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QTextEdit Class Reference

The QTextEdit class provides a widget that is used to edit and display both plain and rich text. More...

#include <QTextEdit>

Inherits QViewport.

Inherited by QTextBrowser.

Public Types

Writable Properties

Read-Only Properties

Public Functions

Public Slots

Signals

Static Public Members

Protected Functions


Detailed Description

The QTextEdit class provides a widget that is used to edit and display both plain and rich text.

Introduction and Concepts

QTextEdit is an advanced WYSIWYG viewer/editor supporting rich text formatting using HTML-style tags. It is optimized to handle large documents and to respond quickly to user input.

QTextEdit works on paragraphs and characters. A paragraph is a formatted string which is word-wrapped to fit into the width of the widget. By default when reading plain text, one newline signifies a paragraph. A document consists of zero or more paragraphs. The words in the paragraph are aligned in accordance with the paragraph's alignment. Paragraphs are separated by hard line breaks. Each character within a paragraph has its own attributes, for example, font and color.

QTextEdit can display images, lists and tables. If the text is too large to view within the text edit's viewport, scrollbars will appear. The text edit can load both plain text and HTML files (a subset of HTML 3.2 and 4).

If you just need to display a small piece of rich text use QLabel.

Note that we do not intend to add a full-featured web browser widget to Qt (because that would easily double Qt's size and only a few applications would benefit from it). The rich text support in Qt is designed to provide a fast, portable and efficient way to add reasonable online help facilities to applications, and to provide a basis for rich text editors.

Using QTextEdit as a Display Widget

QTextEdit can display a large HTML subset, including tables and images.

The text is set or replaced using setHtml() which deletes any existing text and replaces it with the text passed in the setHtml() call. If you call setHtml() with legacy HTML, and then call text(), the text that is returned may have different markup, but will render the same. The entire text can be deleted with clear().

Text itself can be inserted using the QTextCursor class or using the convenience functions insertHtml(), insertPlainText(), append() or paste(). QTextCursor is also able to insert complex objects like tables or lists into the document, and it deals with creating selections and applying changes to selected text.

By default the text edit wraps words at whitespace to fit within the text edit widget. The setWordWrap() function is used to specify the kind of word wrap you want, or NoWrap if you don't want any wrapping. Call setWordWrap() to set a fixed pixel width FixedPixelWidth, or character column (e.g. 80 column) FixedColumnWidth with the pixels or columns specified with setWrapColumnOrWidth(). If you use word wrap to the widget's width WidgetWidth, you can specify whether to break on whitespace or anywhere with setWrapPolicy().

The find() function can be used to find and select a given string within the text.

Read-only key bindings

When QTextEdit is used read-only the key-bindings are limited to navigation, and text may only be selected with the mouse:

KeypressesAction
Qt::UpArrowMove one line up
Qt::DownArrowMove one line down
Qt::LeftArrowMove one character left
Qt::RightArrowMove one character right
PageUpMove one (viewport) page up
PageDownMove one (viewport) page down
HomeMove to the beginning of the text
EndMove to the end of the text
Shift+WheelScroll the page horizontally (the Wheel is the mouse wheel)
Ctrl+WheelZoom the text

The text edit may be able to provide some meta-information. For example, the documentTitle() function will return the text from within HTML <title> tags.

Using QTextEdit as an Editor

All the information about using QTextEdit as a display widget also applies here.

The current char format's attributes are set with setFontItalic(), setFontBold(), setFontUnderline(), setFontFamily(), setFontPointSize(), setTextColor() and setCurrentFont(). The current paragraph's alignment is set with setAlignment().

Selection of text is handled by the QTextCursor class, which provides functionality for creating selections, retrieving the text contents or deleting selections. You can retrieve the object that corresponds with the user-visible cursor using the textCursor() method. If you want to set a selection in QTextEdit just create one on a QTextCursor object and then make that cursor the visible cursor using setCursor(). The selection can be copied to the clipboard with copy(), or cut to the clipboard with cut(). The entire text can be selected using selectAll().

When the cursor is moved and the underlying formatting attributes change, the currentCharFormatChanged() signal is emitted to reflect the new attributes at the new cursor position.

QTextEdit holds a QTextDocument object which can be retrieved using the document() method. You can also set your own document object using setDocument(). QTextDocument emits a textChanged() signal if the text changes and it also provides a isModified() function which will return true if the text has been modified since it was either loaded or since the last call to setModified with false as argument. In addition it provides methods for undo and redo.

