GUI for rule-based labeling

This code has been funded by Tuscany Region (Italy) - SITA (CIG: 63526840AE) and commissioned to Gis3W s.a.s.

Author: wonder-sk

src/app/qgisapp.cpp

@@ -5178,7 +5178,7 @@ void QgisApp::labeling()
 
   QDialog *dlg = new QDialog( this );
   dlg->setWindowTitle( tr( "Layer labeling settings" ) );
-  QgsLabelingGui *labelingGui = new QgsLabelingGui( vlayer, mMapCanvas, dlg );
+  QgsLabelingGui *labelingGui = new QgsLabelingGui( vlayer, mMapCanvas, 0, dlg );
   labelingGui->init(); // load QgsPalLayerSettings for layer
   labelingGui->layout()->setContentsMargins( 0, 0, 0, 0 );
   QVBoxLayout *layout = new QVBoxLayout( dlg );

src/app/qgslabelinggui.cpp

@@ -33,6 +33,7 @@
 #include "qgssymbollayerv2utils.h"
 #include "qgscharacterselectdialog.h"
 #include "qgssvgselectorwidget.h"
+#include "qgsvectorlayerlabeling.h"
 
 #include <QCheckBox>
 #include <QSettings>
@@ -52,10 +53,11 @@ static QgsExpressionContext _getExpressionContext( const void* context )
   return expContext;
 }
 
-QgsLabelingGui::QgsLabelingGui( QgsVectorLayer* layer, QgsMapCanvas* mapCanvas, QWidget* parent )
+QgsLabelingGui::QgsLabelingGui( QgsVectorLayer* layer, QgsMapCanvas* mapCanvas, const QgsPalLayerSettings* settings, QWidget* parent )
     : QWidget( parent )
     , mLayer( layer )
     , mMapCanvas( mapCanvas )
+    , mSettings( settings )
     , mMode( NoLabels )
     , mCharDlg( 0 )
     , mQuadrantBtnGrp( 0 )
@@ -308,7 +310,10 @@ void QgsLabelingGui::init()
 {
   // load labeling settings from layer
   QgsPalLayerSettings lyr;
-  lyr.readFromLayer( mLayer );
+  if ( mSettings )
+    lyr = *mSettings;
+  else
+    lyr.readFromLayer( mLayer );
 
   blockInitSignals( true );
 
@@ -587,6 +592,9 @@ void QgsLabelingGui::apply()
 
 void QgsLabelingGui::writeSettingsToLayer()
 {
+  mLayer->setLabeling( new QgsVectorLayerSimpleLabeling );
+
+  // all configuration is still in layer's custom properties
   QgsPalLayerSettings settings = layerSettings();
   settings.writeToLayer( mLayer );
 }

src/app/qgslabelinggui.h

@@ -33,13 +33,14 @@ class APP_EXPORT QgsLabelingGui : public QWidget, private Ui::QgsLabelingGuiBase
     Q_OBJECT
 
   public:
-    QgsLabelingGui( QgsVectorLayer* layer, QgsMapCanvas* mapCanvas, QWidget* parent );
+    QgsLabelingGui( QgsVectorLayer* layer, QgsMapCanvas* mapCanvas, const QgsPalLayerSettings* settings, QWidget* parent );
     ~QgsLabelingGui();
 
     QgsPalLayerSettings layerSettings();
     void writeSettingsToLayer();
 
-    enum LabelMode {
+    enum LabelMode
+    {
       NoLabels,
       Labels,
       ObstaclesOnly,
@@ -105,6 +106,7 @@ class APP_EXPORT QgsLabelingGui : public QWidget, private Ui::QgsLabelingGuiBase
   private:
     QgsVectorLayer* mLayer;
     QgsMapCanvas* mMapCanvas;
+    const QgsPalLayerSettings* mSettings;
     LabelMode mMode;
     QFontDatabase mFontDB;
     QgsCharacterSelectorDialog* mCharDlg;

src/app/qgslabelingwidget.cpp

@@ -9,25 +9,23 @@ QgsLabelingWidget::QgsLabelingWidget( QgsVectorLayer* layer, QgsMapCanvas* canva
     : QWidget( parent )
     , mLayer( layer )
     , mCanvas( canvas )
+    , mWidget( 0 )
 {
   setupUi( this );
 
   connect( mEngineSettingsButton, SIGNAL( clicked() ), this, SLOT( showEngineConfigDialog() ) );
 
