From b3d11c75c0a4af007b9b3feb342bc792f9fc6e03 Mon Sep 17 00:00:00 2001
From: Nyall Dawson <nyall.dawson@gmail.com>
Date: Wed, 20 May 2015 00:33:40 +1000
Subject: [PATCH] Fix point displacement renderer not ignoring features with no
 symbol

Previously, the renderer would incorrectly draw circles and
displace features which were proximal to features with no symbols.
This caused issues with the rule based renderer, were some
features should not be drawn.

cherry-picked from 81f4e4471f696215113bb67f91d114cecde029bd
---
 .../qgspointdisplacementrenderer.cpp          | 19 ++++++++++++-------
 .../qgspointdisplacementrenderer.h            |  2 +-
 2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/core/symbology-ng/qgspointdisplacementrenderer.cpp b/src/core/symbology-ng/qgspointdisplacementrenderer.cpp
index ac89ef147ff3..afc47850d607 100644
--- a/src/core/symbology-ng/qgspointdisplacementrenderer.cpp
+++ b/src/core/symbology-ng/qgspointdisplacementrenderer.cpp
@@ -85,6 +85,12 @@ bool QgsPointDisplacementRenderer::renderFeature( QgsFeature& feature, QgsRender
   if ( !feature.geometry() )
     return false;
 
+  QgsSymbolV2* symbol = firstSymbolForFeature( mRenderer, feature );
+
+  //if the feature has no symbol (eg, no matching rule in a rule-based renderer), skip it
+  if ( !symbol )
+    return false;
+
   //point position in screen coords
   QgsGeometry* geom = feature.geometry();
   QGis::WkbType geomType = geom->wkbType();
@@ -103,7 +109,7 @@ bool QgsPointDisplacementRenderer::renderFeature( QgsFeature& feature, QgsRender
     mSpatialIndex->insertFeature( feature );
     // create new group
     DisplacementGroup newGroup;
-    newGroup.insert( feature.id(), feature );
+    newGroup.insert( feature.id(), qMakePair( feature, symbol ) );
     mDisplacementGroups.push_back( newGroup );
     // add to group index
     mGroupIndex.insert( feature.id(), mDisplacementGroups.count() - 1 );
@@ -117,7 +123,7 @@ bool QgsPointDisplacementRenderer::renderFeature( QgsFeature& feature, QgsRender
   DisplacementGroup& group = mDisplacementGroups[groupIdx];
 
   // add to a group
-  group.insert( feature.id(), feature );
+  group.insert( feature.id(), qMakePair( feature, symbol ) );
   // add to group index
   mGroupIndex.insert( feature.id(), groupIdx );
   return true;
@@ -125,7 +131,7 @@ bool QgsPointDisplacementRenderer::renderFeature( QgsFeature& feature, QgsRender
 
 void QgsPointDisplacementRenderer::drawGroup( const DisplacementGroup& group, QgsRenderContext& context )
 {
-  const QgsFeature& feature = group.begin().value();
+  const QgsFeature& feature = group.begin().value().first;
   bool selected = mSelectedFeatures.contains( feature.id() ); // maybe we should highlight individual features instead of the whole group?
 
   QPointF pt;
@@ -137,9 +143,8 @@ void QgsPointDisplacementRenderer::drawGroup( const DisplacementGroup& group, Qg
 
   for ( DisplacementGroup::const_iterator attIt = group.constBegin(); attIt != group.constEnd(); ++attIt )
   {
-    labelAttributeList << ( mDrawLabels ? getLabel( attIt.value() ) : QString() );
-    QgsFeature& f = const_cast<QgsFeature&>( attIt.value() ); // other parts of API use non-const ref to QgsFeature :-/
-    symbolList << dynamic_cast<QgsMarkerSymbolV2*>( firstSymbolForFeature( mRenderer, f ) );
+    labelAttributeList << ( mDrawLabels ? getLabel( attIt.value().first ) : QString() );
+    symbolList << dynamic_cast<QgsMarkerSymbolV2*>( attIt.value().second );
   }
 
   //draw symbol
@@ -413,7 +418,7 @@ void QgsPointDisplacementRenderer::printInfoDisplacementGroups()
   for ( int i = 0; i < nGroups; ++i )
   {
     QgsDebugMsg( "***************displacement group " + QString::number( i ) );
-    QMap<QgsFeatureId, QgsFeature>::const_iterator it = mDisplacementGroups.at( i ).constBegin();
+    DisplacementGroup::const_iterator it = mDisplacementGroups.at( i ).constBegin();
     for ( ; it != mDisplacementGroups.at( i ).constEnd(); ++it )
     {
       QgsDebugMsg( FID_TO_STRING( it.key() ) );
diff --git a/src/core/symbology-ng/qgspointdisplacementrenderer.h b/src/core/symbology-ng/qgspointdisplacementrenderer.h
index 5e19c589e15e..e4299250ce61 100644
--- a/src/core/symbology-ng/qgspointdisplacementrenderer.h
+++ b/src/core/symbology-ng/qgspointdisplacementrenderer.h
@@ -143,7 +143,7 @@ class CORE_EXPORT QgsPointDisplacementRenderer: public QgsFeatureRendererV2
     /**Maximum scale denominator for label display. Negative number means no scale limitation*/
     double mMaxLabelScaleDenominator;
 
-    typedef QMap<QgsFeatureId, QgsFeature> DisplacementGroup;
+    typedef QMap<QgsFeatureId, QPair< QgsFeature, QgsSymbolV2* > > DisplacementGroup;
     /**Groups of features that have the same position*/
     QList<DisplacementGroup> mDisplacementGroups;
     /**Mapping from feature ID to its group index*/