Contents

• Public Types
• Properties
• Public Functions
• Public Slots
• Signals
• Protected Functions
• Detailed Description

Detailed Description

TheQTextDocument class holds formatted text that can be viewed and edited using aQTextEdit.

QTextDocument is a container for structured rich text documents, providing support for styled text and various types of document elements, such as lists, tables, frames, and images. They can be created for use in aQTextEdit, or used independently.

Each document element is described by an associated format object. Each format object is treated as a unique object by QTextDocuments, and can be passed toobjectForFormat() to obtain the document element that it is applied to.

AQTextDocument can be edited programmatically using aQTextCursor, and its contents can be examined by traversing the document structure. The entire document structure is stored as a hierarchy of document elements beneath the root frame, found with therootFrame() function. Alternatively, if you just want to iterate over the textual contents of the document you can usebegin(),end(), andfindBlock() to retrieve text blocks that you can examine and iterate over.

The layout of a document is determined by thedocumentLayout(); you can create your ownQAbstractTextDocumentLayout subclass and set it usingsetDocumentLayout() if you want to use your own layout logic. The document's title and other meta-information can be obtained by calling themetaInformation() function. For documents that are exposed to users through theQTextEdit class, the document title is also available via theQTextEdit::documentTitle() function.

ThetoPlainText() andtoHtml() convenience functions allow you to retrieve the contents of the document as plain text and HTML. The document's text can be searched using thefind() functions.

Undo/redo of operations performed on the document can be controlled using thesetUndoRedoEnabled() function. The undo/redo system can be controlled by an editor widget through theundo() andredo() slots; the document also providescontentsChanged(),undoAvailable(), andredoAvailable() signals that inform connected editor widgets about the state of the undo/redo system. The following are the undo/redo operations of aQTextDocument:

• Insertion or removal of characters. A sequence of insertions or removals within the same text block are regarded as a single undo/redo operation.
• Insertion or removal of text blocks. Sequences of insertion or removals in a single operation (e.g., by selecting and then deleting text) are regarded as a single undo/redo operation.
• Text character format changes.
• Text block format changes.
• Text block group format changes.

Member Type Documentation

enum QTextDocument::FindFlag
flags QTextDocument::FindFlags

This enum describes the options available toQTextDocument's find function. The options can be OR-ed together from the following list:

The FindFlags type is a typedef forQFlags<FindFlag>. It stores an OR combination of FindFlag values.

enum QTextDocument::MetaInformation

This enum describes the different types of meta information that can be added to a document.

See alsometaInformation() andsetMetaInformation().

enum QTextDocument::ResourceType

This enum describes the types of resources that can be loaded byQTextDocument'sloadResource() function.

See alsoloadResource().

enum QTextDocument::Stacks

Property Documentation

blockCount : constint

Returns the number of text blocks in the document.

The value of this property is undefined in documents with tables or frames.

By default, if defined, this property contains a value of 1.

This property was introduced in Qt 4.2.

Access functions:

See alsolineCount() andcharacterCount().

defaultFont :QFont

This property holds the default font used to display the document's text.

Access functions:

defaultStyleSheet :QString

The default style sheet is applied to all newly HTML formatted text that is inserted into the document, for example usingsetHtml() orQTextCursor::insertHtml().

The style sheet needs to be compliant to CSS 2.1 syntax.

Note: Changing the default style sheet does not have any effect to the existing content of the document.

This property was introduced in Qt 4.2.

Access functions:

See alsoSupported HTML Subset.

defaultTextOption :QTextOption

This property holds the default text option will be set on all QTextLayouts in the document.

WhenQTextBlocks are created, the defaultTextOption is set on theirQTextLayout. This allows setting global properties for the document such as the default word wrap mode.

Access functions:

documentMargin :qreal

The margin around the document. The default is 4.

This property was introduced in Qt 4.5.

Access functions:

indentWidth :qreal

Returns the width used for text list and text block indenting.

The indent properties ofQTextListFormat andQTextBlockFormat specify multiples of this value. The default indent width is 40.

This property was introduced in Qt 4.4.

Access functions:

maximumBlockCount :int

This property specifies the limit for blocks in the document.

Specifies the maximum number of blocks the document may have. If there are more blocks in the document that specified with this property blocks are removed from the beginning of the document.

A negative or zero value specifies that the document may contain an unlimited amount of blocks.

The default value is 0.

Note that setting this property will apply the limit immediately to the document contents.

Setting this property also disables the undo redo history.