-  mWidgetSimple = new QgsLabelingGui( layer, canvas, this );
-  mWidgetRules = new QgsRuleBasedLabelingWidget( layer, canvas, this );
-  mStackedWidget->addWidget( mWidgetSimple );
-  mStackedWidget->addWidget( mWidgetRules );
+  mLabelModeComboBox->setCurrentIndex( -1 );
 
-  mStackedWidget->setCurrentIndex( 0 );
-}
+  connect( mLabelModeComboBox, SIGNAL( currentIndexChanged( int ) ), this, SLOT( labelModeChanged( int ) ) );
 
-void QgsLabelingWidget::init()
-{
-  if ( !mLayer->labeling() || mLayer->labeling()->type() == "simple" )
+  // pick the right mode of the layer
+  if ( mLayer->labeling() && mLayer->labeling()->type() == "rule-based" )
+  {
+    mLabelModeComboBox->setCurrentIndex( 3 );
+  }
+  else
   {
-    mStackedWidget->setCurrentIndex( 0 );
-
     // load labeling settings from layer
     QgsPalLayerSettings lyr;
     lyr.readFromLayer( mLayer );
@@ -41,41 +39,56 @@ void QgsLabelingWidget::init()
     {
       mLabelModeComboBox->setCurrentIndex( lyr.drawLabels ? 1 : 2 );
     }
-
-    mWidgetSimple->init();
-  }
-  else if ( mLayer->labeling() && mLayer->labeling()->type() == "rule-based" )
-  {
-    mStackedWidget->setCurrentIndex( 1 );
-    mWidgetRules->init();
   }
 }
 
 void QgsLabelingWidget::writeSettingsToLayer()
 {
-  if ( mLabelModeComboBox->currentIndex() < 3 )
+  if ( mLabelModeComboBox->currentIndex() == 3 )
   {
-    mWidgetSimple->writeSettingsToLayer();
+    qobject_cast<QgsRuleBasedLabelingWidget*>( mWidget )->writeSettingsToLayer();
   }
   else
   {
-    mWidgetRules->writeSettingsToLayer();
+    qobject_cast<QgsLabelingGui*>( mWidget )->writeSettingsToLayer();
   }
 }
 
 
-void QgsLabelingWidget::on_mLabelModeComboBox_currentIndexChanged( int index )
+void QgsLabelingWidget::labelModeChanged( int index )
 {
   if ( index < 3 )
   {
-    mStackedWidget->setCurrentIndex( 0 );
-    mWidgetSimple->setLabelMode( ( QgsLabelingGui::LabelMode ) index );
+    if ( QgsLabelingGui* widgetSimple = qobject_cast<QgsLabelingGui*>( mWidget ) )
+    {
+      // lighter variant - just change the mode of existing widget
+      widgetSimple->setLabelMode(( QgsLabelingGui::LabelMode ) index );
+      return;
+    }
+  }
+
+  // in general case we need to recreate the widget
+
+  if ( mWidget )
+    mStackedWidget->removeWidget( mWidget );
+
+  delete mWidget;
+  mWidget = 0;
+
+  if ( index == 3 )
+  {
+    mWidget = new QgsRuleBasedLabelingWidget( mLayer, mCanvas, this );
   }
   else
   {
-    // rule-based labeling
-    mStackedWidget->setCurrentIndex( 1 );
+    QgsLabelingGui* w = new QgsLabelingGui( mLayer, mCanvas, 0, this );
+    w->setLabelMode(( QgsLabelingGui::LabelMode ) index );
+    w->init();
+    mWidget = w;
   }
+
+  mStackedWidget->addWidget( mWidget );
+  mStackedWidget->setCurrentWidget( mWidget );
 }
 
 void QgsLabelingWidget::showEngineConfigDialog()

src/app/qgslabelingwidget.h

@@ -19,23 +19,20 @@ class QgsLabelingWidget : public QWidget, private Ui::QgsLabelingWidget
   public:
     QgsLabelingWidget( QgsVectorLayer* layer, QgsMapCanvas* canvas, QWidget* parent = 0 );
 
-    //! load config from layer
-    void init();
     //! save config to layer
     void writeSettingsToLayer();
 
   signals:
 
   protected slots:
-    void on_mLabelModeComboBox_currentIndexChanged( int index );
+    void labelModeChanged( int index );
     void showEngineConfigDialog();
 
   protected:
     QgsVectorLayer* mLayer;
     QgsMapCanvas* mCanvas;
 
-    QgsLabelingGui* mWidgetSimple;
-    QgsRuleBasedLabelingWidget* mWidgetRules;
+    QWidget* mWidget;
 };
 
 #endif // QGSLABELINGWIDGET_H