src/app/qgisapp.cpp

@@ -3846,7 +3846,14 @@ void QgisApp::dxfExport()
       {
         dxfExport.setMapUnits( r->mapUnits() );
       }
+
+      //extent
+      if ( d.exportMapExtent() )
+      {
+        dxfExport.setExtent( mapCanvas()->extent() );
+      }
     }
+
     QFile dxfFile( d.saveFile() );
     if ( dxfExport.writeToFile( &dxfFile ) == 0 )
     {

src/app/qgsdxfexportdialog.cpp

@@ -1,3 +1,20 @@
+/***************************************************************************
+                         qgsdxfexportdialog.cpp
+                         ----------------------
+    begin                : September 2013
+    copyright            : (C) 2013 by Marco Hugentobler
+    email                : marco at sourcepole dot ch
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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 "qgsdxfexportdialog.h"
 #include "qgsmaplayer.h"
 #include "qgsmaplayerregistry.h"
@@ -123,6 +140,11 @@ void QgsDxfExportDialog::setOkEnabled()
   btn->setEnabled( fi.absoluteDir().exists() );
 }
 
+bool QgsDxfExportDialog::exportMapExtent() const
+{
+  return mMapExtentCheckBox->isChecked();
+}
+
 void QgsDxfExportDialog::saveSettings()
 {
   QSettings s;

src/app/qgsdxfexportdialog.h

@@ -1,3 +1,20 @@
+/***************************************************************************
+                         qgsdxfexportdialog.h
+                         --------------------
+    begin                : September 2013
+    copyright            : (C) 2013 by Marco Hugentobler
+    email                : marco at sourcepole dot ch
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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 QGSDXFEXPORTDIALOG_H
 #define QGSDXFEXPORTDIALOG_H
 
@@ -15,6 +32,7 @@ class QgsDxfExportDialog: public QDialog, private Ui::QgsDxfExportDialogBase
     double symbologyScale() const;
     QgsDxfExport::SymbologyExport symbologyMode() const;
     QString saveFile() const;
+    bool exportMapExtent() const;
 
   public slots:
     /** change the selection of layers in the list */

src/core/dxf/qgsdxfexport.cpp

@@ -467,7 +467,7 @@ void QgsDxfExport::writeTables()
   {
     writeGroup( 0, "LAYER" );
     QString layerName = *layerIt ? ( *layerIt )->name() : "";
-    writeGroup( 2, layerName );
+    writeGroup( 2, dxfLayerName( layerName ) );
     writeGroup( 70, 64 );
     writeGroup( 62, 1 );
     writeGroup( 6, "CONTINUOUS" );
@@ -565,15 +565,19 @@ void QgsDxfExport::writeEntities()
       renderer->stopRender( ctx );
     }
 
-
-    QgsFeatureIterator featureIt = vl->getFeatures( QgsFeatureRequest().setSubsetOfAttributes(
-                                     renderer->usedAttributes(), dp->fields() ) );
+    QgsFeatureRequest freq = QgsFeatureRequest().setSubsetOfAttributes(
+                               renderer->usedAttributes(), dp->fields() );
+    if ( !mExtent.isEmpty() )
+    {
+      freq.setFilterRect( mExtent );
+    }
+    QgsFeatureIterator featureIt = vl->getFeatures( freq );
     QgsFeature fet;
     while ( featureIt.nextFeature( fet ) )
     {
       if ( mSymbologyExport == NoSymbology )
       {
-        addFeature( fet, vl->name(), 0, 0 ); //no symbology at all
+        addFeature( fet, dxfLayerName( vl->name() ), 0, 0 ); //no symbology at all
       }
       else
       {
@@ -593,7 +597,7 @@ void QgsDxfExport::writeEntities()
         {
           continue;
         }
-        addFeature( fet, vl->name(), s->symbolLayer( 0 ), s );
+        addFeature( fet, dxfLayerName( vl->name() ), s->symbolLayer( 0 ), s );
       }
     }
     renderer->stopRender( ctx );
@@ -625,6 +629,10 @@ void QgsDxfExport::writeEntitiesSymbolLevels( QgsVectorLayer* layer )
     req.setFlags( QgsFeatureRequest::NoGeometry );
   }
   req.setSubsetOfAttributes( QStringList( renderer->usedAttributes() ), layer->pendingFields() );
+  if ( !mExtent.isEmpty() )
+  {
+    req.setFilterRect( mExtent );
+  }
   QgsFeatureIterator fit = layer->getFeatures( req );
 
   //fetch features
@@ -1323,6 +1331,38 @@ QString QgsDxfExport::lineNameFromPenStyle( Qt::PenStyle style )
   }
 }
 
+QString QgsDxfExport::dxfLayerName( const QString& name )
+{
+  //dxf layers can be max 31 characters long
+  QString layerName = name.left( 31 );
+
+  //allowed characters are 0-9, A-Z, $, -, _
+  for ( int i = 0; i < layerName.size(); ++i )
+  {
+    QChar c = layerName.at( i );
+    if ( c > 122 )
+    {
+      layerName[i] = '_';
+      continue;
+    }
+
+    if ( c.isNumber() )
+    {
+      continue;
+    }
+    if ( c == '$' || c == '-' || c == '_' )
+    {
+      continue;
+    }
+
+    if ( !c.isLetter() )
+    {
+      layerName[i] = '_';
+    }
+  }
+  return layerName;
+}
+
 /******************************************************Test with AC_1018 methods***************************************************************/
 
 void QgsDxfExport::writeHeaderAC1018( QTextStream& stream )

src/core/dxf/qgsdxfexport.h

@@ -56,6 +56,9 @@ class CORE_EXPORT QgsDxfExport
     void setSymbologyExport( SymbologyExport e ) { mSymbologyExport = e; }
     SymbologyExport symbologyExport() const { return mSymbologyExport; }
 
+    void setExtent( const QgsRectangle& r ) { mExtent = r; }
+    QgsRectangle extent() const { return mExtent; }
+
     //get closest entry in dxf palette
     static int closestColorMatch( QRgb pixel );
 
@@ -83,6 +86,8 @@ class CORE_EXPORT QgsDxfExport
   private:
 
     QList< QgsMapLayer* > mLayers;
+    /**Extent for export, only intersecting features are exported. If the extent is an empty rectangle, all features are exported*/
+    QgsRectangle mExtent;
     /**Scale for symbology export (used if symbols units are mm)*/
     double mSymbologyScaleDenominator;
     SymbologyExport mSymbologyExport;
@@ -155,6 +160,7 @@ class CORE_EXPORT QgsDxfExport
     double dashSeparatorSize() const;
     double sizeToMapUnits( double s ) const;
     static QString lineNameFromPenStyle( Qt::PenStyle style );
+    static QString dxfLayerName( const QString& name );
 };
 
 #endif // QGSDXFEXPORT_H

src/ui/qgsdxfexportdialogbase.ui

@@ -115,6 +115,13 @@
      </item>
     </layout>
    </item>
+   <item row="3" column="1">
+    <widget class="QCheckBox" name="mMapExtentCheckBox">
+     <property name="text">
+      <string>Export features intersecting the current map extent</string>
+     </property>
+    </widget>
+   </item>
   </layout>
  </widget>
  <resources/>