
     160                 :            :       //! To which geometry properties of this layers a snapping should happen.
     161                 :            :       QgsPointLocator::Types type;
     162                 :            :       //! The range around snapping targets in which snapping should occur.
     163                 :            :       double tolerance;
     164                 :            :       //! The units in which the tolerance is specified.
     165                 :            :       QgsTolerance::UnitType unit;
     166                 :            :     };
     167                 :            : 
     168                 :            :     //! Query layers used for snapping
     169                 :            :     QList<QgsSnappingUtils::LayerConfig> layers() const { return mLayers; }
     170                 :            : 
     171                 :            :     /**
     172                 :            :      * Gets extra information about the instance
     173                 :            :      * \since QGIS 2.14
     174                 :            :      */
     175                 :            :     QString dump();
     176                 :            : 
     177                 :            :     /**
     178                 :            :      * The snapping configuration controls the behavior of this object
     179                 :            :      */
     180                 :            :     QgsSnappingConfig config() const;
     181                 :            : 
     182                 :            :     /**
     183                 :            :      * Set if invisible features must be snapped or not.
     184                 :            :      *
     185                 :            :      * \param enable Enable or not this feature
     186                 :            :      *
     187                 :            :      * \since QGIS 3.2
     188                 :            :      */
     189                 :            :     void setEnableSnappingForInvisibleFeature( bool enable );
     190                 :            : 
     191                 :            :     /**
     192                 :            :      * Supply an extra snapping layer (typically a memory layer).
     193                 :            :      * This can be used by map tools to provide additional
     194                 :            :      * snappings points.
     195                 :            :      *
     196                 :            :      * \see removeExtraSnapLayer()
     197                 :            :      * \see getExtraSnapLayers()
     198                 :            :      *
     199                 :            :      * \since QGIS 3.14
     200                 :            :      */
     201                 :            :     void addExtraSnapLayer( QgsVectorLayer *vl )
     202                 :            :     {
     203                 :            :       mExtraSnapLayers.insert( vl );
     204                 :            :     }
     205                 :            : 
     206                 :            :     /**
     207                 :            :      * Removes an extra snapping layer
     208                 :            :      *
     209                 :            :      * \see addExtraSnapLayer()
     210                 :            :      * \see getExtraSnapLayers()
     211                 :            :      *
     212                 :            :      * \since QGIS 3.14
     213                 :            :      */
     214                 :            :     void removeExtraSnapLayer( QgsVectorLayer *vl )
     215                 :            :     {
     216                 :            :       mExtraSnapLayers.remove( vl );
     217                 :            :     }
     218                 :            : 
     219                 :            :     /**
     220                 :            :      * Returns the list of extra snapping layers
     221                 :            :      *
     222                 :            :      * \see addExtraSnapLayer()
     223                 :            :      * \see removeExtraSnapLayer()
     224                 :            :      *
     225                 :            :      * \since QGIS 3.14
     226                 :            :      */
     227                 :            :     QSet<QgsVectorLayer *> getExtraSnapLayers()
     228                 :            :     {
     229                 :            :       return mExtraSnapLayers;
     230                 :            :     }
     231                 :            : 
     232                 :            : 
     233                 :            :   public slots:
     234                 :            : 
     235                 :            :     /**
     236                 :            :      * The snapping configuration controls the behavior of this object
     237                 :            :      */
     238                 :            :     void setConfig( const QgsSnappingConfig &snappingConfig );
     239                 :            : 
     240                 :            :     /**
     241                 :            :      * Toggles the state of snapping
     242                 :            :      *
     243                 :            :      * \since QGIS 3.0
     244                 :            :      */
     245                 :            :     void toggleEnabled();
     246                 :            : 
     247                 :            :   signals:
     248                 :            : 
     249                 :            :     /**
     250                 :            :      * Emitted when the snapping settings object changes.
