sl@0: /*
sl@0: * Copyright (c) 1998-2009 Nokia Corporation and/or its subsidiary(-ies).
sl@0: * All rights reserved.
sl@0: * This component and the accompanying materials are made available
sl@0: * under the terms of "Eclipse Public License v1.0"
sl@0: * which accompanies this distribution, and is available
sl@0: * at the URL "http://www.eclipse.org/legal/epl-v10.html".
sl@0: *
sl@0: * Initial Contributors:
sl@0: * Nokia Corporation - initial contribution.
sl@0: *
sl@0: * Contributors:
sl@0: *
sl@0: * Description: 
sl@0: * The Open Font rasterizer plug-in Interface Definition class.
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: #ifndef OPENFONTRASTERIZER_H
sl@0: #define OPENFONTRASTERIZER_H
sl@0: 
sl@0: #include <ecom/ecom.h>
sl@0: 
sl@0: class COpenFontFile;
sl@0: 
sl@0: /**
sl@0: Supplied to COpenFontRasterizer::ExtendedInterface() to access the extended
sl@0: API interface MOpenFontLinkedTypefaceExtension.
sl@0: 
sl@0: @see	COpenFontRasterizer::ExtendedInterface()
sl@0: @see	MOpenFontLinkedTypefaceExtension
sl@0: @publishedPartner
sl@0: @prototype
sl@0: */
sl@0: const TUid KUidLinkedTypefaceRasterizerExtension = {0x10285EAA};
sl@0: 
sl@0: /**
sl@0: The Open Font rasterizer plug-in Interface Definition class. 
sl@0: 
sl@0: This interface allows the implementation of an Open Font rasterizer plug-in,
sl@0: which can then be dynamically loaded at run time by the ECOM plug-in framework. 
sl@0: The plug-in implementation is instantiated by calling NewL(), passing the implementation 
sl@0: UID so that ECOM can instantiate the correct implementation. 
sl@0: 
sl@0: The rasterizer interface declares a single pure virtual functions, which the 
sl@0: plug-in derived from this interface must implement. The function reads font files, and creates 
sl@0: a COpenFontFile object if the font file is of the right type.
sl@0: 
sl@0: Writing derived classes:
sl@0: 
sl@0: Open font rasterizers should derive from this class and implement the 
sl@0: NewFontFileL() function.
sl@0: 
sl@0: Derived classes should also define the factory function. It is a static function 
sl@0: which takes no arguments. It creates a COpenFontRasterizer derived object on the heap, and returns it 
sl@0: to the caller. This factory function, together with the implementation UID will form 
sl@0: the TImplementationProxy used by the ECOM framework to instatiate the plug-in. 
sl@0: 
sl@0: The rasterizer class may also need to store an 'engine context'. This is an 
sl@0: object derived from COpenFontRasterizerContext, which provides functions that 
sl@0: make it easier to write the glyph bitmap during rasterization.
sl@0: 
sl@0: 
sl@0: @publishedPartner
sl@0: @released
sl@0: */
sl@0: class COpenFontRasterizer: public CBase
sl@0: 	{
sl@0: public:
sl@0: 	/** Creates a COpenFontFile derived object for loading font files in the 
sl@0: 	new format. 
sl@0: 
sl@0: 	This function is called by the framework during font and bitmap server 
sl@0: 	startup. It creates a font file object for font files in the \\resource\\fonts 
sl@0: 	directory on all drives, using the default search path. The first font of 
sl@0: 	a given name overrides subsequent ones. The directory search path is soft 
sl@0: 	to hard: Y:, X:, W:, ..., C:, B:, A:, Z:. Files may also be added 
sl@0: 	dynamically after startup using CWsScreenDevice::AddFile(), which 
sl@0: 	indirectly calls this function.
sl@0: 
sl@0: 	Implementations of this function should examine the file aFileName, and if 
sl@0: 	it is of the correct type attempt to create a COpenFontFile derived object 
sl@0: 	to load it. The caller is responsible for deleting the object. The function 
sl@0: 	must return NULL if it cannot recognise the file, and it may also leave if 
sl@0: 	there is an error. 
sl@0: 
sl@0: 	@param aUid An ID to be used for the file. UIDs are required by the font 
sl@0: 	framework, so the font store allocates them for non Symbian OS-native font 
sl@0: 	files. This ID persists until the font is unloaded, e.g. if the device is 
sl@0: 	rebooted.
sl@0: 	@param	aFileName		The full path and filename of the file from which the COpenFontFile
sl@0: 							object is created, if the file is the correct type.
sl@0: 	@param	aFileSession	The file session owned by the Font and Bitmap server. This file session 
sl@0: 							should be used for any file access. If COpenFontFile objects need to keep 
sl@0: 							files open, aFileSession should be stored in a place that is accessible to them. 
sl@0: 	@return	A pointer to a new COpenFontFile derived object, or NULL if the file type is not recognised.
sl@0: 	@see	CWsScreenDevice::AddFile() */
sl@0: 	virtual COpenFontFile* NewFontFileL(TInt aUid,const TDesC& aFileName,RFs& aFileSession) = 0;
sl@0: 	inline static COpenFontRasterizer* NewL(TUid aInterfaceImplUid);
sl@0: 	inline virtual ~COpenFontRasterizer();
sl@0: 	IMPORT_C virtual void ExtendedInterface(TUid aUid, TAny*& aParam);
sl@0: private:
sl@0: 	TUid iDtor_ID_Key;//ECOM identifier used during destruction
sl@0: 	};
sl@0: 
sl@0: /** Uses ECOM plug-in framework to instantiate the Open Font rasterizer interface 
sl@0: implementation given its implementation UID. 
sl@0: 
sl@0: @param	aInterfaceImplUid	The UID of the interface implementation required
sl@0: 
sl@0: @return	COpenFontRasterizer*	A pointer to a COpenFontRasterizer object. */
sl@0: inline COpenFontRasterizer* COpenFontRasterizer::NewL(TUid aInterfaceImplUid)
sl@0: {
sl@0: 	return reinterpret_cast <COpenFontRasterizer*> (
sl@0: 		REComSession::CreateImplementationL(
sl@0: 			aInterfaceImplUid,
sl@0: 			_FOFF(COpenFontRasterizer, iDtor_ID_Key))); 
sl@0: }
sl@0: 
sl@0: /** Default destructor */
sl@0: inline COpenFontRasterizer::~COpenFontRasterizer()
sl@0: {
sl@0: 	REComSession::DestroyedImplementation(iDtor_ID_Key);
sl@0: }
sl@0: 
sl@0: #endif /*OPENFONTRASTERIZER_H*/