// Copyright (c) 2005-2009 Nokia Corporation and/or its subsidiary(-ies).

// All rights reserved.

// This component and the accompanying materials are made available

// under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

// which accompanies this distribution, and is available

// at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// This is the extension to the plugin API for the Image Display framework

// 

//

#ifndef EXIFIMAGEDISPLAYEXT_H

#define EXIFIMAGEDISPLAYEXT_H

#include <e32base.h>

#include <icl/imagedisplaypluginext.h>

#include <icl/exifimagedisplay.hrh>

const TUid KExifImageDisplayExtensionUid={KUidExifImageDisplayExtension};

class MExifMetadataReader;

/**

This class extends the functionality of the Image Display Library client API defined 

in the class CImageDisplay. This extension is supported only by the EXIF-specific framework

plug-ins. In order to invoke the extended functionality, the user needs to call the 

CImageDisplay::ExtensionInterface( ) with the KExifImageDisplayExtensionUid interface UID

and an interface pointer to the object of this class.

@publishedAll

@released

*/

class MExifImageDisplayExtension :public MImageDisplayPluginExtension

	{

public:

	/**

	Obtains an MExifMetadataReader that can be used to access the EXIF metadata of the image.

	@param aPtr A reference to a pointer to the MExifMetadataReader that can be used to access the EXIF

				metadata of the image.

	@return A system-wide error code.

	*/

	virtual TInt GetExifMetadataReader(MExifMetadataReader*& aPtr)=0;

	/**

	Sets the level of quality for the scaling algorithm.

	If quality level is not set by calling this function then 

	the fastest/lowest quality algorithm is used.

	Note: This function must be called before calling CImageDisplay::Play()

	@param aQualityLevel Quality level value for the scaling algorithm.

				See CBitmapScaler::TQualityAlgorithm for a set of possible values.

	@return A system-wide error code.

	*/	

	virtual TInt SetScaleQuality(TInt aQualityLevel)=0;

	/**

	Sets the maximum quality reduction factor for image decoding.

	By default, the plug-in calculates an optimal maximum reduction factor 

	and uses it to produce a series of roughly-decoded images, passing each of 

	them to the observer interface with the CImageDisplayPlugin::EStatusPartialFrame flag set.

	Note: This function must be called before calling CImageDisplay::Play().

	@param aMaxReductionFactor

				The maximum quality reduction factor.

				Usually the maximum reduction can be specfied in range of 0-3.

				A value of 0 means no quality reduction is allowed, so a full-quality image will be decoded as the first frame.

				A value of 1 means (1/2)^1=1/2 of the original image quality. 

				A value of 3 means (1/2)^3=1/8 of the original image quality. 

				If the reduction factor is not set by calling this function then

				the reduction factor value of 3 is used for jpeg images.

	@return KErrArgument if the aMaxReductionFactor parameter is not in the supported range, or a system-wide error code.

	*/	

	virtual TInt SetMaximumReductionFactor(TInt aMaxReductionFactor)=0;

	};

#endif // EXIFIMAGEDISPLAYEXT_H