First implementation of dxf feature writing (but it does not work yet)

src/core/qgsdxfexport.cpp

@@ -16,6 +16,10 @@
  ***************************************************************************/
 
 #include "qgsdxfexport.h"
+#include "qgsvectordataprovider.h"
+#include "qgspoint.h"
+#include "qgsrendererv2.h"
+#include "qgsvectorlayer.h"
 #include <QIODevice>
 #include <QTextStream>
 
@@ -28,7 +32,7 @@ QgsDxfExport::~QgsDxfExport()
 
 }
 
-int QgsDxfExport::writeToFile( QIODevice* d )
+int QgsDxfExport::writeToFile( QIODevice* d, SymbologyExport s )
 {
   if ( !d )
   {
@@ -42,6 +46,8 @@ int QgsDxfExport::writeToFile( QIODevice* d )
 
   QTextStream outStream( d );
   writeHeader( outStream );
+  writeEntities( outStream );
+  writeEndFile( outStream );
   return 0;
 }
 
@@ -61,8 +67,83 @@ void QgsDxfExport::writeHeader( QTextStream& stream )
   stream << "ENDSEC\n";
 }
 
+void QgsDxfExport::writeEntities( QTextStream& stream )
+{
+  stream << "0\n";
+  stream << "SECTION\n";
+  stream << "  2\n";
+  stream << "ENTITIES\n";
+
+  //iterate through the maplayers
+  QList< QgsMapLayer* >::iterator layerIt = mLayers.begin();
+  for ( ; layerIt != mLayers.end(); ++layerIt )
+  {
+    QgsVectorLayer* vl = qobject_cast<QgsVectorLayer*>( *layerIt );
+    if ( !vl )
+    {
+      continue;
+    }
+    QgsVectorDataProvider* dp = vl->dataProvider();
+    if ( !dp )
+    {
+      continue;
+    }
+
+    QgsFeatureRendererV2* renderer = vl->rendererV2();
+    QgsFeatureIterator featureIt = vl->getFeatures( QgsFeatureRequest().setSubsetOfAttributes(
+                                     renderer->usedAttributes(), dp->fields() ) );
+    QgsFeature fet;
+    while ( featureIt.nextFeature( fet ) )
+    {
+      //get geometry and write it. Todo: consider symbolisation
+      QgsGeometry* geom = fet.geometry();
+      if ( geom )
+      {
+        //try with line first
+        writePolyline( stream, geom->asPolyline(), vl->name() ); //todo.......
+      }
+    }
+  }
+
+  stream << "  0\n";
+  stream << "ENDSEC\n";
+}
+
 void QgsDxfExport::writeEndFile( QTextStream& stream )
 {
   stream << "  0\n";
   stream << "ENDSEC\n";
 }
+
+void QgsDxfExport::writePolyline( QTextStream& stream, const QgsPolyline& line, const QString& layer, bool closed )
+{
+  stream << "  0\n";
+  stream << "POLYLINE\n";
+  stream << "  8\n";
+  stream << layer << "\n";
+  stream << " 66\n";
+  stream << "  1\n";
+  stream << " 70\n";
+  int type = closed ? 32 : 0;
+  stream << type << "\n";
+
+  QgsPolyline::const_iterator lineIt = line.constBegin();
+  for ( ; lineIt != line.constEnd(); ++lineIt )
+  {
+    writeVertex( stream, *lineIt, layer );
+  }
+}
+
+void QgsDxfExport::writeVertex( QTextStream& stream, const QgsPoint& pt, const QString& layer )
+{
+  stream << "  0\n";
+  stream << "VERTEX\n";
+  stream << "  8\n";
+  stream << layer << "\n";
+  stream << " 10\n";
+  stream << pt.x() << "\n";
+  stream << " 20\n";
+  stream << pt.y() << "\n";
+  stream << " 30\n";
+  stream << "0.0\n";
+}

src/core/qgsdxfexport.h

@@ -18,27 +18,41 @@
 #ifndef QGSDXFEXPORT_H
 #define QGSDXFEXPORT_H
 
+#include "qgsgeometry.h"
 #include <QList>
 
 class QgsMapLayer;
+class QgsPoint;
 class QIODevice;
 class QTextStream;
 
 class QgsDxfExport
 {
   public:
+    enum SymbologyExport
+    {
+      NoSymbology = 0, //export only data
+      FeatureSymbology, //Keeps the number of features and export symbology per feature
+      SymbolLayerSymbology //Exports one feature per symbol layer (considering symbol levels)
+    };
+
     QgsDxfExport();
     ~QgsDxfExport();
 
     void addLayers( QList< QgsMapLayer* >& layers ) { mLayers = layers; }
-    int writeToFile( QIODevice* d );  //maybe add progress dialog? //other parameters (e.g. scale, dpi)?
+    int writeToFile( QIODevice* d, SymbologyExport s = SymbolLayerSymbology );  //maybe add progress dialog? //other parameters (e.g. scale, dpi)?
 
   private:
 
     QList< QgsMapLayer* > mLayers;
 
     void writeHeader( QTextStream& stream );
+    void writeEntities( QTextStream& stream );
     void writeEndFile( QTextStream& stream );
+
+    void writePolyline( QTextStream& stream, const QgsPolyline& line, const QString& layer, bool closed = false );
+    void writeVertex( QTextStream& stream, const QgsPoint& pt, const QString& layer );
+
     //collect styles
     //writeEntities