#8725-R: FeatureIterator use SimplifyMethod

AbstractFeatureIterator use SimplifyMethod to simplify locally the geometries fetched from data source (provider)
qgis · Jan 15, 2014 · 0ec7d35 · 0ec7d35
1 parent c283402
commit 0ec7d35
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Showing 4 changed files with 68 additions and 65 deletions.
diff --git a/src/core/qgsfeatureiterator.cpp b/src/core/qgsfeatureiterator.cpp
@@ -15,33 +15,79 @@
 #include "qgsfeatureiterator.h"
 #include "qgslogger.h"
 
+#include "qgsgeometrysimplifier.h"
+#include "qgsmaptopixelgeometrysimplifier.h"
+#include "qgssimplifymethod.h"
+
 QgsAbstractFeatureIterator::QgsAbstractFeatureIterator( const QgsFeatureRequest& request )
     : mRequest( request )
     , mClosed( false )
     , refs( 0 )
+    , mGeometrySimplifier( NULL )
 {
+  const QgsSimplifyMethod& simplifyMethod = request.simplifyMethod();
+
+  if ( simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification && simplifyMethod.forceLocalOptimization() )
+  {
+    QgsSimplifyMethod::MethodType methodType = simplifyMethod.methodType();
+
+    if ( methodType == QgsSimplifyMethod::OptimizeForRendering )
+    {
+      int simplifyFlags = QgsMapToPixelSimplifier::SimplifyGeometry | QgsMapToPixelSimplifier::SimplifyEnvelope;
+      mGeometrySimplifier = new QgsMapToPixelSimplifier( simplifyFlags, simplifyMethod.tolerance() );
+    }
+    else
+    if ( methodType == QgsSimplifyMethod::PreserveTopology )
+    {
+      mGeometrySimplifier = new QgsTopologyPreservingSimplifier( simplifyMethod.tolerance() );
+    }
+    else
+    {
+      QgsDebugMsg( QString( "Simplification method type (%1) is not recognised" ).arg( methodType ) );
+    }
+  }
 }
 
 QgsAbstractFeatureIterator::~QgsAbstractFeatureIterator()
 {
+  if ( mGeometrySimplifier )
+  {
+    delete mGeometrySimplifier;
+    mGeometrySimplifier = NULL;
+  }
 }
 
 bool QgsAbstractFeatureIterator::nextFeature( QgsFeature& f )
 {
+  bool dataOk = false;
+
   switch ( mRequest.filterType() )
   {
     case QgsFeatureRequest::FilterExpression:
-      return nextFeatureFilterExpression( f );
+      dataOk = nextFeatureFilterExpression( f );
       break;
 
     case QgsFeatureRequest::FilterFids:
-      return nextFeatureFilterFids( f );
+      dataOk = nextFeatureFilterFids( f );
       break;
 
     default:
-      return fetchFeature( f );
+      dataOk = fetchFeature( f );
       break;
   }
+
+  // simplify locally the geometry using the simplifier defined in constructor
+  if ( dataOk && mGeometrySimplifier )
+  {
+    QgsGeometry* geometry = f.geometry();
+
+    if ( geometry ) 
+    {
+      QGis::GeometryType geometryType = geometry->type();
+      if ( geometryType == QGis::Line || geometryType == QGis::Polygon ) mGeometrySimplifier->simplifyGeometry( geometry );
+    }
+  }
+  return dataOk;
 }
 
 bool QgsAbstractFeatureIterator::nextFeatureFilterExpression( QgsFeature& f )

diff --git a/src/core/qgsfeatureiterator.h b/src/core/qgsfeatureiterator.h
@@ -18,6 +18,7 @@
 #include "qgsfeaturerequest.h"
 #include "qgslogger.h"
 
+class QgsAbstractGeometrySimplifier;
 
 /** \ingroup core
  * Internal feature iterator to be implemented within data providers
@@ -85,6 +86,10 @@ class CORE_EXPORT QgsAbstractFeatureIterator
     void ref(); //!< add reference
     void deref(); //!< remove reference, delete if refs == 0
     friend class QgsFeatureIterator;
+
+  private:
+    //! optional object to locally simplify geometries fetched by this feature iterator
+    QgsAbstractGeometrySimplifier* mGeometrySimplifier;
 };
 