Editing key bindings

The list of key-bindings which are implemented for editing:

KeypressesAction
BackspaceDelete the character to the left of the cursor
DeleteDelete the character to the right of the cursor
Ctrl+AMove the cursor to the beginning of the line
Ctrl+BMove the cursor one character left
Ctrl+CCopy the marked text to the clipboard (also Ctrl+Insert under Windows)
Ctrl+DDelete the character to the right of the cursor
Ctrl+EMove the cursor to the end of the line
Ctrl+FMove the cursor one character right
Ctrl+HDelete the character to the left of the cursor
Ctrl+KDelete to end of line
Ctrl+NMove the cursor one line down
Ctrl+PMove the cursor one line up
Ctrl+VPaste the clipboard text into line edit (also Shift+Insert under Windows)
Ctrl+XCut the marked text, copy to clipboard (also Shift+Delete under Windows)
Ctrl+ZUndo the last operation
Ctrl+YRedo the last operation
Qt::LeftArrowMove the cursor one character left
Ctrl+Qt::LeftArrowMove the cursor one word left
Qt::RightArrowMove the cursor one character right
Ctrl+Qt::RightArrowMove the cursor one word right
Qt::UpArrowMove the cursor one line up
Ctrl+Qt::UpArrowMove the cursor one word up
Qt::DownArrowMove the cursor one line down
Ctrl+Down ArrowMove the cursor one word down
PageUpMove the cursor one page up
PageDownMove the cursor one page down
HomeMove the cursor to the beginning of the line
Ctrl+HomeMove the cursor to the beginning of the text
EndMove the cursor to the end of the line
Ctrl+EndMove the cursor to the end of the text
Shift+WheelScroll the page horizontally (the Wheel is the mouse wheel)
Ctrl+WheelZoom the text

To select (mark) text hold down the Shift key whilst pressing one of the movement keystrokes, for example, Shift+Right Arrow will select the character to the right, and Shift+Ctrl+Right Arrow will select the word to the right, etc.

See also QTextDocument, QTextCursor, document(), textCursor(), setDocument(), and setTextCursor().


Member Type Documentation

enum QTextEdit::AutoFormattingFlag
typedef QTextEdit::AutoFormatting

QTextEdit::AutoNoneDon't do any automatic formatting.
QTextEdit::AutoBulletListAutomatically create bullet lists (e.g. when the user enters an asterisk ('*') in the left most column, or presses Enter in an existing list item.
QTextEdit::AutoAllApply all automatic formatting. Currently only automatic bullet lists are supported.

The AutoFormatting typedef can store a combination of AutoFormattingFlag values.

enum QTextEdit::CursorAction

QTextEdit::MoveBackward 
QTextEdit::MoveForward 
QTextEdit::MoveWordBackward 
QTextEdit::MoveWordForward 
QTextEdit::MoveUp 
QTextEdit::MoveDown 
QTextEdit::MoveLineStart 
QTextEdit::MoveLineEnd 
QTextEdit::MoveHome 
QTextEdit::MoveEnd 
QTextEdit::MovePageUp 
QTextEdit::MovePageDown 

enum QTextEdit::WordWrap

QTextEdit::NoWrap 
QTextEdit::WidgetWidth 
QTextEdit::FixedPixelWidth 
QTextEdit::FixedColumnWidth 

Property Documentation

autoFormatting : AutoFormatting

This property holds the enabled set of auto formatting features.

The value can be any combination of the values in the AutoFormattingFlag enum. The default is AutoAll. Choose AutoNone to disable all automatic formatting.

Currently, the only automatic formatting feature provided is AutoBulletList; future versions of Qt may offer more.

Access functions:

documentTitle : QString

This property holds the title of the document parsed from the text.

Access functions:

readOnly : bool

This property holds whether the text edit is read-only.

In a read-only text edit the user can only navigate through the text and select text; modifying the text is not possible.

This property's default is false.

Access functions:

tabChangesFocus : bool

This property holds whether TAB changes focus or is accepted as input.

In some occasions text edits should not allow the user to input tabulators or change indentation using the TAB key, as this breaks the focus chain. The default is false.

Access functions:

undoRedoEnabled : bool

This property holds whether undo and redo are enabled.

Users are only able to undo or redo actions if this property is true, and if there is an action that can be undone (or redone).

Access functions:

wordWrap : WordWrap

This property holds the word wrap mode.

