Don't open multiple presentation widgets when slotShowPresentation() is called

multiple times (e.g. when the watched PDF has changed)

svn path=/trunk/kdegraphics/kpdf/; revision=383178

part.cpp

@@ -687,7 +687,10 @@ void Part::slotShowProperties()
 
 void Part::slotShowPresentation()
 {
-    new PresentationWidget( m_document );
+    if ( m_presentationWidget )
+      delete (PresentationWidget*) m_presentationWidget;
+
+    m_presentationWidget = new PresentationWidget( m_document );
 }
 
 void Part::slotPrint()

part.h

@@ -18,6 +18,7 @@
 
 #include <kparts/browserextension.h>
 #include <kparts/part.h>
+#include <qguardedptr.h>
 #include "core/observer.h"
 #include "dcop.h"
 
@@ -38,6 +39,7 @@ class KPDFDocument;
 class ThumbnailList;
 class ThumbnailController;
 class PageView;
+class PresentationWidget;
 class SearchWidget;
 
 namespace KPDF {
@@ -123,6 +125,7 @@ private:
 	SearchWidget *m_searchWidget;
 	ThumbnailList *m_thumbnailList;
 	PageView *m_pageView;
+  QGuardedPtr<PresentationWidget> m_presentationWidget;
 
 	// static instances counter
 	static unsigned int m_count;