sl@0: /*
sl@0: * Copyright (c) 1999-2009 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: * FORM global parameters; held in thread-local storage.
sl@0: *
sl@0: */
sl@0: 
sl@0: 
sl@0: #ifndef __FRMPARAM_H__
sl@0: #define __FRMPARAM_H__
sl@0: 
sl@0: #include <gdi.h>
sl@0: 
sl@0: 
sl@0: /** 
sl@0: Specifies the protocol for getting system colours for use in text views. A
sl@0: class which implements this protocol allows an application (or a thread,
sl@0: because a pointer to the object is held in thread-local storage) to use system
sl@0: colours in text views.
sl@0: 
sl@0: You should create an object of an MFormParam-derived class which implements the
sl@0: SystemColor() function. Then, pass a pointer to the object to the static
sl@0: function MFormParam::Set(). The MFormParam-derived object is owned by the
sl@0: caller of Set(). When system colours are no longer needed, you should cancel
sl@0: them by calling MFormParam::Set(NULL). It is the caller's responsibility to
sl@0: cause the text view to be redrawn after system colours are changed.
sl@0: 
sl@0: CTextLayout uses the colour translation function SystemColor() (if an
sl@0: MFormParam-derived object is present) to set the pen and brush colours for
sl@0: drawing components of the text view. It calls MFormParam::Get() before each
sl@0: draw. This enables an application to introduce system colours, change the
sl@0: parameter object, or abolish system colours, and redraw everything correctly;
sl@0: no information is left over from the last draw.
sl@0: @publishedAll
sl@0: @released
sl@0: */
sl@0: class MFormParam
sl@0: 
sl@0: 	{
sl@0: 	public:
sl@0: 
sl@0: 	/** Translates 8-bit logical colour indices to physical colours pure
sl@0: 	virtual function.
sl@0: 
sl@0: 	The colour index is stored in a TLogicalRgb object and is returned by
sl@0: 	TLogicalRgb::SystemColorIndex().
sl@0: 
sl@0: 	There are three reserved index values:
sl@0: 
sl@0: 	Zero means the logical colour does not map to a system colour: the logical
sl@0: 	colour is in fact an ordinary TRgb. This function should not normally be
sl@0: 	called with this value.
sl@0: 
sl@0: 	254 and 255 are default foreground and background colours respectively, and
sl@0: 	should be converted to the GUI's standard foreground and background colours
sl@0: 
sl@0: 	The values 1-253 are reserved for the use of the GUI and can be interpreted
sl@0: 	as convenient. These can be interpreted as
sl@0: 	TLogicalColor::EColorWindowBackground upward; this mapping can be done by
sl@0: 	subtracting one from the index number aColorIndex.
sl@0: 
sl@0: 	@param aColorIndex Logical colour index. Between 1 and 255 inclusive.
sl@0: 	@param aDefaultColor The default colour. This is the colour to be used if
sl@0: 	no translation is performed. This allows translation to change certain
sl@0: 	indices but not others, (by passing the default colour back unchanged).
sl@0: 	@return The physical colour which maps to the logical colour index. */
sl@0: 	virtual TRgb SystemColor(TUint aColorIndex,TRgb aDefaultColor) const = 0;
sl@0: 	IMPORT_C virtual void Reserved();
sl@0: 	IMPORT_C static void Set(const MFormParam* aParam);
sl@0: 	IMPORT_C static const MFormParam* Get();
sl@0: 	};
sl@0: 
sl@0: #endif // __FRMPARAM_H__