[composer] Simplify and consolidate loading of templates

On behalf of Faunalia, sponsored by ENEL

(cherry-picked from 656e56e)

src/app/composer/qgscomposer.cpp

@@ -877,6 +877,21 @@ void QgsComposer::setTitle( const QString& title )
   }
 }
 
+bool QgsComposer::loadFromTemplate( const QDomDocument& templateDoc, bool clearExisting )
+{
+  // provide feedback, since composer will be hidden when loading template (much faster)
+  QScopedPointer< QDialog > dlg( new QgsBusyIndicatorDialog( tr( "Loading template into composer..." ), this ) );
+  dlg->setStyleSheet( mQgis->styleSheet() );
+  dlg->show();
+
+  setUpdatesEnabled( false );
+  bool result = mComposition->loadFromTemplate( templateDoc, nullptr, false, clearExisting );
+  setUpdatesEnabled( true );
+
+  dlg->close();
+  return result;
+}
+
 void QgsComposer::updateStatusCursorPos( QPointF cursorPosition )
 {
   if ( !mComposition )
@@ -3040,11 +3055,9 @@ void QgsComposer::on_mActionSaveAsTemplate_triggered()
 
 void QgsComposer::on_mActionLoadFromTemplate_triggered()
 {
-  loadTemplate( false );
-}
+  if ( !mComposition )
+    return;
 
-void QgsComposer::loadTemplate( const bool newComposer )
-{
   QSettings settings;
   QString openFileDir = settings.value( "UI/lastComposerTemplateDir", QDir::homePath() ).toString();
   QString openFileString = QFileDialog::getOpenFileName( nullptr, tr( "Load template" ), openFileDir, "*.qpt" );
@@ -3064,48 +3077,10 @@ void QgsComposer::loadTemplate( const bool newComposer )
     return;
   }
 
-  QgsComposer* c = nullptr;
-  QgsComposition* comp = nullptr;
-
-  if ( newComposer )
+  QDomDocument templateDoc;
+  if ( templateDoc.setContent( &templateFile ) )
   {
-    QString newTitle;
-    if ( !mQgis->uniqueComposerTitle( this, newTitle, true ) )
-    {
-      return;
-    }
-    c = mQgis->createNewComposer( newTitle );
-    if ( !c )
-    {
-      QMessageBox::warning( this, tr( "Composer error" ), tr( "Error, could not create new composer" ) );
-      return;
-    }
-    comp = c->composition();
-  }
-  else
-  {
-    c = this;
-    comp = mComposition;
-  }
-
-  if ( comp )
-  {
-    QDomDocument templateDoc;
-    if ( templateDoc.setContent( &templateFile ) )
-    {
-      // provide feedback, since composer will be hidden when loading template (much faster)
-      QDialog* dlg = new QgsBusyIndicatorDialog( tr( "Loading template into composer..." ) );
-      dlg->setStyleSheet( mQgis->styleSheet() );
-      dlg->show();
-
-      c->setUpdatesEnabled( false );
-      comp->loadFromTemplate( templateDoc, nullptr, false, newComposer );
-      c->setUpdatesEnabled( true );
-
-      dlg->close();
-      delete dlg;
-      dlg = nullptr;
-    }
+    loadFromTemplate( templateDoc, false );
   }
 }
 

src/app/composer/qgscomposer.h

@@ -99,9 +99,12 @@ class QgsComposer: public QMainWindow, private Ui::QgsComposerBase
     const QString& title() const {return mTitle;}
     void setTitle( const QString& title );
 
-    //! Load template into current or blank composer
-    //! @param newComposer whether to create a new composer first
-    void loadTemplate( const bool newComposer );
+    /** Loads the contents of a template document into the composer's composition.
+     * @param templateDoc template document to load
+     * @param clearExisting set to true to remove all existing composition settings and items before loading template
+     * @returns true if template load was successful
+     */
+    bool loadFromTemplate( const QDomDocument& templateDoc, bool clearExisting );
 
   protected:
     //! Move event

src/app/composer/qgscomposermanager.cpp

@@ -289,19 +289,8 @@ void QgsComposerManager::on_mAddButton_clicked()
     QDomDocument templateDoc;
     if ( templateDoc.setContent( &templateFile, false ) )
     {
-      // provide feedback, since composer will be hidden when loading template (much faster)
-      // (not needed for empty composer)
-      QDialog* dlg = new QgsBusyIndicatorDialog( tr( "Loading template into composer..." ) );
-      dlg->setStyleSheet( QgisApp::instance()->styleSheet() );
-      dlg->show();
-
-      newComposer->hide();
-      loadedOK = newComposer->composition()->loadFromTemplate( templateDoc, nullptr, false );
+      loadedOK = newComposer->loadFromTemplate( templateDoc, true );
       newComposer->activate();
-
-      dlg->close();
-      delete dlg;
-      dlg = nullptr;
     }
   }
 

src/app/qgisapp.cpp

@@ -6137,16 +6137,14 @@ QgsComposer* QgisApp::duplicateComposer( QgsComposer* currentComposer, QString t
 
   // hiding composer until template is loaded is much faster, provide feedback to user
   newComposer->hide();
-  QApplication::setOverrideCursor( Qt::BusyCursor );
-  if ( !newComposer->composition()->loadFromTemplate( currentDoc, nullptr, false ) )
+  if ( !newComposer->loadFromTemplate( currentDoc, true ) )
   {
     deleteComposer( newComposer );
     newComposer = nullptr;
     QgsDebugMsg( "Error, composer could not be duplicated" );
     return newComposer;
   }
   newComposer->activate();
-  QApplication::restoreOverrideCursor();
 
   return newComposer;
 }