qtextcursor.cpp

奇趣公司比较新的qt/emd版本

{
    d->adjusted_anchor = d->anchor = d->position = frame->firstPosition();
}


/*!
    Constructs a cursor pointing to the beginning of the \a block.
*/
QTextCursor::QTextCursor(const QTextBlock &block)
    : d(new QTextCursorPrivate(block.docHandle()))
{
    d->adjusted_anchor = d->anchor = d->position = block.position();
}


/*!
  \internal
 */
QTextCursor::QTextCursor(QTextDocumentPrivate *p, int pos)
    : d(new QTextCursorPrivate(p))
{
    d->adjusted_anchor = d->anchor = d->position = pos;

    d->setX();
}

/*!
    \internal
*/
QTextCursor::QTextCursor(QTextCursorPrivate *d)
{
    Q_ASSERT(d);
    this->d = d;
}

/*!
    Constructs a new cursor that is a copy of \a cursor.
 */
QTextCursor::QTextCursor(const QTextCursor &cursor)
{
    d = cursor.d;
}

/*!
    Makes a copy of \a cursor and assigns it to this QTextCursor.
 */
QTextCursor &QTextCursor::operator=(const QTextCursor &cursor)
{
    d = cursor.d;
    return *this;
}

/*!
    Destroys the QTextCursor.
 */
QTextCursor::~QTextCursor()
{
}

/*!
    Returns true if the cursor is null; otherwise returns false. A null
    cursor is created by the default constructor.
 */
bool QTextCursor::isNull() const
{
    return !d || !d->priv;
}

/*!
    Moves the cursor to the absolute position in the document specified by
    \a pos using a \c MoveMode specified by \a m. The cursor is positioned
    between characters.

    \sa position() movePosition() anchor()
*/
void QTextCursor::setPosition(int pos, MoveMode m)
{
    if (!d || !d->priv)
        return;

    if (pos < 0 || pos >= d->priv->length()) {
        qWarning("QTextCursor::setPosition: Position '%d' out of range", pos);
        return;
    }

    d->setPosition(pos);
    if (m == MoveAnchor) {
        d->anchor = pos;
        d->adjusted_anchor = pos;
    } else { // keep anchor
        QTextCursor::MoveOperation op;
        if (pos < d->anchor)
            op = QTextCursor::Left;
        else
            op = QTextCursor::Right;
        d->adjustCursor(op);
    }
    d->setX();
}

/*!
    Returns the absolute position of the cursor within the document.
    The cursor is positioned between characters.

    \sa setPosition() movePosition() anchor()
*/
int QTextCursor::position() const
{
    if (!d || !d->priv)
        return -1;
    return d->position;
}

/*!
    Returns the anchor position; this is the same as position() unless
    there is a selection in which case position() marks one end of the
    selection and anchor() marks the other end. Just like the cursor
    position, the anchor position is between characters.

    \sa position() setPosition() movePosition() selectionStart() selectionEnd()
*/
int QTextCursor::anchor() const
{
    if (!d || !d->priv)
        return -1;
    return d->anchor;
}

/*!
    \fn bool QTextCursor::movePosition(MoveOperation operation, MoveMode mode, int n)

    Moves the cursor by performing the given \a operation \a n times, using the specified
    \a mode, and returns true if all operations were completed successfully; otherwise
    returns false.

    For example, if this function is repeatedly used to seek to the end of the next
    word, it will eventually fail when the end of the document is reached.

    By default, the move operation is performed once (\a n = 1).

    If \a mode is \c KeepAnchor, the cursor selects the text it moves
    over. This is the same effect that the user achieves when they
    hold down the Shift key and move the cursor with the cursor keys.
*/
bool QTextCursor::movePosition(MoveOperation op, MoveMode mode, int n)
{
    if (!d || !d->priv)
        return false;
    switch (op) {
        case Start:
        case StartOfLine:
        case End:
        case EndOfLine:
            n = 1;
            break;
        default: break;
    }
    for (; n > 0; --n) {
        if (!d->movePosition(op, mode))
            return false;
    }
    return true;
}

/*!
    Inserts \a text at the current position, using the current
    character format.

