qitemselectionmodel.cpp

奇趣公司比较新的qt/emd版本

        QModelIndex br = bottomRight.sibling(bottom, right);
        append(QItemSelectionRange(tl, br));
        return;
    }
    append(QItemSelectionRange(topLeft, bottomRight));
}

/*!
    Returns true if the selection contains the given \a index; otherwise
    returns false.
*/

bool QItemSelection::contains(const QModelIndex &index) const
{
    QList<QItemSelectionRange>::const_iterator it = begin();
    for (; it != end(); ++it)
        if ((*it).contains(index))
            return true;
    return false;
}

/*!
    Returns a list of model indexes that correspond to the selected items.
*/

QModelIndexList QItemSelection::indexes() const
{
    QModelIndexList result;
    QList<QItemSelectionRange>::const_iterator it = begin();
    for (; it != end(); ++it)
        result += (*it).indexes();
    return result;
}

/*!
  Merges the \a other selection with this QItemSelection using the
  \a command given. This method guarantees that no ranges are overlapping.

  Note that only QItemSelectionModel::Select,
  QItemSelectionModel::Deselect, and QItemSelectionModel::Toggle are
  supported.

  \sa split()
*/
void QItemSelection::merge(const QItemSelection &other, QItemSelectionModel::SelectionFlags command)
{
    if (other.isEmpty() ||
          !(command & QItemSelectionModel::Select ||
          command & QItemSelectionModel::Deselect ||
          command & QItemSelectionModel::Toggle))
        return;

    QItemSelection newSelection = other;
    // Collect intersections
    QItemSelection intersections;
    QItemSelection::iterator it = newSelection.begin();
    while (it != newSelection.end()) {
        if (!(*it).isValid()) {
            it = newSelection.erase(it);
            continue;
        }
        for (int t = 0; t < count(); ++t) {
            if ((*it).intersects(at(t)))
                intersections.append(at(t).intersected(*it));
        }
        ++it;
    }

    //  Split the old (and new) ranges using the intersections
    for (int i = 0; i < intersections.count(); ++i) { // for each intersection
        for (int t = 0; t < count();) { // splitt each old range
            if (at(t).intersects(intersections.at(i))) {
                split(at(t), intersections.at(i), this);
                removeAt(t);
            } else {
                ++t;
            }
        }
        // only split newSelection if Toggle is specified
        for (int n = 0; (command & QItemSelectionModel::Toggle) && n < newSelection.count();) {
            if (newSelection.at(n).intersects(intersections.at(i))) {
                split(newSelection.at(n), intersections.at(i), &newSelection);
                newSelection.removeAt(n);
            } else {
                ++n;
            }
        }
    }
    // do not add newSelection for Deselect
    if (!(command & QItemSelectionModel::Deselect))
        operator+=(newSelection);
}

/*!
  Splits the selection \a range using the selection \a other range.
  Removes all items in \a other from \a range and puts the result in \a result.
  This can be compared with the semantics of the \e subtract operation of a set.
  \sa merge()
*/

void QItemSelection::split(const QItemSelectionRange &range,
                           const QItemSelectionRange &other, QItemSelection *result)
{
    if (range.parent() != other.parent())
        return;

    QModelIndex parent = other.parent();
    int top = range.top();
    int left = range.left();
    int bottom = range.bottom();
    int right = range.right();
    int other_top = other.top();
    int other_left = other.left();
    int other_bottom = other.bottom();
    int other_right = other.right();
    const QAbstractItemModel *model = range.model();
    Q_ASSERT(model);
    if (other_top > top) {
        QModelIndex tl = model->index(top, left, parent);
        QModelIndex br = model->index(other_top - 1, right, parent);
        result->append(QItemSelectionRange(tl, br));
        top = other_top;
    }
    if (other_bottom < bottom) {
        QModelIndex tl = model->index(other_bottom + 1, left, parent);
        QModelIndex br = model->index(bottom, right, parent);
        result->append(QItemSelectionRange(tl, br));
        bottom = other_bottom;
    }
    if (other_left > left) {
        QModelIndex tl = model->index(top, left, parent);
        QModelIndex br = model->index(bottom, other_left - 1, parent);
        result->append(QItemSelectionRange(tl, br));
        left = other_left;
    }
    if (other_right < right) {
        QModelIndex tl = model->index(top, other_right + 1, parent);
        QModelIndex br = model->index(bottom, right, parent);
        result->append(QItemSelectionRange(tl, br));
        right = other_right;
    }
}

