From 7940c39555610d7b4585a2165dc7a8c90ef50fcb Mon Sep 17 00:00:00 2001
From: Nathan Woodrow <madmanwoo@gmail.com>
Date: Thu, 27 Oct 2011 19:02:28 +1000
Subject: [PATCH 1/4] Enable multiline labels by default

---
 src/core/qgspallabeling.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/qgspallabeling.cpp b/src/core/qgspallabeling.cpp
index d348932f04ff..aba233e77793 100644
--- a/src/core/qgspallabeling.cpp
+++ b/src/core/qgspallabeling.cpp
@@ -152,7 +152,7 @@ QgsPalLayerSettings::QgsPalLayerSettings()
   plusSign = false;
   labelPerPart = false;
   mergeLines = false;
-  multiLineLabels = false;
+  multiLineLabels = true;
   minFeatureSize = 0.0;
   vectorScaleFactor = 1.0;
   rasterCompressFactor = 1.0;

From 9b2bf0afd6b022c20e0b7720a74cc9d6180bd4a1 Mon Sep 17 00:00:00 2001
From: Nathan Woodrow <madmanwoo@gmail.com>
Date: Fri, 28 Oct 2011 06:51:35 +1000
Subject: [PATCH 2/4] Fix grabbing of first QgsFeature; Cache QgsFeature being
 used to eval; Handle layers with no objects

---
 src/gui/qgsexpressionbuilderwidget.cpp | 25 ++++++++++++++++++-------
 src/gui/qgsexpressionbuilderwidget.h   |  2 +-
 2 files changed, 19 insertions(+), 8 deletions(-)

diff --git a/src/gui/qgsexpressionbuilderwidget.cpp b/src/gui/qgsexpressionbuilderwidget.cpp
index 058dd5f66475..6d0b79b8a12c 100644
--- a/src/gui/qgsexpressionbuilderwidget.cpp
+++ b/src/gui/qgsexpressionbuilderwidget.cpp
@@ -230,13 +230,24 @@ void QgsExpressionBuilderWidget::on_txtExpressionString_textChanged()
   // Maybe just calling exp.evaluate()?
   if ( mLayer )
   {
-    // TODO We should really cache the feature.
-    QgsFeature feature;
-    mLayer->featureAtId( 0 , feature );
-    QVariant value = exp.evaluate( &feature, mLayer->pendingFields() );
-
-    if ( !exp.hasEvalError() )
-      lblPreview->setText( value.toString() );
+    if ( !mFeature.isValid() )
+    {
+        mLayer->select( mLayer->pendingAllAttributesList() );
+        mLayer->nextFeature( mFeature );
+    }
+
+    if ( mFeature.isValid() )
+    {
+        QVariant value = exp.evaluate( &mFeature, mLayer->pendingFields() );
+        if ( !exp.hasEvalError() )
+          lblPreview->setText( value.toString() );
+    }
+    else
+    {
+        // The feautre is invaild because we don't have one but that doesn't mean user can't
+        // build a expression string.  They just get no preview.
+        lblPreview->setText("");
+    }
   }
 
   if ( exp.hasParserError() || exp.hasEvalError() )
diff --git a/src/gui/qgsexpressionbuilderwidget.h b/src/gui/qgsexpressionbuilderwidget.h
index 653f5c01b464..54067c0bb126 100644
--- a/src/gui/qgsexpressionbuilderwidget.h
+++ b/src/gui/qgsexpressionbuilderwidget.h
@@ -164,7 +164,7 @@ class GUI_EXPORT QgsExpressionBuilderWidget : public QWidget, private Ui::QgsExp
     QStandardItemModel *mModel;
     QgsExpressionItemSearchProxy *mProxyModel;
     QMap<QString, QgsExpressionItem*> mExpressionGroups;
-    QgsFeature* mFeature;
+    QgsFeature mFeature;
 };
 
 #endif // QGSEXPRESSIONBUILDER_H

From f5bf2b4110b5766cc127ad25fbad00c9dccd2b25 Mon Sep 17 00:00:00 2001
From: Nathan Woodrow <madmanwoo@gmail.com>
Date: Sat, 29 Oct 2011 12:49:13 +1000
Subject: [PATCH 3/4] Remove debug noise for expression labels

---
 src/core/qgspallabeling.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/core/qgspallabeling.cpp b/src/core/qgspallabeling.cpp
index aba233e77793..98bca6863776 100644
--- a/src/core/qgspallabeling.cpp
+++ b/src/core/qgspallabeling.cpp
@@ -471,14 +471,13 @@ void QgsPalLayerSettings::registerFeature( QgsVectorLayer* layer,  QgsFeature& f
     QgsExpression* exp = getLabelExpression();
     if ( exp->hasParserError() )
     {
-      QgsDebugMsg( "PASER HAS ERROR:" + exp->parserErrorString() );
+      QgsDebugMsg( "Expression parser error:" + exp->parserErrorString() );
       return;
     }
     QVariant result = exp->evaluate( &f, layer->dataProvider()->fields() );
-    QgsDebugMsg( "VALUE = " + result.toString() );
     if ( exp->hasEvalError() )
     {
-      QgsDebugMsg( "Expression Label Error = " + exp->evalErrorString() );
+      QgsDebugMsg( "Expression parser eval error:" + exp->evalErrorString() );
       return;
     }
     labelText  = result.toString();

From a739750e456c8d5387798b770aad65f7d0728364 Mon Sep 17 00:00:00 2001
From: Nathan Woodrow <madmanwoo@gmail.com>
Date: Fri, 28 Oct 2011 23:20:58 +1000
Subject: [PATCH 4/4] Fix multiline overlap - Fix for #4454

---
 src/core/qgspallabeling.cpp | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/core/qgspallabeling.cpp b/src/core/qgspallabeling.cpp
index 98bca6863776..9d9a174234de 100644
--- a/src/core/qgspallabeling.cpp
+++ b/src/core/qgspallabeling.cpp
@@ -434,10 +434,11 @@ void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF* fm, QString t
   {
     text.append( ">" );
   }
-  QRectF labelRect = fm->boundingRect( text );
+
   double w, h;
   if ( !multiLineLabels )
   {
+    QRectF labelRect = fm->boundingRect( text );
     w = labelRect.width() / rasterCompressFactor;
     h = labelRect.height() / rasterCompressFactor;
   }
@@ -452,9 +453,9 @@ void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF* fm, QString t
       if ( width > w )
       {
         w = width;
-      }
-      w /= rasterCompressFactor;
+      } 
     }
+    w /= rasterCompressFactor;
   }
   QgsPoint ptSize = xform->toMapCoordinatesF( w, h );