 

diff --git a/src/core/qgsmaptopixelgeometrysimplifier.cpp b/src/core/qgsmaptopixelgeometrysimplifier.cpp
@@ -18,11 +18,9 @@
 #include "qgsmaptopixelgeometrysimplifier.h"
 #include "qgsapplication.h"
 
-QgsMapToPixelSimplifier::QgsMapToPixelSimplifier( int simplifyFlags, const QgsCoordinateTransform* coordinateTransform, const QgsMapToPixel* mapTolPixel, float mapToPixelTol )
+QgsMapToPixelSimplifier::QgsMapToPixelSimplifier( int simplifyFlags, double map2pixelTol )
     : mSimplifyFlags( simplifyFlags )
-    , mMapCoordTransform( coordinateTransform )
-    , mMapToPixel( mapTolPixel )
-    , mMapToPixelTol( mapToPixelTol )
+    , mMapToPixelTol( map2pixelTol )
 {
 }
 QgsMapToPixelSimplifier::~QgsMapToPixelSimplifier()
@@ -41,32 +39,6 @@ float QgsMapToPixelSimplifier::calculateLengthSquared2D( double x1, double y1, d
   return vx*vx + vy*vy;
 }
 
-//! Returns the MapTolerance for transform between map coordinates and device coordinates
-float QgsMapToPixelSimplifier::calculateViewPixelTolerance( const QgsRectangle& boundingRect, const QgsCoordinateTransform* ct, const QgsMapToPixel* mapToPixel )
-{
-  double mapUnitsPerPixel = mapToPixel ? mapToPixel->mapUnitsPerPixel() : 1.0;
-  double mapUnitsFactor = 1;
-
-  // Calculate one aprox factor of the size of the BBOX from the source CoordinateSystem to the target CoordinateSystem
-  if ( ct && !(( QgsCoordinateTransform* )ct )->isShortCircuited() )
-  {
-    QgsRectangle sourceRect = boundingRect;
-    QgsRectangle targetRect = ct->transform( sourceRect );
-
-    QgsPoint minimumSrcPoint( sourceRect.xMinimum(), sourceRect.yMinimum() );
-    QgsPoint maximumSrcPoint( sourceRect.xMaximum(), sourceRect.yMaximum() );
-    QgsPoint minimumDstPoint( targetRect.xMinimum(), targetRect.yMinimum() );
-    QgsPoint maximumDstPoint( targetRect.xMaximum(), targetRect.yMaximum() );
-
-    double sourceHypothenuse = sqrt( calculateLengthSquared2D( minimumSrcPoint.x(), minimumSrcPoint.y(), maximumSrcPoint.x(), maximumSrcPoint.y() ) );
-    double targetHypothenuse = sqrt( calculateLengthSquared2D( minimumDstPoint.x(), minimumDstPoint.y(), maximumDstPoint.x(), maximumDstPoint.y() ) );
-
-    if ( targetHypothenuse != 0 )
-      mapUnitsFactor = sourceHypothenuse / targetHypothenuse;
-  }
-  return ( float )( mapUnitsPerPixel * mapUnitsFactor );
-}
-
 //! Returns the BBOX of the specified WKB-point stream
 inline static QgsRectangle calculateBoundingBox( QGis::WkbType wkbType, unsigned char* wkb, size_t numPoints )
 {
@@ -169,7 +141,7 @@ inline static bool generalizeWkbGeometry( QGis::WkbType wkbType, unsigned char*
 }
 
 //! Simplify the WKB-geometry using the specified tolerance
-bool QgsMapToPixelSimplifier::simplifyWkbGeometry( int simplifyFlags, QGis::WkbType wkbType, unsigned char* sourceWkb, size_t sourceWkbSize, unsigned char* targetWkb, size_t& targetWkbSize, const QgsRectangle& envelope, float map2pixelTol, bool writeHeader, bool isaLinearRing )
+bool QgsMapToPixelSimplifier::simplifyWkbGeometry( int simplifyFlags, QGis::WkbType wkbType, unsigned char* sourceWkb, size_t sourceWkbSize, unsigned char* targetWkb, size_t& targetWkbSize, const QgsRectangle& envelope, double map2pixelTol, bool writeHeader, bool isaLinearRing )
 {
   bool canbeGeneralizable = true;
   bool hasZValue = QGis::wkbDimensions( wkbType ) == 3;
@@ -339,10 +311,8 @@ bool QgsMapToPixelSimplifier::simplifyWkbGeometry( int simplifyFlags, QGis::WkbT
 //////////////////////////////////////////////////////////////////////////////////////////////
 