     251                 :            :      */
     252                 :            :     void configChanged( const QgsSnappingConfig &snappingConfig );
     253                 :            : 
     254                 :            :   protected:
     255                 :            : 
     256                 :            :     //! Called when starting to index with snapToMap - can be overridden and e.g. progress dialog can be provided
     257                 :            :     virtual void prepareIndexStarting( int count ) { Q_UNUSED( count ); }
     258                 :            :     //! Called when finished indexing a layer with snapToMap. When index == count the indexing is complete
     259                 :            :     virtual void prepareIndexProgress( int index ) { Q_UNUSED( index ); }
     260                 :            : 
     261                 :            :     //! Deletes all existing locators (e.g. when destination CRS has changed and we need to reindex)
     262                 :            :     void clearAllLocators();
     263                 :            : 
     264                 :            :   private slots:
     265                 :            : 
     266                 :            :     //! called whenever a point locator has finished
     267                 :            :     void onInitFinished( bool ok );
     268                 :            : 
     269                 :            :   private:
     270                 :            :     void onIndividualLayerSettingsChanged( const QHash<QgsVectorLayer *, QgsSnappingConfig::IndividualLayerSettings> &layerSettings );
     271                 :            :     //! Gets destination CRS from map settings, or an invalid CRS if projections are disabled
     272                 :            :     QgsCoordinateReferenceSystem destinationCrs() const;
     273                 :            : 
     274                 :            :     //! Returns a locator (temporary or not) according to the indexing strategy
     275                 :            :     QgsPointLocator *locatorForLayerUsingStrategy( QgsVectorLayer *vl, const QgsPointXY &pointMap, double tolerance );
     276                 :            :     //! Returns a temporary locator with index only for a small area (will be replaced by another one on next request)
     277                 :            :     QgsPointLocator *temporaryLocatorForLayer( QgsVectorLayer *vl, const QgsPointXY &pointMap, double tolerance );
     278                 :            : 
     279                 :            :     typedef QPair< QgsVectorLayer *, QgsRectangle > LayerAndAreaOfInterest;
     280                 :            : 
     281                 :            :     //! Returns TRUE if \a loc index is ready to be used in the area of interest \a areaOfInterest
     282                 :            :     bool isIndexPrepared( QgsPointLocator *loc, const QgsRectangle &areaOfInterest );
     283                 :            :     //! initialize index for layers where it makes sense (according to the indexing strategy)
     284                 :            :     void prepareIndex( const QList<LayerAndAreaOfInterest> &layers, bool relaxed );
     285                 :            : 
     286                 :            :   private:
     287                 :            :     // environment
     288                 :            :     QgsMapSettings mMapSettings;
     289                 :            :     QgsVectorLayer *mCurrentLayer = nullptr;
     290                 :            : 
     291                 :            :     QgsSnappingConfig mSnappingConfig;
     292                 :            : 
     293                 :            :     // configuration
     294                 :            :     IndexingStrategy mStrategy = IndexHybrid;
     295                 :            :     QList<LayerConfig> mLayers;
     296                 :            : 
     297                 :            :     // internal data
     298                 :            :     typedef QMap<QgsVectorLayer *, QgsPointLocator *> LocatorsMap;
     299                 :            :     //! on-demand locators used (locators are owned)
     300                 :            :     LocatorsMap mLocators;
     301                 :            :     //! temporary locators (indexing just a part of layers). owned by the instance
     302                 :            :     LocatorsMap mTemporaryLocators;
     303                 :            :     //! list of layer IDs that are too large to be indexed (hybrid strategy will use temporary locators for those)
     304                 :            :     QSet<QString> mHybridNonindexableLayers;
     305                 :            :     //! list of additional snapping layers
     306                 :            :     QSet<QgsVectorLayer *> mExtraSnapLayers;
     307                 :            : 
     308                 :            :     /**
     309                 :            :      * a record for each layer seen:
     310                 :            :      *
     311                 :            :      * - value -1  == it is small layer -> fully indexed
     312                 :            :      * - value > 0 == maximum area (in map units) for which it may make sense to build index.
     313                 :            :      *
     314                 :            :      * This means that index is built in area around the point with this total area, because
     315                 :            :      * for a larger area the number of features will likely exceed the limit. When the limit
     316                 :            :      * is exceeded, the maximum area is lowered to prevent that from happening.
     317                 :            :      * When requesting snap in area that is not currently indexed, layer's index is destroyed
     318                 :            :      * and a new one is built in the different area.
     319                 :            :      */
     320                 :            :     QHash<QString, double> mHybridMaxAreaPerLayer;
     321                 :            :     //! if using hybrid strategy, how many features of one layer may be indexed (to limit amount of consumed memory)
     322                 :            :     int mHybridPerLayerFeatureLimit = 50000;
     323                 :            : 
     324                 :            :     //! Disable or not the snapping on all features. By default is always TRUE except for non visible features on map canvas.
     325                 :            :     bool mEnableSnappingForInvisibleFeature = true;
     326                 :            : };
     327                 :            : 
     328                 :            : 
     329                 :            : #endif // QGSSNAPPINGUTILS_H