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MLayDoc Class Reference

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. static CTextLayout *NewL( MLayDoc *aDoc, TInt aWrapWidth)

Public Member Functions
void	CancelSelectLabel ()
TBool	EnquirePageBreak ( TInt , TInt )
void	GetChars ( TPtrC &, TCharFormat &, TInt )
void	GetParagraphFormatL ( CParaFormat *, TInt )
TInt	GetPictureSizeInTwips ( TSize &, TInt )
TInt	LdDocumentLength ()
TInt	LdToParagraphStart ( TInt &)
IMPORT_C void	MLayDoc_Reserved_1 ()
CPicture *	PictureHandleL ( TInt , TForcePictureLoad )
TBool	SelectParagraphLabel ( TInt )

Public Member Enumerations
enum	TForcePictureLoad { EForceLoadFalse , EForceLoadTrue }

Member Functions Documentation

CancelSelectLabel()

void

CancelSelectLabel

(

)

[pure virtual]

Cancels a paragraph label selection made by a call to SelectParagraphLabel() so that the main document reverts back to the main body of text.

EnquirePageBreak(TInt, TInt)

TBool	EnquirePageBreak	(	TInt	aPos,
			TInt	aLength = 0
		)	const [pure virtual]

Tests whether a page break occurs within a range of characters. A page table should have been set up first: see CPlainText::SetPageTable() .

Parameters

TInt aPos	The document position from which to begin searching for a page break.
TInt aLength = 0	The number of characters to search for a page break, beginning at aPos. The default is zero.

GetChars(TPtrC &, TCharFormat &, TInt)

void	GetChars	(	TPtrC &	aView,
			TCharFormat &	aFormat,
			TInt	aStartPos
		)	const [pure virtual]

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.

Parameters

TPtrC & aView	On return, a constant pointer to a portion of the text.
TCharFormat & aFormat	On return, contains the character formatting of the text.
TInt aStartPos	The start position for the view. Must be a valid document position, or a panic occurs.

GetParagraphFormatL(CParaFormat *, TInt)

void	GetParagraphFormatL	(	CParaFormat *	aFormat,
			TInt	aPos
		)	const [pure virtual]

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.

Parameters

CParaFormat * aFormat	On return, filled with the paragraph's effective paragraph formatting.
TInt aPos	Any document position within the paragraph of interest.

GetPictureSizeInTwips(TSize &, TInt)

TInt	GetPictureSizeInTwips	(	TSize &	aSize,
			TInt	aPos
		)	const [pure virtual]

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.

Parameters

TSize & aSize	On return, contains the size of the picture located at aPos.
TInt aPos	Document position of the picture.

LdDocumentLength()

TInt

LdDocumentLength

(

)

const [pure virtual]

Gets the the number of characters in the document.

LdToParagraphStart(TInt &)

TInt

LdToParagraphStart

(

TInt &

aCurrentPos

)

const [pure virtual]

Gets the document position of the start of the paragraph containing a specified position.

Parameters

TInt & aCurrentPos

A valid document position. On return contains the document position of the first character in the paragraph.

MLayDoc_Reserved_1()

IMPORT_C void

MLayDoc_Reserved_1

(

)

[virtual]

This function is reserved for future purpose. It should not be used externally for now.

PictureHandleL(TInt, TForcePictureLoad)

CPicture *	PictureHandleL	(	TInt	aPos,
			TForcePictureLoad	aForceLoad = EForceLoadTrue
		)	const [pure virtual]

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.

Parameters

TInt aPos	Document position of the picture character.
TForcePictureLoad aForceLoad = EForceLoadTrue	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.

SelectParagraphLabel(TInt)

TBool

SelectParagraphLabel

(

TInt

aPos

)

[pure virtual]

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).

Parameters

TInt aPos

A document position within a paragraph. This paragraph's label should be set as the main MLayDoc document.

Member Enumerations Documentation

Enum TForcePictureLoad

Used as a parameter to the PictureHandleL() function to control whether picture data should be loaded into memory or not.

Enumerators

EForceLoadFalse	Do not load the picture data into memory.
EForceLoadTrue	Load the picture data into memory.