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These rights are described in the Digia Qt LGPL Exception ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. ** ** GNU General Public License Usage ** Alternatively, this file may be used under the terms of the GNU ** General Public License version 3.0 as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL included in the ** packaging of this file. Please review the following information to ** ensure the GNU General Public License version 3.0 requirements will be ** met: http://www.gnu.org/copyleft/gpl.html. ** ** ** $QT_END_LICENSE$ ** ****************************************************************************/ #include "qboxlayout.h" #include "qapplication.h" #include "qwidget.h" #include "qlist.h" #include "qsizepolicy.h" #include "qvector.h" #include "qlayoutengine_p.h" #include "qlayout_p.h" QT_BEGIN_NAMESPACE /* Returns true if the \a widget can be added to the \a layout; otherwise returns false. */ static bool checkWidget(QLayout *layout, QWidget *widget) { if (!widget) { qWarning("QLayout: Cannot add null widget to %s/%s", layout->metaObject()->className(), layout->objectName().toLocal8Bit().data()); return false; } return true; } struct QBoxLayoutItem { QBoxLayoutItem(QLayoutItem *it, int stretch_ = 0) : item(it), stretch(stretch_), magic(false) { } ~QBoxLayoutItem() { delete item; } int hfw(int w) { if (item->hasHeightForWidth()) { return item->heightForWidth(w); } else { return item->sizeHint().height(); } } int mhfw(int w) { if (item->hasHeightForWidth()) { return item->heightForWidth(w); } else { return item->minimumSize().height(); } } int hStretch() { if (stretch == 0 && item->widget()) { return item->widget()->sizePolicy().horizontalStretch(); } else { return stretch; } } int vStretch() { if (stretch == 0 && item->widget()) { return item->widget()->sizePolicy().verticalStretch(); } else { return stretch; } } QLayoutItem *item; int stretch; bool magic; }; class QBoxLayoutPrivate : public QLayoutPrivate { Q_DECLARE_PUBLIC(QBoxLayout) public: QBoxLayoutPrivate() : hfwWidth(-1), dirty(true), spacing(-1) { } ~QBoxLayoutPrivate(); void setDirty() { geomArray.clear(); hfwWidth = -1; hfwHeight = -1; dirty = true; } QList list; QVector geomArray; int hfwWidth; int hfwHeight; int hfwMinHeight; QSize sizeHint; QSize minSize; QSize maxSize; int leftMargin, topMargin, rightMargin, bottomMargin; Qt::Orientations expanding; uint hasHfw : 1; uint dirty : 1; QBoxLayout::Direction dir; int spacing; inline void deleteAll() { while (!list.isEmpty()) delete list.takeFirst(); } void setupGeom(); void calcHfw(int); void effectiveMargins(int *left, int *top, int *right, int *bottom) const; }; QBoxLayoutPrivate::~QBoxLayoutPrivate() { } static inline bool horz(QBoxLayout::Direction dir) { return dir == QBoxLayout::RightToLeft || dir == QBoxLayout::LeftToRight; } /** * The purpose of this function is to make sure that widgets are not laid out outside its layout. * E.g. the layoutItemRect margins are only meant to take of the surrounding margins/spacings. * However, if the margin is 0, it can easily cover the area of a widget above it. */ void QBoxLayoutPrivate::effectiveMargins(int *left, int *top, int *right, int *bottom) const { int l = leftMargin; int t = topMargin; int r = rightMargin; int b = bottomMargin; #ifdef Q_OS_MAC Q_Q(const QBoxLayout); if (horz(dir)) { QBoxLayoutItem *leftBox = 0; QBoxLayoutItem *rightBox = 0; if (left || right) { leftBox = list.value(0); rightBox = list.value(list.count() - 1); if (dir == QBoxLayout::RightToLeft) qSwap(leftBox, rightBox); int leftDelta = 0; int rightDelta = 0; if (leftBox) { QLayoutItem *itm = leftBox->item; if (QWidget *w = itm->widget()) leftDelta = itm->geometry().left() - w->geometry().left(); } if (rightBox) { QLayoutItem *itm = rightBox->item; if (QWidget *w = itm->widget()) rightDelta = w->geometry().right() - itm->geometry().right(); } QWidget *w = q->parentWidget(); Qt::LayoutDirection layoutDirection = w ? w->layoutDirection() : QApplication::layoutDirection(); if (layoutDirection == Qt::RightToLeft) qSwap(leftDelta, rightDelta); l = qMax(l, leftDelta); r = qMax(r, rightDelta); } int count = top || bottom ? list.count() : 0; for (int i = 0; i < count; ++i) { QBoxLayoutItem *box = list.at(i); QLayoutItem *itm = box->item; QWidget *w = itm->widget(); if (w) { QRect lir = itm->geometry(); QRect wr = w->geometry(); if (top) t = qMax(t, lir.top() - wr.top()); if (bottom) b = qMax(b, wr.bottom() - lir.bottom()); } } } else { // vertical layout QBoxLayoutItem *topBox = 0; QBoxLayoutItem *bottomBox = 0; if (top || bottom) { topBox = list.value(0); bottomBox = list.value(list.count() - 1); if (dir == QBoxLayout::BottomToTop) { qSwap(topBox, bottomBox); } if (top && topBox) { QLayoutItem *itm = topBox->item; QWidget *w = itm->widget(); if (w) t = qMax(t, itm->geometry().top() - w->geometry().top()); } if (bottom && bottomBox) { QLayoutItem *itm = bottomBox->item; QWidget *w = itm->widget(); if (w) b = qMax(b, w->geometry().bottom() - itm->geometry().bottom()); } } int count = left || right ? list.count() : 0; for (int i = 0; i < count; ++i) { QBoxLayoutItem *box = list.at(i); QLayoutItem *itm = box->item; QWidget *w = itm->widget(); if (w) { QRect lir = itm->geometry(); QRect wr = w->geometry(); if (left) l = qMax(l, lir.left() - wr.left()); if (right) r = qMax(r, wr.right() - lir.right()); } } } #endif if (left) *left = l; if (top) *top = t; if (right) *right = r; if (bottom) *bottom = b; } /* Initializes the data structure needed by qGeomCalc and recalculates max/min and size hint. */ void QBoxLayoutPrivate::setupGeom() { if (!dirty) return; Q_Q(QBoxLayout); int maxw = horz(dir) ? 0 : QLAYOUTSIZE_MAX; int maxh = horz(dir) ? QLAYOUTSIZE_MAX : 0; int minw = 0; int minh = 0; int hintw = 0; int hinth = 0; bool horexp = false; bool verexp = false; hasHfw = false; int n = list.count(); geomArray.clear(); QVector a(n); QSizePolicy::ControlTypes controlTypes1; QSizePolicy::ControlTypes controlTypes2; int fixedSpacing = q->spacing(); int previousNonEmptyIndex = -1; QStyle *style = 0; if (fixedSpacing < 0) { if (QWidget *parentWidget = q->parentWidget()) style = parentWidget->style(); } for (int i = 0; i < n; i++) { QBoxLayoutItem *box = list.at(i); QSize max = box->item->maximumSize(); QSize min = box->item->minimumSize(); QSize hint = box->item->sizeHint(); Qt::Orientations exp = box->item->expandingDirections(); bool empty = box->item->isEmpty(); int spacing = 0; if (!empty) { if (fixedSpacing >= 0) { spacing = (previousNonEmptyIndex >= 0) ? fixedSpacing : 0; #ifdef Q_OS_MAC if (!horz(dir) && previousNonEmptyIndex >= 0) { QBoxLayoutItem *sibling = (dir == QBoxLayout::TopToBottom ? box : list.at(previousNonEmptyIndex)); if (sibling) { QWidget *wid = sibling->item->widget(); if (wid) spacing = qMax(spacing, sibling->item->geometry().top() - wid->geometry().top()); } } #endif } else { controlTypes1 = controlTypes2; controlTypes2 = box->item->controlTypes(); if (previousNonEmptyIndex >= 0) { QSizePolicy::ControlTypes actual1 = controlTypes1; QSizePolicy::ControlTypes actual2 = controlTypes2; if (dir == QBoxLayout::RightToLeft || dir == QBoxLayout::BottomToTop) qSwap(actual1, actual2); if (style) { spacing = style->combinedLayoutSpacing(actual1, actual2, horz(dir) ? Qt::Horizontal : Qt::Vertical, 0, q->parentWidget()); if (spacing < 0) spacing = 0; } } } if (previousNonEmptyIndex >= 0) a[previousNonEmptyIndex].spacing = spacing; previousNonEmptyIndex = i; } bool ignore = empty && box->item->widget(); // ignore hidden widgets bool dummy = true; if (horz(dir)) { bool expand = (exp & Qt::Horizontal || box->stretch > 0); horexp = horexp || expand; maxw += spacing + max.width(); minw += spacing + min.width(); hintw += spacing + hint.width(); if (!ignore) qMaxExpCalc(maxh, verexp, dummy, max.height(), exp & Qt::Vertical, box->item->isEmpty()); minh = qMax(minh, min.height()); hinth = qMax(hinth, hint.height()); a[i].sizeHint = hint.width(); a[i].maximumSize = max.width(); a[i].minimumSize = min.width(); a[i].expansive = expand; a[i].stretch = box->stretch ? box->stretch : box->hStretch(); } else { bool expand = (exp & Qt::Vertical || box->stretch > 0); verexp = verexp || expand; maxh += spacing + max.height(); minh += spacing + min.height(); hinth += spacing + hint.height(); if (!ignore) qMaxExpCalc(maxw, horexp, dummy, max.width(), exp & Qt::Horizontal, box->item->isEmpty()); minw = qMax(minw, min.width()); hintw = qMax(hintw, hint.width()); a[i].sizeHint = hint.height(); a[i].maximumSize = max.height(); a[i].minimumSize = min.height(); a[i].expansive = expand; a[i].stretch = box->stretch ? box->stretch : box->vStretch(); } a[i].empty = empty; a[i].spacing = 0; // might be initialized with a non-zero value in a later iteration hasHfw = hasHfw || box->item->hasHeightForWidth(); } geomArray = a; expanding = (Qt::Orientations) ((horexp ? Qt::Horizontal : 0) | (verexp ? Qt::Vertical : 0)); minSize = QSize(minw, minh); maxSize = QSize(maxw, maxh).expandedTo(minSize); sizeHint = QSize(hintw, hinth).expandedTo(minSize).boundedTo(maxSize); q->getContentsMargins(&leftMargin, &topMargin, &rightMargin, &bottomMargin); int left, top, right, bottom; effectiveMargins(&left, &top, &right, &bottom); QSize extra(left + right, top + bottom); minSize += extra; maxSize += extra; sizeHint += extra; dirty = false; } /* Calculates and stores the preferred height given the width \a w. */ void QBoxLayoutPrivate::calcHfw(int w) { QVector &a = geomArray; int n = a.count(); int h = 0; int mh = 0; Q_ASSERT(n == list.size()); if (horz(dir)) { qGeomCalc(a, 0, n, 0, w); for (int i = 0; i < n; i++) { QBoxLayoutItem *box = list.at(i); h = qMax(h, box->hfw(a.at(i).size)); mh = qMax(mh, box->mhfw(a.at(i).size)); } } else { for (int i = 0; i < n; ++i) { QBoxLayoutItem *box = list.at(i); int spacing = a.at(i).spacing; h += box->hfw(w); mh += box->mhfw(w); h += spacing; mh += spacing; } } hfwWidth = w; hfwHeight = h; hfwMinHeight = mh; } /*! \class QBoxLayout \brief The QBoxLayout class lines up child widgets horizontally or vertically. \ingroup geomanagement \inmodule QtWidgets QBoxLayout takes the space it gets (from its parent layout or from the parentWidget()), divides it up into a row of boxes, and makes each managed widget fill one box. \image qhboxlayout-with-5-children.png Horizontal box layout with five child widgets If the QBoxLayout's orientation is Qt::Horizontal the boxes are placed in a row, with suitable sizes. Each widget (or other box) will get at least its minimum size and at most its maximum size. Any excess space is shared according to the stretch factors (more about that below). \image qvboxlayout-with-5-children.png Vertical box layout with five child widgets If the QBoxLayout's orientation is Qt::Vertical, the boxes are placed in a column, again with suitable sizes. The easiest way to create a QBoxLayout is to use one of the convenience classes, e.g. QHBoxLayout (for Qt::Horizontal boxes) or QVBoxLayout (for Qt::Vertical boxes). You can also use the QBoxLayout constructor directly, specifying its direction as LeftToRight, RightToLeft, TopToBottom, or BottomToTop. If the QBoxLayout is not the top-level layout (i.e. it is not managing all of the widget's area and children), you must add it to its parent layout before you can do anything with it. The normal way to add a layout is by calling parentLayout-\>addLayout(). Once you have done this, you can add boxes to the QBoxLayout using one of four functions: \list \li addWidget() to add a widget to the QBoxLayout and set the widget's stretch factor. (The stretch factor is along the row of boxes.) \li addSpacing() to create an empty