qtextedit.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

{
    if (cursor.isNull())
        return;

    cursor.setPosition(undoPosition + charsAdded);
    // don't call ensureCursorVisible here but wait until the text is layouted, which will
    // be the case in QTextEdit::undo() after calling undo() on the document.
}

/*!
    \class QTextEdit
    \brief The QTextEdit class provides a widget that is used to edit and display
    both plain and rich text.

    \ingroup text
    \mainclass

    \tableofcontents

    \section1 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.

    \section1 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 setLineWrapMode() function is used to
    specify the kind of line wrap you want, or \l NoWrap if you don't
    want any wrapping. Call setLineWrapMode() to set a fixed pixel width
    \l FixedPixelWidth, or character column (e.g. 80 column) \l
    FixedColumnWidth with the pixels or columns specified with
    setLineWrapColumnOrWidth(). If you use word wrap to the widget's width
    \l WidgetWidth, you can specify whether to break on whitespace or
    anywhere with setWordWrapMode().

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

    \section2 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:
    \table
    \header \i Keypresses \i Action
    \row \i Qt::UpArrow        \i Moves one line up.
    \row \i Qt::DownArrow        \i Moves one line down.
    \row \i Qt::LeftArrow        \i Moves one character to the left.
    \row \i Qt::RightArrow        \i Moves one character to the right.
    \row \i PageUp        \i Moves one (viewport) page up.
    \row \i PageDown        \i Moves one (viewport) page down.
    \row \i Home        \i Moves to the beginning of the text.
    \row \i End                \i Moves to the end of the text.
    \row \i Alt+Wheel
         \i Scrolls the page horizontally (the Wheel is the mouse wheel).
    \row \i Ctrl+Wheel        \i Zooms the text.
    \row \i Ctrl+A            \i Selects all text.
    \endtable

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

    \section1 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(),
    setFontWeight(), 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.

    \section2 Editing Key Bindings

    The list of key bindings which are implemented for editing:
    \table
    \header \i Keypresses \i Action
    \row \i Backspace \i Deletes the character to the left of the cursor.
    \row \i Delete \i Deletes the character to the right of the cursor.
    \row \i Ctrl+C \i Copy the selected text to the clipboard.
    \row \i Ctrl+Insert \i Copy the selected text to the clipboard.
    \row \i Ctrl+K \i Deletes to the end of the line.
    \row \i Ctrl+V \i Pastes the clipboard text into text edit.
    \row \i Shift+Insert \i Pastes the clipboard text into text edit.
    \row \i Ctrl+X \i Deletes the selected text and copies it to the clipboard.
    \row \i Shift+Delete \i Deletes the selected text and copies it to the clipboard.
    \row \i Ctrl+Z \i Undoes the last operation.
    \row \i Ctrl+Y \i Redoes the last operation.
    \row \i LeftArrow \i Moves the cursor one character to the left.
    \row \i Ctrl+LeftArrow \i Moves the cursor one word to the left.
    \row \i RightArrow \i Moves the cursor one character to the right.
    \row \i Ctrl+RightArrow \i Moves the cursor one word to the right.
    \row \i UpArrow \i Moves the cursor one line up.
    \row \i Ctrl+UpArrow \i Moves the cursor one word up.
    \row \i DownArrow \i Moves the cursor one line down.
    \row \i Ctrl+Down Arrow \i Moves the cursor one word down.
    \row \i PageUp \i Moves the cursor one page up.
    \row \i PageDown \i Moves the cursor one page down.
    \row \i Home \i Moves the cursor to the beginning of the line.
    \row \i Ctrl+Home \i Moves the cursor to the beginning of the text.
    \row \i End \i Moves the cursor to the end of the line.
    \row \i Ctrl+End \i Moves the cursor to the end of the text.
    \row \i Alt+Wheel \i Scrolls the page horizontally (the Wheel is the mouse wheel).
    \row \i Ctrl+Wheel \i Zooms the text.
    \endtable

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

    \sa QTextDocument QTextCursor document() textCursor() setDocument() setTextCursor()

*/

/*!
    \property QTextEdit::undoRedoEnabled
    \brief 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).
*/

/*!
    \enum QTextEdit::LineWrapMode

    \value NoWrap
    \value WidgetWidth
    \value FixedPixelWidth
    \value FixedColumnWidth
*/

/*!
    \enum QTextEdit::AutoFormattingFlag

    \value AutoNone Don't do any automatic formatting.
    \value AutoBulletList Automatically create bullet lists (e.g. when
    the user enters an asterisk ('*') in the left most column, or
    presses Enter in an existing list item.
    \value AutoAll Apply all automatic formatting. Currently only
    automatic bullet lists are supported.
*/

