/*

* Copyright (c) 2006-2006 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:    Quick thumbnail generation task.

*

*/

/**

 * @internal reviewed 30/07/2007 by Simon Brooks

 */

#ifndef C_GLXTNQUICKTHUMBNAILTASK_H

#define C_GLXTNQUICKTHUMBNAILTASK_H

#include "glxtnloadthumbnailtask.h"

#include "glxthumbnailinfo.h"

// Forward declarations

class CGlxtnFileUtility;

class CGlxtnVideoUtility;

class CFbsBitmap;

/**

 * Task to quickly produce a thumbnail for an item, usually from the EXIF

 * thumbnail.

 *

 * The task first attempts to extract the EXIF thumbnail data from the file

 * using ExifLib.  If this succeeds, an instance of CImageDecoder is constructed

 * from the data and used to produce a bitmap.

 *

 * If this fails, an instance of CImageDecoder is constructed from the file,

 * and set to use the thumbnail.  If this fails, it is assumed that there is no

 * EXIF thumbnail in the file, and the decoder is set to scale the main image

 * as close as possible to the required thumbnail size.

 *

 * No scaling or image enhancement is applied to the decoded bitmap.

 *

 * @author Dan Rhodes

 * @ingroup glx_thumbnail_creator

 */

NONSHARABLE_CLASS( CGlxtnQuickThumbnailTask ) : public CGlxtnLoadThumbnailTask

    {

public:

    /**

    * Two-phased constructor.

    * @param aRequestInfo Parameters for the thumbnail request.

    * @param aFileUtility File utility for use by the task.

    * @param aClient Client initiating the request.

    */

	static CGlxtnQuickThumbnailTask* NewL(

        const TGlxThumbnailRequest& aRequestInfo,

        CGlxtnFileUtility& aFileUtility, MGlxtnThumbnailCreatorClient& aClient);

    /**

    * Destructor.

    */

    ~CGlxtnQuickThumbnailTask();

protected:  // From CGlxtnTask

    TBool DoStartL(TRequestStatus& aStatus);

	void DoCancel();

	TBool DoRunL(TRequestStatus& aStatus);

    TBool DoRunError(TInt aError);

private:

    /**

    * C++ default constructor.

    * @param aRequestInfo Parameters for the thumbnail request.

    * @param aFileUtility File utility for use by the task.

    * @param aClient Client initiating the request.

    */

    CGlxtnQuickThumbnailTask(const TGlxThumbnailRequest& aRequestInfo,

        CGlxtnFileUtility& aFileUtility, MGlxtnThumbnailCreatorClient& aClient);

    /**

    * Start asynchronous decoding process for a low quality thumbnail.

    * @param aStatus Request status for the asynchronous operation.

    */

    void QuickDecodeL(TRequestStatus& aStatus);

    /**

    * Decode an image file using thumbnail embedded in the file if possible.

    * @param aStatus Request status for the asynchronous operation.

    */

    void ReadThumbnailL(TRequestStatus& aStatus);

    /**

    * Read thumbnail data from the file using ExifLib.

    */

    void ReadExifThumbnailL();

    void QuickScaleL();

private:

    /** Quality of thumbnail (high if loaded, low if generated) */

    TGlxThumbnailQuality iQuality;

    /** Utility to get thumbnail from video (owned) */

    CGlxtnVideoUtility* iUtility;

    /** Bitmap to hold video frame (owned) */

    CFbsBitmap* iVideoFrame;

    /** Whether the media file is a video */

    TBool iVideo;

    /** Flag to show BadFileMarker not created so no need to delete **/

    TBool iBadFileMarkerNotNeededFlag;

    };

#endif // C_GLXTNQUICKTHUMBNAILTASK_H