box; this is one of the functions you use to create nice and spacious dialogs. See below for ways to set margins. \li addStretch() to create an empty, stretchable box. \li addLayout() to add a box containing another QLayout to the row and set that layout's stretch factor. \endlist Use insertWidget(), insertSpacing(), insertStretch() or insertLayout() to insert a box at a specified position in the layout. QBoxLayout also includes two margin widths: \list \li setContentsMargins() sets the width of the outer border on each side of the widget. This is the width of the reserved space along each of the QBoxLayout's four sides. \li setSpacing() sets the width between neighboring boxes. (You can use addSpacing() to get more space at a particular spot.) \endlist The margin default is provided by the style. The default margin most Qt styles specify is 9 for child widgets and 11 for windows. The spacing defaults to the same as the margin width for a top-level layout, or to the same as the parent layout. To remove a widget from a layout, call removeWidget(). Calling QWidget::hide() on a widget also effectively removes the widget from the layout until QWidget::show() is called. You will almost always want to use QVBoxLayout and QHBoxLayout rather than QBoxLayout because of their convenient constructors. \sa QGridLayout, QStackedLayout, {Layout Management} */ /*! \enum QBoxLayout::Direction This type is used to determine the direction of a box layout. \value LeftToRight Horizontal from left to right. \value RightToLeft Horizontal from right to left. \value TopToBottom Vertical from top to bottom. \value BottomToTop Vertical from bottom to top. \omitvalue Down \omitvalue Up */ /*! Constructs a new QBoxLayout with direction \a dir and parent widget \a parent. \sa direction() */ QBoxLayout::QBoxLayout(Direction dir, QWidget *parent) : QLayout(*new QBoxLayoutPrivate, 0, parent) { Q_D(QBoxLayout); d->dir = dir; } /*! Destroys this box layout. The layout's widgets aren't destroyed. */ QBoxLayout::~QBoxLayout() { Q_D(QBoxLayout); d->deleteAll(); // must do it before QObject deletes children, so can't be in ~QBoxLayoutPrivate } /*! Reimplements QLayout::spacing(). If the spacing property is valid, that value is returned. Otherwise, a value for the spacing property is computed and returned. Since layout spacing in a widget is style dependent, if the parent is a widget, it queries the style for the (horizontal or vertical) spacing of the layout. Otherwise, the parent is a layout, and it queries the parent layout for the spacing(). \sa QLayout::spacing(), setSpacing() */ int QBoxLayout::spacing() const { Q_D(const QBoxLayout); if (d->spacing >=0) { return d->spacing; } else { return qSmartSpacing(this, d->dir == LeftToRight || d->dir == RightToLeft ? QStyle::PM_LayoutHorizontalSpacing : QStyle::PM_LayoutVerticalSpacing); } } /*! Reimplements QLayout::setSpacing(). Sets the spacing property to \a spacing. \sa QLayout::setSpacing(), spacing() */ void QBoxLayout::setSpacing(int spacing) { Q_D(QBoxLayout); d->spacing = spacing; invalidate(); } /*! \reimp */ QSize QBoxLayout::sizeHint() const { Q_D(const QBoxLayout); if (d->dirty) const_cast(this)->d_func()->setupGeom(); return d->sizeHint; } /*! \reimp */ QSize QBoxLayout::minimumSize() const { Q_D(const QBoxLayout); if (d->dirty) const_cast(this)->d_func()->setupGeom(); return d->minSize; } /*! \reimp */ QSize QBoxLayout::maximumSize() const { Q_D(const QBoxLayout); if (d->dirty) const_cast(this)->d_func()->setupGeom(); QSize s = d->maxSize.boundedTo(QSize(QLAYOUTSIZE_MAX, QLAYOUTSIZE_MAX)); if (alignment() & Qt::AlignHorizontal_Mask) s.setWidth(QLAYOUTSIZE_MAX); if (alignment() & Qt::AlignVertical_Mask) s.setHeight(QLAYOUTSIZE_MAX); return s; } /*! \reimp */ bool QBoxLayout::hasHeightForWidth() const { Q_D(const QBoxLayout); if (d->dirty) const_cast(this)->d_func()->setupGeom(); return d->hasHfw; } /*! \reimp */ int QBoxLayout::heightForWidth(int w) const { Q_D(const QBoxLayout); if (!hasHeightForWidth()) return -1; int left, top, right, bottom; d->effectiveMargins(&left, &top, &right, &bottom); w -= left + right; if (w != d->hfwWidth) const_cast(this)->d_func()->calcHfw(w); return d->hfwHeight + top + bottom; } /*! \reimp */ int QBoxLayout::minimumHeightForWidth(int w) const { Q_D(const QBoxLayout); (void) heightForWidth(w); int top, bottom; d->effectiveMargins(0, &top, 0, &bottom); return d->hasHfw ? (d->hfwMinHeight + top + bottom) : -1; } /*! Resets cached information. */ void QBoxLayout::invalidate() { Q_D(QBoxLayout); d->setDirty(); QLayout::invalidate(); } /*! \reimp */ int QBoxLayout::count() const { Q_D(const QBoxLayout); return d->list.count(); } /*! \reimp */ QLayoutItem *QBoxLayout::itemAt(int index) const { Q_D(const QBoxLayout); return index >= 0 && index < d->list.count() ? d->list.at(index)->item : 0; } /*! \reimp */ QLayoutItem *QBoxLayout::takeAt(int index) { Q_D(QBoxLayout); if (index < 0 || index >= d->list.count()) return 0; QBoxLayoutItem *b = d->list.takeAt(index); QLayoutItem *item = b->item; b->item = 0; delete b; if (QLayout *l = item->layout()) { // sanity check in case the user passed something weird to QObject::setParent() if (l->parent() == this) l->setParent(0); } invalidate(); return item; } /*! \reimp */ Qt::Orientations QBoxLayout::expandingDirections() const { Q_D(const QBoxLayout); if (d->dirty) const_cast(this)->d_func()->setupGeom(); return d->expanding; } /*! \reimp */ void QBoxLayout::setGeometry(const QRect &r) { Q_D(QBoxLayout); if (d->dirty || r != geometry()) { QRect oldRect = geometry(); QLayout::setGeometry(r); if (d->dirty) d->setupGeom(); QRect cr = alignment() ? alignmentRect(r) : r; int left, top, right, bottom; d->effectiveMargins(&left, &top, &right, &bottom); QRect s(cr.x() + left, cr.y() + top, cr.width() - (left + right), cr.height() - (top + bottom)); QVector a = d->geomArray; int pos = horz(d->dir) ? s.x() : s.y(); int space = horz(d->dir) ? s.width() : s.height(); int n = a.count(); if (d->hasHfw && !horz(d->dir)) { for (int i = 0; i < n; i++) { QBoxLayoutItem *box = d->list.at(i); if (box->item->hasHeightForWidth()) { int width = qBound(box->item->minimumSize().width(), s.width(), box->item->maximumSize().width()); a[i].sizeHint = a[i].minimumSize = box->item->heightForWidth(width); } } } Direction visualDir = d->dir; QWidget *parent = parentWidget(); if (parent && parent->isRightToLeft()) { if (d->dir == LeftToRight) visualDir = RightToLeft; else if (d->dir == RightToLeft) visualDir = LeftToRight; } qGeomCalc(a, 0, n, pos, space); bool reverse = (horz(visualDir) ? ((r.right() > oldRect.right()) != (visualDir == RightToLeft)) : r.bottom() > oldRect.bottom()); for (int j = 0; j < n; j++) { int i = reverse ? n-j-1 : j; QBoxLayoutItem *box = d->list.at(i); switch (visualDir) { case LeftToRight: box->item->setGeometry(QRect(a.at(i).pos, s.y(), a.at(i).size, s.height())); break; case RightToLeft: box->item->setGeometry(QRect(s.left() + s.right() - a.at(i).pos - a.at(i).size + 1, s.y(), a.at(i).size, s.height())); break; case TopToBottom: box->item->setGeometry(QRect(s.x(), a.at(i).pos, s.width(), a.at(i).size)); break; case BottomToTop: box->item->setGeometry(QRect(s.x(), s.top() + s.bottom() - a.at(i).pos - a.at(i).size + 1, s.width(), a.at(i).size)); } } } } /*! \reimp */ void QBoxLayout::addItem(QLayoutItem *item) { Q_D(QBoxLayout); QBoxLayoutItem *it = new QBoxLayoutItem(item); d->list.append(it); invalidate(); } /*! Inserts \a item into this box layout at position \a index. If \a index is negative, the item is added at the end. \sa addItem(), insertWidget(), insertLayout(), insertStretch(), insertSpacing() */ void QBoxLayout::insertItem(int index, QLayoutItem *item) { Q_D(QBoxLayout); if (index < 0) // append index = d->list.count(); QBoxLayoutItem *it = new