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Diffstat (limited to 'src/gui/graphicsview/qgraphicsanchorlayout.cpp')
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diff --git a/src/gui/graphicsview/qgraphicsanchorlayout.cpp b/src/gui/graphicsview/qgraphicsanchorlayout.cpp new file mode 100644 index 0000000..13abd52 --- /dev/null +++ b/src/gui/graphicsview/qgraphicsanchorlayout.cpp @@ -0,0 +1,477 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Nokia Corporation (qt-info@nokia.com) +** +** This file is part of the QtGui module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the Technology Preview License Agreement accompanying +** this package. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** If you have questions regarding the use of this file, please contact +** Nokia at qt-info@nokia.com. +** +** +** +** +** +** +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! + \class QGraphicsAnchorLayout + \brief The QGraphicsAnchorLayout class provides a layout where one can anchor widgets + together in Graphics View. + \since 4.6 + \ingroup appearance + \ingroup geomanagement + \ingroup graphicsview-api + + The anchor layout is a layout where one can specify how widgets should be placed relative to + each other. The specification is called an anchor, and it is set up by calling anchor(). + Anchors are always set up between edges of an item, where the "center" is also considered to + be an edge. Considering this example: + \code + QGraphicsAnchorLayout *l = new QGraphicsAnchorLayout; + QGraphicsWidget *a = new QGraphicsWidget; + QGraphicsWidget *b = new QGraphicsWidget; + l->anchor(a, Qt::AnchorRight, b, Qt::AnchorLeft); + \endcode + + Here is the right edge of item A anchored to the left edge of item B, with the result that + item B will be placed to the right of item A, with a spacing between A and B. If the + spacing is negative, the items will overlap to some extent. Items that are anchored are + automatically added to the layout, and if items are removed, all their anchors will be + automatically removed + + \section1 Size Hints and Size Policies in QGraphicsAnchorLayout + + QGraphicsAnchorLayout respects each item's size hints and size policies. However it does + not respect stretch factors currently. This might change in the future, so please refrain + from using stretch factors in anchor layout to avoid any future regressions. + + \section1 Spacing within QGraphicsAnchorLayout + + Between the items, the layout can distribute some space. If the spacing has not been + explicitly specified, the actual amount of space will usually be 0, but if the first edge + is the "opposite" of the second edge (i.e. Right is anchored to Left or vice-versa), the + size of the anchor will be queried from the style through the pixelMetric + PM_LayoutHorizontalSpacing (or PM_LayoutVerticalSpacing for vertical anchors). +*/ + +#include "qgraphicsanchorlayout_p.h" + +QT_BEGIN_NAMESPACE + +/*! + Constructs a QGraphicsAnchorLayout instance. \a parent is passed to + QGraphicsLayout's constructor. + */ +QGraphicsAnchorLayout::QGraphicsAnchorLayout(QGraphicsLayoutItem *parent) + : QGraphicsLayout(*new QGraphicsAnchorLayoutPrivate(), parent) +{ + Q_D(QGraphicsAnchorLayout); + d->createLayoutEdges(); +} + +/*! + Destroys the QGraphicsAnchorLayout object. +*/ +QGraphicsAnchorLayout::~QGraphicsAnchorLayout() +{ + Q_D(QGraphicsAnchorLayout); + + for (int i = count() - 1; i >= 0; --i) { + QGraphicsLayoutItem *item = d->items.at(i); + removeAt(i); + if (item) { + if (item->ownedByLayout()) + delete item; + } + } + + d->removeCenterConstraints(this, QGraphicsAnchorLayoutPrivate::Horizontal); + d->removeCenterConstraints(this, QGraphicsAnchorLayoutPrivate::Vertical); + d->deleteLayoutEdges(); + + Q_ASSERT(d->itemCenterConstraints[0].isEmpty()); + Q_ASSERT(d->itemCenterConstraints[1].isEmpty()); + Q_ASSERT(d->items.isEmpty()); + Q_ASSERT(d->m_vertexList.isEmpty()); +} + +/*! + * Creates