The default mode is WidgetWidth which causes words to be wrapped at the right edge of the text edit. Wrapping occurs at whitespace, keeping whole words intact. If you want wrapping to occur within words use setWrapPolicy(). If you set a wrap mode of FixedPixelWidth or FixedColumnWidth you should also call setWrapColumnOrWidth() with the width you want.

Access functions:

See also WordWrap, wrapColumnOrWidth, and wrapPolicy.

wrapColumnOrWidth : int

This property holds the position (in pixels or columns depending on the wrap mode) where text will be wrapped.

If the wrap mode is FixedPixelWidth, the value is the number of pixels from the left edge of the text edit at which text should be wrapped. If the wrap mode is FixedColumnWidth, the value is the column number (in character columns) from the left edge of the text edit at which text should be wrapped.

Access functions:

See also wordWrap.


Member Function Documentation

QTextEdit::QTextEdit ( QWidget * parent = 0 )

Constructs an empty QTextEdit with parent parent.

QTextEdit::QTextEdit ( const QString & text, QWidget * parent = 0 )

Constructs a QTextEdit with parent parent. The text edit will display the text text. The text is interpreted as html.

QTextEdit::~QTextEdit ()   [virtual]

Destructor.

Qt::Alignment QTextEdit::alignment () const

Returns the alignment of the current paragraph.

See also setAlignment().

void QTextEdit::append ( const QString & text )

Appends a new paragraph with text to the end of the text edit.

void QTextEdit::clear ()   [slot]

Deletes all the text in the text edit.

See also cut(), removeSelectedText(), setPlainText(), and setHtml().

void QTextEdit::copy ()   [slot]

Copies any selected text to the clipboard.

See also copyAvailable().

void QTextEdit::copyAvailable ( bool yes )   [signal]

This signal is emitted when text is selected or de-selected in the text edit.

When text is selected this signal will be emitted with yes set to true. If no text has been selected or if the selected text is de-selected this signal is emitted with yes set to false.

If yes is true then copy() can be used to copy the selection to the clipboard. If yes is false then copy() does nothing.

See also selectionChanged().

QMenu * QTextEdit::createPopupMenu ( const QPoint & pos )   [virtual protected]

This function is called to create a right mouse button popup menu at the document position pos. If you want to create a custom popup menu, reimplement this function and return the created popup menu. Ownership of the popup menu is transferred to the caller.

QTextCharFormat QTextEdit::currentCharFormat () const

Returns the char format that is used when inserting new text.

void QTextEdit::currentCharFormatChanged ( const QTextCharFormat & f )   [signal]

This signal is emitted if the current character format has changed, for example caused by a change of the cursor position.

The new format is f.

See also setCurrentCharFormat().

QFont QTextEdit::currentFont () const

Returns the font of the current format.

See also setCurrentFont(), setFontFamily(), and setFontPointSize().

void QTextEdit::cursorPositionChanged ()   [signal]

This signal is emitted whenever the position of the cursor changed.

void QTextEdit::cut ()   [slot]

Copies the selected text to the clipboard and deletes it from the text edit.

If there is no selected text nothing happens.

See also copy() and paste().

QTextDocument * QTextEdit::document () const

Returns a pointer to the underlying document.

See also setDocument().

void QTextEdit::ensureCursorVisible ()

Ensures that the cursor is visible by scrolling the text edit if necessary.

bool QTextEdit::find ( const QString & exp, QTextDocument::FindFlags options = 0, QTextDocument::FindDirection direction = QTextDocument::FindForward )

Finds the next occurrence of the string, exp, using the given options searching in direction direction. Returns true if exp was found and changes the cursor to select the match; otherwise returns false;

QString QTextEdit::fontFamily () const

Returns the font family of the current format.

See also setFontFamily(), setCurrentFont(), and setFontPointSize().

bool QTextEdit::fontItalic () const

Returns true if the font of the current format is italic; otherwise returns false.

See also setFontItalic().

float QTextEdit::fontPointSize () const

Returns the point size of the font of the current format.

See also setFontFamily(), setCurrentFont(), and setFontPointSize().

bool QTextEdit::fontUnderline () const

Returns true if the font of the current format is underlined; otherwise returns false.

See also setFontUnderline().

int QTextEdit::fontWeight () const

Returns the font weight of the current format.

See also setFontWeight(), setCurrentFont(), and setFontPointSize().

int QTextEdit::heightForWidth ( int width ) const   [virtual]

Returns how many pixels high the text edit needs to be to display all the text if the text edit is width pixels wide.

Reimplemented from QWidget.

void QTextEdit::insertHtml ( const QString & text )   [slot]

Convenience slot that inserts text which is assumed to be of html formatting at the current cursor position.