This property is undefined in documents with tables or frames.

This property was introduced in Qt 4.2.

Access functions:

modified :bool

This property holds whether the document has been modified by the user.

By default, this property is false.

Access functions:

See alsomodificationChanged().

pageSize :QSizeF

This property holds the page size that should be used for laying out the document.

By default, for a newly-created, empty document, this property contains an undefined size.

Access functions:

See alsomodificationChanged().

size : constQSizeF

Returns the actual size of the document. This is equivalent todocumentLayout()->documentSize();

The size of the document can be changed either by setting a text width or setting an entire page size.

Note that the width is always >=pageSize().width().

By default, for a newly-created, empty document, this property contains a configuration-dependent size.

This property was introduced in Qt 4.2.

Access functions:

See alsosetTextWidth(),setPageSize(), andidealWidth().

textWidth :qreal

The text width specifies the preferred width for text in the document. If the text (or content in general) is wider than the specified with it is broken into multiple lines and grows vertically. If the text cannot be broken into multiple lines to fit into the specified text width it will be larger and thesize() and theidealWidth() property will reflect that.

If the text width is set to -1 then the text will not be broken into multiple lines unless it is enforced through an explicit line break or a new paragraph.

The default value is -1.

Setting the text width will also set the page height to -1, causing the document to grow or shrink vertically in a continuous way. If you want the document layout to break the text into multiple pages then you have to set thepageSize property instead.

This property was introduced in Qt 4.2.

Access functions:

See alsosize(),idealWidth(), andpageSize().

undoRedoEnabled :bool

This property holds whether undo/redo are enabled for this document.

This defaults to true. If disabled, the undo stack is cleared and no items will be added to it.

Access functions:

useDesignMetrics :bool

This property holds whether the document uses design metrics of fonts to improve the accuracy of text layout.

If this property is set to true, the layout will use design metrics. Otherwise, the metrics of the paint device as set onQAbstractTextDocumentLayout::setPaintDevice() will be used.

Using design metrics makes a layout have a width that is no longer dependent on hinting and pixel-rounding. This means that WYSIWYG text layout becomes possible because the width scales much more linearly based on paintdevice metrics than it would otherwise.

By default, this property is false.

This property was introduced in Qt 4.1.

Access functions:

Member Function Documentation

QTextDocument::QTextDocument(QObject * parent = 0)

Constructs an emptyQTextDocument with the givenparent.

QTextDocument::QTextDocument(constQString & text,QObject * parent = 0)

Constructs aQTextDocument containing the plain (unformatted)text specified, and with the givenparent.

QTextDocument::~QTextDocument()

Destroys the document.

void QTextDocument::addResource(int type, constQUrl & name, constQVariant & resource)

Adds the resourceresource to the resource cache, usingtype andname as identifiers.type should be a value fromQTextDocument::ResourceType.

For example, you can add an image as a resource in order to reference it from within the document:

    document->addResource(QTextDocument::ImageResource,QUrl("mydata://image.png"),QVariant(image));

The image can be inserted into the document using theQTextCursor API:

QTextImageFormat imageFormat;    imageFormat.setName("mydata://image.png");    cursor.insertImage(imageFormat);

Alternatively, you can insert images using the HTMLimg tag:

    editor->append("<img src=\"mydata://image.png\" />");

void QTextDocument::adjustSize()

Adjusts the document to a reasonable size.

This function was introduced in Qt 4.2.

See alsoidealWidth(),textWidth, andsize.

QVector<QTextFormat> QTextDocument::allFormats() const

Returns a vector of text formats for all the formats used in the document.

int QTextDocument::availableRedoSteps() const

Returns the number of available redo steps.

This function was introduced in Qt 4.6.

See alsoisRedoAvailable().

int QTextDocument::availableUndoSteps() const

Returns the number of available undo steps.

This function was introduced in Qt 4.6.

See alsoisUndoAvailable().

QTextBlock QTextDocument::begin() const

Returns the document's first text block.

See alsofirstBlock().

[signal]void QTextDocument::blockCountChanged(int newBlockCount)

This signal is emitted when the total number of text blocks in the document changes. The value passed innewBlockCount is the new total.

This function was introduced in Qt 4.3.

QChar QTextDocument::characterAt(int pos) const

Returns the character at positionpos, or a null character if the position is out of range.

This function was introduced in Qt 4.5.

See alsocharacterCount().

int QTextDocument::characterCount() const

Returns the number of characters of this document.

