1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/os/textandloc/textrendering/texthandling/inc/TXTLAYDC.H Fri Jun 15 03:10:57 2012 +0200
1.3 @@ -0,0 +1,180 @@
1.4 +/*
1.5 +* Copyright (c) 2003-2009 Nokia Corporation and/or its subsidiary(-ies).
1.6 +* All rights reserved.
1.7 +* This component and the accompanying materials are made available
1.8 +* under the terms of "Eclipse Public License v1.0"
1.9 +* which accompanies this distribution, and is available
1.10 +* at the URL "http://www.eclipse.org/legal/epl-v10.html".
1.11 +*
1.12 +* Initial Contributors:
1.13 +* Nokia Corporation - initial contribution.
1.14 +*
1.15 +* Contributors:
1.16 +*
1.17 +* Description:
1.18 +*
1.19 +*/
1.20 +
1.21 +
1.22 +#ifndef __TXTLAYDC_H__
1.23 +#define __TXTLAYDC_H__
1.24 +
1.25 +#include <e32std.h>
1.26 +
1.27 +class CParaFormat;
1.28 +class TCharFormat;
1.29 +class CPicture;
1.30 +
1.31 +
1.32 +class MLayDoc
1.33 +/**
1.34 +Specifies the interface for providing the information needed by the text
1.35 +layout engine to lay out a text object.
1.36 +
1.37 +Examples of derived classes are CRichText and CGlobalText.
1.38 +
1.39 +At the heart of the interface are two interrogation functions; one gives the
1.40 +paragraph formatting for a document position, and the other gives a pointer
1.41 +descriptor to a series of contiguous characters with identical character
1.42 +formatting, and their character formatting. This information is sufficient
1.43 +for the layout engine to find the formatting and content of an entire document.
1.44 +
1.45 +The constructor for the layout engine (CTextLayout) is prototyped as:
1.46 +static CTextLayout *NewL(MLayDoc *aDoc,TInt aWrapWidth);
1.47 +By viewing the text object purely in terms of the MLayDoc interface, the layout
1.48 +engine is insulated from any editable text implementation issues.
1.49 +@see static CTextLayout *NewL(MLayDoc *aDoc,TInt aWrapWidth)
1.50 +@publishedAll
1.51 +@released
1.52 +*/
1.53 + {
1.54 + // Defines interface for extracting content & format information from text source.
1.55 + // Designed to be 'mixed-in' with other classes.
1.56 + //
1.57 +public:
1.58 +
1.59 + /** Used as a parameter to the PictureHandleL() function to control whether
1.60 + picture data should be loaded into memory or not. */
1.61 + enum TForcePictureLoad
1.62 + {
1.63 + /** Do not load the picture data into memory. */
1.64 + EForceLoadFalse,
1.65 + /** Load the picture data into memory. */
1.66 + EForceLoadTrue
1.67 + };
1.68 +public:
1.69 +
1.70 + /** Gets the the number of characters in the document.
1.71 +
1.72 + @return The number of characters contained in the document. */
1.73 + virtual TInt LdDocumentLength()const=0; // Does not include final document terminator
1.74 +
1.75 + /** Gets the document position of the start of the paragraph containing a
1.76 + specified position.
1.77 +
1.78 + @param aCurrentPos A valid document position. On return contains the
1.79 + document position of the first character in the paragraph.
1.80 + @return The number of characters skipped in scanning to the start of the
1.81 + paragraph. */
1.82 + virtual TInt LdToParagraphStart(TInt& aCurrentPos)const=0;
1.83 +
1.84 + /** Gets the effective paragraph formatting which applies to the paragraph
1.85 + which contains a specified document position. On return, aFormat is filled
1.86 + with values for all paragraph format attributes.
1.87 +
1.88 + @param aFormat On return, filled with the paragraph's effective paragraph
1.89 + formatting.
1.90 + @param aPos Any document position within the paragraph of interest. */
1.91 + virtual void GetParagraphFormatL(CParaFormat* aFormat,TInt aPos)const=0;
1.92 +
1.93 + /** Gets a constant pointer descriptor to a portion of the text object with
1.94 + constant character formatting. The view starts at the document position
1.95 + specified, and ends at:
1.96 +
1.97 + the last character which shares the same character formatting (rich text
1.98 + only), or
1.99 +
1.100 + the end of the document, or
1.101 +
1.102 + the end of the segment, if segmented storage is being used
1.103 +
1.104 + whichever occurs first.
