#8725-R: define QgsSimplifyMethod

Define QgsSimplifyMethod to use as optional parameter in
QgsFeatureRequest

Author: ahuarte47

src/core/CMakeLists.txt

@@ -75,6 +75,7 @@ SET(QGIS_CORE_SRCS
   qgsgeometrycache.cpp
   qgsgeometryvalidator.cpp
   qgsgeometrysimplifier.cpp
+  qgssimplifymethod.cpp
   qgsgml.cpp
   qgsgmlschema.cpp
   qgshttptransaction.cpp

src/core/qgsfeaturerequest.cpp

@@ -70,6 +70,7 @@ QgsFeatureRequest& QgsFeatureRequest::operator=( const QgsFeatureRequest & rh )
     mFilterExpression = 0;
   }
   mAttrs = rh.mAttrs;
+  mSimplifyMethod = rh.mSimplifyMethod;
   return *this;
 }
 
@@ -120,7 +121,6 @@ QgsFeatureRequest& QgsFeatureRequest::setSubsetOfAttributes( const QgsAttributeL
   return *this;
 }
 
-
 QgsFeatureRequest& QgsFeatureRequest::setSubsetOfAttributes( const QStringList& attrNames, const QgsFields& fields )
 {
   mFlags |= SubsetOfAttributes;
@@ -135,6 +135,12 @@ QgsFeatureRequest& QgsFeatureRequest::setSubsetOfAttributes( const QStringList&
   return *this;
 }
 
+QgsFeatureRequest& QgsFeatureRequest::setSimplifyMethod( const QgsSimplifyMethod& simplifyMethod )
+{
+  mSimplifyMethod = simplifyMethod;
+  return *this;
+}
+
 bool QgsFeatureRequest::acceptFeature( const QgsFeature& feature )
 {
   switch ( mFilter )

src/core/qgsfeaturerequest.h

@@ -20,6 +20,7 @@
 #include "qgsfeature.h"
 #include "qgsrectangle.h"
 #include "qgsexpression.h"
+#include "qgssimplifymethod.h"
 
 #include <QList>
 typedef QList<int> QgsAttributeList;
@@ -36,6 +37,7 @@ typedef QList<int> QgsAttributeList;
  * For efficiency, it is also possible to tell provider that some data is not required:
  * - NoGeometry flag
  * - SubsetOfAttributes flag
+ * - SimplifyMethod for geometries to fetch
  *
  * The options may be chained, e.g.:
  *   QgsFeatureRequest().setFilterRect(QgsRectangle(0,0,1,1)).setFlags(QgsFeatureRequest::ExactIntersect)
@@ -120,6 +122,10 @@ class CORE_EXPORT QgsFeatureRequest
     //! Set a subset of attributes by names that will be fetched
     QgsFeatureRequest& setSubsetOfAttributes( const QStringList& attrNames, const QgsFields& fields );
 
+    //! Set a simplification method for geometries that will be fetched
+    QgsFeatureRequest& setSimplifyMethod( const QgsSimplifyMethod& simplifyMethod );
+    const QgsSimplifyMethod& simplifyMethod() const { return mSimplifyMethod; }
+
     /**
      * Check if a feature is accepted by this requests filter
      *
@@ -143,6 +149,7 @@ class CORE_EXPORT QgsFeatureRequest
     QgsExpression* mFilterExpression;
     Flags mFlags;
     QgsAttributeList mAttrs;
+    QgsSimplifyMethod mSimplifyMethod;
 };
 
 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsFeatureRequest::Flags )

src/core/qgssimplifymethod.cpp

@@ -0,0 +1,52 @@
+/***************************************************************************
+    qgssimplifymethod.cpp
+    ---------------------
+    begin                : December 2013
+    copyright            : (C) 2013 by Matthias Kuhn / Alvaro Huarte
+    email                : 
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgssimplifymethod.h"
+
+QgsSimplifyMethod::QgsSimplifyMethod()
+  : mMethodType( QgsSimplifyMethod::NoSimplification )
+  , mTolerance( 1 )
+  , mForceLocalOptimization( true )
+{
+}
+
+QgsSimplifyMethod::QgsSimplifyMethod( const QgsSimplifyMethod &rh )
+{
+  operator=( rh );
+}
+
+QgsSimplifyMethod& QgsSimplifyMethod::operator=( const QgsSimplifyMethod &rh )
+{
+  mMethodType = rh.mMethodType;
+  mTolerance = rh.mTolerance;
+  mForceLocalOptimization = rh.mForceLocalOptimization;
+
+  return *this;
+}
+
+void QgsSimplifyMethod::setMethodType( MethodType methodType )
+{
+  mMethodType = methodType;
+}
+
+void QgsSimplifyMethod::setTolerance( double tolerance )
+{
+  mTolerance = tolerance;
+}
+
+void QgsSimplifyMethod::setForceLocalOptimization( bool localOptimization )
+{
+  mForceLocalOptimization = localOptimization;
+}

src/core/qgssimplifymethod.h

@@ -0,0 +1,63 @@
+/***************************************************************************
+    qgssimplifymethod.h
+    ---------------------
+    begin                : December 2013
+    copyright            : (C) 2013 by Matthias Kuhn / Alvaro Huarte
+    email                : 
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSSIMPLIFYMETHOD_H
+#define QGSSIMPLIFYMETHOD_H
+
+/**
+ * This class contains information about how to simplify geometries fetched from a QgsFeatureIterator
+ */
+class CORE_EXPORT QgsSimplifyMethod
+{
+  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 );
+    //! assignment operator
+    QgsSimplifyMethod& operator=( const QgsSimplifyMethod& rh );
+
+    //! Sets the simplification type
+    void setMethodType( MethodType methodType );
+    //! Gets the simplification type
+    inline MethodType methodType() const { return mMethodType; }
+
+    //! 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
+    inline double tolerance() const { return mTolerance; }
+
+    //! 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
+    inline bool forceLocalOptimization() const { return mForceLocalOptimization; }
+
+  protected:
+    //! Simplification method
+    MethodType mMethodType;
+    //! Tolerance of simplification, it represents the maximum distance between two coordinates which can be considered equal
+    double mTolerance;
+    //! Simplification executes after fetch the geometries from provider, otherwise it executes, when supported, in provider before fetch the geometries
+    bool mForceLocalOptimization;
+};
+
+#endif // QGSSIMPLIFYMETHOD_H