qlayoutitem.cpp

奇趣公司比较新的qt/emd版本

    return 0;
}

/*!
    Returns the widget managed by this item.
*/
QWidget *QWidgetItem::widget()
{
    return wid;
}

/*!
    Returns true if this layout's preferred height depends on its
    width; otherwise returns false. The default implementation returns
    false.

    Reimplement this function in layout managers that support height
    for width.

    \sa heightForWidth(), QWidget::heightForWidth()
*/
bool QLayoutItem::hasHeightForWidth() const
{
    return false;
}

/*!
    Returns the minimum height this widget needs for the given width,
    \a w. The default implementation simply returns heightForWidth(\a
    w).
*/
int QLayoutItem::minimumHeightForWidth(int w) const
{
    return heightForWidth(w);
}


/*!
    Returns the preferred height for this layout item, given the width
    \a w.

    The default implementation returns -1, indicating that the
    preferred height is independent of the width of the item. Using
    the function hasHeightForWidth() will typically be much faster
    than calling this function and testing for -1.

    Reimplement this function in layout managers that support height
    for width. A typical implementation will look like this:
    \code
        int MyLayout::heightForWidth(int w) const
        {
            if (cache_dirty || cached_width != w) {
                // not all C++ compilers support "mutable"
                MyLayout *that = (MyLayout*)this;
                int h = calculateHeightForWidth(w);
                that->cached_hfw = h;
                return h;
            }
            return cached_hfw;
        }
    \endcode

    Caching is strongly recommended; without it layout will take
    exponential time.

    \sa hasHeightForWidth()
*/
int QLayoutItem::heightForWidth(int /* w */) const
{
    return -1;
}

/*!
    Returns the control type(s) for the layout item. For a
    QWidgetItem, the control type comes from the widget's size
    policy; for a QLayoutItem, the control types is derived from the
    layout's contents.

    \sa QSizePolicy::controlType()
*/
QSizePolicy::ControlTypes QLayoutItem::controlTypes() const
{
    // ### Qt 5: This function should probably be virtual instead
    if (const QWidget *widget = const_cast<QLayoutItem*>(this)->widget()) {
        return widget->sizePolicy().controlType();
    } else if (const QLayout *layout = const_cast<QLayoutItem*>(this)->layout()) {
        QSizePolicy::ControlTypes types;
        for (int i = layout->count() - 1; i >= 0; --i)
            types |= layout->itemAt(i)->controlTypes();
        return types;
    }
    return QSizePolicy::DefaultType;
}

/*!
    \reimp
*/
void QSpacerItem::setGeometry(const QRect &r)
{
    rect = r;
}

/*!
    \reimp
*/
void QWidgetItem::setGeometry(const QRect &rect)
{
    if (isEmpty())
        return;

    QRect r = !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
            ? fromLayoutItemRect(wid->d_func(), rect)
            : rect;
    QSize s = r.size().boundedTo(qSmartMaxSize(this));
    int x = r.x();
    int y = r.y();
    if (align & (Qt::AlignHorizontal_Mask | Qt::AlignVertical_Mask)) {
        QSize pref = wid->sizeHint().expandedTo(wid->minimumSize()); //###
        if (align & Qt::AlignHorizontal_Mask)
            s.setWidth(qMin(s.width(), pref.width()));
        if (align & Qt::AlignVertical_Mask) {
            if (hasHeightForWidth())
                s.setHeight(qMin(s.height(), heightForWidth(s.width())));
            else
                s.setHeight(qMin(s.height(), pref.height()));
        }
    }
    Qt::Alignment alignHoriz = QStyle::visualAlignment(wid->layoutDirection(), align);
    if (alignHoriz & Qt::AlignRight)
        x = x + (r.width() - s.width());
    else if (!(alignHoriz & Qt::AlignLeft))
        x = x + (r.width() - s.width()) / 2;

    if (align & Qt::AlignBottom)
        y = y + (r.height() - s.height());
    else if (!(align & Qt::AlignTop))
        y = y + (r.height() - s.height()) / 2;

    wid->setGeometry(x, y, s.width(), s.height());
}

/*!
    \reimp
*/
QRect QSpacerItem::geometry() const
{
    return rect;
}

/*!
    \reimp
*/
QRect QWidgetItem::geometry() const
{
    return !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
           ? toLayoutItemRect(wid->d_func(), wid->geometry())
           : wid->geometry();
}


