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Diffstat (limited to 'src/gui/graphicsview/qgraphicsanchorlayout_p.cpp')
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diff --git a/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp new file mode 100644 index 000000000..9a34ad5a2 --- /dev/null +++ b/src/gui/graphicsview/qgraphicsanchorlayout_p.cpp @@ -0,0 +1,2104 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** 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 1.0, 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. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include <QtGui/qwidget.h> +#include <QtCore/qlinkedlist.h> +#include <QtCore/qstack.h> + +#ifdef QT_DEBUG +#include <QtCore/qfile.h> +#endif + +#include "qgraphicsanchorlayout_p.h" + +QT_BEGIN_NAMESPACE + +void AnchorData::refreshSizeHints(qreal effectiveSpacing) +{ + if (!isLayoutAnchor && from->m_item == to->m_item) { + bool hasCenter = false; + QGraphicsLayoutItem *item = from->m_item; + + if (QGraphicsAnchorLayoutPrivate::edgeOrientation(from->m_edge) + == QGraphicsAnchorLayoutPrivate::Horizontal) { + minSize = item->minimumWidth(); + prefSize = item->preferredWidth(); + maxSize = item->maximumWidth(); + hasCenter = (from->m_edge == Qt::AnchorHorizontalCenter + || to->m_edge == Qt::AnchorHorizontalCenter); + } else { + minSize = item->minimumHeight(); + prefSize = item->preferredHeight(); + maxSize = item->maximumHeight(); + hasCenter = (from->m_edge == Qt::AnchorVerticalCenter + || to->m_edge == Qt::AnchorVerticalCenter); + } + + if (hasCenter) { + minSize /= 2; + prefSize /= 2; + maxSize /= 2; + } + + // Set the anchor effective sizes to preferred. + // + // Note: The idea here is that all items should remain at their + // preferred size unless where that's impossible. In cases where + // the item is subject to restrictions (anchored to the layout + // edges, for instance), the simplex solver will be run to + // recalculate and override the values we set here. + sizeAtMinimum = prefSize; + sizeAtPreferred = prefSize; + sizeAtMaximum = prefSize; + + } else if (!hasSize) { + // Anchor has no size defined, use given default information + minSize = effectiveSpacing; + prefSize = effectiveSpacing; + maxSize = effectiveSpacing; + + sizeAtMinimum = prefSize; + sizeAtPreferred = prefSize; + sizeAtMaximum = prefSize; + } +} + +void ParallelAnchorData::updateChildrenSizes() +{ + firstEdge->sizeAtMinimum = secondEdge->sizeAtMinimum = sizeAtMinimum; + firstEdge->sizeAtPreferred = secondEdge->sizeAtPreferred = sizeAtPreferred; + firstEdge->sizeAtMaximum = secondEdge->sizeAtMaximum = sizeAtMaximum; + + firstEdge->updateChildrenSizes(); + secondEdge->updateChildrenSizes(); +} + +void ParallelAnchorData::refreshSizeHints(qreal effectiveSpacing) +{ + // First refresh children information + firstEdge->refreshSizeHints(effectiveSpacing); + secondEdge->refreshSizeHints(effectiveSpacing); + + // ### should we warn if the parallel connection is invalid? + // e.g. 1-2-3 with 10-20-30, the minimum of the latter is + // bigger than the maximum of the former. + + minSize = qMax(firstEdge->minSize, secondEdge->minSize); + maxSize = qMin(firstEdge->maxSize, secondEdge->maxSize); + + prefSize = qMax(firstEdge->prefSize, secondEdge->prefSize); + prefSize = qMin(prefSize, maxSize); + + // See comment in AnchorData::refreshSizeHints() about sizeAt* values + sizeAtMinimum = prefSize; + sizeAtPreferred = prefSize; + sizeAtMaximum = prefSize; +} + +/*! + \internal + returns the factor in the interval [-1, 1]. + -1 is at Minimum + 0 is at Preferred + 1 is at Maximum +*/ +static qreal getFactor(qreal value, qreal min, qreal pref, qreal max) +{ + // ### Maybe remove some of the assertions? (since outside is asserting us) + Q_ASSERT(value > min || qFuzzyCompare(value, min)); + Q_ASSERT(value < max || qFuzzyCompare(value, max)); + + if (qFuzzyCompare(value, min)) { + return -1.0; + } else if (qFuzzyCompare(value, pref)) { + return 0.0; + } else if (qFuzzyCompare(value, max)) { + return 1.0; + } else if (value < pref) { + // Since value < pref and value != pref and min <= value, + // we can assert that min < pref. + Q_ASSERT(min < pref); + return (value - min) / (pref - min) - 1; + } else { + // Since value > pref and value != pref and max >= value, + // we can assert that max > pref. + Q_ASSERT(max > pref); + return (value - pref) / (max - pref); + } +} + +void SequentialAnchorData::updateChildrenSizes() +{ + // ### REMOVE ME + // ### check whether we are guarantee to get those or we need to warn stuff at this + // point. + Q_ASSERT(sizeAtMinimum > minSize || qFuzzyCompare(sizeAtMinimum, minSize)); + Q_ASSERT(sizeAtMinimum < maxSize || qFuzzyCompare(sizeAtMinimum, maxSize)); + Q_ASSERT(sizeAtPreferred > minSize || qFuzzyCompare(sizeAtPreferred, minSize)); + Q_ASSERT(sizeAtPreferred < maxSize || qFuzzyCompare(sizeAtPreferred, maxSize)); + Q_ASSERT(sizeAtMaximum > minSize || qFuzzyCompare(sizeAtMaximum, minSize)); + Q_ASSERT(sizeAtMaximum < maxSize || qFuzzyCompare(sizeAtMaximum, maxSize)); + + // Band here refers if the value is in the Minimum To Preferred + // band (the lower band) or the Preferred To Maximum (the upper band). + + qreal minFactor = getFactor(sizeAtMinimum, minSize, prefSize, maxSize); + qreal prefFactor = getFactor(sizeAtPreferred, minSize, prefSize, maxSize); + qreal maxFactor = getFactor(sizeAtMaximum, minSize, prefSize, maxSize); + + for (int i = 0; i < m_edges.count(); ++i) { + AnchorData *e = m_edges.at(i); + + qreal bandSize = minFactor > 0 ? e->maxSize - e->prefSize : e->prefSize - e->minSize; + e->sizeAtMinimum = e->prefSize + bandSize * minFactor; + + bandSize = prefFactor > 0 ? e->maxSize - e->prefSize : e->prefSize - e->minSize; + e->sizeAtPreferred = e->prefSize + bandSize * prefFactor; + + bandSize = maxFactor > 0 ? e->maxSize - e->prefSize : e->prefSize - e->minSize; + e->sizeAtMaximum = e->prefSize + bandSize * maxFactor; + + e->updateChildrenSizes(); + } +} + +void SequentialAnchorData::refreshSizeHints(qreal effectiveSpacing) +{ + minSize = 0; + prefSize = 0; + maxSize = 0; + + for (int i = 0; i < m_edges.count(); ++i) { + AnchorData *edge = m_edges.at(i); + + // First refresh children information + edge->refreshSizeHints(effectiveSpacing); + + minSize += edge->minSize; + prefSize += edge->prefSize; + maxSize += edge->maxSize; + } + + // See comment in AnchorData::refreshSizeHints() about