qlayoutitem.cpp

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#include "qlayout.h"

#include "qapplication.h"
#include "qlayoutengine_p.h"
#include "qmenubar.h"
#include "qtoolbar.h"
#include "qevent.h"
#include "qstyle.h"
#include "qvariant.h"
#include "qwidget_p.h"

QT_BEGIN_NAMESPACE

inline static QRect fromLayoutItemRect(QWidgetPrivate *priv, const QRect &rect)
{
    return rect.adjusted(priv->leftLayoutItemMargin, priv->topLayoutItemMargin,
                         -priv->rightLayoutItemMargin, -priv->bottomLayoutItemMargin);
}

inline static QSize fromLayoutItemSize(QWidgetPrivate *priv, const QSize &size)
{
    return fromLayoutItemRect(priv, QRect(QPoint(0, 0), size)).size();
}

inline static QRect toLayoutItemRect(QWidgetPrivate *priv, const QRect &rect)
{
    return rect.adjusted(-priv->leftLayoutItemMargin, -priv->topLayoutItemMargin,
                         priv->rightLayoutItemMargin, priv->bottomLayoutItemMargin);
}

inline static QSize toLayoutItemSize(QWidgetPrivate *priv, const QSize &size)
{
    return toLayoutItemRect(priv, QRect(QPoint(0, 0), size)).size();
}

QSizePolicy::operator QVariant() const
{
    return QVariant(QVariant::SizePolicy, this);
}

void QLayoutItem::setAlignment(Qt::Alignment alignment)
{
    align = alignment;
}

void QSpacerItem::changeSize(int w, int h, QSizePolicy::Policy hPolicy,
                             QSizePolicy::Policy vPolicy)
{
    width = w;
    height = h;
    sizeP = QSizePolicy(hPolicy, vPolicy);
}

QLayoutItem::~QLayoutItem()
{
}

void QLayoutItem::invalidate()
{
}

QLayout * QLayoutItem::layout()
{
    return 0;
}

QSpacerItem * QLayoutItem::spacerItem()
{
    return 0;
}

QLayout * QLayout::layout()
{
    return this;
}

QSpacerItem * QSpacerItem::spacerItem()
{
    return this;
}

QWidget * QLayoutItem::widget()
{
    return 0;
}

QWidget *QWidgetItem::widget()
{
    return wid;
}

bool QLayoutItem::hasHeightForWidth() const
{
    return false;
}

int QLayoutItem::minimumHeightForWidth(int w) const
{
    return heightForWidth(w);
}


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

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()) {
        if (layout->count() == 0)
            return QSizePolicy::DefaultType;
        QSizePolicy::ControlTypes types;
        for (int i = layout->count() - 1; i >= 0; --i)
            types |= layout->itemAt(i)->controlTypes();
        return types;
    }
    return QSizePolicy::DefaultType;
}

void QSpacerItem::setGeometry(const QRect &r)
{
    rect = r;
}

void QWidgetItem::setGeometry(const QRect &rect)
{
    if (isEmpty())
        return;

    QRect r = !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect)
            ? fromLayoutItemRect(wid->d_func(), rect)
            : rect;
    const QSize widgetRectSurplus = r.size() - rect.size(); 

    /* 
       For historical reasons, this code is done using widget rect 
       coordinates, not layout item rect coordinates. However, 
       QWidgetItem's sizeHint(), maximumSize(), and heightForWidth() 
       all work in terms of layout item rect coordinates, so we have to 
       add or subtract widgetRectSurplus here and there. The code could 
       be much simpler if we did everything using layout item rect 
       coordinates and did the conversion right before the call to 
       QWidget::setGeometry(). 
     */ 

    QSize s = r.size().boundedTo(maximumSize() + widgetRectSurplus);  
    int x = r.x();
    int y = r.y();
    if (align & (Qt::AlignHorizontal_Mask | Qt::AlignVertical_Mask)) {
        QSize pref(sizeHint());
        QSizePolicy sp = wid->sizePolicy();
        if (sp.horizontalPolicy() == QSizePolicy::Ignored)
            pref.setWidth(wid->sizeHint().expandedTo(wid->minimumSize()).width());
        if (sp.verticalPolicy() == QSizePolicy::Ignored)
            pref.setHeight(wid->sizeHint().expandedTo(wid->minimumSize()).height());
        pref += widgetRectSurplus;
        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() - widgetRectSurplus.width()) 
                                 + widgetRectSurplus.height()));
            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());
}

QRect QSpacerItem::geometry() const
{
    return rect;
}

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


bool QWidgetItem::hasHeightForWidth() const
{
    if (isEmpty())
        return false;
    return wid->d_func()->hasHeightForWidth();
}

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;
}

Qt::Orientations QSpacerItem::expandingDirections() const
{
    return sizeP.expandingDirections();
}

Qt::Orientations QWidgetItem::expandingDirections() const
{
    if (isEmpty())
        return Qt::Orientations(0);

