Add min/max scale-based visibility to advanced labeling data defined …

…columns

- Layer-level options, if set, will override data defined values (correct behavior IMHO)
- Spinboxes for min and max added to Change Label tool's dialog
- Seems to still be a bug in renderer scale-to-value comparison, where equal scales are not always equal if user directly enters values in the map canvas scale combobox

src/app/qgslabelinggui.cpp

@@ -354,6 +354,8 @@ QgsPalLayerSettings QgsLabelingGui::layerSettings()
   setDataDefinedProperty( mLabelDistanceComboBox, QgsPalLayerSettings::LabelDistance, lyr );
   setDataDefinedProperty( mRotationComboBox, QgsPalLayerSettings::Rotation, lyr );
   setDataDefinedProperty( mShowLabelAttributeComboBox, QgsPalLayerSettings::Show, lyr );
+  setDataDefinedProperty( mMinScaleAttributeComboBox, QgsPalLayerSettings::MinScale, lyr );
+  setDataDefinedProperty( mMaxScaleAttributeComboBox, QgsPalLayerSettings::MaxScale, lyr );
 
   return lyr;
 }
@@ -419,6 +421,8 @@ void QgsLabelingGui::populateDataDefinedCombos( QgsPalLayerSettings& s )
   comboList << mLabelDistanceComboBox;
   comboList << mRotationComboBox;
   comboList << mShowLabelAttributeComboBox;
+  comboList << mMinScaleAttributeComboBox;
+  comboList << mMaxScaleAttributeComboBox;
 
   QList<QComboBox*>::iterator comboIt = comboList.begin();
   for ( ; comboIt != comboList.end(); ++comboIt )
@@ -453,6 +457,8 @@ void QgsLabelingGui::populateDataDefinedCombos( QgsPalLayerSettings& s )
   setCurrentComboValue( mLabelDistanceComboBox, s, QgsPalLayerSettings::LabelDistance );
   setCurrentComboValue( mRotationComboBox, s, QgsPalLayerSettings::Rotation );
   setCurrentComboValue( mShowLabelAttributeComboBox, s, QgsPalLayerSettings::Show );
+  setCurrentComboValue( mMinScaleAttributeComboBox, s, QgsPalLayerSettings::MinScale );
+  setCurrentComboValue( mMaxScaleAttributeComboBox, s, QgsPalLayerSettings::MaxScale );
 }
 
 void QgsLabelingGui::changePreviewBackground()

src/app/qgslabelpropertydialog.cpp

@@ -96,6 +96,8 @@ void QgsLabelPropertyDialog::init( const QString& layerId, int featureId )
   mBufferColorButton->setColor( layerSettings.textColor );
   mLabelDistanceSpinBox->setValue( layerSettings.dist );
   mBufferSizeSpinBox->setValue( layerSettings.bufferSize );
+  mMinScaleSpinBox->setValue( layerSettings.scaleMin );
+  mMaxScaleSpinBox->setValue( layerSettings.scaleMax );
   mHaliComboBox->setCurrentIndex( mHaliComboBox->findText( "Left" ) );
   mValiComboBox->setCurrentIndex( mValiComboBox->findText( "Bottom" ) );
 
@@ -112,6 +114,14 @@ void QgsLabelPropertyDialog::init( const QString& layerId, int featureId )
         mShowLabelChkbx->setEnabled( true );
         mShowLabelChkbx->setChecked( attributeValues[propIt.value()].toInt() != 0 );
         break;
+      case QgsPalLayerSettings::MinScale:
+        mMinScaleSpinBox->setEnabled( true );
+        mMinScaleSpinBox->setValue( attributeValues[propIt.value()].toInt() );
+        break;
+      case QgsPalLayerSettings::MaxScale:
+        mMaxScaleSpinBox->setEnabled( true );
+        mMaxScaleSpinBox->setValue( attributeValues[propIt.value()].toInt() );
+        break;
       case QgsPalLayerSettings::Size:
         mFontSizeSpinBox->setEnabled( true );
         mLabelFont.setPointSizeF( attributeValues[propIt.value()].toDouble() );
@@ -181,6 +191,8 @@ void QgsLabelPropertyDialog::init( const QString& layerId, int featureId )
 void QgsLabelPropertyDialog::disableGuiElements()
 {
   mShowLabelChkbx->setEnabled( false );
+  mMinScaleSpinBox->setEnabled( false );
+  mMaxScaleSpinBox->setEnabled( false );
   mFontSizeSpinBox->setEnabled( false );
   mBufferSizeSpinBox->setEnabled( false );
   mFontPushButton->setEnabled( false );
@@ -197,6 +209,8 @@ void QgsLabelPropertyDialog::disableGuiElements()
 void QgsLabelPropertyDialog::blockElementSignals( bool block )
 {
   mShowLabelChkbx->blockSignals( block );
+  mMinScaleSpinBox->blockSignals( block );
+  mMaxScaleSpinBox->blockSignals( block );
   mFontSizeSpinBox->blockSignals( block );
   mBufferSizeSpinBox->blockSignals( block );
   mFontPushButton->blockSignals( block );
@@ -229,6 +243,16 @@ void QgsLabelPropertyDialog::on_mShowLabelChkbx_toggled( bool chkd )
   insertChangedValue( QgsPalLayerSettings::Show, ( chkd ? 1 : 0 ) );
 }
 
