#8725-R: simplify edited geometries in QgsVectorLayerFeatureIterator

qgis · Jan 15, 2014 · 61041da · 61041da
1 parent 4cc82e6
commit 61041da
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Showing 9 changed files with 153 additions and 25 deletions.
diff --git a/python/core/core.sip b/python/core/core.sip
@@ -37,6 +37,7 @@
 %Include qgsfield.sip
 %Include qgsgeometry.sip
 %Include qgsgeometryvalidator.sip
+%Include qgsgeometrysimplifier.sip
 %Include qgsgml.sip
 %Include qgsgmlschema.sip
 %Include qgshttptransaction.sip
@@ -75,6 +76,7 @@
 %Include qgsrunprocess.sip
 %Include qgsscalecalculator.sip
 %Include qgsscaleutils.sip
+%Include qgssimplifymethod.sip
 %Include qgssnapper.sip
 %Include qgsspatialindex.sip
 %Include qgstolerance.sip

diff --git a/python/core/qgsgeometrysimplifier.sip b/python/core/qgsgeometrysimplifier.sip
@@ -0,0 +1,23 @@
+
+/** Abstract base class for simplify geometries using a specific algorithm */
+class QgsAbstractGeometrySimplifier
+{
+%TypeHeaderCode
+#include "qgsgeometrysimplifier.h"
+%End
+
+  public:
+    virtual ~QgsAbstractGeometrySimplifier();
+
+    /** Returns a simplified version the specified geometry */
+    virtual QgsGeometry* simplify( QgsGeometry* geometry ) const = 0;
+    /** Simplifies the specified geometry */
+    virtual bool simplifyGeometry( QgsGeometry* geometry ) const = 0;
+
+    // MapToPixel simplification helper methods
+  public:
+    /** Returns whether the device-envelope can be replaced by its BBOX when is applied the specified tolerance */
+    static bool canbeGeneralizedByDeviceBoundingBox( const QgsRectangle&   envelope, float mapToPixelTol = 1.0f );
+    /** Returns whether the device-geometry can be replaced by its BBOX when is applied the specified tolerance */
+    static bool canbeGeneralizedByDeviceBoundingBox( const QVector<QPointF>& points, float mapToPixelTol = 1.0f );
+};
diff --git a/python/core/qgssimplifymethod.sip b/python/core/qgssimplifymethod.sip
@@ -0,0 +1,39 @@
+
+/** This class contains information about how to simplify geometries fetched from a QgsFeatureIterator */
+class QgsSimplifyMethod
+{
+%TypeHeaderCode
+#include "qgssimplifymethod.h"
+%End
+
+  public:
+    enum MethodType
+    {
+      NoSimplification,     //!< No simplification is applied
+      OptimizeForRendering, //!< Simplify using the map2pixel data to optimize the rendering of geometries
+      PreserveTopology      //!< Simplify using the Douglas-Peucker algorithm ensuring that the result is a valid geometry
+    };
+
+    //! construct a default method
+    QgsSimplifyMethod();
+    //! copy constructor
+    QgsSimplifyMethod( const QgsSimplifyMethod& rh );
+
+    /** Sets the simplification type */
+    void setMethodType( MethodType methodType );
+    /** Gets the simplification type */
+    MethodType methodType() const;
+
+    /** Sets the tolerance of simplification. Represents the maximum distance between two coordinates which can be considered equal */
+    void setTolerance( double tolerance );
+    /** Gets the tolerance of simplification */
+    double tolerance() const;
+
+    /** Sets whether the simplification executes after fetch the geometries from provider, otherwise it executes, when supported, in provider before fetch the geometries */
+    void setForceLocalOptimization( bool localOptimization );
+    /** Gets whether the simplification executes after fetch the geometries from provider, otherwise it executes, when supported, in provider before fetch the geometries */
+    bool forceLocalOptimization() const;
+
+    /** Creates a geometry simplifier according to specified method */
+    static QgsAbstractGeometrySimplifier* createGeometrySimplifier( const QgsSimplifyMethod& simplifyMethod );
+};
diff --git a/src/core/qgsfeatureiterator.cpp b/src/core/qgsfeatureiterator.cpp
@@ -16,7 +16,6 @@
 #include "qgslogger.h"
 
 #include "qgsgeometrysimplifier.h"
-#include "qgsmaptopixelgeometrysimplifier.h"
 #include "qgssimplifymethod.h"
 
 QgsAbstractFeatureIterator::QgsAbstractFeatureIterator( const QgsFeatureRequest& request )
@@ -104,27 +103,11 @@ bool QgsAbstractFeatureIterator::prepareSimplification( const QgsSimplifyMethod&
     mGeometrySimplifier = NULL;
   }
 