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

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

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

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

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);
    }
}

QSize QSpacerItem::sizeHint() const
{
    return QSize(width, height);
}

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;
}

bool QSpacerItem::isEmpty() const
{
    return true;
}

bool QWidgetItem::isEmpty() const
{
    return wid->isHidden() || wid->isWindow();
}

inline bool QWidgetItemV2::useSizeCache() const
{
    return wid->d_func()->widgetItem == this;
}

void QWidgetItemV2::updateCacheIfNecessary() const
{
    if (q_cachedMinimumSize.width() != Dirty)
        return;

    const QSize sizeHint(wid->sizeHint());
    const QSize minimumSizeHint(wid->minimumSizeHint());
    const QSize minimumSize(wid->minimumSize());
    const QSize maximumSize(wid->maximumSize());
    const QSizePolicy sizePolicy(wid->sizePolicy());
    const QSize expandedSizeHint(sizeHint.expandedTo(minimumSizeHint));

    const QSize smartMinSize(qSmartMinSize(sizeHint, minimumSizeHint, minimumSize, maximumSize, sizePolicy));
    const QSize smartMaxSize(qSmartMaxSize(expandedSizeHint, minimumSize, maximumSize, sizePolicy, align));

    const bool useLayoutItemRect = !wid->testAttribute(Qt::WA_LayoutUsesWidgetRect);

    q_cachedMinimumSize = useLayoutItemRect
           ? toLayoutItemSize(wid->d_func(), smartMinSize)
           : smartMinSize;

    q_cachedSizeHint = expandedSizeHint;
    q_cachedSizeHint = q_cachedSizeHint.boundedTo(maximumSize)
                                       .expandedTo(minimumSize);
    q_cachedSizeHint = useLayoutItemRect
           ? toLayoutItemSize(wid->d_func(), q_cachedSizeHint)
           : q_cachedSizeHint;

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

    q_cachedMaximumSize = useLayoutItemRect
               ? toLayoutItemSize(wid->d_func(), smartMaxSize)
               : smartMaxSize;
}

QWidgetItemV2::QWidgetItemV2(QWidget *widget)
    : QWidgetItem(widget),
      q_cachedMinimumSize(Dirty, Dirty),
      q_cachedSizeHint(Dirty, Dirty),
      q_cachedMaximumSize(Dirty, Dirty),
      q_firstCachedHfw(0),
      q_hfwCacheSize(0),
      d(0)
{
    QWidgetPrivate *wd = wid->d_func();
    if (!wd->widgetItem)
        wd->widgetItem = this;
}

QWidgetItemV2::~QWidgetItemV2()
{
    if (wid) {
        QWidgetPrivate *wd = wid->d_func();
        if (wd->widgetItem == this)
            wd->widgetItem = 0;
    }
}

QSize QWidgetItemV2::sizeHint() const
{
    if (isEmpty())
        return QSize(0, 0);

    if (useSizeCache()) {
        updateCacheIfNecessary();
        return q_cachedSizeHint;
    } else {
        return QWidgetItem::sizeHint();
    }
}

QSize QWidgetItemV2::minimumSize() const
{
    if (isEmpty())
        return QSize(0, 0);

    if (useSizeCache()) {
        updateCacheIfNecessary();
        return q_cachedMinimumSize;
    } else {
        return QWidgetItem::minimumSize();
    }
}

QSize QWidgetItemV2::maximumSize() const
{
    if (isEmpty())
        return QSize(0, 0);

    if (useSizeCache()) {
        updateCacheIfNecessary();
        return q_cachedMaximumSize;
    } else {
        return QWidgetItem::maximumSize();
    }
}

/*
    The height-for-width cache is organized as a circular buffer. The entries

        q_hfwCachedHfws[q_firstCachedHfw],
        ...,
        q_hfwCachedHfws[(q_firstCachedHfw + q_hfwCacheSize - 1) % HfwCacheMaxSize]

    contain the last cached values. When the cache is full, the first entry to
    be erased is the entry before q_hfwCachedHfws[q_firstCachedHfw]. When
    values are looked up, we try to move q_firstCachedHfw to point to that new
    entry (unless the cache is not full, in which case it would leave the cache
    in a broken state), so that the most recently used entry is also the last
    to be erased.
*/

int QWidgetItemV2::heightForWidth(int width) const
{
    if (isEmpty())
        return -1;

    for (int i = 0; i < q_hfwCacheSize; ++i) {
        int offset = q_firstCachedHfw + i;
        const QSize &size = q_cachedHfws[offset % HfwCacheMaxSize];
        if (size.width() == width) {
            if (q_hfwCacheSize == HfwCacheMaxSize)
                q_firstCachedHfw = offset;
            return size.height();
        }
    }

    if (q_hfwCacheSize < HfwCacheMaxSize)
        ++q_hfwCacheSize;
    q_firstCachedHfw = (q_firstCachedHfw + HfwCacheMaxSize - 1) % HfwCacheMaxSize;

    int height = QWidgetItem::heightForWidth(width);
    q_cachedHfws[q_firstCachedHfw] = QSize(width, height);
    return height;
}

QT_END_NAMESPACE