/*!
  \internal

  returns a QItemSelection where all ranges have been expanded to:
  Rows: left: 0 and right: columnCount()-1
  Columns: top: 0 and bottom: rowCount()-1
*/

QItemSelection QItemSelectionModelPrivate::expandSelection(const QItemSelection &selection,
                                                           QItemSelectionModel::SelectionFlags command) const
{
    if (selection.isEmpty() && !((command & QItemSelectionModel::Rows) ||
                                 (command & QItemSelectionModel::Columns)))
        return selection;

    QItemSelection expanded;
    if (command & QItemSelectionModel::Rows) {
        for (int i = 0; i < selection.count(); ++i) {
            QModelIndex parent = selection.at(i).parent();
            int colCount = model->columnCount(parent);
            QModelIndex tl = model->index(selection.at(i).top(), 0, parent);
            QModelIndex br = model->index(selection.at(i).bottom(), colCount - 1, parent);
            expanded.append(QItemSelectionRange(tl, br));
        }
    }
    if (command & QItemSelectionModel::Columns) {
        for (int i = 0; i < selection.count(); ++i) {
            QModelIndex parent = selection.at(i).parent();
            int rowCount = model->rowCount(parent);
            QModelIndex tl = model->index(0, selection.at(i).left(), parent);
            QModelIndex br = model->index(rowCount - 1, selection.at(i).right(), parent);
            expanded.append(QItemSelectionRange(tl, br));
        }
    }
    return expanded;
}

/*!
  \internal
*/
void QItemSelectionModelPrivate::_q_rowsAboutToBeRemoved(const QModelIndex &parent,
                                                         int start, int end)
{
    Q_Q(QItemSelectionModel);

    // update current index
    if (currentIndex.isValid() && parent == currentIndex.parent()
        && currentIndex.row() >= start && currentIndex.row() <= end) {
        QModelIndex old = currentIndex;
        if (start > 0) // there are rows left above the change
            currentIndex = model->index(start - 1, old.column(), parent);
        else if (model && end < model->rowCount(parent) - 1) // there are rows left below the change
            currentIndex = model->index(end + 1, old.column(), parent);
        else // there are no rows left in the table
            currentIndex = QModelIndex();
        emit q->currentChanged(currentIndex, old);
        emit q->currentRowChanged(currentIndex, old);
        if (currentIndex.column() != old.column())
            emit q->currentColumnChanged(currentIndex, old);
    }

    // update selectionsx
    QModelIndex tl = model->index(start, 0, parent);
    QModelIndex br = model->index(end, model->columnCount(parent) - 1, parent);
    q->select(QItemSelection(tl, br), QItemSelectionModel::Deselect);
    finalize();
}

/*!
  \internal
*/
void QItemSelectionModelPrivate::_q_columnsAboutToBeRemoved(const QModelIndex &parent,
                                                            int start, int end)
{
    Q_Q(QItemSelectionModel);

    // update current index
    if (currentIndex.isValid() && parent == currentIndex.parent()
        && currentIndex.column() >= start && currentIndex.column() <= end) {
        QModelIndex old = currentIndex;
        if (start > 0) // there are columns to the left of the change
            currentIndex = model->index(old.row(), start - 1, parent);
        else if (model && end < model->columnCount() - 1) // there are columns to the right of the change
            currentIndex = model->index(old.row(), end + 1, parent);
        else // there are no columns left in the table
            currentIndex = QModelIndex();
        emit q->currentChanged(currentIndex, old);
        if (currentIndex.row() != old.row())
            emit q->currentRowChanged(currentIndex, old);
        emit q->currentColumnChanged(currentIndex, old);
    }

    // update selections
    QModelIndex tl = model->index(0, start, parent);
    QModelIndex br = model->index(model->rowCount(parent) - 1, end, parent);
    q->select(QItemSelection(tl, br), QItemSelectionModel::Deselect);
    finalize();
}