+void QgsLabelPropertyDialog::on_mMinScaleSpinBox_valueChanged( int i )
+{
+  insertChangedValue( QgsPalLayerSettings::MinScale, i );
+}
+
+void QgsLabelPropertyDialog::on_mMaxScaleSpinBox_valueChanged(int i )
+{
+  insertChangedValue( QgsPalLayerSettings::MaxScale, i );
+}
+
 void QgsLabelPropertyDialog::on_mLabelDistanceSpinBox_valueChanged( double d )
 {
   insertChangedValue( QgsPalLayerSettings::LabelDistance, d );

src/app/qgslabelpropertydialog.h

@@ -38,6 +38,8 @@ class QgsLabelPropertyDialog: public QDialog, private Ui::QgsLabelPropertyDialog
 
   private slots:
     void on_mShowLabelChkbx_toggled( bool chkd );
+    void on_mMinScaleSpinBox_valueChanged(int i );
+    void on_mMaxScaleSpinBox_valueChanged( int i );
     void on_mLabelDistanceSpinBox_valueChanged( double d );
     void on_mXCoordSpinBox_valueChanged( double d );
     void on_mYCoordSpinBox_valueChanged( double d );

src/core/qgspallabeling.cpp

@@ -245,7 +245,7 @@ static void _writeDataDefinedPropertyMap( QgsVectorLayer* layer, const QMap< Qgs
   {
     return;
   }
-  for ( int i = 0; i < 16; ++i )
+  for ( int i = 0; i < 18; ++i )
   {
     QMap< QgsPalLayerSettings::DataDefinedProperties, int >::const_iterator it = propertyMap.find(( QgsPalLayerSettings::DataDefinedProperties )i );
     QVariant propertyValue;
@@ -301,6 +301,8 @@ static void _readDataDefinedPropertyMap( QgsVectorLayer* layer, QMap< QgsPalLaye
   _readDataDefinedProperty( layer, QgsPalLayerSettings::LabelDistance, propertyMap );
   _readDataDefinedProperty( layer, QgsPalLayerSettings::Rotation, propertyMap );
   _readDataDefinedProperty( layer, QgsPalLayerSettings::Show, propertyMap );
+  _readDataDefinedProperty( layer, QgsPalLayerSettings::MinScale, propertyMap );
+  _readDataDefinedProperty( layer, QgsPalLayerSettings::MaxScale, propertyMap );
 }
 
 void QgsPalLayerSettings::readFromLayer( QgsVectorLayer* layer )
@@ -486,6 +488,40 @@ void QgsPalLayerSettings::registerFeature( QgsVectorLayer* layer,  QgsFeature& f
     }
   }
 
+  // data defined min scale?
+  QMap< DataDefinedProperties, int >::const_iterator minScaleIt = dataDefinedProperties.find( QgsPalLayerSettings::MinScale );
+  if ( minScaleIt != dataDefinedProperties.constEnd() )
+  {
+    QVariant minScaleValue = f.attributeMap().value( *minScaleIt );
+    if ( minScaleValue.isValid() )
+    {
+      bool conversionOk;
+      int minScale = minScaleValue.toInt( &conversionOk );
+      // TODO: occasional floating point issues?
+      if ( conversionOk && int( context.rendererScale() ) < minScale  )
+      {
+        return;
+      }
+    }
+  }
+
+  // data defined max scale?
+  QMap< DataDefinedProperties, int >::const_iterator maxScaleIt = dataDefinedProperties.find( QgsPalLayerSettings::MaxScale );
+  if ( maxScaleIt != dataDefinedProperties.constEnd() )
+  {
+    QVariant maxScaleValue = f.attributeMap().value( *maxScaleIt );
+    if ( maxScaleValue.isValid() )
+    {
+      bool conversionOk;
+      int maxScale = maxScaleValue.toInt( &conversionOk );
+      // TODO: occasional floating point issues?
+      if ( conversionOk && int( context.rendererScale() ) > maxScale )
+      {
+        return;
+      }
+    }
+  }
+
   QString labelText;
   // Check to see if we are a expression string.
   if ( isExpression )

src/core/qgspallabeling.h

@@ -98,7 +98,9 @@ class CORE_EXPORT QgsPalLayerSettings
       Vali, //vertical alignment for data defined label position (Bottom, Base, Half, Cap, Top)
       LabelDistance,
       Rotation, //data defined rotation (only useful in connection with data defined position)
-      Show
+      Show,
+      MinScale,
+      MaxScale
     };
 
     QString fieldName;

src/ui/qgslabelingguibase.ui

@@ -2047,7 +2047,7 @@
               <item row="1" column="1">
                <widget class="QComboBox" name="mMinScaleAttributeComboBox">
                 <property name="enabled">
-                 <bool>false</bool>
+                 <bool>true</bool>
                 </property>
                </widget>
               </item>
@@ -2085,7 +2085,7 @@
               <item row="2" column="1">
                <widget class="QComboBox" name="mMaxScaleAttributeComboBox">
                 <property name="enabled">
-                 <bool>false</bool>
+                 <bool>true</bool>
                 </property>
                </widget>
               </item>