photosgallery/slideshow/engine/coresrc/shwthumbnailloader.h
changeset 0 4e91876724a2
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/photosgallery/slideshow/engine/coresrc/shwthumbnailloader.h	Thu Dec 17 08:45:44 2009 +0200
@@ -0,0 +1,124 @@
+/*
+* 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:    Utility that handles thumbnail loading
+ *
+*/
+
+
+
+
+#ifndef __CSHWTHUMBNAILLOADER_H__
+#define __CSHWTHUMBNAILLOADER_H__
+
+// INCLUDES
+#include <e32std.h>
+#include <e32base.h>
+
+// FORWARD DECLARATIONS
+class MGlxMediaList;
+
+// CLASS DECLARATIONS
+
+/**
+ * MShwThumbnailLoadObserver
+ * Interface to handle errors in thumbnail loading
+ * for the slide show
+ */
+NONSHARABLE_CLASS( MShwThumbnailLoadObserver )
+	{
+	public:
+
+		/**
+		 * This method gets called when given thumbnail is loaded
+		 * @param aIndex the index for which thumbnail is loaded
+		 */
+		virtual void HandleThumbnailLoadedL( TInt aIndex ) = 0;
+
+		/**
+		 * This method gets called when thumbnail loading
+		 * fails for a given index
+		 * @param aIndex the index for which thumbnail load fails
+		 */
+		virtual void HandleThumbnailLoadFailureL( TInt aIndex ) = 0;
+    
+		/**
+		 * This method gets called when the media list
+		 * becomes empty
+		 */
+        virtual void HandleMediaListEmpty() = 0;
+
+	};
+
+/**
+ * CShwThumbnailLoader
+ * Class to handle proper thumbnail loading and image size retrieval
+ * for the slide show
+ * @lib shwslideshowengine.lib
+ */
+NONSHARABLE_CLASS( CShwThumbnailLoader ) 
+	: public CBase
+	{
+	public: // Constructors and destructor
+
+		/**
+		 * Constructor.
+		 * @param aMedialist used for thumbnail loading
+		 */
+		static CShwThumbnailLoader* NewL( 
+			MGlxMediaList& aMedialist,
+			MShwThumbnailLoadObserver& aErrorHandler );
+		
+		/**
+		 * Destructor.
+		 */
+		~CShwThumbnailLoader();
+
+	public: // the API
+
+		/**
+		 * This method is used to load a thumbnail and get a callback once it
+		 * is loaded. Note! This method is always asynchronous.
+		 * @param aIndex the index
+		 * @param aSize the thumbnail size
+		 */
+		void LoadAndNotifyL( TInt aIndex, TSize aSize );
+		
+		/**
+		 * This method is used to unload a thumbnail
+		 * @param aIndex the index
+		 */
+		void Unload( TInt aIndex );
+		
+		/**
+		 * This method retrieves the size of an image for a given index.
+		 * It is the caller's responsibility to give a valid index!
+		 * If the imagesize is not yet loaded the method returns 
+		 * TSize( KErrNotFound, KErrNotFound );
+		 * @param aIndex the index
+		 * @return the size of the image
+		 */
+		TSize ImageSizeL( TInt aIndex );
+		
+	private:	// Data & Implementation
+
+		/// C++ constructor, no derivation intended
+		CShwThumbnailLoader();
+
+		/// Own: The implementation details
+		class CShwThumbnailLoaderImpl;
+		CShwThumbnailLoaderImpl* iImpl;
+
+	};
+
+#endif // __CSHWTHUMBNAILLOADER_H__