QTextDocument Class

Member Function Documentation

QTextDocument::QTextDocument(const QString &text, QObject *parent = nullptr)

Constructs a QTextDocument containing the plain (unformatted) text specified, and with the given parent.

QTextDocument::QTextDocument(QObject *parent = nullptr)

Constructs an empty QTextDocument with the given parent.

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

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

[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 the position 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 also QAbstractTextDocumentLayout::documentChanged() and contentsChanged().

[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 also contentsChange().

[signal] void QTextDocument::cursorPositionChanged(const QTextCursor &cursor)

This signal is emitted whenever the position of a cursor changed due to an editing operation. The cursor that changed is passed in cursor. If the document is used with the QTextEdit class and you need a signal when the cursor is moved with the arrow keys you can use the cursorPositionChanged() signal in QTextEdit.

[signal] void QTextDocument::documentLayoutChanged()

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

See also setDocumentLayout().

[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. If changed is true, the document has been modified; otherwise it is false.

For example, calling setModified(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.

[slot] void QTextDocument::redo()

This is an overloaded function.

Redoes the last editing operation on the document if redo 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).

[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 the Qt Undo Framework documentation for details.

See also undo() and isUndoRedoEnabled().

[signal] void QTextDocument::undoCommandAdded()

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

[virtual] QTextDocument::~QTextDocument()

Destroys the document.

void QTextDocument::addResource(int type, const QUrl &name, const QVariant &resource)

Adds the resource resource to the resource cache, using type and name as identifiers. type should be a value from QTextDocument::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 the QTextCursor API:

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

Alternatively, you can insert images using the HTML img tag:

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

void QTextDocument::adjustSize()

Adjusts the document to a reasonable size.

See also idealWidth(), textWidth, and size.

QList<QTextFormat> QTextDocument::allFormats() const

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

int QTextDocument::availableRedoSteps() const

Returns the number of available redo steps.

See also isRedoAvailable().

int QTextDocument::availableUndoSteps() const

Returns the number of available undo steps.

See also isUndoAvailable().

[since 6.0] qreal QTextDocument::baselineOffset() const

Returns the the baseline offset in % used in the document layout.

This function was introduced in Qt 6.0.

See also setBaselineOffset(), setSubScriptBaseline(), subScriptBaseline(), setSuperScriptBaseline(), and superScriptBaseline().

QTextBlock QTextDocument::begin() const

Returns the document's first text block.

See also firstBlock().

QChar QTextDocument::characterAt(int pos) const

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

See also characterCount().

int QTextDocument::characterCount() const

Returns the number of characters of this document.

See also blockCount() and characterAt().

[virtual] void QTextDocument::clear()

Clears the document.

void QTextDocument::clearUndoRedoStacks(QTextDocument::Stacks stacksToClear = UndoAndRedoStacks)

Clears the stacks specified by stacksToClear.

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() or QTextDocument::redoAvailable().

See also QTextDocument::undoAvailable() and QTextDocument::redoAvailable().

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

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

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

Creates and returns a new document object (a QTextObject), based on the given format.

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

Qt::CursorMoveStyle QTextDocument::defaultCursorMoveStyle() const

The default cursor movement style is used by all QTextCursor objects created from the document. The default is Qt::LogicalMoveStyle.

See also setDefaultCursorMoveStyle().

QFont QTextDocument::defaultFont() const

Returns the default font to be used in the document layout.

Note: Getter function for property defaultFont.

See also setDefaultFont().

[static, since 6.1] QTextDocument::ResourceProvider QTextDocument::defaultResourceProvider()

Returns the default resource provider.

This function was introduced in Qt 6.1.

See also setDefaultResourceProvider(), resourceProvider(), and loadResource().

QTextOption QTextDocument::defaultTextOption() const

The default text option is used on all QTextLayout objects in the document. This allows setting global properties for the document such as the default word wrap mode.

Note: Getter function for property defaultTextOption.

See also setDefaultTextOption().

QAbstractTextDocumentLayout *QTextDocument::documentLayout() const

Returns the document layout for this document.

See also setDocumentLayout().

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

Draws the content of the document with painter p, clipped to rect. If rect is a null rectangle (default) then the document is painted unclipped.

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())
    std::cout << it.text().toStdString() << "\n";

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

See also lastBlock().

QTextCursor QTextDocument::find(const QString &subString, const QTextCursor &cursor, QTextDocument::FindFlags options = FindFlags()) const

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

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

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

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

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

This is an overloaded function.

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

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

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

[since 5.5] QTextCursor QTextDocument::find(const QRegularExpression &expr, int from = 0, QTextDocument::FindFlags options = FindFlags()) const

Finds the next occurrence that matches the given regular expression, expr, within the same paragraph in the document.

The search starts at the given from position, and proceeds forwards through the document unless specified otherwise in the search options. The options control the type of search performed.

