Better method to autogenerate composer names

Author: nyalldawson

python/core/composer/qgslayoutmanager.sip

@@ -19,6 +19,7 @@ class QgsLayoutManager : QObject
     QDomElement writeXml( QDomDocument &doc ) const;
     bool saveAsTemplate( const QString &name, QDomDocument &doc ) const;
     QgsComposition *duplicateComposition( const QString &name, const QString &newName );
+    QString generateUniqueTitle() const;
 
   signals:
     void compositionAdded( const QString& name );

src/app/qgisapp.cpp

@@ -1082,7 +1082,6 @@ QgisApp::QgisApp( QSplashScreen *splash, bool restorePlugins, bool skipVersionCh
 
   mMapCanvas->freeze( false );
   mMapCanvas->clearExtentHistory(); // reset zoomnext/zoomlast
-  mLastComposerId = 0;
 
   QShortcut *zoomInShortCut = new QShortcut( QKeySequence( tr( "Ctrl++" ) ), this );
   connect( zoomInShortCut, &QShortcut::activated, mMapCanvas, &QgsMapCanvas::zoomIn );
@@ -1268,7 +1267,6 @@ QgisApp::QgisApp()
   , mMapStyleWidget( nullptr )
   , mComposerManager( nullptr )
   , mpTileScaleWidget( nullptr )
-  , mLastComposerId( 0 )
   , mpGpsWidget( nullptr )
   , mLastMapToolMessage( nullptr )
   , mLogViewer( nullptr )
@@ -6957,6 +6955,7 @@ bool QgisApp::uniqueComposerTitle( QWidget *parent, QString &composerTitle, bool
       else
       {
         titleValid = true;
+        newTitle = QgsProject::instance()->layoutManager()->generateUniqueTitle();
       }
     }
     else if ( cNames.indexOf( newTitle, 1 ) >= 0 )
@@ -6977,11 +6976,9 @@ bool QgisApp::uniqueComposerTitle( QWidget *parent, QString &composerTitle, bool
 
 QgsComposer *QgisApp::createNewComposer( QString title )
 {
-  //ask user about name
-  mLastComposerId++;
   if ( title.isEmpty() )
   {
-    title = tr( "Composer %1" ).arg( mLastComposerId );
+    title = QgsProject::instance()->layoutManager()->generateUniqueTitle();
   }
   //create new composition object
   QgsComposition *composition = new QgsComposition( QgsProject::instance() );
@@ -7060,7 +7057,6 @@ void QgisApp::deletePrintComposers()
     emit composerRemoved( c->view() );
     delete ( c );
   }
-  mLastComposerId = 0;
 }
 
 void QgisApp::composerMenuAboutToShow()

src/app/qgisapp.h

@@ -1884,8 +1884,6 @@ class APP_EXPORT QgisApp : public QMainWindow, private Ui::MainWindow
 
     QList<QgsDecorationItem *> mDecorationItems;
 
-    int mLastComposerId;
-
     //! Persistent GPS toolbox
     QgsGPSInformationWidget *mpGpsWidget = nullptr;
 

src/core/composer/qgslayoutmanager.cpp

@@ -175,6 +175,23 @@ QgsComposition *QgsLayoutManager::duplicateComposition( const QString &name, con
   }
 }
 
+QString QgsLayoutManager::generateUniqueTitle() const
+{
+  QStringList names;
+  Q_FOREACH ( QgsComposition *c, mCompositions )
+  {
+    names << c->name();
+  }
+  QString name;
+  int id = 1;
+  while ( name.isEmpty() || names.contains( name ) )
+  {
+    name = tr( "Composer %1" ).arg( id );
+    id++;
+  }
+  return name;
+}
+
 QgsComposition *QgsLayoutManager::createCompositionFromXml( const QDomElement &element, const QDomDocument &doc ) const
 {
   QDomNodeList compositionNodeList = element.elementsByTagName( QStringLiteral( "Composition" ) );

src/core/composer/qgslayoutmanager.h

@@ -113,6 +113,12 @@ class CORE_EXPORT QgsLayoutManager : public QObject
      */
     QgsComposition *duplicateComposition( const QString &name, const QString &newName );
 
+    /**
+     * Generates a unique title for a new composition, which does not
+     * clash with any already contained by the manager.
+     */
+    QString generateUniqueTitle() const;
+
   signals:
 
     //! Emitted when a composition has been added to the manager

tests/src/python/test_qgslayoutmanager.py

@@ -233,6 +233,24 @@ def testDuplicateComposition(self):
         self.assertEqual(result.paperHeight(), 200)
         self.assertEqual(result.paperWidth(), 100)
 
+    def testGenerateUniqueTitle(self):
+        project = QgsProject()
+        manager = QgsLayoutManager(project)
+        self.assertEqual(manager.generateUniqueTitle(), 'Composer 1')
+
+        composition = QgsComposition(project)
+        composition.setName(manager.generateUniqueTitle())
+        manager.addComposition(composition)
+
+        self.assertEqual(manager.generateUniqueTitle(), 'Composer 2')
+        composition2 = QgsComposition(project)
+        composition2.setName(manager.generateUniqueTitle())
+        manager.addComposition(composition2)
+
+        self.assertEqual(manager.generateUniqueTitle(), 'Composer 3')
+        manager.clear()
+        self.assertEqual(manager.generateUniqueTitle(), 'Composer 1')
+
 
 if __name__ == '__main__':
     unittest.main()