diff -r 000000000000 -r bde4ae8d615e os/textandloc/textrendering/texthandling/inc/TXTLAYDC.H --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/os/textandloc/textrendering/texthandling/inc/TXTLAYDC.H Fri Jun 15 03:10:57 2012 +0200 @@ -0,0 +1,180 @@ +/* +* Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies). +* All rights reserved. +* This component and the accompanying materials are made available +* under the terms of "Eclipse Public License v1.0" +* which accompanies this distribution, and is available +* at the URL "http://www.eclipse.org/legal/epl-v10.html". +* +* Initial Contributors: +* Nokia Corporation - initial contribution. +* +* Contributors: +* +* Description: +* +*/ + + +#ifndef __TXTLAYDC_H__ +#define __TXTLAYDC_H__ + +#include + +class CParaFormat; +class TCharFormat; +class CPicture; + + +class MLayDoc +/** +Specifies the interface for providing the information needed by the text +layout engine to lay out a text object. + +Examples of derived classes are CRichText and CGlobalText. + +At the heart of the interface are two interrogation functions; one gives the +paragraph formatting for a document position, and the other gives a pointer +descriptor to a series of contiguous characters with identical character +formatting, and their character formatting. This information is sufficient +for the layout engine to find the formatting and content of an entire document. + +The constructor for the layout engine (CTextLayout) is prototyped as: +static CTextLayout *NewL(MLayDoc *aDoc,TInt aWrapWidth); +By viewing the text object purely in terms of the MLayDoc interface, the layout +engine is insulated from any editable text implementation issues. +@see static CTextLayout *NewL(MLayDoc *aDoc,TInt aWrapWidth) +@publishedAll +@released +*/ + { + // Defines interface for extracting content & format information from text source. + // Designed to be 'mixed-in' with other classes. + // +public: + + /** Used as a parameter to the PictureHandleL() function to control whether + picture data should be loaded into memory or not. */ + enum TForcePictureLoad + { + /** Do not load the picture data into memory. */ + EForceLoadFalse, + /** Load the picture data into memory. */ + EForceLoadTrue + }; +public: + + /** Gets the the number of characters in the document. + + @return The number of characters contained in the document. */ + virtual TInt LdDocumentLength()const=0; // Does not include final document terminator + + /** Gets the document position of the start of the paragraph containing a + specified position. + + @param aCurrentPos A valid document position. On return contains the + document position of the first character in the paragraph. + @return The number of characters skipped in scanning to the start of the + paragraph. */ + virtual TInt LdToParagraphStart(TInt& aCurrentPos)const=0; + + /** Gets the effective paragraph formatting which applies to the paragraph + which contains a specified document position. On return, aFormat is filled + with values for all paragraph format attributes. + + @param aFormat On return, filled with the paragraph's effective paragraph + formatting. + @param aPos Any document position within the paragraph of interest. */ + virtual void GetParagraphFormatL(CParaFormat* aFormat,TInt aPos)const=0; + + /** Gets a constant pointer descriptor to a portion of the text object with + constant character formatting. The view starts at the document position + specified, and ends at: + + the last character which shares the same character formatting (rich text + only), or + + the end of the document, or + + the end of the segment, if segmented storage is being used + + whichever occurs first. + + Also fills a character format object with the character formatting of the + range of characters. + + @param aView On return, a constant pointer to a portion of the text. + @param aFormat On return, contains the character formatting of the text. + @param aStartPos The start position for the view. Must be a valid document + position, or a panic occurs. */ + virtual void GetChars(TPtrC& aView,TCharFormat& aFormat,TInt aStartPos)const=0; + + /** Gets the size of a picture located at a specified document position. + + Note: The global text implementation of this function always returns + KErrNotFound because global text does not support pictures. + + @param aSize On return, contains the size of the picture located at aPos. + @param aPos Document position of the picture. + @return KErrNotFound if there is no picture at the specified document + position, KErrNone if there is. */ + virtual TInt GetPictureSizeInTwips(TSize& aSize, TInt aPos)const=0; + + /** Gets a pointer to the picture located at a specified document position, + if one exists. If the picture is not in memory, the function loads it (if + the second argument has a value of EForceLoadTrue). + + Note: The global text implementation of this function always returns NULL + because global text does not support pictures. + + @param aPos Document position of the picture character. + @param aForceLoad If the picture is not loaded into memory, EForceLoadTrue + loads it using the picture factory; EForceLoadFalse does not, and in this + case, the function returns NULL. + @return A pointer to the picture located at aPos. NULL if aPos does not + specify a picture character, or if there is a picture at aPos which is not + in memory, and the second argument is EForceLoadFalse. */ + virtual CPicture* PictureHandleL(TInt aPos,TForcePictureLoad aForceLoad=EForceLoadTrue)const=0; + + /** Tests whether a page break occurs within a range of characters. A page + table should have been set up first: see CPlainText::SetPageTable(). + + @param aPos The document position from which to begin searching for a page + break. + @param aLength The number of characters to search for a page break, + beginning at aPos. The default is zero. + @return ETrue if a page break occurs within the specified range, otherwise + EFalse. */ + virtual TBool EnquirePageBreak(TInt aPos,TInt aLength=0)const=0; + + /** This function should be implemented by text objects which support + paragraph labels. Each paragraph may have at most one label. By default, + the functions provided by MLayDoc apply to the main body of text. This + function is provided to change this so that the MLayDoc object is an + individual paragraph label, (each of which is treated as a separate + document). Paragraph labelling has not been implemented by global or rich + text. + + This function should select the paragraph label associated with the + paragraph containing document position aPos (aPos is a document position + in the main document). + + @param aPos A document position within a paragraph. This paragraph's label + should be set as the main MLayDoc document. + @return Should return EFalse if the paragraph has no label, in which case + the function has no effect, ETrue otherwise. */ + virtual TBool SelectParagraphLabel(TInt aPos)=0; + + /** Cancels a paragraph label selection made by a call to + SelectParagraphLabel() so that the main document reverts back to the main + body of text. */ + virtual void CancelSelectLabel()=0; + + /** This function is reserved for future purpose. + It should not be used externally for now. + @internalAll */ + IMPORT_C virtual void MLayDoc_Reserved_1(); + }; + +#endif +