sizeAt* values + sizeAtMinimum = prefSize; + sizeAtPreferred = prefSize; + sizeAtMaximum = prefSize; +} + +#ifdef QT_DEBUG +void AnchorData::dump(int indent) { + if (type == Parallel) { + qDebug("%*s type: parallel:", indent, ""); + ParallelAnchorData *p = static_cast<ParallelAnchorData *>(this); + p->firstEdge->dump(indent+2); + p->secondEdge->dump(indent+2); + } else if (type == Sequential) { + SequentialAnchorData *s = static_cast<SequentialAnchorData *>(this); + int kids = s->m_edges.count(); + qDebug("%*s type: sequential(%d):", indent, "", kids); + for (int i = 0; i < kids; ++i) { + s->m_edges.at(i)->dump(indent+2); + } + } else { + qDebug("%*s type: Normal:", indent, ""); + } +} + +#endif + +QSimplexConstraint *GraphPath::constraint(const GraphPath &path) const +{ + // Calculate + QSet<AnchorData *> cPositives; + QSet<AnchorData *> cNegatives; + QSet<AnchorData *> intersection; + + cPositives = positives + path.negatives; + cNegatives = negatives + path.positives; + + intersection = cPositives & cNegatives; + + cPositives -= intersection; + cNegatives -= intersection; + + // Fill + QSimplexConstraint *c = new QSimplexConstraint; + QSet<AnchorData *>::iterator i; + for (i = cPositives.begin(); i != cPositives.end(); ++i) + c->variables.insert(*i, 1.0); + + for (i = cNegatives.begin(); i != cNegatives.end(); ++i) + c->variables.insert(*i, -1.0); + + return c; +} + +#ifdef QT_DEBUG +QString GraphPath::toString() const +{ + QString string(QLatin1String("Path: ")); + foreach(AnchorData *edge, positives) + string += QString::fromAscii(" (+++) %1").arg(edge->toString()); + + foreach(AnchorData *edge, negatives) + string += QString::fromAscii(" (---) %1").arg(edge->toString()); + + return string; +} +#endif + +QGraphicsAnchorLayoutPrivate::QGraphicsAnchorLayoutPrivate() + : calculateGraphCacheDirty(1) +{ + for (int i = 0; i < NOrientations; ++i) { + spacings[i] = -1; + graphSimplified[i] = false; + } +} + +Qt::AnchorPoint QGraphicsAnchorLayoutPrivate::oppositeEdge(Qt::AnchorPoint edge) +{ + switch (edge) { + case Qt::AnchorLeft: + edge = Qt::AnchorRight; + break; + case Qt::AnchorRight: + edge = Qt::AnchorLeft; + break; + case Qt::AnchorTop: + edge = Qt::AnchorBottom; + break; + case Qt::AnchorBottom: + edge = Qt::AnchorTop; + break; + default: + break; + } + return edge; +} + + +/*! + * \internal + * + * helper function in order to avoid overflowing anchor sizes + * the returned size will never be larger than FLT_MAX + * + */ +inline static qreal checkAdd(qreal a, qreal b) +{ + if (FLT_MAX - b < a) + return FLT_MAX; + return a + b; +} + +/*! + * \internal + * + * Takes the sequence of vertices described by (\a before, \a vertices, \a after) and replaces + * all anchors connected to the vertices in \a vertices with one simplified anchor between + * \a before and \a after. The simplified anchor will be a placeholder for all the previous + * anchors between \a before and \a after, and can be restored back to the anchors it is a + * placeholder for. + */ +static bool simplifySequentialChunk(Graph<AnchorVertex, AnchorData> *graph, + AnchorVertex *before, + const QVector<AnchorVertex*> &vertices, + AnchorVertex *after) +{ + int i; +#if defined(QT_DEBUG) && 0 + QString strVertices; + for (i = 0; i < vertices.count(); ++i) + strVertices += QString::fromAscii("%1 - ").arg(vertices.at(i)->toString()); + QString strPath = QString::fromAscii("%1 - %2%3").arg(before->toString(), strVertices, after->toString()); + qDebug("simplifying [%s] to [%s - %s]", qPrintable(strPath), qPrintable(before->toString()), qPrintable(after->toString())); +#endif + + qreal min = 0; + qreal pref = 0; + qreal max = 0; + + SequentialAnchorData *sequence = new SequentialAnchorData; + AnchorVertex *prev = before; + AnchorData *data; + for (i = 0; i <= vertices.count(); ++i) { + AnchorVertex *next = (i < vertices.count()) ? vertices.at(i) : after; + data = graph->takeEdge(prev, next); + min += data->minSize; + pref += data->prefSize; + max = checkAdd(max, data->maxSize); + sequence->m_edges.append(data); + prev = next; + } + + // insert new + sequence->minSize = min; + sequence->prefSize = pref; + sequence->maxSize = max; + + // Unless these values are overhidden by the simplex solver later-on, + // anchors will keep their own preferred size. + sequence->sizeAtMinimum = pref; + sequence->sizeAtPreferred = pref; + sequence->sizeAtMaximum = pref; + + sequence->setVertices(vertices); + + sequence->from = before; + sequence->to = after; + + // data here is the last edge in the sequence + // ### this seems to be here for supporting reverse order sequences, + // but doesnt seem to be used right now + if (data->from != vertices.last()) + qSwap(sequence->from, sequence->to); + + // Note that since layout 'edges' can't be simplified away from + // the graph, it's safe to assume that if there's a layout + // 'edge', it'll be in the boundaries of the sequence. + sequence->isLayoutAnchor = (sequence->m_edges.first()->isLayoutAnchor + || sequence->m_edges.last()->isLayoutAnchor); + + AnchorData *newAnchor = sequence; + if (AnchorData *oldAnchor = graph->takeEdge(before, after)) { + newAnchor = new ParallelAnchorData(oldAnchor, sequence); + + newAnchor->isLayoutAnchor = (oldAnchor->isLayoutAnchor + || sequence->isLayoutAnchor); + + min = qMax(oldAnchor->minSize, sequence->minSize); + max = qMin(oldAnchor->maxSize, sequence->maxSize); + + pref = qMax(oldAnchor->prefSize, sequence->prefSize); + pref = qMin(pref, max); + + newAnchor->minSize = min; + newAnchor->prefSize = pref; + newAnchor->maxSize = max; + + // Same as above, by default, keep preferred size. + newAnchor->sizeAtMinimum = pref; + newAnchor->sizeAtPreferred = pref; + newAnchor->sizeAtMaximum = pref; + } + graph->createEdge(before, after, newAnchor); + + // True if we created a parallel anchor + return newAnchor != sequence; +} + +/*! + \internal + + The purpose of this function is to simplify the graph. + Simplification serves two purposes: + 1. Reduce the number of edges in the graph, (thus the number of variables to the equation + solver is reduced, and the solver performs better). + 2. Be able to do distribution of sequences of edges more intelligently (esp. with sequential + anchors) + + It is essential that it must be possible to restore simplified anchors back to their "original" + form. This is done by restoreSimplifiedAnchor(). + + There