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

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

This function was introduced in Qt 5.5.

[since 5.5] QTextCursor QTextDocument::find(const QRegularExpression &expr, const QTextCursor &cursor, QTextDocument::FindFlags options = FindFlags()) const

Finds the next occurrence that matches the given regular expression, expr, within the same paragraph in the document.

The search starts at the position of the given cursor, and proceeds forwards through the document unless specified otherwise in the search options. The options control the type of search performed.

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

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

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

This function was introduced in Qt 5.5.

QTextBlock QTextDocument::findBlock(int pos) const

Returns the text block that contains the pos-th character.

QTextBlock QTextDocument::findBlockByLineNumber(int lineNumber) const

Returns the text block that contains the specified lineNumber.

See also QTextBlock::firstLineNumber().

QTextBlock QTextDocument::findBlockByNumber(int blockNumber) const

Returns the text block with the specified blockNumber.

See also QTextBlock::blockNumber().

QTextBlock QTextDocument::firstBlock() const

Returns the document's first text block.

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().

See also adjustSize() and textWidth.

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 also isUndoAvailable() and availableRedoSteps().

bool QTextDocument::isUndoAvailable() const

Returns true if undo is available; otherwise returns false.

See also isRedoAvailable() and availableUndoSteps().

QTextBlock QTextDocument::lastBlock() const

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

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.

See also blockCount() and characterCount().

[virtual protected invokable] QVariant QTextDocument::loadResource(int type, const QUrl &name)

Loads data of the specified type from the resource with the given name.

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

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

If the QTextDocument is a child object of a QObject that has an invokable loadResource method such as QTextEdit, QTextBrowser or a QTextDocument itself then the default implementation tries to retrieve the data from the parent.

Note: This function can be invoked via the meta-object system and from QML. See Q_INVOKABLE.

See also QTextDocument::ResourceProvider.

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

Marks the contents specified by the given position and length as "dirty", informing the document that it needs to be laid out again.

QString QTextDocument::metaInformation(QTextDocument::MetaInformation info) const

Returns meta information about the document of the type specified by info.

See also setMetaInformation().

QTextObject *QTextDocument::object(int objectIndex) const

Returns the text object associated with the given objectIndex.

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

Returns the text object associated with the format f.

int QTextDocument::pageCount() const

returns the number of pages in this document.

void QTextDocument::print(QPagedPaintDevice *printer) const

Prints the document to the given printer. The QPagedPaintDevice 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 the pageSize() property it is printed as-is.

If the document is not paginated, like for example a document used in a QTextEdit, then a temporary copy of the document is created and the copy is broken into multiple pages according to the size of the paint device'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.

See also QTextEdit::print().

void QTextDocument::redo(QTextCursor *cursor)

Redoes the last editing operation on the document if redo is available.

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

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

Returns data of the specified type from the resource with the given name.

This function is called by the rich text engine to request data that isn't directly stored by QTextDocument, but still associated with it. For example, images are referenced indirectly by the name attribute of a QTextImageFormat 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 use addResource to add the resource to the cache.

If loadResource does not load the resource, then the resourceProvider and lastly the defaultResourceProvider will be called, if set. Note that the result from the provider will not be added automatically to the cache.

See also QTextDocument::ResourceType and resourceProvider().

[since 6.1] QTextDocument::ResourceProvider QTextDocument::resourceProvider() const

Returns the resource provider for this text document.

This function was introduced in Qt 6.1.

See also setResourceProvider(), defaultResourceProvider(), and loadResource().

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.

See also QTextBlock::revision() and isModified().

QTextFrame *QTextDocument::rootFrame() const

Returns the document's root frame.

[since 6.0] void QTextDocument::setBaselineOffset(qreal baseline)

Sets the base line as a% of font height to use in the document layout to baseline. The default value is 0. A positive value moves up the text, by the corresponding %; a negative value moves it down.

This function was introduced in Qt 6.0.

See also baselineOffset(), setSubScriptBaseline(), subScriptBaseline(), setSuperScriptBaseline(), and superScriptBaseline().

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

Sets the default cursor movement style to the given style.

See also defaultCursorMoveStyle().

void QTextDocument::setDefaultFont(const QFont &font)

Sets the default font to use in the document layout.

Note: Setter function for property defaultFont.

See also defaultFont().

[static, since 6.1] void QTextDocument::setDefaultResourceProvider(const QTextDocument::ResourceProvider &provider)

Sets the default resource provider to provider.

The default provider will be used by all QTextDocuments that don't have an explicit provider set.

This function was introduced in Qt 6.1.

See also defaultResourceProvider(), setResourceProvider(), and loadResource().

void QTextDocument::setDefaultTextOption(const QTextOption &option)

Sets the default text option to option.

Note: Setter function for property defaultTextOption.