/*!
  \internal

  Split selection ranges if columns are about to be inserted in the middle.
*/
void QItemSelectionModelPrivate::_q_columnsAboutToBeInserted(const QModelIndex &parent,
                                                             int start, int end)
{
    Q_UNUSED(end);
    finalize();
    QList<QItemSelectionRange> split;
    QList<QItemSelectionRange>::iterator it = ranges.begin();
    for (; it != ranges.end(); ) {
        if ((*it).isValid() && (*it).parent() == parent
            && (*it).left() <= start && (*it).right() >= start) {
            QModelIndex bottomMiddle = model->index((*it).bottom(), start - 1, (*it).parent());
            QItemSelectionRange left((*it).topLeft(), bottomMiddle);
            QModelIndex topMiddle = model->index((*it).top(), start, (*it).parent());
            QItemSelectionRange right(topMiddle, (*it).bottomRight());
            it = ranges.erase(it);
            split.append(left);
            split.append(right);
        } else {
            ++it;
        }
    }
    ranges += split;
}

/*!
  \internal

  Split selection ranges if rows are about to be inserted in the middle.
*/
void QItemSelectionModelPrivate::_q_rowsAboutToBeInserted(const QModelIndex &parent,
                                                          int start, int end)
{
    Q_UNUSED(end);
    finalize();
    QList<QItemSelectionRange> split;
    QList<QItemSelectionRange>::iterator it = ranges.begin();
    for (; it != ranges.end(); ) {
        if ((*it).isValid() && (*it).parent() == parent
            && (*it).top() <= start && (*it).bottom() >= start) {
            QModelIndex middleRight = model->index(start - 1, (*it).right(), (*it).parent());
            QItemSelectionRange top((*it).topLeft(), middleRight);
            QModelIndex middleLeft = model->index(start, (*it).left(), (*it).parent());
            QItemSelectionRange bottom(middleLeft, (*it).bottomRight());
            it = ranges.erase(it);
            split.append(top);
            split.append(bottom);
        } else {
            ++it;
        }
    }
    ranges += split;
}

/*!
  \internal

  Split selection into individual (persistent) indexes. This is done in
  preparation for the layoutChanged() signal, where the indexes can be
  merged again.
*/
void QItemSelectionModelPrivate::_q_layoutAboutToBeChanged()
{
    savedPersistentIndexes.clear();
    savedPersistentCurrentIndexes.clear();
    QModelIndexList indexes = ranges.indexes();
    QModelIndexList::const_iterator it;
    for (it = indexes.constBegin(); it != indexes.constEnd(); ++it)
        savedPersistentIndexes.append(QPersistentModelIndex(*it));
    indexes = currentSelection.indexes();
    for (it = indexes.constBegin(); it != indexes.constEnd(); ++it)
        savedPersistentCurrentIndexes.append(QPersistentModelIndex(*it));
}

/*!
  \internal

  Merges \a indexes into an item selection made up of ranges.
  Assumes that the indexes are sorted.
*/
static QItemSelection mergeIndexes(const QList<QPersistentModelIndex> &indexes)
{
    QItemSelection colSpans;
    // merge columns
    int i = 0;
    while (i < indexes.count()) {
        QModelIndex tl = indexes.at(i);
        QModelIndex br = tl;
        while (++i < indexes.count()) {
            QModelIndex next = indexes.at(i);
            if ((next.parent() == br.parent())
                 && (next.row() == br.row())
                 && (next.column() == br.column() + 1))
                br = next;
            else
                break;
        }
        colSpans.append(QItemSelectionRange(tl, br));
    }
    // merge rows
    QItemSelection rowSpans;
    i = 0;
    while (i < colSpans.count()) {
        QModelIndex tl = colSpans.at(i).topLeft();
        QModelIndex br = colSpans.at(i).bottomRight();
        QModelIndex prevTl = tl;
        while (++i < colSpans.count()) {
            QModelIndex nextTl = colSpans.at(i).topLeft();
            QModelIndex nextBr = colSpans.at(i).bottomRight();
            if ((nextTl.column() == prevTl.column()) && (nextBr.column() == br.column())
                && (nextTl.row() == prevTl.row() + 1) && (nextBr.row() == br.row() + 1)) {
                br = nextBr;
                prevTl = nextTl;
            } else {
                break;
            }
        }
        rowSpans.append(QItemSelectionRange(tl, br));
    }
    return rowSpans;
}

/*!
  \internal