qgis issue 1219 combined patch

1219_3.patch

diff --git a/src/core/pal/layer.cpp b/src/core/pal/layer.cpp
index 28d0041..c0fec47 100644
--- a/src/core/pal/layer.cpp
+++ b/src/core/pal/layer.cpp
@@ -60,7 +60,7 @@ namespace pal
 
   Layer::Layer( const char *lyrName, double min_scale, double max_scale, Arrangement arrangement, Units label_unit, double defaultPriority, bool obstacle, bool active, bool toLabel, Pal *pal, bool displayAll )
       :  pal( pal ), obstacle( obstacle ), active( active ),
-      toLabel( toLabel ), displayAll( displayAll ), label_unit( label_unit ),
+      toLabel( toLabel ), displayAll( displayAll ), ignoreInvalidGeometries( true ), label_unit( label_unit ),
       min_scale( min_scale ), max_scale( max_scale ),
       arrangement( arrangement ), arrangementFlags( 0 ), mode( LabelPerFeature ), mergeLines( false )
   {
@@ -157,7 +157,6 @@ namespace pal
     this->arrangement = arrangement;
   }
 
-
   bool Layer::isObstacle()
   {
     return obstacle;
@@ -289,7 +288,8 @@ namespace pal
       const GEOSGeometry* geom = simpleGeometries->pop_front();
 
       // ignore invalid geometries (e.g. polygons with self-intersecting rings)
-      if ( GEOSisValid( geom ) != 1 ) // 0=invalid, 1=valid, 2=exception
+      int geomvalid = GEOSisValid( geom ); // 0=invalid, 1=valid, 2=exception
+      if ( geomvalid == 2 || ( ignoreInvalidGeometries && geomvalid == 0 ) )
       {
         std::cerr << "ignoring invalid feature " << geom_id << std::endl;
         continue;
diff --git a/src/core/pal/layer.h b/src/core/pal/layer.h
index c4518de..940262e 100644
--- a/src/core/pal/layer.h
+++ b/src/core/pal/layer.h
@@ -101,6 +101,7 @@ namespace pal
       bool active;
       bool toLabel;
       bool displayAll;
+      bool ignoreInvalidGeometries;
 
       Units label_unit;
 
@@ -183,6 +184,9 @@ namespace pal
       unsigned long getArrangementFlags() const { return arrangementFlags; }
       void setArrangementFlags( unsigned long flags ) { arrangementFlags = flags; }
 
+      bool getIgnoreInvalidGeometries() const { return ignoreInvalidGeometries; }
+      void setIgnoreInvalidGeometries( bool ignoreInvalid ) { ignoreInvalidGeometries = ignoreInvalid; }
+
       /**
        * \brief get units for label size
        */
diff --git a/src/core/qgsmaptopixelgeometrysimplifier.cpp b/src/core/qgsmaptopixelgeometrysimplifier.cpp
index 6c49e66..265e167 100644
--- a/src/core/qgsmaptopixelgeometrysimplifier.cpp
+++ b/src/core/qgsmaptopixelgeometrysimplifier.cpp
@@ -147,6 +147,11 @@ bool QgsMapToPixelSimplifier::simplifyWkbGeometry( int simplifyFlags, QGis::WkbT
   bool hasZValue = QGis::wkbDimensions( wkbType ) == 3;
   bool result = false;
 
+  // Save initial WKB settings to use when the simplification creates invalid geometries
+  unsigned char* sourcePrevWkb = sourceWkb;
+  unsigned char* targetPrevWkb = targetWkb;
+  size_t targetWkbPrevSize = targetWkbSize;
+
   // Can replace the geometry by its BBOX ?
   if (( simplifyFlags & QgsMapToPixelSimplifier::SimplifyEnvelope ) && ( envelope.xMaximum() - envelope.xMinimum() ) < map2pixelTol && ( envelope.yMaximum() - envelope.yMinimum() ) < map2pixelTol )
   {
@@ -181,6 +186,11 @@ bool QgsMapToPixelSimplifier::simplifyWkbGeometry( int simplifyFlags, QGis::WkbT
   {
     double x, y, lastX = 0, lastY = 0;
 
+    double xmin =  std::numeric_limits<double>::max();
+    double ymin =  std::numeric_limits<double>::max();
+    double xmax = -std::numeric_limits<double>::max();
+    double ymax = -std::numeric_limits<double>::max();
+
     int sizeOfDoubleX = sizeof( double );
     int sizeOfDoubleY = QGis::wkbDimensions( wkbType ) == 3 /*hasZValue*/ ? 2 * sizeof( double ) : sizeof( double );
 
@@ -209,10 +219,21 @@ bool QgsMapToPixelSimplifier::simplifyWkbGeometry( int simplifyFlags, QGis::WkbT
         memcpy( ptr, &y, sizeof( double ) ); lastY = y; ptr++;
         numTargetPoints++;
       }
+      if ( xmin > x ) xmin = x;
+      if ( ymin > y ) ymin = y;
+      if ( xmax < x ) xmax = x;
+      if ( ymax < y ) ymax = y;
     }
     targetWkb = wkb2 + 4;
 
     // Fix the topology of the geometry
+    if ( numTargetPoints <= ( isaLinearRing ? 2 : 1 ) )
+    {
+      sourceWkb = sourcePrevWkb;
+      targetWkb = targetPrevWkb;
+      targetWkbSize = targetWkbPrevSize;
+      return generalizeWkbGeometry( wkbType, sourceWkb, sourceWkbSize, targetWkb, targetWkbSize, QgsRectangle( xmin, ymin, xmax, ymax ), writeHeader );
+    }
     if ( isaLinearRing )
     {
       memcpy( &x, targetWkb + 0, sizeof( double ) );
diff --git a/src/core/qgspallabeling.cpp b/src/core/qgspallabeling.cpp
index 9fbfeb2..15ae51e 100644
--- a/src/core/qgspallabeling.cpp
+++ b/src/core/qgspallabeling.cpp
@@ -1840,6 +1840,12 @@ void QgsPalLayerSettings::registerFeature( QgsFeature& f, const QgsRenderContext
     }
   }
 
+  // fix invalid polygons
+  if ( QGis::singleType( QGis::flatType( geom->wkbType() ) ) == QGis::WKBPolygon && !geom->isGeosValid() )
+  {
+    geom->fromGeos( GEOSBuffer( geom->asGeos(), 0, 0 ) );
+  }
+
   // CLIP the geometry if it is bigger than the extent
   // don't clip if centroid is requested for whole feature
   bool do_clip = false;
@@ -3276,6 +3282,9 @@ int QgsPalLabeling::prepareLayer( QgsVectorLayer* layer, QStringList& attrNames,
   // set whether adjacent lines should be merged
   l->setMergeConnectedLines( lyr.mergeLines );
 
+  // set whether invalid geometries (e.g. polygons with self-intersecting rings) should be processed
+  l->setIgnoreInvalidGeometries( false );
+
   // set how to show upside-down labels
   Layer::UpsideDownLabels upsdnlabels;
   switch ( lyr.upsidedownLabels )