QBoxLayoutItem(item); d->list.insert(index, it); invalidate(); } /*! Inserts a non-stretchable space (a QSpacerItem) at position \a index, with size \a size. If \a index is negative the space is added at the end. The box layout has default margin and spacing. This function adds additional space. \sa addSpacing(), insertItem(), QSpacerItem */ void QBoxLayout::insertSpacing(int index, int size) { Q_D(QBoxLayout); if (index < 0) // append index = d->list.count(); QLayoutItem *b; if (horz(d->dir)) b = QLayoutPrivate::createSpacerItem(this, size, 0, QSizePolicy::Fixed, QSizePolicy::Minimum); else b = QLayoutPrivate::createSpacerItem(this, 0, size, QSizePolicy::Minimum, QSizePolicy::Fixed); QT_TRY { QBoxLayoutItem *it = new QBoxLayoutItem(b); it->magic = true; d->list.insert(index, it); } QT_CATCH(...) { delete b; QT_RETHROW; } invalidate(); } /*! Inserts a stretchable space (a QSpacerItem) at position \a index, with zero minimum size and stretch factor \a stretch. If \a index is negative the space is added at the end. \sa addStretch(), insertItem(), QSpacerItem */ void QBoxLayout::insertStretch(int index, int stretch) { Q_D(QBoxLayout); if (index < 0) // append index = d->list.count(); QLayoutItem *b; if (horz(d->dir)) b = QLayoutPrivate::createSpacerItem(this, 0, 0, QSizePolicy::Expanding, QSizePolicy::Minimum); else b = QLayoutPrivate::createSpacerItem(this, 0, 0, QSizePolicy::Minimum, QSizePolicy::Expanding); QBoxLayoutItem *it = new QBoxLayoutItem(b, stretch); it->magic = true; d->list.insert(index, it); invalidate(); } /*! \since 4.4 Inserts \a spacerItem at position \a index, with zero minimum size and stretch factor. If \a index is negative the space is added at the end. \sa addSpacerItem(), insertStretch(), insertSpacing() */ void QBoxLayout::insertSpacerItem(int index, QSpacerItem *spacerItem) { Q_D(QBoxLayout); if (index < 0) // append index = d->list.count(); QBoxLayoutItem *it = new QBoxLayoutItem(spacerItem); it->magic = true; d->list.insert(index, it); invalidate(); } /*! Inserts \a layout at position \a index, with stretch factor \a stretch. If \a index is negative, the layout is added at the end. \a layout becomes a child of the box layout. \sa addLayout(), insertItem() */ void QBoxLayout::insertLayout(int index, QLayout *layout, int stretch) { Q_D(QBoxLayout); addChildLayout(layout); if (index < 0) // append index = d->list.count(); QBoxLayoutItem *it = new QBoxLayoutItem(layout, stretch); d->list.insert(index, it); invalidate(); } /*! Inserts \a widget at position \a index, with stretch factor \a stretch and alignment \a alignment. If \a index is negative, the widget is added at the end. The stretch factor applies only in the \l{direction()}{direction} of the QBoxLayout, and is relative to the other boxes and widgets in this QBoxLayout. Widgets and boxes with higher stretch factors grow more. If the stretch factor is 0 and nothing else in the QBoxLayout has a stretch factor greater than zero, the space is distributed according to the QWidget:sizePolicy() of each widget that's involved. The alignment is specified by \a alignment. The default alignment is 0, which means that the widget fills the entire cell. \sa addWidget(), insertItem() */ void QBoxLayout::insertWidget(int index, QWidget *widget, int stretch, Qt::Alignment alignment) { Q_D(QBoxLayout); if (!checkWidget(this, widget)) return; addChildWidget(widget); if (index < 0) // append index = d->list.count(); QWidgetItem *b = QLayoutPrivate::createWidgetItem(this, widget); b->setAlignment(alignment); QBoxLayoutItem *it; QT_TRY{ it = new QBoxLayoutItem(b, stretch); } QT_CATCH(...) { delete b; QT_RETHROW; } QT_TRY{ d->list.insert(index, it); } QT_CATCH(...) { delete it; QT_RETHROW; } invalidate(); } /*! Adds a non-stretchable space (a QSpacerItem) with size \a size to the end of this box layout. QBoxLayout provides default margin and spacing. This