are two types of simplification that can be done: + 1. Sequential simplification + Sequential simplification means that all sequences of anchors will be merged into one single + anchor. Only anhcors that points in the same direction will be merged. + 2. Parallel simplification + If a simplified sequential anchor is about to be inserted between two vertices in the graph + and there already exist an anchor between those two vertices, a parallel anchor will be + created that serves as a placeholder for the sequential anchor and the anchor that was + already between the two vertices. + + The process of simplification can be described as: + + 1. Simplify all sequences of anchors into one anchor. + If no further simplification was done, go to (3) + - If there already exist an anchor where the sequential anchor is supposed to be inserted, + take that anchor out of the graph + - Then create a parallel anchor that holds the sequential anchor and the anchor just taken + out of the graph. + 2. Go to (1) + 3. Done + + + * Gathering sequential anchors * + The algorithm walks the graph in depth-first order, and only collects vertices that has two + edges connected to it. If the vertex does not have two edges or if it is a layout edge, + it will take all the previously collected vertices and try to create a simplified sequential + anchor representing all the previously collected vertices. + Once the simplified anchor is inserted, the collected list is cleared in order to find the next + sequence to simplify. + Note that there are some catches to this that are not covered by the above explanation. +*/ +void QGraphicsAnchorLayoutPrivate::simplifyGraph(Orientation orientation) +{ + static bool noSimplification = !qgetenv("QT_ANCHORLAYOUT_NO_SIMPLIFICATION").isEmpty(); + if (noSimplification) + return; + + if (graphSimplified[orientation]) + return; + graphSimplified[orientation] = true; + +#if 0 + qDebug("Simplifying Graph for %s", + orientation == Horizontal ? "Horizontal" : "Vertical"); +#endif + + AnchorVertex *rootVertex = graph[orientation].rootVertex(); + + if (!rootVertex) + return; + + bool dirty; + do { + dirty = simplifyGraphIteration(orientation); + } while (dirty); +} + +bool QGraphicsAnchorLayoutPrivate::simplifyGraphIteration(QGraphicsAnchorLayoutPrivate::Orientation orientation) +{ + Q_Q(QGraphicsAnchorLayout); + Graph<AnchorVertex, AnchorData> &g = graph[orientation]; + AnchorVertex *v = g.rootVertex(); + + QSet<AnchorVertex *> visited; + QStack<AnchorVertex *> stack; + stack.push(v); + QVector<AnchorVertex*> candidates; + + const Qt::AnchorPoint centerEdge = pickEdge(Qt::AnchorHorizontalCenter, orientation); + const Qt::AnchorPoint layoutEdge = oppositeEdge(v->m_edge); + + bool dirty = false; + + // walk depth-first. + while (!stack.isEmpty()) { + v = stack.pop(); + QList<AnchorVertex *> vertices = g.adjacentVertices(v); + const int count = vertices.count(); + bool endOfSequence = (v->m_item == q && v->m_edge == layoutEdge) || count != 2; + if (count == 2 && v->m_item != q) { + candidates.append(v); + if (visited.contains(vertices.first()) && visited.contains(vertices.last())) { + // in case of a cycle + endOfSequence = true; + } + } + if (endOfSequence && candidates.count() >= 2) { + int i; + AnchorVertex *afterSequence= 0; + QList<AnchorVertex *> adjacentOfSecondLastVertex = g.adjacentVertices(candidates.last()); + Q_ASSERT(adjacentOfSecondLastVertex.count() == 2); + if (adjacentOfSecondLastVertex.first() == candidates.at(candidates.count() - 2)) + afterSequence = adjacentOfSecondLastVertex.last(); + else + afterSequence = adjacentOfSecondLastVertex.first(); + + AnchorVertex *beforeSequence = 0; + QList<AnchorVertex *> adjacentOfSecondVertex = g.adjacentVertices(candidates.first()); + Q_ASSERT(adjacentOfSecondVertex.count() == 2); + if (adjacentOfSecondVertex.first() == candidates.at(1)) + beforeSequence = adjacentOfSecondVertex.last(); + else + beforeSequence = adjacentOfSecondVertex.first(); + // The complete path of the sequence to simplify is: beforeSequence, <candidates>, afterSequence + // where beforeSequence and afterSequence are the endpoints where the anchor is inserted + // between. +#if defined(QT_DEBUG) && 0 + // ### DEBUG + QString strCandidates; + for (i = 0; i < candidates.count(); ++i) + strCandidates += QString::fromAscii("%1 - ").arg(candidates.at(i)->toString()); + QString strPath = QString::fromAscii("%1 - %2%3").arg(beforeSequence->toString(), strCandidates, afterSequence->toString()); + qDebug("candidate list for sequential simplification:\n[%s]", qPrintable(strPath)); +#endif + + bool forward; + AnchorVertex *prev = beforeSequence; + int intervalFrom = 0; + + // Check for directionality (from). We don't want to destroy that information, + // thus we only combine anchors with the same direction. + + // "i" is the index *including* the beforeSequence and afterSequence vertices. + for (i = 1; i <= candidates.count() + 1; ++i) { + bool atVertexAfter = i > candidates.count(); + AnchorVertex *v1 = atVertexAfter ? afterSequence : candidates.at(i - 1); + AnchorData *data = g.edgeData(prev, v1); + Q_ASSERT(data); + if (i == 1) { + forward = (prev == data->from ? true : false); + } else if (forward != (prev == data->from) || atVertexAfter) { + int intervalTo = i; + if (forward != (prev == data->from)) + --intervalTo; + + // intervalFrom and intervalTo should now be indices to the vertex before and + // after the sequential anchor. + if (intervalTo - intervalFrom >= 2) { + // simplify in the range [intervalFrom, intervalTo] + + // Trim off internal center anchors (Left-Center/Center-Right) from the + // start and the end of the sequence. We never want to simplify internal + // center anchors where there is an external anchor connected to the center. + AnchorVertex *intervalVertexFrom = intervalFrom == 0 ? beforeSequence : candidates.at(intervalFrom - 1); + if (intervalVertexFrom->m_edge == centerEdge + && intervalVertexFrom->m_item == candidates.at(intervalFrom)->m_item) { + ++intervalFrom; + intervalVertexFrom = candidates.at(intervalFrom - 1); + } + AnchorVertex *intervalVertexTo = intervalTo <= candidates.count() ? candidates.at(intervalTo - 1) : afterSequence; + if (intervalVertexTo->m_edge == centerEdge + && intervalVertexTo->m_item == candidates.at(intervalTo - 2)->m_item) { + --intervalTo; + intervalVertexTo = candidates.at(intervalTo - 