This function was introduced in Qt 4.5.

See alsoblockCount() andcharacterAt().

[virtual]void QTextDocument::clear()

Clears the document.

void QTextDocument::clearUndoRedoStacks(Stacks stacksToClear = UndoAndRedoStacks)

Clears the stacks specified bystacksToClear.

This method clears any commands on the undo stack, the redo stack, or both (the default). If commands are cleared, the appropriate signals are emitted,QTextDocument::undoAvailable() orQTextDocument::redoAvailable().

This function was introduced in Qt 4.7.

See alsoQTextDocument::undoAvailable() andQTextDocument::redoAvailable().

QTextDocument * QTextDocument::clone(QObject * parent = 0) const

Creates a newQTextDocument that is a copy of this text document.parent is the parent of the returned text document.

[signal]void QTextDocument::contentsChange(int position,int charsRemoved,int charsAdded)

This signal is emitted whenever the document's content changes; for example, when text is inserted or deleted, or when formatting is applied.

Information is provided about theposition of the character in the document where the change occurred, the number of characters removed (charsRemoved), and the number of characters added (charsAdded).

The signal is emitted before the document's layout manager is notified about the change. This hook allows you to implement syntax highlighting for the document.

See alsoQAbstractTextDocumentLayout::documentChanged() andcontentsChanged().

[signal]void QTextDocument::contentsChanged()

This signal is emitted whenever the document's content changes; for example, when text is inserted or deleted, or when formatting is applied.

See alsocontentsChange().

[virtual protected]QTextObject * QTextDocument::createObject(constQTextFormat & format)

Creates and returns a new document object (aQTextObject), based on the givenformat.

QTextObjects will always get created through this method, so you must reimplement it if you use custom text objects inside your document.

[signal]void QTextDocument::cursorPositionChanged(constQTextCursor & cursor)

This signal is emitted whenever the position of a cursor changed due to an editing operation. The cursor that changed is passed incursor. If you need a signal when the cursor is moved with the arrow keys you can use thecursorPositionChanged() signal inQTextEdit.

Qt::CursorMoveStyle QTextDocument::defaultCursorMoveStyle() const

The default cursor movement style is used by allQTextCursor objects created from the document. The default isQt::LogicalMoveStyle.

This function was introduced in Qt 4.8.

See alsosetDefaultCursorMoveStyle().

QAbstractTextDocumentLayout * QTextDocument::documentLayout() const

Returns the document layout for this document.

See alsosetDocumentLayout().

[signal]void QTextDocument::documentLayoutChanged()

This signal is emitted when a new document layout is set.

This function was introduced in Qt 4.4.

See alsosetDocumentLayout().

void QTextDocument::drawContents(QPainter * p, constQRectF & rect = QRectF())

Draws the content of the document with painterp, clipped torect. Ifrect is a null rectangle (default) then the document is painted unclipped.

This function was introduced in Qt 4.2.

QTextBlock QTextDocument::end() const

This function returns a block to test for the end of the document while iterating over it.

for (QTextBlock it= doc->begin(); it!= doc->end(); it= it.next())        cout<< it.text().toStdString()<< endl;

The block returned is invalid and represents the block after the last block in the document. You can uselastBlock() to retrieve the last valid block of the document.

See alsolastBlock().

QTextCursor QTextDocument::find(constQString & subString, constQTextCursor & cursor,FindFlags options = 0) const

Finds the next occurrence of the string,subString, in the document. The search starts at the position of the givencursor, and proceeds forwards through the document unless specified otherwise in the search options. Theoptions control the type of search performed.

Returns a cursor with the match selected ifsubString was found; otherwise returns a null cursor.

If the givencursor has a selection, the search begins after the selection; otherwise it begins at the cursor's position.

By default the search is case-sensitive, and can match text anywhere in the document.

QTextCursor QTextDocument::find(constQRegExp & expr, constQTextCursor & cursor,FindFlags options = 0) const

Finds the next occurrence, matching the regular expression,expr, in the document. The search starts at the position of the givencursor, and proceeds forwards through the document unless specified otherwise in the search options. Theoptions control the type of search performed. TheFindCaseSensitively option is ignored for this overload, useQRegExp::caseSensitivity instead.

Returns a cursor with the match selected if a match was found; otherwise returns a null cursor.

If the givencursor has a selection, the search begins after the selection; otherwise it begins at the cursor's position.

By default the search is case-sensitive, and can match text anywhere in the document.