an anchor between the edge \a firstEdge of item \a firstItem and the edge \a secondEdge + * of item \a secondItem. The magnitude of the anchor is picked up from the style. Anchors + * between a layout edge and an item edge will have a size of 0. + * If there is already an anchor between the edges, the the new anchor will replace the old one. + * + * \a firstItem and \a secondItem are automatically added to the layout if they are not part + * of the layout. This means that count() can increase with up to 2. + * + * The spacing an anchor will get depends on the type of anchor. For instance, anchors from the + * Right edge of one item to the Left edge of another (or vice versa) will use the default + * horizontal spacing. The same behaviour applies to Bottom to Top anchors, (but they will use + * the default vertical spacing). For all other anchor combinations, the spacing will be 0. + * All anchoring functions will follow this rule. + * + * The spacing can also be set manually by using setAnchorSpacing() method. + * + * \sa removeAnchor(), addCornerAnchors(), addLeftAndRightAnchors(), addTopAndBottomAnchors(), + * addAllAnchors() + */ +void QGraphicsAnchorLayout::addAnchor(QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge, + QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge) +{ + Q_D(QGraphicsAnchorLayout); + d->anchor(firstItem, firstEdge, secondItem, secondEdge); + invalidate(); +} + +/*! + * Creates two anchors between \a firstItem and \a secondItem, where one is for the horizontal + * edge and another one for the vertical edge that the corners \a firstCorner and \a + * secondCorner specifies. + * The magnitude of the anchors is picked up from the style. + * + * This is a convenience function, since anchoring corners can be expressed as anchoring two edges. + * For instance, + * \code + * layout->addAnchor(layout, Qt::AnchorTop, b, Qt::AnchorTop); + * layout->addAnchor(layout, Qt::AnchorLeft, b, Qt::AnchorLeft); + * \endcode + * + * has the same effect as + * + * \code + * layout->addCornerAnchors(layout, Qt::TopLeft, b, Qt::TopLeft); + * \endcode + * + * If there is already an anchor between the edge pairs, it will be replaced by the anchors that + * this function specifies. + * + * \a firstItem and \a secondItem are automatically added to the layout if they are not part + * of the layout. This means that count() can increase with up to 2. + */ +void QGraphicsAnchorLayout::addCornerAnchors(QGraphicsLayoutItem *firstItem, + Qt::Corner firstCorner, + QGraphicsLayoutItem *secondItem, + Qt::Corner secondCorner) +{ + Q_D(QGraphicsAnchorLayout); + + // Horizontal anchor + Qt::AnchorPoint firstEdge = (firstCorner & 1 ? Qt::AnchorRight: Qt::AnchorLeft); + Qt::AnchorPoint secondEdge = (secondCorner & 1 ? Qt::AnchorRight: Qt::AnchorLeft); + d->anchor(firstItem, firstEdge, secondItem, secondEdge); + + // Vertical anchor + firstEdge = (firstCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop); + secondEdge = (secondCorner & 2 ? Qt::AnchorBottom: Qt::AnchorTop); + d->anchor(firstItem, firstEdge, secondItem, secondEdge); + + invalidate(); +} + +/*! + \fn QGraphicsAnchorLayout::addLeftAndRightAnchors(QGraphicsLayoutItem *firstItem, QGraphicsLayoutItem *secondItem) + + Anchors the left and right edges of \a firstItem to the same edges of + \a secondItem. + + This convenience function is equivalent to calling + \code + l->addAnchor(firstItem, Qt::AnchorLeft, secondItem, Qt::AnchorLeft); + l->addAnchor(firstItem, Qt::AnchorRight, secondItem, Qt::AnchorRight); + \endcode +*/ + +/*! + \fn QGraphicsAnchorLayout::addTopAndBottomAnchors(QGraphicsLayoutItem *firstItem, QGraphicsLayoutItem *secondItem) + + Anchors the top and bottom edges of \a firstItem to the same edges of + \a