-  // setup the local simplification of geometries to fetch, it uses the settings of current FeatureRequest
+  // setup the local simplification of geometries to fetch
   if ( simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification && simplifyMethod.forceLocalOptimization() && !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) )
   {
-    QgsSimplifyMethod::MethodType methodType = simplifyMethod.methodType();
-
-    if ( methodType == QgsSimplifyMethod::OptimizeForRendering )
-    {
-      int simplifyFlags = QgsMapToPixelSimplifier::SimplifyGeometry | QgsMapToPixelSimplifier::SimplifyEnvelope;
-      mGeometrySimplifier = new QgsMapToPixelSimplifier( simplifyFlags, simplifyMethod.tolerance() );
-      return true;
-    }
-    else
-    if ( methodType == QgsSimplifyMethod::PreserveTopology )
-    {
-      mGeometrySimplifier = new QgsTopologyPreservingSimplifier( simplifyMethod.tolerance() );
-      return true;
-    }
-    else
-    {
-      QgsDebugMsg( QString( "Simplification method type (%1) is not recognised" ).arg( methodType ) );
-    }
+    mGeometrySimplifier = QgsSimplifyMethod::createGeometrySimplifier( simplifyMethod );
+    return mGeometrySimplifier != NULL;
   }
   return false;
 }

diff --git a/src/core/qgssimplifymethod.cpp b/src/core/qgssimplifymethod.cpp
@@ -14,6 +14,9 @@
  ***************************************************************************/
 
 #include "qgssimplifymethod.h"
+#include "qgslogger.h"
+#include "qgsgeometrysimplifier.h"
+#include "qgsmaptopixelgeometrysimplifier.h"
 
 QgsSimplifyMethod::QgsSimplifyMethod()
   : mMethodType( QgsSimplifyMethod::NoSimplification )
@@ -50,3 +53,25 @@ void QgsSimplifyMethod::setForceLocalOptimization( bool localOptimization )
 {
   mForceLocalOptimization = localOptimization;
 }
+
+QgsAbstractGeometrySimplifier* QgsSimplifyMethod::createGeometrySimplifier( const QgsSimplifyMethod& simplifyMethod )
+{
+  QgsSimplifyMethod::MethodType methodType = simplifyMethod.methodType();
+
+  // returns a geometry simplifier according to specified method
+  if ( methodType == QgsSimplifyMethod::OptimizeForRendering )
+  {
+    int simplifyFlags = QgsMapToPixelSimplifier::SimplifyGeometry | QgsMapToPixelSimplifier::SimplifyEnvelope;
+    return new QgsMapToPixelSimplifier( simplifyFlags, simplifyMethod.tolerance() );
+  }
+  else
+  if ( methodType == QgsSimplifyMethod::PreserveTopology )
+  {
+    return new QgsTopologyPreservingSimplifier( simplifyMethod.tolerance() );
+  }
+  else
+  {
+    QgsDebugMsg( QString( "Simplification method type (%1) is not recognised" ).arg( methodType ) );
+    return NULL;
+  }
+}
diff --git a/src/core/qgssimplifymethod.h b/src/core/qgssimplifymethod.h
@@ -16,6 +16,8 @@
 #ifndef QGSSIMPLIFYMETHOD_H
 #define QGSSIMPLIFYMETHOD_H
 
+class QgsAbstractGeometrySimplifier;
+
 /**
  * This class contains information about how to simplify geometries fetched from a QgsFeatureIterator
  */
@@ -51,6 +53,9 @@ class CORE_EXPORT QgsSimplifyMethod
     //! Gets whether the simplification executes after fetch the geometries from provider, otherwise it executes, when supported, in provider before fetch the geometries
     inline bool forceLocalOptimization() const { return mForceLocalOptimization; }
 
+    //! Creates a geometry simplifier according to specified method
+    static QgsAbstractGeometrySimplifier* createGeometrySimplifier( const QgsSimplifyMethod& simplifyMethod );
+
   protected:
     //! Simplification method
     MethodType mMethodType;

diff --git a/src/core/qgsvectorlayerfeatureiterator.cpp b/src/core/qgsvectorlayerfeatureiterator.cpp
@@ -19,9 +19,11 @@
 #include "qgsvectorlayer.h"
 #include "qgsvectorlayereditbuffer.h"
 #include "qgsvectorlayerjoinbuffer.h"
+#include "qgsgeometrysimplifier.h"
+#include "qgssimplifymethod.h"
 
 QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator( QgsVectorLayer* layer, const QgsFeatureRequest& request )
-    : QgsAbstractFeatureIterator( request ), L( layer )
+    : QgsAbstractFeatureIterator( request ), L( layer ), mEditGeometrySimplifier( NULL )
 {
   QgsVectorLayerJoinBuffer* joinBuffer = L->mJoinBuffer;
 
@@ -86,21 +88,27 @@ QgsVectorLayerFeatureIterator::QgsVectorLayerFeatureIterator( QgsVectorLayer* la
       mProviderIterator = L->dataProvider()->getFeatures( mProviderRequest );
     }
 
-    // prepare if required the local simplification of geometries to fetch
-    prepareSimplification( request.simplifyMethod() );
-
     rewindEditBuffer();
   }
 
   if ( mRequest.filterType() == QgsFeatureRequest::FilterExpression )
   {
     mRequest.filterExpression()->prepare( L->pendingFields() );
   }
+
+  // prepare if required the local simplification of geometries to fetch
+  prepareSimplification( request.simplifyMethod() );
 }
 