QTextCursor QTextDocument::find(constQString & subString,int position = 0,FindFlags options = 0) const

This is an overloaded function.

Finds the next occurrence of the string,subString, in the document. The search starts at the givenposition, and proceeds forwards through the document unless specified otherwise in the search options. Theoptions control the type of search performed.

Returns a cursor with the match selected ifsubString was found; otherwise returns a null cursor.

If theposition is 0 (the default) the search begins from the beginning of the document; otherwise it begins at the specified position.

QTextCursor QTextDocument::find(constQRegExp & expr,int position = 0,FindFlags options = 0) const

This is an overloaded function.

Finds the next occurrence, matching the regular expression,expr, in the document. The search starts at the givenposition, and proceeds forwards through the document unless specified otherwise in the search options. Theoptions control the type of search performed. TheFindCaseSensitively option is ignored for this overload, useQRegExp::caseSensitivity instead.

Returns a cursor with the match selected if a match was found; otherwise returns a null cursor.

If theposition is 0 (the default) the search begins from the beginning of the document; otherwise it begins at the specified position.

QTextBlock QTextDocument::findBlock(int pos) const

Returns the text block that contains thepos-th character.

QTextBlock QTextDocument::findBlockByLineNumber(int lineNumber) const

Returns the text block that contains the specifiedlineNumber.

This function was introduced in Qt 4.5.

See alsoQTextBlock::firstLineNumber().

QTextBlock QTextDocument::findBlockByNumber(int blockNumber) const

Returns the text block with the specifiedblockNumber.

This function was introduced in Qt 4.4.

See alsoQTextBlock::blockNumber().

QTextBlock QTextDocument::firstBlock() const

Returns the document's first text block.

This function was introduced in Qt 4.4.

qreal QTextDocument::idealWidth() const

Returns the ideal width of the text document. The ideal width is the actually used width of the document without optional alignments taken into account. It is always <=size().width().

This function was introduced in Qt 4.2.

See alsoadjustSize() andtextWidth.

bool QTextDocument::isEmpty() const

Returns true if the document is empty; otherwise returns false.

bool QTextDocument::isRedoAvailable() const

Returns true if redo is available; otherwise returns false.

See alsoisUndoAvailable() andavailableRedoSteps().

bool QTextDocument::isUndoAvailable() const

Returns true if undo is available; otherwise returns false.

See alsoisRedoAvailable() andavailableUndoSteps().

QTextBlock QTextDocument::lastBlock() const

Returns the document's last (valid) text block.

This function was introduced in Qt 4.4.

int QTextDocument::lineCount() const

Returns the number of lines of this document (if the layout supports this). Otherwise, this is identical to the number of blocks.

This function was introduced in Qt 4.5.

See alsoblockCount() andcharacterCount().

[virtual protected]QVariant QTextDocument::loadResource(int type, constQUrl & name)

Loads data of the specifiedtype from the resource with the givenname.

This function is called by the rich text engine to request data that isn't directly stored byQTextDocument, but still associated with it. For example, images are referenced indirectly by the name attribute of aQTextImageFormat object.

When called by Qt,type is one of the values ofQTextDocument::ResourceType.

If theQTextDocument is a child object of aQTextEdit,QTextBrowser, or aQTextDocument itself then the default implementation tries to retrieve the data from the parent.

void QTextDocument::markContentsDirty(int position,int length)

Marks the contents specified by the givenposition andlength as "dirty", informing the document that it needs to be laid out again.

QString QTextDocument::metaInformation(MetaInformation info) const

Returns meta information about the document of the type specified byinfo.

See alsosetMetaInformation().

[signal]void QTextDocument::modificationChanged(bool changed)

This signal is emitted whenever the content of the document changes in a way that affects the modification state. Ifchanged is true, the document has been modified; otherwise it is false.

For example, callingsetModified(false) on a document and then inserting text causes the signal to get emitted. If you undo that operation, causing the document to return to its original unmodified state, the signal will get emitted again.

QTextObject * QTextDocument::object(int objectIndex) const

Returns the text object associated with the givenobjectIndex.

QTextObject * QTextDocument::objectForFormat(constQTextFormat & f) const

Returns the text object associated with the formatf.

int QTextDocument::pageCount() const

returns the number of pages in this document.

void QTextDocument::print(QPrinter * printer) const

Prints the document to the givenprinter. TheQPrinter must be set up before being used with this function.

This is only a convenience method to print the whole document to the printer.

If the document is already paginated through a specified height in thepageSize() property it is printed as-is.