secondItem. + + This convenience function is equivalent to calling + \code + l->addAnchor(firstItem, Qt::AnchorTop, secondItem, Qt::AnchorTop); + l->addAnchor(firstItem, Qt::AnchorBottom, secondItem, Qt::AnchorBottom); + \endcode +*/ + +/*! + \fn QGraphicsAnchorLayout::addAllAnchors(QGraphicsLayoutItem *firstItem, QGraphicsLayoutItem *secondItem) + + Anchors all edges (left, right, top and bottom) of \a firstItem to the same edges of + \a secondItem. + + This convenience function is equivalent to calling + \code + l->addLeftAndRightAnchors(firstItem, secondItem); + l->addTopAndBottomAnchors(firstItem, secondItem); + \endcode +*/ + +/*! + Set the spacing between the anchor point defined by \a firstItem and \a firstEdge and + \a secondItem and \a secondEdge to be \a spacing. +*/ +void QGraphicsAnchorLayout::setAnchorSpacing(const QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge, + const QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge, + qreal spacing) +{ + Q_D(QGraphicsAnchorLayout); + + if (!d->setAnchorSize(firstItem, firstEdge, secondItem, secondEdge, &spacing)) { + qWarning("setAnchorSpacing: The anchor does not exist."); + return; + } + invalidate(); +} + +/*! + Returns the spacing between the anchor point defined by \a firstItem and \a firstEdge and + \a secondItem and \a secondEdge. The anchor must exist. +*/ +qreal QGraphicsAnchorLayout::anchorSpacing(const QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge, + const QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge) const +{ + Q_D(const QGraphicsAnchorLayout); + qreal size = 0; + if (!d->anchorSize(firstItem, firstEdge, secondItem, secondEdge, 0, &size)) { + qWarning("anchorSpacing: The anchor does not exist."); + } + return size; +} + +/*! + Resets the spacing between the anchor point defined by \a firstItem and \a firstEdge and + \a secondItem and \a secondEdge to be the default spacing. Depending on the anchor type, the + default spacing is either 0 or a value returned from the style. + + \sa setAnchorSpacing(), anchorSpacing(), addAnchor() +*/ +void QGraphicsAnchorLayout::unsetAnchorSpacing(const QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge, + const QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge) +{ + Q_D(QGraphicsAnchorLayout); + + if (!d->setAnchorSize(firstItem, firstEdge, secondItem, secondEdge, 0)) { + qWarning("unsetAnchorSpacing: The anchor does not exist."); + } + invalidate(); +} + +/*! + Removes the anchor between the edge \a firstEdge of item \a firstItem and the edge \a secondEdge + of item \a secondItem. If such an anchor does not exist, the layout will be left unchanged. +*/ +void QGraphicsAnchorLayout::removeAnchor(QGraphicsLayoutItem *firstItem, Qt::AnchorPoint firstEdge, + QGraphicsLayoutItem *secondItem, Qt::AnchorPoint secondEdge) +{ + Q_D(QGraphicsAnchorLayout); + if ((firstItem == 0) || (secondItem == 0)) { + qWarning("QGraphicsAnchorLayout::removeAnchor: " + "Cannot remove anchor between NULL items"); + return; + } + + if (firstItem == secondItem) { + qWarning("QGraphicsAnchorLayout::removeAnchor: " + "Cannot remove anchor from the item to itself"); + return; + } + + if (d->edgeOrientation(secondEdge) != d->edgeOrientation(firstEdge)) { + qWarning("QGraphicsAnchorLayout::removeAnchor: " + "Cannot remove anchor from edges of different orientations"); + return; + } + + d->removeAnchor(firstItem, firstEdge, secondItem, secondEdge); + invalidate(); +} + +/*! + Sets the default horizontal spacing for the anchor layout to \a spacing. + + \sa horizontalSpacing(), setVerticalSpacing(), setSpacing() +*/ +void QGraphicsAnchorLayout::setHorizontalSpacing(qreal spacing) +{ + Q_D(QGraphicsAnchorLayout); + d->spacings[0] = spacing; + invalidate(); +} + +/*! + Sets the default vertical spacing for the anchor layout to \a spacing. + + \sa verticalSpacing(), setHorizontalSpacing(), setSpacing() +*/ +void QGraphicsAnchorLayout::setVerticalSpacing(qreal spacing) +{ + Q_D(QGraphicsAnchorLayout); + d->spacings[1] = spacing; + invalidate(); +} + +/*! + Sets the default horizontal and the default vertical spacing for the anchor layout to \a spacing. + + If an item is anchored with no spacing associated with the anchor, it will use the default + spacing. + \sa setHorizontalSpacing(), setVerticalSpacing() +*/ +void QGraphicsAnchorLayout::setSpacing(qreal spacing) +{ + Q_D(QGraphicsAnchorLayout); + d->spacings[0] = d->spacings[1] = spacing; + invalidate(); +} + +/*! + Returns the default horizontal spacing for the anchor layout. + + \sa verticalSpacing(), setHorizontalSpacing() +*/ +qreal QGraphicsAnchorLayout::horizontalSpacing() const +{ + Q_D(const QGraphicsAnchorLayout); + return d->effectiveSpacing(QGraphicsAnchorLayoutPrivate::Horizontal); +} + +/*! + Returns the default vertical spacing for the anchor layout. + + \sa horizontalSpacing(), setVerticalSpacing() +*/ +qreal QGraphicsAnchorLayout::verticalSpacing() const +{ + Q_D(const QGraphicsAnchorLayout); + return d->effectiveSpacing(QGraphicsAnchorLayoutPrivate::Vertical); +} + +/*! + \reimp +*/ +void QGraphicsAnchorLayout::setGeometry(const QRectF &geom) +{ + Q_D(QGraphicsAnchorLayout); + + QGraphicsLayout::setGeometry(geom); + d->calculateVertexPositions(QGraphicsAnchorLayoutPrivate::Horizontal); + d->calculateVertexPositions(QGraphicsAnchorLayoutPrivate::Vertical); + d->setItemsGeometries(); +} + +/*! + Removes the layout item at \a index without destroying it. Ownership of + the item is transferred to the caller. + + Removing an item will also remove any of the anchors associated with it. + + \sa itemAt(), count() +*/ +void QGraphicsAnchorLayout::removeAt(int index) +{ + Q_D(QGraphicsAnchorLayout); + QGraphicsLayoutItem *item = d->items.value(index); + + if (!item) + return; + + // Removing an item affects both horizontal and vertical graphs + d->restoreSimplifiedGraph(QGraphicsAnchorLayoutPrivate::Horizontal); + d->restoreSimplifiedGraph(QGraphicsAnchorLayoutPrivate::Vertical); + + d->removeCenterConstraints(item, QGraphicsAnchorLayoutPrivate::Horizontal); + d->removeCenterConstraints(item, QGraphicsAnchorLayoutPrivate::Vertical); + d->removeAnchors(item); + d->items.remove(index); + + item->setParentLayoutItem(0); + invalidate(); +} + +/*! + \reimp +*/ +int QGraphicsAnchorLayout::count() const +{ + Q_D(const QGraphicsAnchorLayout); + return d->items.size(); +} + +/*! + \reimp +*/ +QGraphicsLayoutItem *QGraphicsAnchorLayout::itemAt(int index) const +{ + Q_D(const QGraphicsAnchorLayout); + return d->items.value(index); +} + +/*! + \reimp +*/ +void QGraphicsAnchorLayout::invalidate() +{ + Q_D(QGraphicsAnchorLayout); + QGraphicsLayout::invalidate(); + d->calculateGraphCacheDirty = 1; +} + +/*! + \reimp +*/ +QSizeF QGraphicsAnchorLayout::sizeHint(Qt::SizeHint which, const QSizeF &constraint) const +{ + Q_UNUSED(which); + Q_UNUSED(constraint); + Q_D(const QGraphicsAnchorLayout); + + // Some setup calculations are delayed until the information is + // actually needed, avoiding unnecessary recalculations when + // adding multiple anchors. + + // sizeHint() / effectiveSizeHint() already have a cache + // mechanism, using invalidate() to force recalculation. However + // sizeHint() is called three times after invalidation (for max, + // min and pref), but we just need do our setup once. + + const_cast<QGraphicsAnchorLayoutPrivate *>(d)->calculateGraphs(); + + // ### apply constraint! + QSizeF engineSizeHint( + d->sizeHints[QGraphicsAnchorLayoutPrivate::Horizontal][which], + d->sizeHints[QGraphicsAnchorLayoutPrivate::Vertical][which]); + + qreal left, top, right, bottom; + getContentsMargins(&left, &top, &right, &bottom); + + return engineSizeHint + QSizeF(left + right, top + bottom); +} + +QT_END_NAMESPACE |