1.105 +
1.106 + Also fills a character format object with the character formatting of the
1.107 + range of characters.
1.108 +
1.109 + @param aView On return, a constant pointer to a portion of the text.
1.110 + @param aFormat On return, contains the character formatting of the text.
1.111 + @param aStartPos The start position for the view. Must be a valid document
1.112 + position, or a panic occurs. */
1.113 + virtual void GetChars(TPtrC& aView,TCharFormat& aFormat,TInt aStartPos)const=0;
1.114 +
1.115 + /** Gets the size of a picture located at a specified document position.
1.116 +
1.117 + Note: The global text implementation of this function always returns
1.118 + KErrNotFound because global text does not support pictures.
1.119 +
1.120 + @param aSize On return, contains the size of the picture located at aPos.
1.121 + @param aPos Document position of the picture.
1.122 + @return KErrNotFound if there is no picture at the specified document
1.123 + position, KErrNone if there is. */
1.124 + virtual TInt GetPictureSizeInTwips(TSize& aSize, TInt aPos)const=0;
1.125 +
1.126 + /** Gets a pointer to the picture located at a specified document position,
1.127 + if one exists. If the picture is not in memory, the function loads it (if
1.128 + the second argument has a value of EForceLoadTrue).
1.129 +
1.130 + Note: The global text implementation of this function always returns NULL
1.131 + because global text does not support pictures.
1.132 +
1.133 + @param aPos Document position of the picture character.
1.134 + @param aForceLoad If the picture is not loaded into memory, EForceLoadTrue
1.135 + loads it using the picture factory; EForceLoadFalse does not, and in this
1.136 + case, the function returns NULL.
1.137 + @return A pointer to the picture located at aPos. NULL if aPos does not
1.138 + specify a picture character, or if there is a picture at aPos which is not
1.139 + in memory, and the second argument is EForceLoadFalse. */
1.140 + virtual CPicture* PictureHandleL(TInt aPos,TForcePictureLoad aForceLoad=EForceLoadTrue)const=0;
1.141 +
1.142 + /** Tests whether a page break occurs within a range of characters. A page
1.143 + table should have been set up first: see CPlainText::SetPageTable().
1.144 +
1.145 + @param aPos The document position from which to begin searching for a page
1.146 + break.
1.147 + @param aLength The number of characters to search for a page break,
1.148 + beginning at aPos. The default is zero.
1.149 + @return ETrue if a page break occurs within the specified range, otherwise
1.150 + EFalse. */
1.151 + virtual TBool EnquirePageBreak(TInt aPos,TInt aLength=0)const=0;
1.152 +
1.153 + /** This function should be implemented by text objects which support
1.154 + paragraph labels. Each paragraph may have at most one label. By default,
1.155 + the functions provided by MLayDoc apply to the main body of text. This
1.156 + function is provided to change this so that the MLayDoc object is an
1.157 + individual paragraph label, (each of which is treated as a separate
1.158 + document). Paragraph labelling has not been implemented by global or rich
1.159 + text.
1.160 +
1.161 + This function should select the paragraph label associated with the
1.162 + paragraph containing document position aPos (aPos is a document position
1.163 + in the main document).
1.164 +
1.165 + @param aPos A document position within a paragraph. This paragraph's label
1.166 + should be set as the main MLayDoc document.
1.167 + @return Should return EFalse if the paragraph has no label, in which case
1.168 + the function has no effect, ETrue otherwise. */
1.169 + virtual TBool SelectParagraphLabel(TInt aPos)=0;
1.170 +
1.171 + /** Cancels a paragraph label selection made by a call to
1.172 + SelectParagraphLabel() so that the main document reverts back to the main
1.173 + body of text. */
1.174 + virtual void CancelSelectLabel()=0;
1.175 +
1.176 + /** This function is reserved for future purpose.
1.177 + It should not be used externally for now.
1.178 + @internalAll */
1.179 + IMPORT_C virtual void MLayDoc_Reserved_1();
1.180 + };
1.181 +
1.182 +#endif
1.183 +