    If there is a selection, the selection is deleted and replaced by
    \a text, for example:
    \code
    cursor.clearSelection();
    cursor.movePosition(QTextCursor::NextWord, QTextCursor::KeepAnchor);
    cursor.insertText("Hello World");
    \endcode
    This clears any existing selection, selects the word at the cursor
    (i.e. from position() forward), and replaces the selection with
    the phrase "Hello World".

    Any ASCII linefeed characters (\\n) in the inserted text are transformed
    into unicode block separators, corresponding to insertBlock() calls.

    \sa charFormat() hasSelection()
*/
void QTextCursor::insertText(const QString &text)
{
    QTextCharFormat fmt = charFormat();
    fmt.clearProperty(QTextFormat::ObjectType);
    insertText(text, fmt);
}

/*!
    \fn void QTextCursor::insertText(const QString &text, const QTextCharFormat &format)
    \overload

    Inserts \a text at the current position with the given \a format.
*/
void QTextCursor::insertText(const QString &text, const QTextCharFormat &_format)
{
    if (!d || !d->priv)
        return;

    Q_ASSERT(_format.isValid());

    QTextCharFormat format = _format;
    format.clearProperty(QTextFormat::ObjectIndex);

    d->priv->beginEditBlock();

    d->remove();
    if (!text.isEmpty()) {
        QTextFormatCollection *formats = d->priv->formatCollection();
        int formatIdx = formats->indexForFormat(format);
        Q_ASSERT(formats->format(formatIdx).isCharFormat());

        QTextBlockFormat blockFmt = blockFormat();

        int textStart = 0;
        for (int i = 0; i < text.length(); ++i) {
            QChar ch = text.at(i);

            const int textEnd = i;

            if (ch == QLatin1Char('\r')
                && (i + 1) < text.length()
                && text.at(i + 1) == QLatin1Char('\n')) {
                ++i;
                ch = text.at(i);
            }

            if (ch == QLatin1Char('\n')
                || ch == QChar::ParagraphSeparator
                || ch == QLatin1Char('\r')) {

                if (textEnd > textStart)
                    d->priv->insert(d->position, QString(text.unicode() + textStart, textEnd - textStart), formatIdx);

                textStart = i + 1;
                d->insertBlock(blockFmt, format);
            }
        }
        if (textStart < text.length())
            d->priv->insert(d->position, QString(text.unicode() + textStart, text.length() - textStart), formatIdx);
    }
    d->priv->endEditBlock();
    if (!d->priv->isInEditBlock())
        d->setX();
}

/*!
    If there is no selected text, deletes the character \e at the
    current cursor position; otherwise deletes the selected text.

    \sa deletePreviousChar() hasSelection() clearSelection()
*/
void QTextCursor::deleteChar()
{
    if (!d || !d->priv)
        return;

    if (d->position == d->anchor) {
        if (!d->canDelete(d->position))
            return;
        d->adjusted_anchor = d->anchor =
                             d->priv->nextCursorPosition(d->anchor, QTextLayout::SkipCharacters);
    }
    d->remove();
    d->setX();
}

/*!
    If there is no selected text, deletes the character \e before the
    current cursor position; otherwise deletes the selected text.