 //! Returns whether the envelope can be replaced by its BBOX when is applied the specified map2pixel context
-bool QgsMapToPixelSimplifier::canbeGeneralizedByMapBoundingBox( const QgsRectangle& envelope, const QgsCoordinateTransform* coordinateTransform, const QgsMapToPixel* mapToPixel, float mapToPixelTol )
+bool QgsMapToPixelSimplifier::canbeGeneralizedByMapBoundingBox( const QgsRectangle& envelope, double map2pixelTol )
 {
-  double map2pixelTol = mapToPixelTol * calculateViewPixelTolerance( envelope, coordinateTransform, mapToPixel );
-
   // Can replace the geometry by its BBOX ?
   if (( envelope.xMaximum() - envelope.xMinimum() ) < map2pixelTol && ( envelope.yMaximum() - envelope.yMinimum() ) < map2pixelTol )
   {
@@ -360,13 +330,13 @@ QgsGeometry* QgsMapToPixelSimplifier::simplify( QgsGeometry* geometry ) const
   unsigned char* wkb = ( unsigned char* )malloc( wkbSize );
   memcpy( wkb, geometry->asWkb(), wkbSize );
   g->fromWkb( wkb, wkbSize );
-  simplifyGeometry( g, mSimplifyFlags, mMapCoordTransform, mMapToPixel, mMapToPixelTol );
+  simplifyGeometry( g, mSimplifyFlags, mMapToPixelTol );
 
   return g;
 }
 
 //! Simplifies the geometry (Removing duplicated points) when is applied the specified map2pixel context
-bool QgsMapToPixelSimplifier::simplifyGeometry( QgsGeometry* geometry, int simplifyFlags, const QgsCoordinateTransform* coordinateTransform, const QgsMapToPixel* mapToPixel, float mapToPixelTol )
+bool QgsMapToPixelSimplifier::simplifyGeometry( QgsGeometry* geometry, int simplifyFlags, double map2pixelTol )
 {
   size_t targetWkbSize = 0;
 
@@ -376,7 +346,6 @@ bool QgsMapToPixelSimplifier::simplifyGeometry( QgsGeometry* geometry, int simpl
 
   QgsRectangle envelope = geometry->boundingBox();
   QGis::WkbType wkbType = geometry->wkbType();
-  double map2pixelTol = mapToPixelTol * calculateViewPixelTolerance( envelope, coordinateTransform, mapToPixel );
 
   unsigned char* wkb = ( unsigned char* )geometry->asWkb( );
   size_t wkbSize = geometry->wkbSize( );
@@ -395,5 +364,5 @@ bool QgsMapToPixelSimplifier::simplifyGeometry( QgsGeometry* geometry, int simpl
 //! Simplifies the geometry (Removing duplicated points) when is applied the specified map2pixel context
 bool QgsMapToPixelSimplifier::simplifyGeometry( QgsGeometry* geometry ) const
 {
-  return simplifyGeometry( geometry, mSimplifyFlags, mMapCoordTransform, mMapToPixel, mMapToPixelTol );
+  return simplifyGeometry( geometry, mSimplifyFlags, mMapToPixelTol );
 }
diff --git a/src/core/qgsmaptopixelgeometrysimplifier.h b/src/core/qgsmaptopixelgeometrysimplifier.h
@@ -32,7 +32,7 @@
 class CORE_EXPORT QgsMapToPixelSimplifier : public QgsAbstractGeometrySimplifier
 {
   public:
-    QgsMapToPixelSimplifier( int simplifyFlags, const QgsCoordinateTransform* coordinateTransform, const QgsMapToPixel* mapToPixel, float mapToPixelTol );
+    QgsMapToPixelSimplifier( int simplifyFlags, double map2pixelTol );
     virtual ~QgsMapToPixelSimplifier();
 
