/*

* Copyright (c) 2006-2007 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:  Thumbnail Manager observer.

 *

*/

#ifndef THUMBNAILMANAGEROBSERVER_H

#define THUMBNAILMANAGEROBSERVER_H

#include "thumbnailobjectsource.h"

class MThumbnailData;

/**

 *  Thumbnail observer.

 *

 *  Callback interface for getting information about completed thumbnail

 *  operations. This should be implemented by the client using the API.

 *

 *  Example of how the client may implement the ThumbnailReady()

 *  method:

 *  @code

 *  void CMyThumbnailControl::ThumbnailReady(

 *      TInt aError,

 *      MThumbnailData& aThumbnail,

 *      TThumbnailRequestId aId )

 *      {

 *      // This function must not leave.

 *      delete iBitmap;

 *      iBitmap = NULL;

 *

 *      if ( !aError )

 *          {

 *          // Claim ownership of the bitmap instance for later use

 *          iBitmap = aThumbnail.DetachBitmap();

 *          // We can now use iBitmap in our Draw() method

 *          DrawDeferred();

 *          }

 *      else

 *          {

 *          // An error occurred while getting the thumbnail.

 *          // Perhaps we should show a broken image icon to the user.

 *          }

 *      }

 *  @endcode

 *  @since S60 v5.0

 */

class MThumbnailManagerObserver

    {

public:

    /**

     * Preview thumbnail generation or loading is complete.

     *

     * This callback is not called unless EOptimizeForQualityWithPreview flag

     * was specified.

     *

     * This callback is not called if any of the following is true:

     * - an error occurred while processing the preview thumbnail

     * - a suitable existing thumbnail was not found

     * - a high quality thumbnail is already available

     *

     * The MThumbnailData instance is only valid for the duration of

     * this call. It may not be stored for later use. If the client should

     * want to use the bitmap data later, it can claim ownership of the

     * CFbsBitmap object by calling DetachBitmap().

     *

     * @since S60 v5.0

     * @param aThumbnail     An object representing the resulting thumbnail.

     * @param aId            Request ID for the operation

     */

    virtual void ThumbnailPreviewReady( MThumbnailData& aThumbnail,

        TThumbnailRequestId aId ) = 0;

    /**

     * Final thumbnail bitmap generation or loading is complete.

     *

     * The MThumbnailData instance is only valid for the duration of

     * this call. It may not be stored for later use. If the client should

     * want to use the bitmap data later, it can claim ownership of the

     * CFbsBitmap object by calling DetachBitmap().

     *

     * @since S60 v5.0

     * @param aError         Error code.

     * @param aThumbnail     An object representing the resulting thumbnail.

     * @param aId            Request ID for the operation.

     */

    virtual void ThumbnailReady( TInt aError, MThumbnailData& aThumbnail,

        TThumbnailRequestId aId ) = 0;

};

#endif // THUMBNAILMANAGEROBSERVER_H