    \sa deleteChar() hasSelection() clearSelection()
*/
void QTextCursor::deletePreviousChar()
{
    if (!d || !d->priv)
        return;

    if (d->position == d->anchor) {
        if (d->anchor < 1 || !d->canDelete(d->anchor-1))
            return;
        d->anchor--;

        QTextDocumentPrivate::FragmentIterator fragIt = d->priv->find(d->anchor);
        const QTextFragmentData * const frag = fragIt.value();
        int fpos = fragIt.position();
        QChar uc = d->priv->buffer().at(d->anchor - fpos + frag->stringPosition);
        if (d->anchor > fpos && uc.unicode() >= 0xdc00 && uc.unicode() < 0xe000) {
            // second half of a surrogate, check if we have the first half as well,
            // if yes delete both at once
            uc = d->priv->buffer().at(d->anchor - 1 - fpos + frag->stringPosition);
            if (uc.unicode() >= 0xd800 && uc.unicode() < 0xdc00)
                --d->anchor;
        }

        d->adjusted_anchor = d->anchor;
    }

    d->remove();
    d->setX();
}

/*!
    Selects text in the document according to the given \a selection.
*/
void QTextCursor::select(SelectionType selection)
{
    if (!d || !d->priv)
        return;

    clearSelection();

    const QTextBlock block = d->block();

    switch (selection) {
        case LineUnderCursor:
            movePosition(StartOfLine);
            movePosition(EndOfLine, KeepAnchor);
            break;
        case WordUnderCursor:
            movePosition(StartOfWord);
            movePosition(EndOfWord, KeepAnchor);
            break;
        case BlockUnderCursor:
            movePosition(StartOfBlock);
            // also select the paragraph separator
            if (movePosition(PreviousBlock)) {
                movePosition(EndOfBlock);
                movePosition(NextBlock, KeepAnchor);
            }
            movePosition(EndOfBlock, KeepAnchor);
            break;
        case Document:
            movePosition(Start);
            movePosition(End, KeepAnchor);
            break;
    }
}

/*!
    Returns true if the cursor contains a selection; otherwise returns false.
*/
bool QTextCursor::hasSelection() const
{
    return !!d && d->position != d->anchor;
}


/*!
    Returns true if the cursor contains a selection that is not simply a
    range from selectionStart() to selectionEnd(); otherwise returns false.

    Complex selections are ones that span at least two cells in a table;
    their extent is specified by selectedTableCells().
*/
bool QTextCursor::hasComplexSelection() const
{
    if (!d)
        return false;

    return d->complexSelectionTable() != 0;
}

/*!
    If the selection spans over table cells, \a firstRow is populated
    with the number of the first row in the selection, \a firstColumn
    with the number of the first column in the selection, and \a
    numRows and \a numColumns with the number of rows and columns in
    the selection. If the selection does not span any table cells the
    results are harmless but undefined.
*/
void QTextCursor::selectedTableCells(int *firstRow, int *numRows, int *firstColumn, int *numColumns) const
{
    *firstRow = -1;
    *firstColumn = -1;
    *numRows = -1;
    *numColumns = -1;

    if (!d || d->position == d->anchor)
        return;

    d->selectedTableCells(firstRow, numRows, firstColumn, numColumns);
}


/*!
    Clears the current selection by setting the anchor to the cursor position.

    Note that it does \bold{not} delete the text of the selection.

    \sa removeSelectedText() hasSelection()
*/
void QTextCursor::clearSelection()
{
    if (!d)
        return;
    d->adjusted_anchor = d->anchor = d->position;
    d->currentCharFormat = -1;
}

/*!
    If there is a selection, its content is deleted; otherwise does
    nothing.

    \sa hasSelection()
*/
void QTextCursor::removeSelectedText()
{
    if (!d || !d->priv || d->position == d->anchor)
        return;

    d->remove();
    d->setX();
}

/*!
    Returns the start of the selection or position() if the
    cursor doesn't have a selection.

    \sa selectionEnd() position() anchor()
*/
int QTextCursor::selectionStart() const
{
    if (!d || !d->priv)
        return -1;
    return qMin(d->position, d->adjusted_anchor);
}

/*!
    Returns the end of the selection or position() if the cursor
    doesn't have a selection.

    \sa selectionStart() position() anchor()
*/
int QTextCursor::selectionEnd() const
{
    if (!d || !d->priv)