     //! Applicable simplification flags
@@ -45,37 +45,22 @@ class CORE_EXPORT QgsMapToPixelSimplifier : public QgsAbstractGeometrySimplifier
 
   private:
     //! Simplify the WKB-geometry using the specified tolerance
-    static bool simplifyWkbGeometry( int simplifyFlags, QGis::WkbType wkbType, unsigned char* sourceWkb, size_t sourceWkbSize, unsigned char* targetWkb, size_t& targetWkbSize, const QgsRectangle& envelope, float map2pixelTol, bool writeHeader = true, bool isaLinearRing = false );
+    static bool simplifyWkbGeometry( int simplifyFlags, QGis::WkbType wkbType, unsigned char* sourceWkb, size_t sourceWkbSize, unsigned char* targetWkb, size_t& targetWkbSize, const QgsRectangle& envelope, double map2pixelTol, bool writeHeader = true, bool isaLinearRing = false );
 
   protected:
     //! Current simplification flags
     int mSimplifyFlags;
 
-    //! For transformation between coordinate systems from current layer to map target. Can be 0 if on-the-fly reprojection is not used
-    const QgsCoordinateTransform* mMapCoordTransform;
-    //! For transformation between map coordinates and device coordinates
-    const QgsMapToPixel* mMapToPixel;
-    //! Factor tolterance to apply in transformation between map coordinates and device coordinates
-    float mMapToPixelTol;
+    //! Map2Pixel tolerance for the simplification
+    double mMapToPixelTol;
 
     //! Returns the squared 2D-distance of the vector defined by the two points specified
     static float calculateLengthSquared2D( double x1, double y1, double x2, double y2 );
-    //! Returns the MapTolerance for transform between map coordinates and device coordinates
-    static float calculateViewPixelTolerance( const QgsRectangle& boundingRect, const QgsCoordinateTransform* ct, const QgsMapToPixel* mapToPixel );
 
   public:
     int simplifyFlags() const { return mSimplifyFlags; }
     void setSimplifyFlags( int simplifyFlags ) { mSimplifyFlags = simplifyFlags; }
 
-    const QgsCoordinateTransform* coordinateTransform() const { return mMapCoordTransform; }
-    void setCoordinateTransform( const QgsCoordinateTransform* ct ) { mMapCoordTransform = ct; }
-
-    const QgsMapToPixel* mapToPixel() const { return mMapToPixel; }
-    void setMapToPixel( const QgsMapToPixel* mtp ) { mMapToPixel = mtp; }
-
-    float mapToPixelTol() const { return mMapToPixelTol; }
-    void setMapToPixelTol( float map2pixelTol ) { mMapToPixelTol = map2pixelTol; }
-
     //! Returns a simplified version the specified geometry
     virtual QgsGeometry* simplify( QgsGeometry* geometry ) const;
     //! Simplifies the specified geometry
@@ -85,15 +70,13 @@ class CORE_EXPORT QgsMapToPixelSimplifier : public QgsAbstractGeometrySimplifier
   public:
 
     //! Returns whether the envelope can be replaced by its BBOX when is applied the specified map2pixel context
-    static bool canbeGeneralizedByMapBoundingBox( const QgsRectangle& envelope,
-        const QgsCoordinateTransform* coordinateTransform, const QgsMapToPixel* mapToPixel, float mapToPixelTol = 1.0f );
+    static bool canbeGeneralizedByMapBoundingBox( const QgsRectangle& envelope, double map2pixelTol );
 
     //! Returns whether the envelope can be replaced by its BBOX when is applied the specified map2pixel context
-    inline bool canbeGeneralizedByMapBoundingBox( const QgsRectangle& envelope ) const { return canbeGeneralizedByMapBoundingBox( envelope, mMapCoordTransform, mMapToPixel, mMapToPixelTol ); }
+    inline bool canbeGeneralizedByMapBoundingBox( const QgsRectangle& envelope ) const { return canbeGeneralizedByMapBoundingBox( envelope, mMapToPixelTol ); }
 
     //! Simplifies the geometry when is applied the specified map2pixel context
-    static bool simplifyGeometry( QgsGeometry* geometry,
-                                  int simplifyFlags, const QgsCoordinateTransform* coordinateTransform, const QgsMapToPixel* mapToPixel, float mapToPixelTol = 1.0f );
+    static bool simplifyGeometry( QgsGeometry* geometry, int simplifyFlags, double map2pixelTol );
 
 };