function adds additional space. \sa insertSpacing(), addItem(), QSpacerItem */ void QBoxLayout::addSpacing(int size) { insertSpacing(-1, size); } /*! Adds a stretchable space (a QSpacerItem) with zero minimum size and stretch factor \a stretch to the end of this box layout. \sa insertStretch(), addItem(), QSpacerItem */ void QBoxLayout::addStretch(int stretch) { insertStretch(-1, stretch); } /*! \since 4.4 Adds \a spacerItem to the end of this box layout. \sa addSpacing(), addStretch() */ void QBoxLayout::addSpacerItem(QSpacerItem *spacerItem) { insertSpacerItem(-1, spacerItem); } /*! Adds \a widget to the end of this box layout, with a stretch factor of \a stretch and alignment \a alignment. The stretch factor applies only in the \l{direction()}{direction} of the QBoxLayout, and is relative to the other boxes and widgets in this QBoxLayout. Widgets and boxes with higher stretch factors grow more. If the stretch factor is 0 and nothing else in the QBoxLayout has a stretch factor greater than zero, the space is distributed according to the QWidget:sizePolicy() of each widget that's involved. The alignment is specified by \a alignment. The default alignment is 0, which means that the widget fills the entire cell. \sa insertWidget(), addItem(), addLayout(), addStretch(), addSpacing(), addStrut() */ void QBoxLayout::addWidget(QWidget *widget, int stretch, Qt::Alignment alignment) { insertWidget(-1, widget, stretch, alignment); } /*! Adds \a layout to the end of the box, with serial stretch factor \a stretch. \sa insertLayout(), addItem(), addWidget() */ void QBoxLayout::addLayout(QLayout *layout, int stretch) { insertLayout(-1, layout, stretch); } /*! Limits the perpendicular dimension of the box (e.g. height if the box is \l LeftToRight) to a minimum of \a size. Other constraints may increase the limit. \sa addItem() */ void QBoxLayout::addStrut(int size) { Q_D(QBoxLayout); QLayoutItem *b; if (horz(d->dir)) b = QLayoutPrivate::createSpacerItem(this, 0, size, QSizePolicy::Fixed, QSizePolicy::Minimum); else b = QLayoutPrivate::createSpacerItem(this, size, 0, QSizePolicy::Minimum, QSizePolicy::Fixed); QBoxLayoutItem *it = new QBoxLayoutItem(b); it->magic = true; d->list.append(it); invalidate(); } /*! Sets the stretch factor for \a widget to \a stretch and returns true if \a widget is found in this layout (not including child layouts); otherwise returns false. \sa setAlignment() */ bool QBoxLayout::setStretchFactor(QWidget *widget, int stretch) { Q_D(QBoxLayout); if (!widget) return false; for (int i = 0; i < d->list.size(); ++i) { QBoxLayoutItem *box = d->list.at(i); if (box->item->widget() == widget) { box->stretch = stretch; invalidate(); return true; } } return false; } /*! \overload Sets the stretch factor for the layout \a layout to \a stretch and returns true if \a layout is found in this layout (not including child layouts); otherwise returns false. */ bool QBoxLayout::setStretchFactor(QLayout *layout, int stretch) { Q_D(QBoxLayout); for (int i = 0; i < d->list.size(); ++i) { QBoxLayoutItem *box = d->list.at(i); if (box->item->layout() == layout) { if (box->stretch != stretch) { box->stretch = stretch; invalidate(); } return true; } } return false; } /*! Sets the stretch factor at position \a index. to \a stretch. \since 4.5 */ void QBoxLayout::setStretch(int index, int stretch) { Q_D(QBoxLayout); if (index >= 0 && index < d->list.size()) { QBoxLayoutItem *box = d->list.at(index); if (box->stretch != stretch) { box->stretch = stretch; invalidate(); } } } /*! Returns the stretch factor at position \a index. \since 4.5 */ int QBoxLayout::stretch(int index) const { Q_D(const QBoxLayout); if (index >= 0 && index < d->list.size()) return d->list.at(index)->stretch; return -1; } /*! Sets the direction of this layout to \a direction. */ void QBoxLayout::setDirection(Direction direction) { Q_D(QBoxLayout); if (d->dir == direction) return; if (horz(d->dir) != horz(direction)) { //swap around the spacers (the "magic" bits) //#### a bit yucky, knows too much. //#### probably best to add access functions to spacerItem //#### or even a QSpacerItem::flip() for (int i = 0; i < d->list.size(); ++i) { QBoxLayoutItem *box = d->list.at(i); if (box->magic) { QSpacerItem *sp = box->item->spacerItem(); if (sp) { if (sp->expandingDirections() == Qt::Orientations(0) /*No Direction*/) { //spacing or strut QSize s = sp->sizeHint(); sp->changeSize(s.height(), s.width(), horz(direction) ? QSizePolicy::Fixed:QSizePolicy::Minimum, horz(direction) ? QSizePolicy::Minimum:QSizePolicy::Fixed); } else { //stretch if (horz(direction)) sp->changeSize(0, 0, QSizePolicy::Expanding, QSizePolicy::Minimum); else sp->changeSize(0, 0, QSizePolicy::Minimum, QSizePolicy::Expanding); } } } } } d->dir = direction; invalidate(); } /*! \fn QBoxLayout::Direction QBoxLayout::direction() const Returns the direction of the box. addWidget() and addSpacing() work in this direction; the stretch stretches in this direction. \sa QBoxLayout::Direction, addWidget(), addSpacing() */ QBoxLayout::Direction QBoxLayout::direction() const { Q_D(const QBoxLayout); return d->dir; } /*! \class QHBoxLayout \brief The QHBoxLayout class lines up widgets horizontally. \ingroup geomanagement \inmodule QtWidgets This class is used to construct horizontal box layout objects. See QBoxLayout for details. The simplest use of the class is like this: \snippet layouts/layouts.cpp 0 \snippet layouts/layouts.cpp 1 \snippet layouts/layouts.cpp 2 \codeline \snippet layouts/layouts.cpp 3 \snippet layouts/layouts.cpp 4 \snippet layouts/layouts.cpp 5 First, we create the widgets we want in the layout. Then, we create the QHBoxLayout object and add the widgets into the layout. Finally, we call QWidget::setLayout() to install the QHBoxLayout object onto the widget. At that point, the widgets in the layout are reparented to have \c window as their parent. \image qhboxlayout-with-5-children.png Horizontal box layout with five child widgets \sa QVBoxLayout, QGridLayout, QStackedLayout, {Layout Management}, {Basic Layouts Example} */ /*! Constructs a new top-level horizontal box with parent \a parent. */ QHBoxLayout::QHBoxLayout(QWidget *parent) : QBoxLayout(LeftToRight, parent) { } /*! Constructs a new horizontal box. You must add it to another layout. */ QHBoxLayout::QHBoxLayout() : QBoxLayout(LeftToRight) { } /*! Destroys this box layout. The layout's widgets aren't destroyed. */ QHBoxLayout::~QHBoxLayout() { } /*! \class QVBoxLayout \brief The QVBoxLayout class lines up widgets vertically. \ingroup geomanagement \inmodule QtWidgets This class is used to construct vertical box layout objects. See QBoxLayout for details. The simplest use of the class is like this: \snippet layouts/layouts.cpp 6 \snippet layouts/layouts.cpp 7 \snippet layouts/layouts.cpp 8 \codeline \snippet layouts/layouts.cpp 9 \snippet layouts/layouts.cpp 10 \snippet layouts/layouts.cpp 11 First, we create the widgets we want in the layout. Then, we create the QVBoxLayout object and add the widgets into the layout. Finally, we call QWidget::setLayout() to install the QVBoxLayout object onto the widget. At that point, the widgets in the layout are reparented to have \c window as their parent. \image qvboxlayout-with-5-children.png Horizontal box layout with five child widgets \sa QHBoxLayout, QGridLayout, QStackedLayout, {Layout Management}, {Basic Layouts Example} */ /*! Constructs a new top-level vertical box with parent \a parent. */ QVBoxLayout::QVBoxLayout(QWidget *parent) : QBoxLayout(TopToBottom, parent) { } /*! Constructs a new vertical box. You must add it to another layout. */ QVBoxLayout::QVBoxLayout() : QBoxLayout(TopToBottom) { } /*! Destroys this box layout. The layout's widgets aren't destroyed. */ QVBoxLayout::~QVBoxLayout() { } QT_END_NAMESPACE