1 frmparam.h

     1 // Copyright (c) 1999-2009 Nokia Corporation and/or its subsidiary(-ies).

     2 // All rights reserved.

     3 // This component and the accompanying materials are made available

     4 // 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

     5 // which accompanies this distribution, and is available

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

     7 //

     8 // Initial Contributors:

     9 // Nokia Corporation - initial contribution.

    10 //

    11 // Contributors:

    12 //

    13 // Description:

    14 // FORM global parameters; held in thread-local storage.

    15 // 

    16 //

    17 

    18 #ifndef __FRMPARAM_H__

    19 #define __FRMPARAM_H__

    20 

    21 #include <gdi.h>

    22 

    23 

    24 /** 

    25 Specifies the protocol for getting system colours for use in text views. A

    26 class which implements this protocol allows an application (or a thread,

    27 because a pointer to the object is held in thread-local storage) to use system

    28 colours in text views.

    29 

    30 You should create an object of an MFormParam-derived class which implements the

    31 SystemColor() function. Then, pass a pointer to the object to the static

    32 function MFormParam::Set(). The MFormParam-derived object is owned by the

    33 caller of Set(). When system colours are no longer needed, you should cancel

    34 them by calling MFormParam::Set(NULL). It is the caller's responsibility to

    35 cause the text view to be redrawn after system colours are changed.

    36 

    37 CTextLayout uses the colour translation function SystemColor() (if an

    38 MFormParam-derived object is present) to set the pen and brush colours for

    39 drawing components of the text view. It calls MFormParam::Get() before each

    40 draw. This enables an application to introduce system colours, change the

    41 parameter object, or abolish system colours, and redraw everything correctly;

    42 no information is left over from the last draw.

    43 @publishedAll

    44 @released

    45 */

    46 class MFormParam

    47 

    48 	{

    49 	public:

    50 

    51 	/** Translates 8-bit logical colour indices to physical colours pure

    52 	virtual function.

    53 

    54 	The colour index is stored in a TLogicalRgb object and is returned by

    55 	TLogicalRgb::SystemColorIndex().

    56 

    57 	There are three reserved index values:

    58 

    59 	Zero means the logical colour does not map to a system colour: the logical

    60 	colour is in fact an ordinary TRgb. This function should not normally be

    61 	called with this value.

    62 

    63 	254 and 255 are default foreground and background colours respectively, and

    64 	should be converted to the GUI's standard foreground and background colours

    65 

    66 	The values 1-253 are reserved for the use of the GUI and can be interpreted

    67 	as convenient. These can be interpreted as

    68 	TLogicalColor::EColorWindowBackground upward; this mapping can be done by

    69 	subtracting one from the index number aColorIndex.

    70 

    71 	@param aColorIndex Logical colour index. Between 1 and 255 inclusive.

    72 	@param aDefaultColor The default colour. This is the colour to be used if

    73 	no translation is performed. This allows translation to change certain

    74 	indices but not others, (by passing the default colour back unchanged).

    75 	@return The physical colour which maps to the logical colour index. */

    76 	virtual TRgb SystemColor(TUint aColorIndex,TRgb aDefaultColor) const = 0;

    77 	IMPORT_C virtual void Reserved();

    78 	IMPORT_C static void Set(const MFormParam* aParam);

    79 	IMPORT_C static const MFormParam* Get();

    80 	};

    81 

    82 #endif // __FRMPARAM_H__