It is equivalent to:

    QTextDocumentFragment fragment = QTextDocumentFragment::fromHtml(text);
    edit->textCursor().insertFragment(fragment);

void QTextEdit::insertPlainText ( const QString & text )   [slot]

Convenience slot that inserts text at the current cursor position.

It is equivalent to

    edit->textCursor().insertText(text);

void QTextEdit::mergeCurrentCharFormat ( const QTextCharFormat & modifier )

If the editor has a selection then the properties of modifier are applied to the selection. Without a selection the properties are applied to the word under the cursor. In addition they are always merged into the current char format.

See also QTextCursor::mergeCharFormat.

void QTextEdit::paste ()   [slot]

Pastes the text from the clipboard into the text edit at the current cursor position.

If there is no text in the clipboard nothing happens.

See also cut() and copy().

void QTextEdit::scrollToAnchor ( const QString & name )   [slot]

Scrolls the text edit so that the anchor with the given name is visible; does nothing if the name is empty, or is already visible, or isn't found.

void QTextEdit::selectAll ()   [slot]

Selects all text.

See also copy(), cut(), and textCursor().

void QTextEdit::selectionChanged ()   [signal]

This signal is emitted whenever the selection changes.

See also copyAvailable().

void QTextEdit::setAlignment ( Qt::Alignment a )   [slot]

Sets the alignment of the current paragraph to a. Valid alignments are Qt::AlignLeft, Qt::AlignRight, Qt::AlignJustify and Qt::AlignCenter (which centers horizontally).

void QTextEdit::setCurrentCharFormat ( const QTextCharFormat & format )

Sets the char format that is be used when inserting new text to format .

void QTextEdit::setCurrentFont ( const QFont & f )   [slot]

Sets the font of the current format to f.

See also currentFont(), setFontPointSize(), and setFontFamily().

void QTextEdit::setDocument ( QTextDocument * document )

Makes document the new document of the text editor.

The parent QObject of the provided document remains the owner of the object. If the current document is a child of the text editor, then it is deleted.

See also document().

void QTextEdit::setFontFamily ( const QString & fontFamily )   [slot]

Sets the font family of the current format to fontFamily.

See also fontFamily() and setCurrentFont().

void QTextEdit::setFontItalic ( bool b )   [slot]

If b is true sets the current format to italic; otherwise sets the current format to non-italic.

See also fontItalic().

void QTextEdit::setFontPointSize ( float s )   [slot]

Sets the point size of the current format to s.

Note that if s is zero or negative, the behavior of this function is not defined.

See also fontPointSize(), setCurrentFont(), and setFontFamily().

void QTextEdit::setFontUnderline ( bool b )   [slot]

If b is true sets the current format to underline; otherwise sets the current format to non-underline.

See also fontUnderline().

void QTextEdit::setFontWeight ( int w )   [slot]

Sets the font weight of the current format to w.

See also fontWeight(), setCurrentFont(), and setFontFamily().

void QTextEdit::setHtml ( const QString & text )   [slot]

Changes the text of the text edit to the string text. Any previous text is removed.

text is interpreted as rich text in html format.

Note that the undo/redo history is cleared by this function.

void QTextEdit::setPlainText ( const QString & text )   [slot]

Changes the text of the text edit to the string text. Any previous text is removed.

text is interpreted as plain text.

Note that the undo/redo history is cleared by this function.

See also toPlainText().

void QTextEdit::setTextColor ( const QColor & c )   [slot]

Sets the text color of the current format to c.

See also textColor().

void QTextEdit::setTextCursor ( const QTextCursor & cursor )

Sets the visible cursor.

QColor QTextEdit::textColor () const

Returns the text color of the current format.

See also setTextColor().

QTextCursor QTextEdit::textCursor () const

Returns a QTextCursor that represents the currently visible cursor.

QString QTextEdit::toHtml () const

Returns the text of the text edit as html.

See also setHtml.

QString QTextEdit::toPlainText () const

Returns the text of the text edit as plain text.

See also setPlainText.

void QTextEdit::zoomIn ( int range = 1 )   [slot]

Zooms in on the text by by making the base font size range points larger and recalculating all font sizes to be the new size. This does not change the size of any images.

See also zoomOut().

void QTextEdit::zoomOut ( int range = 1 )   [slot]

Zooms out on the text by making the base font size range points smaller and recalculating all font sizes to be the new size. This does not change the size of any images.

See also zoomIn().


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Qt 4.0.0-b1