1); + } + + QVector<AnchorVertex*> subCandidates; + if (forward) { + subCandidates = candidates.mid(intervalFrom, intervalTo - intervalFrom - 1); + } else { + // reverse the order of the candidates. + qSwap(intervalVertexFrom, intervalVertexTo); + do { + ++intervalFrom; + subCandidates.prepend(candidates.at(intervalFrom - 1)); + } while (intervalFrom < intervalTo - 1); + } + if (simplifySequentialChunk(&g, intervalVertexFrom, subCandidates, intervalVertexTo)) { + dirty = true; + break; + } + // finished simplification of chunk with same direction + } + if (forward == (prev == data->from)) + --intervalTo; + intervalFrom = intervalTo; + + forward = !forward; + } + prev = v1; + } + + if (dirty) + break; + } + + if (endOfSequence) + candidates.clear(); + + for (int i = 0; i < count; ++i) { + AnchorVertex *next = vertices.at(i); + if (next->m_item == q && next->m_edge == centerEdge) + continue; + if (visited.contains(next)) + continue; + stack.push(next); + } + + visited.insert(v); + } + + return dirty; +} + +static void restoreSimplifiedAnchor(Graph<AnchorVertex, AnchorData> &g, + AnchorData *edge, + AnchorVertex *before, + AnchorVertex *after) +{ + Q_ASSERT(edge->type != AnchorData::Normal); +#if 0 + static const char *anchortypes[] = {"Normal", + "Sequential", + "Parallel"}; + qDebug("Restoring %s edge.", anchortypes[int(edge->type)]); +#endif + if (edge->type == AnchorData::Sequential) { + SequentialAnchorData* seqEdge = static_cast<SequentialAnchorData*>(edge); + // restore the sequential anchor + AnchorVertex *prev = before; + AnchorVertex *last = after; + if (edge->from != prev) + qSwap(last, prev); + + for (int i = 0; i < seqEdge->m_edges.count(); ++i) { + AnchorVertex *v1 = (i < seqEdge->m_children.count()) ? seqEdge->m_children.at(i) : last; + AnchorData *data = seqEdge->m_edges.at(i); + if (data->type != AnchorData::Normal) { + restoreSimplifiedAnchor(g, data, prev, v1); + } else { + g.createEdge(prev, v1, data); + } + prev = v1; + } + } else if (edge->type == AnchorData::Parallel) { + ParallelAnchorData* parallelEdge = static_cast<ParallelAnchorData*>(edge); + AnchorData *parallelEdges[2] = {parallelEdge->firstEdge, + parallelEdge->secondEdge}; + for (int i = 0; i < 2; ++i) { + AnchorData *data = parallelEdges[i]; + if (data->type == AnchorData::Normal) { + g.createEdge(before, after, data); + } else { + restoreSimplifiedAnchor(g, data, before, after); + } + } + } +} + +void QGraphicsAnchorLayoutPrivate::restoreSimplifiedGraph(Orientation orientation) +{ + if (!graphSimplified[orientation]) + return; + graphSimplified[orientation] = false; + +#if 0 + qDebug("Restoring Simplified Graph for %s", + orientation == Horizontal ? "Horizontal" : "Vertical"); +#endif + + Graph<AnchorVertex, AnchorData> &g = graph[orientation]; + + QList<QPair<AnchorVertex*, AnchorVertex*> > connections = g.connections(); + for (int i = 0; i < connections.count(); ++i) { + AnchorVertex *v1 = connections.at(i).first; + AnchorVertex *v2 = connections.at(i).second; + AnchorData *edge = g.edgeData(v1, v2); + if (edge->type != AnchorData::Normal) { + AnchorData *oldEdge = g.takeEdge(v1, v2); + restoreSimplifiedAnchor(g, edge, v1, v2); + delete oldEdge; + } + } +} + +QGraphicsAnchorLayoutPrivate::Orientation +QGraphicsAnchorLayoutPrivate::edgeOrientation(Qt::AnchorPoint edge) +{ + return edge > Qt::AnchorRight ? Vertical : Horizontal; +} + +/*! + \internal + + Create internal anchors to connect the layout edges (Left to Right and + Top to Bottom). + + These anchors doesn't have size restrictions, that will be enforced by + other anchors and items in the layout. +*/ +void QGraphicsAnchorLayoutPrivate::createLayoutEdges() +{ + Q_Q(QGraphicsAnchorLayout); + QGraphicsLayoutItem *layout = q; + + // Horizontal + AnchorData *data = new AnchorData(0, 0, QWIDGETSIZE_MAX); + addAnchor(layout, Qt::AnchorLeft, layout, + Qt::AnchorRight, data); + data->skipInPreferred = 1; + + // Set the Layout Left edge as the root of the horizontal graph. + AnchorVertex *v = internalVertex(layout, Qt::AnchorLeft); + graph[Horizontal].setRootVertex(v); + + // Vertical + data = new AnchorData(0, 0, QWIDGETSIZE_MAX); + addAnchor(layout, Qt::AnchorTop, layout, + Qt::AnchorBottom, data); + data->skipInPreferred = 1; + + // Set the Layout Top edge as the root of the vertical graph. + v = internalVertex(layout, Qt::AnchorTop); + graph[Vertical].setRootVertex(v); +} + +void QGraphicsAnchorLayoutPrivate::deleteLayoutEdges() +{ + Q_Q(QGraphicsAnchorLayout); + + Q_ASSERT(internalVertex(q, Qt::AnchorHorizontalCenter) == NULL); + Q_ASSERT(internalVertex(q, Qt::AnchorVerticalCenter) == NULL); + + removeAnchor(q, Qt::AnchorLeft, q, Qt::AnchorRight); + removeAnchor(q, Qt::AnchorTop, q, Qt::AnchorBottom); +} + +void QGraphicsAnchorLayoutPrivate::createItemEdges(QGraphicsLayoutItem *item) +{ + Q_ASSERT(!graphSimplified[Horizontal] && !graphSimplified[Vertical]); + + items.append(item); + + // Horizontal + int minimumSize = item->minimumWidth(); + int preferredSize = item->preferredWidth(); + int maximumSize = item->maximumWidth(); + + AnchorData *data = new AnchorData(minimumSize, preferredSize, maximumSize); + addAnchor(item, Qt::AnchorLeft, item, + Qt::AnchorRight, data); + + // Vertical + minimumSize = item->minimumHeight(); + preferredSize = item->preferredHeight(); + maximumSize = item->maximumHeight(); + + data = new AnchorData(minimumSize, preferredSize, maximumSize); + addAnchor(item, Qt::AnchorTop, item, + Qt::AnchorBottom, data); +} + +/*! + \internal + + By default, each item in the layout is represented internally as + a single anchor in each direction. For instance, from Left to Right. + + However, to support anchorage of items to the center of items, we + must split this internal anchor into two half-anchors. From Left + to Center and then from Center to Right, with the restriction that + these anchors must have the same time at all times. +*/ +void QGraphicsAnchorLayoutPrivate::createCenterAnchors( + QGraphicsLayoutItem *item, Qt::AnchorPoint centerEdge) +{ + Orientation orientation; + switch (centerEdge) { + case Qt::AnchorHorizontalCenter: + orientation = Horizontal; + break; + case Qt::AnchorVerticalCenter: + orientation = Vertical; + break; + default: + // Don't create center edges unless needed + return; + } + + Q_ASSERT(!graphSimplified[orientation]); + + // Check if vertex already exists + if (internalVertex(item, centerEdge)) + return; + + // Orientation code + Qt::AnchorPoint firstEdge; + Qt::AnchorPoint lastEdge; + + if (orientation == Horizontal) { + firstEdge = Qt::AnchorLeft; + lastEdge = Qt::AnchorRight; + } else { + firstEdge = Qt::AnchorTop; + lastEdge = Qt::AnchorBottom; + } + + AnchorVertex *first = internalVertex(item, firstEdge); + AnchorVertex *last = internalVertex(item, lastEdge); + Q_ASSERT(first && last); + + // Create new anchors + AnchorData *oldData = graph[orientation].edgeData(first, last); + + int minimumSize = oldData->minSize / 2; + int preferredSize = oldData->prefSize / 2; + int maximumSize = oldData->maxSize / 2; + + QSimplexConstraint *c = new QSimplexConstraint; + AnchorData *data = new AnchorData(minimumSize, preferredSize, maximumSize); + c->variables.insert(data, 1.0); + addAnchor(item, firstEdge, item, centerEdge, data); + + data = new AnchorData(minimumSize, preferredSize, maximumSize); + c->variables.insert(data, -1.0); + addAnchor(item, centerEdge, item, lastEdge, data); + + itemCenterConstraints[orientation].append(c); + + // Remove old one + removeAnchor(item, firstEdge, item, lastEdge); +} + +void QGraphicsAnchorLayoutPrivate::removeCenterAnchors( + QGraphicsLayoutItem *item, Qt::AnchorPoint centerEdge, + bool substitute) +{ + Orientation orientation; + switch (centerEdge) { + case Qt::AnchorHorizontalCenter: + orientation = Horizontal; + break; + case Qt::AnchorVerticalCenter: + orientation = Vertical; + break; + default: + // Don't remove edges that not the center ones + return; + } + + Q_ASSERT(!graphSimplified[orientation]); + + // Orientation code + Qt::AnchorPoint firstEdge; + Qt::AnchorPoint lastEdge; + + if (orientation == Horizontal) { + firstEdge = Qt::AnchorLeft; + lastEdge = Qt::AnchorRight; + } else { + firstEdge = Qt::AnchorTop; + lastEdge = Qt::AnchorBottom; + } + + AnchorVertex *center = internalVertex(item, centerEdge); + if (!center) + return; + AnchorVertex *first = internalVertex(item, firstEdge); + + Q_ASSERT(first); + Q_ASSERT(center); + + Graph<AnchorVertex, AnchorData> &g = graph[orientation]; + + + AnchorData *oldData = g.edgeData(first, center); + // Remove center constraint + for (int i = itemCenterConstraints[orientation].count() - 1; i >= 0; --i) { + if (itemCenterConstraints[orientation][i]->variables.contains(oldData)) { + delete itemCenterConstraints[orientation].takeAt(i); + break; + } + } + + if (substitute) { + // Create the new anchor that should substitute the left-center-right anchors. + AnchorData *oldData = g.edgeData(first, center); + + int minimumSize = oldData->minSize * 2; + int preferredSize = oldData->prefSize * 2; + int maximumSize = oldData->maxSize * 2; + + AnchorData *data = new AnchorData(minimumSize, preferredSize, maximumSize); + addAnchor(item, firstEdge, item, lastEdge, data); + + // Remove old anchors + removeAnchor(item, firstEdge, item, centerEdge); + removeAnchor(item, centerEdge, item, lastEdge); + + } else { + // this is only called from removeAnchors() + // first, remove all non-internal anchors + QList<AnchorVertex*> adjacents = g.adjacentVertices(center); + for (int i = 0; i < adjacents.count(); ++i) { + AnchorVertex *v = adjacents.at(i); + if (v->m_item != item) { + removeAnchor(item, centerEdge, v->m_item, v->m_edge); + } + } + // when all non-internal anchors is removed it will automatically merge the + // center anchor into a left-right (or top-bottom) anchor. We must also delete that. + // by this time, the center vertex is deleted and merged into a non-centered internal anchor + removeAnchor(item, firstEdge, item, lastEdge); + } +} + + +void QGraphicsAnchorLayoutPrivate::removeCenterConstraints(QGraphicsLayoutItem *item, + Orientation orientation) +{ + Q_ASSERT(!graphSimplified[orientation]); + + // Remove the item center constraints associated to this item + // ### This is a temporary solution. We should probably use a better + // data structure to hold items and/or their associated constraints + // so that we can remove those easily + + AnchorVertex *first = internalVertex(item, orientation == Horizontal ? + Qt::AnchorLeft : + Qt::AnchorTop); + AnchorVertex *center = internalVertex(item, orientation == Horizontal ? + Qt::AnchorHorizontalCenter : + Qt::AnchorVerticalCenter); + + // Skip if no center constraints exist + if (!center) + return; + + Q_ASSERT(first); + AnchorData *internalAnchor = graph[orientation].edgeData(first, center); + + // Look for our anchor in all item center constraints, then remove it + for (int i = 0; i < itemCenterConstraints[orientation].size(); ++i) { + if (itemCenterConstraints[orientation][i]->variables.contains(internalAnchor)) { + delete itemCenterConstraints[orientation].takeAt(i); + break; + } + } +} + +/*! + * \internal + * + * Helper function that is called from the anchor functions in the public API. + * If \a spacing is 0, it will pick up the spacing defined by the style. + */ +void QGraphicsAnchorLayoutPrivate::anchor(QGraphicsLayoutItem *firstItem, + Qt::AnchorPoint firstEdge, + QGraphicsLayoutItem *secondItem, + Qt::AnchorPoint secondEdge, + qreal *spacing) +{ + Q_Q(QGraphicsAnchorLayout); + if ((firstItem == 0) || (secondItem == 0)) { + qWarning("QGraphicsAnchorLayout::addAnchor(): " + "Cannot anchor NULL items"); + return; + } + + if (firstItem == secondItem) { + qWarning("QGraphicsAnchorLayout::addAnchor(): " + "Cannot anchor the item to itself"); + return; + } + + if (edgeOrientation(secondEdge) != edgeOrientation(firstEdge)) { + qWarning("QGraphicsAnchorLayout::addAnchor(): " + "Cannot anchor edges of different orientations"); + return; + } + + // Guarantee that the graph is no simplified when adding this anchor, + // anchor manipulation always happen in the full graph + restoreSimplifiedGraph(edgeOrientation(firstEdge)); + + // In QGraphicsAnchorLayout, items are represented in its internal + // graph as four anchors that connect: + // - Left -> HCenter + // - HCenter-> Right + // - Top -> VCenter + // - VCenter -> Bottom + + // Ensure that the internal anchors have been created for both items. + if (firstItem != q && !items.contains(firstItem)) { + restoreSimplifiedGraph(edgeOrientation(firstEdge) == Horizontal ? Vertical : Horizontal); + createItemEdges(firstItem); + addChildLayoutItem(firstItem); + } + if (secondItem != q && !items.contains(secondItem)) { + restoreSimplifiedGraph(edgeOrientation(firstEdge) == Horizontal ? Vertical : Horizontal); + createItemEdges(secondItem); + addChildLayoutItem(secondItem); + } + + // Create center edges if needed + createCenterAnchors(firstItem, firstEdge); + createCenterAnchors(secondItem, secondEdge); + + // Use heuristics to find out what the user meant with this anchor. + correctEdgeDirection(firstItem, firstEdge, secondItem, secondEdge); + + AnchorData *data; + if (!spacing) { + // If firstItem or secondItem is the layout itself, the spacing will default to 0. + // Otherwise, the following matrix is used (questionmark means that the spacing + // is queried from the style): + // from + // to Left HCenter Right + // Left 0 0 ? + // HCenter 0 0 0 + // Right ? 