If the document is not paginated, like for example a document used in aQTextEdit, then a temporary copy of the document is created and the copy is broken into multiple pages according to the size of theQPrinter's paperRect(). By default a 2 cm margin is set around the document contents. In addition the current page number is printed at the bottom of each page.

Note thatQPrinter::Selection is not supported as print range with this function since the selection is a property ofQTextCursor. If you have aQTextEdit associated with yourQTextDocument then you can useQTextEdit's print() function becauseQTextEdit has access to the user's selection.

See alsoQTextEdit::print().

void QTextDocument::redo(QTextCursor * cursor)

Redoes the last editing operation on the document ifredo is available.

The providedcursor is positioned at the end of the location where the edition operation was redone.

This function was introduced in Qt 4.2.

[slot]void QTextDocument::redo()

This is an overloaded function.

Redoes the last editing operation on the document ifredo is available.

[signal]void QTextDocument::redoAvailable(bool available)

This signal is emitted whenever redo operations become available (available is true) or unavailable (available is false).

QVariant QTextDocument::resource(int type, constQUrl & name) const

Returns data of the specifiedtype from the resource with the givenname.

This function is called by the rich text engine to request data that isn't directly stored byQTextDocument, but still associated with it. For example, images are referenced indirectly by the name attribute of aQTextImageFormat object.

Resources are cached internally in the document. If a resource can not be found in the cache,loadResource is called to try to load the resource.loadResource should then useaddResource to add the resource to the cache.

See alsoQTextDocument::ResourceType.

int QTextDocument::revision() const

Returns the document's revision (if undo is enabled).

The revision is guaranteed to increase when a document that is not modified is edited.

This function was introduced in Qt 4.4.

See alsoQTextBlock::revision() andisModified().

QTextFrame * QTextDocument::rootFrame() const

Returns the document's root frame.

void QTextDocument::setDefaultCursorMoveStyle(Qt::CursorMoveStyle style)

Sets the default cursor movement style to the givenstyle.

This function was introduced in Qt 4.8.

See alsodefaultCursorMoveStyle().

void QTextDocument::setDocumentLayout(QAbstractTextDocumentLayout * layout)

Sets the document to use the givenlayout. The previous layout is deleted.

See alsodocumentLayoutChanged().

void QTextDocument::setHtml(constQString & html)

Replaces the entire contents of the document with the given HTML-formatted text in thehtml string.

The HTML formatting is respected as much as possible; for example, "<b>bold</b> text" will produce text where the first word has a font weight that gives it a bold appearance: "bold text".

Note:It is the responsibility of the caller to make sure that the text is correctly decoded when aQString containing HTML is created and passed to setHtml().

See alsosetPlainText() andSupported HTML Subset.

void QTextDocument::setMetaInformation(MetaInformation info, constQString & string)

Sets the document's meta information of the type specified byinfo to the givenstring.

See alsometaInformation().

void QTextDocument::setPlainText(constQString & text)

Replaces the entire contents of the document with the given plaintext.

See alsosetHtml().

QString QTextDocument::toHtml(constQByteArray & encoding = QByteArray()) const

Returns a string containing an HTML representation of the document.

Theencoding parameter specifies the value for the charset attribute in the html header. For example if 'utf-8' is specified then the beginning of the generated html will look like this:

<html><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"></head><body>...

If no encoding is specified then no such meta information is generated.

If you later on convert the returned html string into a byte array for transmission over a network or when saving to disk you should specify the encoding you're going to use for the conversion to a byte array here.

See alsoSupported HTML Subset.

QString QTextDocument::toPlainText() const

Returns the plain text contained in the document. If you want formatting information use aQTextCursor instead.

See alsotoHtml().

void QTextDocument::undo(QTextCursor * cursor)

Undoes the last editing operation on the document if undo is available. The providedcursor is positioned at the end of the location where the edition operation was undone.

See theQt Undo Framework documentation for details.

This function was introduced in Qt 4.2.

See alsoundoAvailable() andisUndoRedoEnabled().

[slot]void QTextDocument::undo()

This is an overloaded function.

[signal]void QTextDocument::undoAvailable(bool available)

This signal is emitted whenever undo operations become available (available is true) or unavailable (available is false).

See theQt Undo Framework documentation for details.

See alsoundo() andisUndoRedoEnabled().

[signal]void QTextDocument::undoCommandAdded()

This signal is emitted every time a new level of undo is added to theQTextDocument.

This function was introduced in Qt 4.4.