--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/photosgallery/slideshow/engine/inc/shwengineobserver.h	Thu Dec 17 08:45:44 2009 +0200
@@ -0,0 +1,85 @@
+/*
+* Copyright (c) 2007-2008 Nokia Corporation and/or its subsidiary(-ies). 
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description:    The event observer interface
+ *
+*/
+
+
+
+
+#ifndef __MSHWENGINEOBSERVER_H__
+#define __MSHWENGINEOBSERVER_H__
+
+// INCLUDES
+#include <e32std.h>
+#include <e32base.h>
+
+// CLASS DECLARATION
+
+/**
+ *  MShwEventObserver
+ */
+class MShwEngineObserver
+	{
+	protected:
+	
+		/**
+		 * Destructor. Dont allow deleting objects through this interface.
+		 */
+		virtual ~MShwEngineObserver() {};
+
+	public: // the API
+
+		/**
+		 * This notification is called once the engine is started,
+		 * meaning that the slideshow is running.
+		 */
+		virtual void EngineStartedL() = 0;
+
+		/**
+		 * This notification is called once the engine is paused,
+		 * meaning that the slideshow is frozen.
+		 */
+		virtual void EnginePausedL() = 0;
+
+		/**
+		 * This notification is called once the engine is resumed,
+		 * meaning that the slideshow is re-running after a pause
+		 */
+		virtual void EngineResumedL() = 0;
+		
+		/**
+         * This notification is called once the selection key, EngineLSKPressedL
+         * pressed.
+         */
+        virtual void EngineToggleUiStateL() = 0;
+        
+        /**
+         * LSk pressed.
+         */
+        virtual void EngineLSKPressedL() = 0;
+
+        /**
+         * This notification is called when there is such an error during 
+         * slideshow that it cannot continue, for example all items got removed.
+         * This method is allowed to leave, in which case slideshow engine panics
+         * with EEngineFatalError. This is ok as in case of error all we can do is
+         * try to exit slideshow, either easy way or hard way :)
+         * @exception EEngineFatalError if this method does leave.
+         */
+        virtual void ErrorDuringSlideshowL() = 0;
+
+	};
+
+#endif // __MSHWENGINEOBSERVER_H__