Added expression based labels, simple dialog for entering expressions.

Code still needs some clean up and testing.

src/app/qgslabelinggui.cpp

@@ -24,13 +24,15 @@
 
 #include "qgspallabeling.h"
 #include "qgslabelengineconfigdialog.h"
+#include "qgssearchstring.h"
+#include "qgsexpressionbuilder.h"
 
 #include <QColorDialog>
 #include <QFontDialog>
-
+#include <QTextEdit>
 #include <iostream>
 #include <QApplication>
-
+#include <QMessageBox>
 
 
 QgsLabelingGui::QgsLabelingGui( QgsPalLabeling* lbl, QgsVectorLayer* layer, QgsMapCanvas* mapCanvas, QWidget* parent )
@@ -44,6 +46,7 @@ QgsLabelingGui::QgsLabelingGui( QgsPalLabeling* lbl, QgsVectorLayer* layer, QgsM
   connect( btnBufferColor, SIGNAL( clicked() ), this, SLOT( changeBufferColor() ) );
   connect( spinBufferSize, SIGNAL( valueChanged( double ) ), this, SLOT( updatePreview() ) );
   connect( btnEngineSettings, SIGNAL( clicked() ), this, SLOT( showEngineConfigDialog() ) );
+  connect( btnExpression, SIGNAL(clicked()), this, SLOT( showExpressionDialog()));
 
   // set placement methods page based on geometry type
   switch ( layer->geometryType() )
@@ -65,12 +68,14 @@ QgsLabelingGui::QgsLabelingGui( QgsPalLabeling* lbl, QgsVectorLayer* layer, QgsM
   label_19->setEnabled( layer->geometryType() != QGis::Point );
   mMinSizeSpinBox->setEnabled( layer->geometryType() != QGis::Point );
 
-  populateFieldNames();
-
   // load labeling settings from layer
   QgsPalLayerSettings lyr;
   lyr.readFromLayer( layer );
+  populateFieldNames();
 
+  //Add the current expression to the bottom of the list.
+  if (lyr.isExpression)
+      cboFieldName->addItem(lyr.fieldName);
   populateDataDefinedCombos( lyr );
 
   // placement
@@ -184,18 +189,23 @@ QgsLabelingGui::~QgsLabelingGui()
 
 void QgsLabelingGui::apply()
 {
-  layerSettings().writeToLayer( mLayer );
-  // trigger refresh
-  if ( mMapCanvas )
-  {
-    mMapCanvas->refresh();
-  }
+    QgsPalLayerSettings settings = layerSettings();
+     // If we get here we are good to go.
+    settings.writeToLayer( mLayer );
+    // trigger refresh
+    if ( mMapCanvas )
+    {
+        mMapCanvas->refresh();
+    }
 }
 
 QgsPalLayerSettings QgsLabelingGui::layerSettings()
 {
   QgsPalLayerSettings lyr;
   lyr.fieldName = cboFieldName->currentText();
+  // Check if we are an expression. Also treats expressions with just a column name as non expressions,
+  // this saves time later so we don't have to parse the expression tree.
+  lyr.isExpression = mLayer->fieldNameIndex( lyr.fieldName ) == -1;
 
   lyr.dist = 0;
   lyr.placementFlags = 0;
@@ -300,7 +310,6 @@ QgsPalLayerSettings QgsLabelingGui::layerSettings()
   return lyr;
 }
 
-
 void QgsLabelingGui::populateFieldNames()
 {
   const QgsFieldMap& fields = mLayer->pendingFields();
@@ -449,6 +458,35 @@ void QgsLabelingGui::showEngineConfigDialog()
   dlg.exec();
 }
 
+void QgsLabelingGui::showExpressionDialog()
+{
+    QDialog* dlg = new QDialog();
+    QDialogButtonBox* buttonBox = new QDialogButtonBox(QDialogButtonBox::Ok
+                                                       | QDialogButtonBox::Cancel);
+    QgsExpressionBuilder* builder = new QgsExpressionBuilder();
+    QGridLayout* layout = new QGridLayout();
+    dlg->setLayout(layout);
+    layout->addWidget(builder);
+    layout->addWidget(buttonBox);
+
+    if ( dlg->exec() )
+    { 
+      QString expression =  builder->getExpressionString();
+      //Do validation here first before applying
+      QgsSearchString searchString;
+      if ( !searchString.setString( expression ) )
+      {
+        //expression not valid
+          QMessageBox::critical( 0, "Syntax error",
+                                 "Invalid expression syntax. The error message of the parser is: '" + searchString.parserErrorMsg() + "'" );
+          return;
+      }
+
+      cboFieldName->addItem(expression);
+      cboFieldName->setCurrentIndex(cboFieldName->count() - 1);
+    }
+ }
+
 void QgsLabelingGui::updateUi()
 {
   // enable/disable scale-based, buffer

src/app/qgslabelinggui.h

@@ -41,6 +41,7 @@ class QgsLabelingGui : public QDialog, private Ui::QgsLabelingGuiBase
     void changeTextColor();
     void changeTextFont();
     void showEngineConfigDialog();
+    void showExpressionDialog();
     void changeBufferColor();
 
     void updateUi();

src/core/qgslabel.cpp

@@ -34,10 +34,14 @@
 #include "qgsmaptopixel.h"
 #include "qgscoordinatetransform.h"
 #include "qgsrendercontext.h"
+#include "qgssearchtreenode.h"
+#include "qgssearchstring.h"
 
