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https://github.com/qgis/QGIS.git
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fa66583e6f
Implemented a simple heuristic that should keep the number of cached features per layer reasonable - and thus lower the amount of consumed memory and CPU for big layers.
119 lines
4.5 KiB
Plaintext
119 lines
4.5 KiB
Plaintext
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class QgsPointLocator : QObject
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{
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%TypeHeaderCode
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#include <qgspointlocator.h>
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%End
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public:
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/** Construct point locator for a layer.
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* @arg destCRS if not null, will do the searches on data reprojected to the given CRS
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* @arg extent if not null, will index only a subset of the layer
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*/
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explicit QgsPointLocator( QgsVectorLayer* layer, const QgsCoordinateReferenceSystem* destCRS = 0, const QgsRectangle* extent = 0 );
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~QgsPointLocator();
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//! Get associated layer
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//! @note added in QGIS 2.14
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QgsVectorLayer* layer() const;
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//! Get destination CRS - may be null if not doing OTF reprojection
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//! @note added in QGIS 2.14
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const QgsCoordinateReferenceSystem* destCRS() const;
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//! Get extent of the area point locator covers - if null then it caches the whole layer
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//! @note added in QGIS 2.14
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const QgsRectangle* extent() const;
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//! Configure extent - if not null, it will index only that area
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//! @note added in QGIS 2.14
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void setExtent( const QgsRectangle* extent );
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enum Type { Invalid, Vertex, Edge, Area, All };
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typedef QFlags<QgsPointLocator::Type> Types;
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/** Prepare the index for queries. Does nothing if the index already exists.
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* If the number of features is greater than the value of maxFeaturesToIndex, creation of index is stopped
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* to make sure we do not run out of memory. If maxFeaturesToIndex is -1, no limits are used. Returns
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* false if the creation of index has been prematurely stopped due to the limit of features, otherwise true */
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bool init( int maxFeaturesToIndex = -1 );
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/** Indicate whether the data have been already indexed */
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bool hasIndex() const;
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struct Match
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{
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//! consruct invalid match
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Match();
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Match( QgsPointLocator::Type t, QgsVectorLayer* vl, QgsFeatureId fid, double dist, const QgsPoint& pt, int vertexIndex = 0 );
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QgsPointLocator::Type type() const;
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bool isValid() const;
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bool hasVertex() const;
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bool hasEdge() const;
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bool hasArea() const;
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//! for vertex / edge match
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//! units depending on what class returns it (geom.cache: layer units, map canvas snapper: dest crs units)
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double distance() const;
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//! for vertex / edge match
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//! coords depending on what class returns it (geom.cache: layer coords, map canvas snapper: dest coords)
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QgsPoint point() const;
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//! for vertex / edge match (first vertex of the edge)
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int vertexIndex() const;
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//! reference vector layer
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QgsVectorLayer* layer() const;
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QgsFeatureId featureId() const;
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//! Only for a valid edge match - obtain endpoints of the edge
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void edgePoints( QgsPoint& pt1 /Out/, QgsPoint& pt2 /Out/ ) const;
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};
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typedef QList<QgsPointLocator::Match> MatchList;
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//! Interface that allows rejection of some matches in intersection queries
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//! (e.g. a match can only belong to a particular feature / match must not be a particular point).
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//! Implement the interface and pass its instance to QgsPointLocator or QgsSnappingUtils methods.
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struct MatchFilter
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{
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virtual ~MatchFilter();
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virtual bool acceptMatch( const QgsPointLocator::Match& match ) = 0;
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};
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// intersection queries
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//! Find nearest vertex to the specified point - up to distance specified by tolerance
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//! Optional filter may discard unwanted matches.
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Match nearestVertex( const QgsPoint& point, double tolerance, QgsPointLocator::MatchFilter* filter = 0 );
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//! Find nearest edges to the specified point - up to distance specified by tolerance
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//! Optional filter may discard unwanted matches.
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Match nearestEdge( const QgsPoint& point, double tolerance, QgsPointLocator::MatchFilter* filter = 0 );
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//! Find edges within a specified recangle
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//! Optional filter may discard unwanted matches.
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MatchList edgesInRect( const QgsRectangle& rect, QgsPointLocator::MatchFilter* filter = 0 );
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//! Override of edgesInRect that construct rectangle from a center point and tolerance
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MatchList edgesInRect( const QgsPoint& point, double tolerance, QgsPointLocator::MatchFilter* filter = 0 );
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// point-in-polygon query
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// TODO: function to return just the first match?
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//! find out if the point is in any polygons
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MatchList pointInPolygon( const QgsPoint& point );
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//
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//! Return how many geometries are cached in the index
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//! @note added in QGIS 2.14
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int cachedGeometryCount() const;
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protected:
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bool rebuildIndex( int maxFeaturesToIndex = -1 );
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void destroyIndex();
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};
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