 
 QgsVectorLayerFeatureIterator::~QgsVectorLayerFeatureIterator()
 {
+  if ( mEditGeometrySimplifier )
+  {
+    delete mEditGeometrySimplifier;
+    mEditGeometrySimplifier = NULL;
+  }
+
   close();
 }
 
@@ -242,8 +250,18 @@ void QgsVectorLayerFeatureIterator::useAddedFeature( const QgsFeature& src, QgsF
   f.setFields( &L->mUpdatedFields );
 
   if ( src.geometry() && !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) )
+  {
     f.setGeometry( *src.geometry() );
 
+    // simplify the edited geometry using its simplifier configured
+    if ( mEditGeometrySimplifier )
+    {
+      QgsGeometry* geometry = f.geometry();
+      QGis::GeometryType geometryType = geometry->type();
+      if ( geometryType == QGis::Line || geometryType == QGis::Polygon ) mEditGeometrySimplifier->simplifyGeometry( geometry );
+    }
+  }
+
   // TODO[MD]: if subset set just some attributes
 
   f.setAttributes( src.attributes() );
@@ -313,8 +331,18 @@ void QgsVectorLayerFeatureIterator::useChangedAttributeFeature( QgsFeatureId fid
   f.setFields( &L->mUpdatedFields );
 
   if ( !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) )
+  {
     f.setGeometry( geom );
 
+    // simplify the edited geometry using its simplifier configured
+    if ( mEditGeometrySimplifier )
+    {
+      QgsGeometry* geometry = f.geometry();
+      QGis::GeometryType geometryType = geometry->type();
+      if ( geometryType == QGis::Line || geometryType == QGis::Polygon ) mEditGeometrySimplifier->simplifyGeometry( geometry );
+    }
+  }
+
   bool subsetAttrs = ( mRequest.flags() & QgsFeatureRequest::SubsetOfAttributes );
   if ( !subsetAttrs || ( subsetAttrs && mRequest.subsetOfAttributes().count() > 0 ) )
   {
@@ -436,6 +464,22 @@ void QgsVectorLayerFeatureIterator::addJoinedAttributes( QgsFeature &f )
   }
 }
 
+bool QgsVectorLayerFeatureIterator::prepareSimplification( const QgsSimplifyMethod& simplifyMethod )
+{
+  if ( mEditGeometrySimplifier )
+  {
+    delete mEditGeometrySimplifier;
+    mEditGeometrySimplifier = NULL;
+  }
+
+  // setup the simplification of edited geometries to fetch
+  if ( simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification && !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) )
+  {
+    mEditGeometrySimplifier = QgsSimplifyMethod::createGeometrySimplifier( simplifyMethod );
+  }
+
+  return QgsAbstractFeatureIterator::prepareSimplification( simplifyMethod );
+}
 
 
 void QgsVectorLayerFeatureIterator::FetchJoinInfo::addJoinedAttributesCached( QgsFeature& f, const QVariant& joinValue ) const

diff --git a/src/core/qgsvectorlayerfeatureiterator.h b/src/core/qgsvectorlayerfeatureiterator.h
@@ -46,6 +46,9 @@ class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureItera
     //! while for others filtering is left to the provider implementation.
     inline virtual bool nextFeatureFilterExpression( QgsFeature &f ) { return fetchFeature( f ); }
 
+    //! Setup the simplification of geometries to fetch using the specified simplify method
+    virtual bool prepareSimplification( const QgsSimplifyMethod& simplifyMethod );
+
     QgsVectorLayer* L;
 
     QgsFeatureRequest mProviderRequest;
@@ -114,6 +117,10 @@ class CORE_EXPORT QgsVectorLayerFeatureIterator : public QgsAbstractFeatureItera
     /** Informations about joins used in the current select() statement.
       Allows faster mapping of attribute ids compared to mVectorJoins */
     QMap<QgsVectorLayer*, FetchJoinInfo> mFetchJoinInfo;
+
+  private:
+    //! optional object to locally simplify edited (changed or added) geometries fetched by this feature iterator
+    QgsAbstractGeometrySimplifier* mEditGeometrySimplifier;
 };
 
 #endif // QGSVECTORLAYERFEATUREITERATOR_H
diff --git a/src/providers/ogr/qgsogrfeatureiterator.cpp b/src/providers/ogr/qgsogrfeatureiterator.cpp
@@ -115,7 +115,7 @@ bool QgsOgrFeatureIterator::prepareSimplification( const QgsSimplifyMethod& simp
     mGeometrySimplifier = NULL;
   }
 
-  // setup if required the simplification of OGR-geometries fetched, it uses the settings of current FeatureRequest
+  // setup if required the simplification of OGR-geometries fetched
   if ( simplifyMethod.methodType() != QgsSimplifyMethod::NoSimplification && !simplifyMethod.forceLocalOptimization() && !( mRequest.flags() & QgsFeatureRequest::NoGeometry ) )
   {
     QgsSimplifyMethod::MethodType methodType = simplifyMethod.methodType();