/*

* 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__