 #include "qgslabelattributes.h"
 #include "qgslabel.h"
 
+#include <QMessageBox>
+
 // use M_PI define PI 3.141592654
 #ifdef WIN32
 #undef M_PI
@@ -103,16 +107,37 @@ void QgsLabel::renderLabel( QgsRenderContext &renderContext,
   double x2 = point.x();
   double scale = ( x2 - x1 ) * 0.001;
 
+  QgsSearchString searchString;
+  if ( !searchString.setString( " to string (Diameter) + 'mm'" ) )
+  {
+    //expression not valid
+    QMessageBox::critical( 0, "Syntax error", "Invalid expression syntax. The error message of the parser is: '" + searchString.parserErrorMsg() + "'" );
+    return;
+  }
+
+  //get QgsSearchTreeNode
+  QgsSearchTreeNode* searchTree = searchString.tree();
+  if ( !searchTree )
+  {
+    return;
+  }
+
+  QgsSearchTreeValue outValue;
+  searchTree->getValue( outValue, searchTree, mField , feature );
+ if (outValue.isError())
+     QMessageBox::critical( 0, "Error in expression tree" , "Error" );
+  text = outValue.string();
+
   /* Text */
-  value = fieldValue( Text, feature );
+  /*value = fieldValue( Text, feature );
   if ( value.isEmpty() )
   {
     text = mLabelAttributes->text();
   }
   else
   {
     text = value;
-  }
+  } */
 
   /* Font */
   value = fieldValue( Family, feature );
@@ -1030,8 +1055,6 @@ void QgsLabel::readXML( const QDomNode& node )
 
 } // QgsLabel::readXML()
 
-
-
 void QgsLabel::writeXML( QDomNode & layer_node, QDomDocument & document ) const
 {
   QDomElement labelattributes = document.createElement( "labelattributes" );

src/core/qgspallabeling.cpp

@@ -41,13 +41,16 @@
 #include "qgsdiagram.h"
 #include "qgsdiagramrendererv2.h"
 #include "qgslabelsearchtree.h"
+#include "qgssearchtreenode.h"
+#include "qgssearchstring.h"
+
 #include <qgslogger.h>
 #include <qgsvectorlayer.h>
 #include <qgsmaplayerregistry.h>
 #include <qgsvectordataprovider.h>
 #include <qgsgeometry.h>
 #include <qgsmaprenderer.h>
-
+#include <QMessageBox>
 
 using namespace pal;
 
@@ -155,6 +158,7 @@ QgsPalLayerSettings::QgsPalLayerSettings( const QgsPalLayerSettings& s )
 {
   // copy only permanent stuff
   fieldName = s.fieldName;
+  isExpression = s.isExpression;
   placement = s.placement;
   placementFlags = s.placementFlags;
   textFont = s.textFont;
@@ -276,6 +280,7 @@ void QgsPalLayerSettings::readFromLayer( QgsVectorLayer* layer )
     return; // there's no information available
 
   fieldName = layer->customProperty( "labeling/fieldName" ).toString();
+  isExpression = layer->customProperty( "labeling/isExpression").toBool();
   placement = ( Placement ) layer->customProperty( "labeling/placement" ).toInt();
   placementFlags = layer->customProperty( "labeling/placementFlags" ).toUInt();
   QString fontFamily = layer->customProperty( "labeling/fontFamily" ).toString();
@@ -311,6 +316,7 @@ void QgsPalLayerSettings::writeToLayer( QgsVectorLayer* layer )
   layer->setCustomProperty( "labeling", "pal" );
 
   layer->setCustomProperty( "labeling/fieldName", fieldName );
+  layer->setCustomProperty( "labeling/isExpression", isExpression );
   layer->setCustomProperty( "labeling/placement", placement );
   layer->setCustomProperty( "labeling/placementFlags", ( unsigned int )placementFlags );
 
@@ -427,9 +433,36 @@ void QgsPalLayerSettings::calculateLabelSize( const QFontMetricsF* fm, QString t
   labelY = qAbs( ptSize.y() - ptZero.y() );
 }
 