See also defaultTextOption().

void QTextDocument::setDocumentLayout(QAbstractTextDocumentLayout *layout)

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

See also documentLayoutChanged().

void QTextDocument::setHtml(const QString &html)

Replaces the entire contents of the document with the given HTML-formatted text in the html string. The undo/redo history is reset when this function is called.

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".

To select a css media rule other than the default "screen" rule, use setMetaInformation() with 'CssMedia' as "info" parameter.

See also setPlainText(), Supported HTML Subset, and setMetaInformation().

void QTextDocument::setIndentWidth(qreal width)

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

The indent properties of QTextListFormat and QTextBlockFormat specify multiples of this value. The default indent width is 40 .

Note: Setter function for property indentWidth.

See also indentWidth().

[since 5.14] void QTextDocument::setMarkdown(const QString &markdown, QTextDocument::MarkdownFeatures features = MarkdownDialectGitHub)

Replaces the entire contents of the document with the given Markdown-formatted text in the markdown string, with the given features supported. By default, all supported GitHub-style Markdown features are included; pass MarkdownDialectCommonMark for a more basic parse.

The Markdown formatting is respected as much as possible; for example, "*bold* text" will produce text where the first word has a font weight that gives it an emphasized appearance.

Parsing of HTML included in the markdown string is handled in the same way as in setHtml; however, Markdown formatting inside HTML blocks is not supported.

Some features of the parser can be enabled or disabled via the features argument:

The default is MarkdownDialectGitHub.

The undo/redo history is reset when this function is called.

This function was introduced in Qt 5.14.

void QTextDocument::setMetaInformation(QTextDocument::MetaInformation info, const QString &string)

Sets the document's meta information of the type specified by info to the given string.

See also metaInformation().

void QTextDocument::setPlainText(const QString &text)

Replaces the entire contents of the document with the given plain text. The undo/redo history is reset when this function is called.

See also setHtml().

[since 6.1] void QTextDocument::setResourceProvider(const QTextDocument::ResourceProvider &provider)

Sets the provider of resources for the text document to provider.

This function was introduced in Qt 6.1.

See also resourceProvider() and loadResource().

[since 6.0] void QTextDocument::setSubScriptBaseline(qreal baseline)

Sets the default subscript's base line as a % of font height to use in the document layout to baseline. The default value is 16.67% (1/6 of height).

This function was introduced in Qt 6.0.

See also subScriptBaseline(), setSuperScriptBaseline(), superScriptBaseline(), setBaselineOffset(), and baselineOffset().

[since 6.0] void QTextDocument::setSuperScriptBaseline(qreal baseline)

Sets the default superscript's base line as a % of font height to use in the document layout to baseline. The default value is 50% (1/2 of height).

This function was introduced in Qt 6.0.

See also superScriptBaseline(), setSubScriptBaseline(), subScriptBaseline(), setBaselineOffset(), and baselineOffset().

[since 6.0] qreal QTextDocument::subScriptBaseline() const

Returns the superscript's base line as a % of font height used in the document layout.

This function was introduced in Qt 6.0.

See also setSubScriptBaseline(), setSuperScriptBaseline(), superScriptBaseline(), setBaselineOffset(), and baselineOffset().

[since 6.0] qreal QTextDocument::superScriptBaseline() const

Returns the superscript's base line as a % of font height used in the document layout.

This function was introduced in Qt 6.0.

See also setSuperScriptBaseline(), setSubScriptBaseline(), subScriptBaseline(), setBaselineOffset(), and baselineOffset().

QString QTextDocument::toHtml() const

Returns a string containing an HTML representation of the document.

The content of the document specifies its encoding to be UTF-8. 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 use QString::toUtf8() to convert the string to a QByteArray.

See also Supported HTML Subset.

[since 5.14] QString QTextDocument::toMarkdown(QTextDocument::MarkdownFeatures features = MarkdownDialectGitHub) const

Returns a string containing a Markdown representation of the document with the given features, or an empty string if writing fails for any reason.

This function was introduced in Qt 5.14.

See also setMarkdown.

QString QTextDocument::toPlainText() const

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

This function returns the same as toRawText(), but will replace some unicode characters with ASCII alternatives. In particular, no-break space (U+00A0) is replaced by a regular space (U+0020), and both paragraph (U+2029) and line (U+2028) separators are replaced by line feed (U+000A). If you need the precise contents of the document, use toRawText() instead.

See also toHtml().

[since 5.9] QString QTextDocument::toRawText() const

Returns the raw text contained in the document without any formatting information. If you want formatting information use a QTextCursor instead.

This function was introduced in Qt 5.9.

See also toPlainText().

void QTextDocument::undo(QTextCursor *cursor)

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

See the Qt Undo Framework documentation for details.

See also undoAvailable() and isUndoRedoEnabled().