/*!
    \reimp
*/
bool QWidgetItem::hasHeightForWidth() const
{
    if (isEmpty())
        return false;
    if (wid->layout())
        return wid->layout()->hasHeightForWidth();
    return wid->sizePolicy().hasHeightForWidth();
}

/*!
    \reimp
*/
int QWidgetItem::heightForWidth(int w) const
{
    if (isEmpty())
        return -1;

    w = !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
      ? fromLayoutItemSize(wid->d_func(), QSize(w, 0)).width()
      : w;

    int hfw;
    if (wid->layout())
        hfw = wid->layout()->totalHeightForWidth(w);
    else
        hfw = wid->heightForWidth(w);

    if (hfw > wid->maximumHeight())
        hfw = wid->maximumHeight();
    if (hfw < wid->minimumHeight())
        hfw = wid->minimumHeight();

    hfw = !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
        ? toLayoutItemSize(wid->d_func(), QSize(0, hfw)).height()
        : hfw;

    if (hfw < 0)
        hfw = 0;
    return hfw;
}

/*!
    \reimp
*/
Qt::Orientations QSpacerItem::expandingDirections() const
{
    return sizeP.expandingDirections();
}

/*!
    \reimp
*/
Qt::Orientations QWidgetItem::expandingDirections() const
{
    if (isEmpty())
        return Qt::Orientations(0);

    Qt::Orientations e = wid->sizePolicy().expandingDirections();
    /*
      If the layout is expanding, we make the widget expanding, even if
      its own size policy isn't expanding. This behavior should be
      reconsidered in Qt 4.0. (###)
    */
    if (wid->layout()) {
        if (wid->sizePolicy().horizontalPolicy() & QSizePolicy::GrowFlag
                && (wid->layout()->expandingDirections() & Qt::Horizontal))
            e |= Qt::Horizontal;
        if (wid->sizePolicy().verticalPolicy() & QSizePolicy::GrowFlag
                && (wid->layout()->expandingDirections() & Qt::Vertical))
            e |= Qt::Vertical;
    }

    if (align & Qt::AlignHorizontal_Mask)
        e &= ~Qt::Horizontal;
    if (align & Qt::AlignVertical_Mask)
        e &= ~Qt::Vertical;
    return e;
}

/*!
    \reimp
*/
QSize QSpacerItem::minimumSize() const
{
    return QSize(sizeP.horizontalPolicy() & QSizePolicy::ShrinkFlag ? 0 : width,
                 sizeP.verticalPolicy() & QSizePolicy::ShrinkFlag ? 0 : height);
}

/*!
    \reimp
*/
QSize QWidgetItem::minimumSize() const
{
    if (isEmpty())
        return QSize(0, 0);
    return !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
           ? toLayoutItemSize(wid->d_func(), qSmartMinSize(this))
           : qSmartMinSize(this);
}

/*!
    \reimp
*/
QSize QSpacerItem::maximumSize() const
{
    return QSize(sizeP.horizontalPolicy() & QSizePolicy::GrowFlag ? QLAYOUTSIZE_MAX : width,
                 sizeP.verticalPolicy() & QSizePolicy::GrowFlag ? QLAYOUTSIZE_MAX : height);
}

/*!
    \reimp
*/
QSize QWidgetItem::maximumSize() const
{
    if (isEmpty()) {
        return QSize(0, 0);
    } else {
        return !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
               ? toLayoutItemSize(wid->d_func(), qSmartMaxSize(this, align))
               : qSmartMaxSize(this, align);
    }
}

/*!
    \reimp
*/
QSize QSpacerItem::sizeHint() const
{
    return QSize(width, height);
}

/*!
    \reimp
*/
QSize QWidgetItem::sizeHint() const
{
    QSize s(0, 0);
    if (!isEmpty()) {
        s = wid->sizeHint().expandedTo(wid->minimumSizeHint());
        s = s.boundedTo(wid->maximumSize())
             .expandedTo(wid->minimumSize());
        s = !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
           ? toLayoutItemSize(wid->d_func(), s)
           : s;

        if (wid->sizePolicy().horizontalPolicy() == QSizePolicy::Ignored)
            s.setWidth(0);
        if (wid->sizePolicy().verticalPolicy() == QSizePolicy::Ignored)
            s.setHeight(0);
    }
    return s;
}

/*!
    Returns true.
*/
bool QSpacerItem::isEmpty() const
{
    return true;
}

/*!
    Returns true if the widget is hidden; otherwise returns false.

    \sa QWidget::isHidden()
*/
bool QWidgetItem::isEmpty() const
{
    return wid->isHidden() || wid->isWindow();
}