1 /*

     2 * Copyright (c) 2006-2006 Nokia Corporation and/or its subsidiary(-ies).

     3 * All rights reserved.

     4 * This component and the accompanying materials are made available

     5 * under the terms of "Eclipse Public License v1.0"

     6 * which accompanies this distribution, and is available

     7 * at the URL "http://www.eclipse.org/legal/epl-v10.html".

     8 *

     9 * Initial Contributors:

    10 * Nokia Corporation - initial contribution.

    11 *

    12 * Contributors:

    13 *

    14 * Description:   Quick thumbnail generation task.

    15 *

    16 */

    17 

    18 

    19 

    20 /**

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

    22  */

    23 

    24 #ifndef C_GLXTNQUICKTHUMBNAILTASK_H

    25 #define C_GLXTNQUICKTHUMBNAILTASK_H

    26 

    27 #include "glxtnloadthumbnailtask.h"

    28 #include "glxthumbnailinfo.h"

    29 

    30 // Forward declarations

    31 class CGlxtnFileUtility;

    32 class CGlxtnVideoUtility;

    33 class CFbsBitmap;

    34 

    35 /**

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

    37  * thumbnail.

    38  *

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

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

    41  * from the data and used to produce a bitmap.

    42  *

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

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

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

    46  * as close as possible to the required thumbnail size.

    47  *

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

    49  *

    50  * @author Dan Rhodes

    51  * @ingroup glx_thumbnail_creator

    52  */

    53 NONSHARABLE_CLASS( CGlxtnQuickThumbnailTask ) : public CGlxtnLoadThumbnailTask

    54     {

    55 public:

    56     /**

    57     * Two-phased constructor.

    58     * @param aRequestInfo Parameters for the thumbnail request.

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

    60     * @param aClient Client initiating the request.

    61     */

    62 	static CGlxtnQuickThumbnailTask* NewL(

    63         const TGlxThumbnailRequest& aRequestInfo,

    64         CGlxtnFileUtility& aFileUtility, MGlxtnThumbnailCreatorClient& aClient);

    65     /**

    66     * Destructor.

    67     */

    68     ~CGlxtnQuickThumbnailTask();

    69 

    70 protected:  // From CGlxtnTask

    71 

    72     TBool DoStartL(TRequestStatus& aStatus);

    73 	void DoCancel();

    74 	TBool DoRunL(TRequestStatus& aStatus);

    75     TBool DoRunError(TInt aError);

    76 

    77 private:

    78     /**

    79     * C++ default constructor.

    80     * @param aRequestInfo Parameters for the thumbnail request.

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

    82     * @param aClient Client initiating the request.

    83     */

    84     CGlxtnQuickThumbnailTask(const TGlxThumbnailRequest& aRequestInfo,

    85         CGlxtnFileUtility& aFileUtility, MGlxtnThumbnailCreatorClient& aClient);

    86 

    87     /**

    88     * Start asynchronous decoding process for a low quality thumbnail.

    89     * @param aStatus Request status for the asynchronous operation.

    90     */

    91     void QuickDecodeL(TRequestStatus& aStatus);

    92     /**

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

    94     * @param aStatus Request status for the asynchronous operation.

    95     */

    96     void ReadThumbnailL(TRequestStatus& aStatus);

    97     /**

    98     * Read thumbnail data from the file using ExifLib.

    99     */

   100     void ReadExifThumbnailL();

   101     void QuickScaleL();

   102 

   103 private:

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

   105     TGlxThumbnailQuality iQuality;

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

   107     CGlxtnVideoUtility* iUtility;

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

   109     CFbsBitmap* iVideoFrame;

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

   111     TBool iVideo;

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

   113     TBool iBadFileMarkerNotNeededFlag;

   114     };

   115 

   116 #endif // C_GLXTNQUICKTHUMBNAILTASK_H