/*!
    \enum QTextEdit::CursorAction

    \value MoveBackward
    \value MoveForward
    \value MoveWordBackward
    \value MoveWordForward
    \value MoveUp
    \value MoveDown
    \value MoveLineStart
    \value MoveLineEnd
    \value MoveHome
    \value MoveEnd
    \value MovePageUp
    \value MovePageDown

    \omitvalue MovePgUp
    \omitvalue MovePgDown
*/

/*!
    Constructs an empty QTextEdit with parent \a
    parent.
*/
QTextEdit::QTextEdit(QWidget *parent)
    : QAbstractScrollArea(*new QTextEditPrivate, parent)
{
    Q_D(QTextEdit);
    d->init();
}

/*!
    \internal
*/
QTextEdit::QTextEdit(QTextEditPrivate &dd, QWidget *parent)
    : QAbstractScrollArea(dd, parent)
{
    Q_D(QTextEdit);
    d->init();
}

/*!
    Constructs a QTextEdit with parent \a parent. The text edit will display
    the text \a text. The text is interpreted as html.
*/
QTextEdit::QTextEdit(const QString &text, QWidget *parent)
    : QAbstractScrollArea(*new QTextEditPrivate, parent)
{
    Q_D(QTextEdit);
    d->init(text);
}

#ifdef QT3_SUPPORT
/*!
    Use one of the constructors that doesn't take the \a name
    argument and then use setObjectName() instead.
*/
QTextEdit::QTextEdit(QWidget *parent, const char *name)
    : QAbstractScrollArea(*new QTextEditPrivate, parent)
{
    Q_D(QTextEdit);
    d->init();
    setObjectName(QString::fromAscii(name));
}
#endif


/*!
    Destructor.
*/
QTextEdit::~QTextEdit()
{
}

/*!
    Returns the point size of the font of the current format.

    \sa setFontFamily() setCurrentFont() setFontPointSize()
*/
qreal QTextEdit::fontPointSize() const
{
    Q_D(const QTextEdit);
    return d->cursor.charFormat().fontPointSize();
}

/*!
    Returns the font family of the current format.

    \sa setFontFamily() setCurrentFont() setFontPointSize()
*/
QString QTextEdit::fontFamily() const
{
    Q_D(const QTextEdit);
    return d->cursor.charFormat().fontFamily();
}

/*!
    Returns the font weight of the current format.

    \sa setFontWeight() setCurrentFont() setFontPointSize() QFont::Weight
*/
int QTextEdit::fontWeight() const
{
    Q_D(const QTextEdit);
    return d->cursor.charFormat().fontWeight();
}

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

    \sa setFontUnderline()
*/
bool QTextEdit::fontUnderline() const
{
    Q_D(const QTextEdit);
    return d->cursor.charFormat().fontUnderline();
}

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

    \sa setFontItalic()
*/
bool QTextEdit::fontItalic() const
{
    Q_D(const QTextEdit);
    return d->cursor.charFormat().fontItalic();
}

/*!
    Returns the text color of the current format.

    \sa setTextColor()
*/
QColor QTextEdit::textColor() const
{
    Q_D(const QTextEdit);
    return d->cursor.charFormat().foreground().color();
}

/*!
    Returns the font of the current format.

    \sa setCurrentFont() setFontFamily() setFontPointSize()
*/
QFont QTextEdit::currentFont() const
{
    Q_D(const QTextEdit);
    return d->cursor.charFormat().font();
}

/*!
    Sets the alignment of the current paragraph to \a a. Valid
    alignments are Qt::AlignLeft, Qt::AlignRight,
    Qt::AlignJustify and Qt::AlignCenter (which centers
    horizontally).
*/
void QTextEdit::setAlignment(Qt::Alignment a)
{
    Q_D(QTextEdit);
    QTextBlockFormat fmt;
    fmt.setAlignment(a);
    d->cursor.mergeBlockFormat(fmt);
    updateMicroFocus();
}

/*!
    Returns the alignment of the current paragraph.

    \sa setAlignment()
*/
Qt::Alignment QTextEdit::alignment() const
{
    Q_D(const QTextEdit);
    return d->cursor.blockFormat().alignment();
}

/*!
    Makes \a 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.

    \sa document()
*/
void QTextEdit::setDocument(QTextDocument *document)
{
    Q_D(QTextEdit);
    if (d->doc == document)
        return;

    d->doc->disconnect(this);
    d->doc->documentLayout()->disconnect(this);
    d->doc->documentLayout()->setPaintDevice(0);

    if (d->doc->parent() == this)
        delete d->doc;

    d->doc = 0;
    d->setContent(Qt::RichText, QString(), document);
    d->relayoutDocument();
}

/*!
    Returns a pointer to the underlying document.

    \sa setDocument()
*/
QTextDocument *QTextEdit::document() const
{
    Q_D(const QTextEdit);
    return d->doc;
}

/*!
    Sets the visible \a cursor.
*/
void QTextEdit::setTextCursor(const QTextCursor &cursor)