QTextDocument Class

See also QTextCursor, QTextEdit, Rich Text Processing, Text Object Example

flags QTextDocument::FindFlags

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

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

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

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Type alias for std::function<QVariant(const QUrl&)>.

This typedef was introduced in Qt 6.1.

This enum describes the types of resources that can be loaded by QTextDocument's loadResource() function or by QTextBrowser::setSource().

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This property holds the base URL used to resolve relative resource URLs within the document.

Resource URLs are resolved to be within the same directory as the target of the base URL meaning any portion of the path after the last '/' will be ignored.

This property was introduced in Qt 5.3.

Access functions:

• baseUrl() const

• void setBaseUrl(const &url)

Notifier signal:

• void baseUrlChanged(const &url)

This property holds 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.

Access functions:

• int blockCount() const

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

Access functions:

• defaultFont() const

• void setDefaultFont(const &font)

The default style sheet is applied to all newly HTML formatted text that is inserted into the document, for example using setHtml() or QTextCursor::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.

Access functions:

• defaultStyleSheet() const

• void setDefaultStyleSheet(const &sheet)

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

When QTextBlocks are created, the defaultTextOption is set on their QTextLayout. This allows setting global properties for the document such as the default word wrap mode.

Access functions:

• defaultTextOption() const

• void setDefaultTextOption(const &option)

The margin around the document. The default is 4.

Access functions:

• qreal documentMargin() const

• void setDocumentMargin(qreal margin)

Returns 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.

Access functions:

• qreal indentWidth() const

• void setIndentWidth(qreal width)

This property holds whether QTextDocument should recalculate the layout after every change

If this property is set to true, any change to the document triggers a layout, which makes everything work as expected but takes time.

Temporarily disabling the layout can save time when making multiple changes (not just text content, but also default font, default text option....) so that the document is only laid out once at the end. This can be useful when the text width or page size isn't yet known, for instance.

By default, this property is true.

This property was introduced in Qt 6.4.

Access functions:

• bool isLayoutEnabled() const

• void setLayoutEnabled(bool b)

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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.

Access functions:

• int maximumBlockCount() const

• void setMaximumBlockCount(int maximum)

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

By default, this property is false.

Access functions:

• bool isModified() const

• void setModified(bool m = true)

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

The units are determined by the underlying paint device. The size is measured in logical pixels when painting to the screen, and in points (1/72 inch) when painting to a printer.

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

Access functions:

• pageSize() const

• void setPageSize(const &size)

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This property holds the actual size of the document. This is equivalent to documentLayout()->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.

Access functions:

• size() const

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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 the size() and the idealWidth() 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 the pageSize property instead.

Access functions:

• qreal textWidth() const

• void setTextWidth(qreal width)

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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:

• bool isUndoRedoEnabled() const

• void setUndoRedoEnabled(bool enable)

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 on QAbstractTextDocumentLayout::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.

Access functions:

• bool useDesignMetrics() const

• void setUseDesignMetrics(bool b)

Constructs an empty QTextDocument with the given parent.

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

Destroys the document.

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\" />");

Adjusts the document to a reasonable size.

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

Returns the number of available redo steps.

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Returns the number of available undo steps.

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

This function was introduced in Qt 6.0.

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Returns the document's first text block.

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

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

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Returns the number of characters of this document.

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Clears the document.

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().

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

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.

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

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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.

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.

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

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

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Returns the default resource provider.

This function was introduced in Qt 6.1.

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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.

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Returns the document layout for this document.

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

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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.

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.

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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.

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.

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.

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.

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

Returns the text block that contains the specified lineNumber.

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Returns the text block with the specified blockNumber.

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Returns the document's first text block.

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().

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

Returns true if redo is available; otherwise returns false.

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Returns true if undo is available; otherwise returns false.

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

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

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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.

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

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

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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.

Returns the text object associated with the given objectIndex.

Returns the text object associated with the format f.

returns the number of pages in this document.

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.

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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.

This is an overloaded function.

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

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

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.

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Returns the resource provider for this text document.

This function was introduced in Qt 6.1.

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

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

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Returns the document's root frame.

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.

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Sets the default cursor movement style to the given style.

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Sets the default font to use in the document layout.

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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.

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Sets the default text option to option.

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

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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.

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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 .

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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.

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

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

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

This function was introduced in Qt 6.1.

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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.

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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.

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

This function was introduced in Qt 6.0.

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

This function was introduced in Qt 6.0.

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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.

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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.

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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.

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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.

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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.

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This is an overloaded function.

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.

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