-void QgsPalLayerSettings::registerFeature( QgsFeature& f, const QgsRenderContext& context )
+void QgsPalLayerSettings::registerFeature(QgsVectorLayer* layer,  QgsFeature& f, const QgsRenderContext& context )
 {
-  QString labelText = f.attributeMap()[fieldIndex].toString();
+    QString labelText;
+    if (isExpression)
+    {
+        QgsSearchString searchString;
+        // We don't do any validating here as we should only have a vaild expression at this point.
+        searchString.setString( fieldName );
+
+       QgsSearchTreeNode* searchTree = searchString.tree();
+        if ( !searchTree )
+        {
+          return;
+        }
+
+        QgsSearchTreeValue outValue;
+        searchTree->getValue( outValue, searchTree, layer->dataProvider()->fields() , f );
+
+        if (outValue.isError())
+        {
+            QgsDebugMsg("EXPRESSION ERROR = " + outValue.string());
+           return;
+        }
+        QgsDebugMsg("EXPRESSION OUT VALUE = " + outValue.string());
+         labelText  = outValue.string();
+  }
+  else
+  {
+      labelText = f.attributeMap()[fieldIndex].toString();
+  }
   double labelX, labelY; // will receive label size
   QFont labelFont = textFont;
 
@@ -569,7 +602,7 @@ void QgsPalLayerSettings::registerFeature( QgsFeature& f, const QgsRenderContext
   // record the created geometry - it will be deleted at the end.
   geometries.append( lbl );
 
-  // register feature to the layer
+  //  feature to the layer
   try
   {
     if ( !palLayer->registerFeature( lbl->strId(), lbl, labelX, labelY, labelText.toUtf8().constData(),
@@ -689,11 +722,15 @@ int QgsPalLabeling::prepareLayer( QgsVectorLayer* layer, QSet<int>& attrIndices,
   if ( !lyrTmp.enabled )
     return 0;
 
-  // find out which field will be needed
-  int fldIndex = layer->fieldNameIndex( lyrTmp.fieldName );
-  if ( fldIndex == -1 )
-    return 0;
-  attrIndices.insert( fldIndex );
+  // If we aren't an expression, we check to see if we can find the column.
+  int fldIndex ;
+  if (!lyrTmp.isExpression)
+  {
+      fldIndex = layer->fieldNameIndex( lyrTmp.fieldName );
+      if ( fldIndex == -1)
+          return 0;
+      attrIndices.insert( fldIndex );
+  }
 
   //add indices of data defined fields
   QMap< QgsPalLayerSettings::DataDefinedProperties, int >::const_iterator dIt = lyrTmp.dataDefinedProperties.constBegin();
@@ -782,7 +819,7 @@ int QgsPalLabeling::addDiagramLayer( QgsVectorLayer* layer, QgsDiagramLayerSetti
 void QgsPalLabeling::registerFeature( QgsVectorLayer* layer, QgsFeature& f, const QgsRenderContext& context )
 {
   QgsPalLayerSettings& lyr = mActiveLayers[layer];
-  lyr.registerFeature( f, context );
+  lyr.registerFeature(layer, f, context );
 }
 
 void QgsPalLabeling::registerDiagramFeature( QgsVectorLayer* layer, QgsFeature& feat, const QgsRenderContext& context )
@@ -836,7 +873,7 @@ void QgsPalLabeling::registerDiagramFeature( QgsVectorLayer* layer, QgsFeature&
     }
   }
 
-  // register feature to the layer
+  //  feature to the layer
   int ddColX = layerIt.value().xPosColumn;
   int ddColY = layerIt.value().yPosColumn;
   double ddPosX = 0.0;
@@ -1212,7 +1249,6 @@ void QgsPalLabeling::drawLabel( pal::LabelPosition* label, QPainter* painter, co
 
   // TODO: optimize access :)
   const QgsPalLayerSettings& lyr = layer( label->getLayerName() );
-
   QString text = (( QgsPalGeometry* )label->getFeaturePart()->getUserGeometry() )->text();
   QString txt = ( label->getPartId() == -1 ? text : QString( text[label->getPartId()] ) );
 

src/core/qgspallabeling.h

@@ -98,6 +98,7 @@ class CORE_EXPORT QgsPalLayerSettings
     };
 
     QString fieldName;
+    bool isExpression;
     Placement placement;
     unsigned int placementFlags;
     QFont textFont;
@@ -125,7 +126,7 @@ class CORE_EXPORT QgsPalLayerSettings
     void calculateLabelSize( const QFontMetricsF* fm, QString text, double& labelX, double& labelY );
 
     // implementation of register feature hook
-    void registerFeature( QgsFeature& f, const QgsRenderContext& context );
+    void registerFeature(QgsVectorLayer* layer, QgsFeature& f, const QgsRenderContext& context );
 
     void readFromLayer( QgsVectorLayer* layer );
     void writeToLayer( QgsVectorLayer* layer );