0 0 + if (firstItem != q + && secondItem != q + && pickEdge(firstEdge, Horizontal) != Qt::AnchorHorizontalCenter + && oppositeEdge(firstEdge) == secondEdge) { + data = new AnchorData; // ask the style later + } else { + data = new AnchorData(0); // spacing should be 0 + } + addAnchor(firstItem, firstEdge, secondItem, secondEdge, data); + } else if (*spacing >= 0) { + data = new AnchorData(*spacing); + addAnchor(firstItem, firstEdge, secondItem, secondEdge, data); + } else { + data = new AnchorData(-*spacing); + addAnchor(secondItem, secondEdge, firstItem, firstEdge, data); + } +} + +void QGraphicsAnchorLayoutPrivate::addAnchor(QGraphicsLayoutItem *firstItem, + Qt::AnchorPoint firstEdge, + QGraphicsLayoutItem *secondItem, + Qt::AnchorPoint secondEdge, + AnchorData *data) +{ + Q_Q(QGraphicsAnchorLayout); + + // Guarantee that the graph is no simplified when adding this anchor, + // anchor manipulation always happen in the full graph + restoreSimplifiedGraph(edgeOrientation(firstEdge)); + + // Is the Vertex (firstItem, firstEdge) already represented in our + // internal structure? + AnchorVertex *v1 = addInternalVertex(firstItem, firstEdge); + AnchorVertex *v2 = addInternalVertex(secondItem, secondEdge); + + // Remove previous anchor + // ### Could we update the existing edgeData rather than creating a new one? + if (graph[edgeOrientation(firstEdge)].edgeData(v1, v2)) + removeAnchor(firstItem, firstEdge, secondItem, secondEdge); + + // Create a bi-directional edge in the sense it can be transversed both + // from v1 or v2. "data" however is shared between the two references + // so we still know that the anchor direction is from 1 to 2. + data->from = v1; + data->to = v2; +#ifdef QT_DEBUG + data->name = QString::fromAscii("%1 --to--> %2").arg(v1->toString()).arg(v2->toString()); +#endif + // Keep track of anchors that are connected to the layout 'edges' + data->isLayoutAnchor = (v1->m_item == q || v2->m_item == q); + + graph[edgeOrientation(firstEdge)].createEdge(v1, v2, data); +} + +void QGraphicsAnchorLayoutPrivate::removeAnchor(QGraphicsLayoutItem *firstItem, + Qt::AnchorPoint firstEdge, + QGraphicsLayoutItem *secondItem, + Qt::AnchorPoint secondEdge) +{ + // Guarantee that the graph is no simplified when adding this anchor, + // anchor manipulation always happen in the full graph + restoreSimplifiedGraph(edgeOrientation(firstEdge)); + + // Look for both vertices + AnchorVertex *v1 = internalVertex(firstItem, firstEdge); + AnchorVertex *v2 = internalVertex(secondItem, secondEdge); + + Q_ASSERT(v1 && v2); + + // Remove edge from graph + graph[edgeOrientation(firstEdge)].removeEdge(v1, v2); + + // Decrease vertices reference count (may trigger a deletion) + removeInternalVertex(firstItem, firstEdge); + removeInternalVertex(secondItem, secondEdge); +} + +bool QGraphicsAnchorLayoutPrivate::setAnchorSize(const QGraphicsLayoutItem *firstItem, + Qt::AnchorPoint firstEdge, + const QGraphicsLayoutItem *secondItem, + Qt::AnchorPoint secondEdge, + const qreal *anchorSize) +{ + // ### we can avoid restoration if we really want to, but we would have to + // search recursively through all composite anchors + restoreSimplifiedGraph(edgeOrientation(firstEdge)); + AnchorVertex *v1 = internalVertex(firstItem, firstEdge); + AnchorVertex *v2 = internalVertex(secondItem, secondEdge); + + AnchorData *data = graph[edgeOrientation(firstEdge)].edgeData(v1, v2); + if (data) { + if (anchorSize) { + data->setFixedSize(*anchorSize); + } else { + data->unsetSize(); + } + } + + return data; +} + +bool QGraphicsAnchorLayoutPrivate::anchorSize(const QGraphicsLayoutItem *firstItem, + Qt::AnchorPoint firstEdge, + const QGraphicsLayoutItem *secondItem, + Qt::AnchorPoint secondEdge, + qreal *minSize, + qreal *prefSize, + qreal *maxSize) const +{ + Q_ASSERT(minSize || prefSize || maxSize); + QGraphicsAnchorLayoutPrivate *that = const_cast<QGraphicsAnchorLayoutPrivate *>(this); + that->restoreSimplifiedGraph(edgeOrientation(firstEdge)); + AnchorVertex *v1 = internalVertex(firstItem, firstEdge); + AnchorVertex *v2 = internalVertex(secondItem, secondEdge); + + AnchorData *data = that->graph[edgeOrientation(firstEdge)].edgeData(v1, v2); + if (data) { + if (minSize) + *minSize = data->minSize; + if (prefSize) + *prefSize = data->prefSize; + if (maxSize) + *maxSize = data->maxSize; + } + return data; +} + +AnchorVertex *QGraphicsAnchorLayoutPrivate::addInternalVertex(QGraphicsLayoutItem *item, + Qt::AnchorPoint edge) +{ + QPair<QGraphicsLayoutItem *, Qt::AnchorPoint> pair(item, edge); + QPair<AnchorVertex *, int> v = m_vertexList.value(pair); + + if (!v.first) { + Q_ASSERT(v.second == 0); + v.first = new AnchorVertex(item, edge); + } + v.second++; + m_vertexList.insert(pair, v); + return v.first; +} + +/** + * \internal + * + * returns the AnchorVertex that was dereferenced, also when it was removed. + * returns 0 if it did not exist. + */ +void QGraphicsAnchorLayoutPrivate::removeInternalVertex(QGraphicsLayoutItem *item, + Qt::AnchorPoint edge) +{ + QPair<QGraphicsLayoutItem *, Qt::AnchorPoint> pair(item, edge); + QPair<AnchorVertex *, int> v = m_vertexList.value(pair); + + if (!v.first) { + qWarning("This item with this edge is not in the graph"); + return; + } + + v.second--; + if (v.second == 0) { + // Remove reference and delete vertex + m_vertexList.remove(pair); + delete v.first; + } else { + // Update reference count + m_vertexList.insert(pair, v); + + if ((v.second == 2) && + ((edge == Qt::AnchorHorizontalCenter) || + (edge == Qt::AnchorVerticalCenter))) { + removeCenterAnchors(item, edge, true); + } + } +} + +void QGraphicsAnchorLayoutPrivate::removeVertex(QGraphicsLayoutItem *item, Qt::AnchorPoint edge) +{ + if (AnchorVertex *v = internalVertex(item, edge)) { + Graph<AnchorVertex, AnchorData> &g = graph[edgeOrientation(edge)]; + const QList<AnchorVertex *> allVertices = graph[edgeOrientation(edge)].adjacentVertices(v); + AnchorVertex *v2; + foreach (v2, allVertices) { + g.removeEdge(v, v2); + removeInternalVertex(item, edge); + removeInternalVertex(v2->m_item, v2->m_edge); + } + } +} + +void QGraphicsAnchorLayoutPrivate::removeAnchors(QGraphicsLayoutItem *item) +{ + Q_ASSERT(!graphSimplified[Horizontal] && !graphSimplified[Vertical]); + + // remove the center anchor first!! + removeCenterAnchors(item, Qt::AnchorHorizontalCenter, false); + removeVertex(item, Qt::AnchorLeft); + removeVertex(item, Qt::AnchorRight); + + removeCenterAnchors(item, Qt::AnchorVerticalCenter, false); + removeVertex(item, Qt::AnchorTop); + removeVertex(item, Qt::AnchorBottom); +} + +/*! + \internal + + Use heuristics to determine the correct orientation of a given anchor. + + After API discussions, we decided we would like expressions like + anchor(A, Left, B, Right) to mean the same as anchor(B, Right, A, Left). + The problem with this is that anchors could become ambiguous, for + instance, what does the anchor A, B of size X mean? + + "pos(B) = pos(A) + X" or "pos(A) = pos(B) + X" ? + + To keep the API user friendly and at the same time, keep our algorithm + deterministic, we use an heuristic to determine a direction for each + added anchor and then keep it. The heuristic is based on the fact + that people usually avoid overlapping items, therefore: + + "A, RIGHT to B, LEFT" means that B is to the LEFT of A. + "B, LEFT to A, RIGHT" is corrected to the above anchor. + + Special correction is also applied when one of the items is the + layout. We handle Layout Left as if it was another items's Right + and Layout Right as another item's Left. +*/ +void QGraphicsAnchorLayoutPrivate::correctEdgeDirection(QGraphicsLayoutItem *&firstItem, + Qt::AnchorPoint &firstEdge, + QGraphicsLayoutItem *&secondItem, + Qt::AnchorPoint &secondEdge) +{ + Q_Q(QGraphicsAnchorLayout); + + Qt::AnchorPoint effectiveFirst = firstEdge; + Qt::AnchorPoint effectiveSecond = secondEdge; + + if (firstItem == q) + effectiveFirst = QGraphicsAnchorLayoutPrivate::oppositeEdge(firstEdge); + if (secondItem == q) + effectiveSecond = QGraphicsAnchorLayoutPrivate::oppositeEdge(secondEdge); + + if (effectiveFirst < effectiveSecond) { + + // ### DEBUG + /* printf("Swapping Anchor from %s %d --to--> %s %d\n", + firstItem->isLayout() ? "<layout>" : + qPrintable(static_cast<QGraphicsWidget *>(firstItem)->data(0).toString()), + firstEdge, + secondItem->isLayout() ? "<layout>" : + qPrintable(static_cast<QGraphicsWidget *>(secondItem)->data(0).toString()), + secondEdge); + */ + qSwap(firstItem, secondItem); + qSwap(firstEdge, secondEdge); + } +} + +qreal QGraphicsAnchorLayoutPrivate::effectiveSpacing(Orientation orientation) const +{ + Q_Q(const QGraphicsAnchorLayout); + qreal s = spacings[orientation]; + if (s < 0) { + // ### make sure behaviour is the same as in QGraphicsGridLayout + QGraphicsLayoutItem *parent = q->parentLayoutItem(); + while (parent && parent->isLayout()) { + parent = parent->parentLayoutItem(); + } + if (parent) { + QGraphicsItem *parentItem = parent->graphicsItem(); + if (parentItem && parentItem->isWidget()) { + QGraphicsWidget *w = static_cast<QGraphicsWidget*>(parentItem); + s = w->style()->pixelMetric(orientation == Horizontal + ? QStyle::PM_LayoutHorizontalSpacing + : QStyle::PM_LayoutVerticalSpacing); + } + } + } + return s; +} + +/*! + \internal + + Called on activation. Uses Linear Programming to define minimum, preferred + and maximum sizes for the layout. Also calculates the sizes that each item + should assume when the layout is in one of such situations. +*/ +void QGraphicsAnchorLayoutPrivate::calculateGraphs() +{ + if (!calculateGraphCacheDirty) + return; + + calculateGraphs(Horizontal); + calculateGraphs(Vertical); + + calculateGraphCacheDirty = 0; +} + +// ### remove me: +QList<AnchorData *> getVariables(QList<QSimplexConstraint *> constraints) +{ + QSet<AnchorData *> variableSet; + for (int i = 0; i < constraints.count(); ++i) { + const QSimplexConstraint *c = constraints[i]; + foreach (QSimplexVariable *var, c->variables.keys()) { + variableSet += static_cast<AnchorData *>(var); + } + } + return variableSet.toList(); +} + +/*! + \internal + + Calculate graphs is the method that puts together all the helper routines + so that the AnchorLayout can calculate the sizes of each item. + + In a nutshell it should do: + + 1) Update anchor nominal sizes, that is, the size that each anchor would + have if no other restrictions applied. This is done by quering the + layout style and the sizeHints of the items belonging to the layout. + + 2) Simplify the graph by grouping together parallel and sequential anchors + into "group anchors". These have equivalent minimum, preferred and maximum + sizeHints as the anchors they replace. + + 3) Check if we got to a trivial case. In some cases, the whole graph can be + simplified into a single anchor. If so, use this information. If not, + then call the Simplex solver to calculate the anchors sizes. + + 4) Once the root anchors had its sizes calculated, propagate that to the + anchors they represent. +*/ +void QGraphicsAnchorLayoutPrivate::calculateGraphs( + QGraphicsAnchorLayoutPrivate::Orientation orientation) +{ + Q_Q(QGraphicsAnchorLayout); + + // Simplify the graph + simplifyGraph(orientation); + + // Reset the nominal sizes of each anchor based on the current item sizes + setAnchorSizeHintsFromItems(orientation); + + // Traverse all graph edges and store the possible paths to each vertex + findPaths(orientation); + + // From the paths calculated above, extract the constraints that the current + // anchor setup impose, to our Linear Programming problem. + constraintsFromPaths(orientation); + + // Split the constraints and anchors into groups that should be fed to the + // simplex solver independently. Currently we find two groups: + // + // 1) The "trunk", that is, the set of anchors (items) that are connected + // to the two opposite sides of our layout, and thus need to stretch in + // order to fit in the current layout size. + // + // 2) The floating or semi-floating anchors (items) that are those which + // are connected to only one (or none) of the layout sides, thus are not + // influenced by the layout size. + QList<QList<QSimplexConstraint *> > parts; + parts = getGraphParts(orientation); + + // Now run the simplex solver to calculate Minimum, Preferred and Maximum sizes + // of the "trunk" set of constraints and variables. + // ### does trunk always exist? empty = trunk is the layout left->center->right + QList<QSimplexConstraint *> trunkConstraints = parts[0]; + QList<QSimplexConstraint *> sizeHintConstraints; + sizeHintConstraints = constraintsFromSizeHints(getVariables(trunkConstraints)); + trunkConstraints += sizeHintConstraints; + + // For minimum and maximum, use the path between the two layout sides as the + // objective function. + + // Retrieve that path + AnchorVertex *v = internalVertex(q, pickEdge(Qt::AnchorRight, orientation)); + GraphPath trunkPath = graphPaths[orientation].value(v); + + if (!trunkConstraints.isEmpty()) { +#if 0 + qDebug("Simplex used for trunk of %s", + orientation == Horizontal ? "Horizontal" : "Vertical"); +#endif + + // Solve min and max size hints for trunk + QPair<qreal, qreal> minMax = solveMinMax(trunkConstraints, trunkPath); + sizeHints[orientation][Qt::MinimumSize] = minMax.first; + sizeHints[orientation][Qt::MaximumSize] = minMax.second; + + // Solve for preferred. The objective function is calculated from the constraints + // and variables internally. + solvePreferred(trunkConstraints); + + // Propagate the new sizes down the simplified graph, ie. tell the + // group anchors to set their children anchors sizes. + + // ### we calculated variables already a few times, can't we reuse that? + QList<AnchorData *> trunkVariables = getVariables(trunkConstraints); + + for (int i = 0; i < trunkVariables.count(); ++i) + trunkVariables.at(i)->updateChildrenSizes(); + + // Calculate and set the preferred size for the layout from the edge sizes that + // were calculated above. + qreal pref(0.0); + foreach (const AnchorData *ad, trunkPath.positives) { + pref += ad->sizeAtPreferred; + } + foreach (const AnchorData *ad, trunkPath.negatives) { + pref -= ad->sizeAtPreferred; + } + sizeHints[orientation][Qt::PreferredSize] = pref; + } else { +#if 0 + qDebug("Simplex NOT used for trunk of %s", + orientation == Horizontal ? "Horizontal" : "Vertical"); +#endif + + // No Simplex is necessary because the path was simplified all the way to a single + // anchor. + Q_ASSERT(trunkPath.positives.count() == 1); + Q_ASSERT(trunkPath.negatives.count() == 0); + + AnchorData *ad = trunkPath.positives.toList()[0]; + ad->sizeAtMinimum = ad->minSize; + ad->sizeAtPreferred = ad->prefSize; + ad->sizeAtMaximum = ad->maxSize; + + // Propagate + ad->updateChildrenSizes(); + + sizeHints[orientation][Qt::MinimumSize] = ad->sizeAtMinimum; + sizeHints[orientation][Qt::PreferredSize] = ad->sizeAtPreferred; + sizeHints[orientation][Qt::MaximumSize] = ad->sizeAtMaximum; + } + + // Delete the constraints, we won't use them anymore. + qDeleteAll(sizeHintConstraints); + sizeHintConstraints.clear(); + + // For the other parts that not the trunk, solve only for the preferred size + // that is the size they will remain at, since they are not stretched by the + // layout. + + // Solve the other only for preferred, skip trunk + for (int i = 1; i < parts.count(); ++i) { + QList<QSimplexConstraint *> partConstraints = parts[i]; + QList<AnchorData *> partVariables = getVariables(partConstraints); + Q_ASSERT(!partVariables.isEmpty()); + + sizeHintConstraints = constraintsFromSizeHints(partVariables); + partConstraints += sizeHintConstraints; + solvePreferred(partConstraints); + + // Propagate size at preferred to other sizes. Semi-floats + // always will be in their sizeAtPreferred. + for (int j = 0; j < partVariables.count(); ++j) { + AnchorData *ad = partVariables[j]; + Q_ASSERT(ad); + ad->sizeAtMinimum = ad->sizeAtPreferred; + ad->sizeAtMaximum = ad->sizeAtPreferred; + ad->updateChildrenSizes(); + } + + // Delete the constraints, we won't use them anymore. + qDeleteAll(sizeHintConstraints); + sizeHintConstraints.clear(); + } + + // Clean up our data structures. They are not needed anymore since + // distribution uses just interpolation. + qDeleteAll(constraints[orientation]); + constraints[orientation].clear(); + graphPaths[orientation].clear(); // ### +} + +/*! + \internal + + For graph edges ("anchors") that represent items, this method updates their + intrinsic size restrictions, based on the item size hints. +*/ +void QGraphicsAnchorLayoutPrivate::setAnchorSizeHintsFromItems(Orientation orientation) +{ + Graph<AnchorVertex, AnchorData> &g = graph[orientation]; + QList<QPair<AnchorVertex *, AnchorVertex *> > vertices = g.connections(); + + qreal spacing = effectiveSpacing(orientation); + + for (int i = 0; i < vertices.count(); ++i) { + AnchorData *data = g.edgeData(vertices.at(i).first, vertices.at(i).second);; + Q_ASSERT(data->from && data->to); + data->refreshSizeHints(spacing); + } +} + +/*! + \internal + + This method walks the graph using a breadth-first search to find paths + between the root vertex and each vertex on the graph. The edges + directions in each path are considered and they are stored as a + positive edge (left-to-right) or negative edge (right-to-left). + + The list of paths is used later to generate a list of constraints. + */ +void QGraphicsAnchorLayoutPrivate::findPaths(Orientation orientation) +{ + QQueue<QPair<AnchorVertex *, AnchorVertex *> > queue; + + QSet<AnchorData *> visited; + + AnchorVertex *root = graph[orientation].rootVertex(); + + graphPaths[orientation].insert(root, GraphPath()); + + foreach (AnchorVertex *v, graph[orientation].adjacentVertices(root)) { + queue.enqueue(qMakePair(root, v)); + } + + while(!queue.isEmpty()) { + QPair<AnchorVertex *, AnchorVertex *> pair = queue.dequeue(); + AnchorData *edge = graph[orientation].edgeData(pair.first, pair.second); + + if (visited.contains(edge)) + continue; + + visited.insert(edge); + GraphPath current = graphPaths[orientation].value(pair.first); + + if (edge->from == pair.first) + current.positives.insert(edge); + else + current.negatives.insert(edge); + + graphPaths[orientation].insert(pair.second, current); + + foreach (AnchorVertex *v, + graph[orientation].adjacentVertices(pair.second)) { + queue.enqueue(qMakePair(pair.second, v)); + } + } +} + +/*! + \internal + + Each vertex on the graph that has more than one path to it + represents a contra int to the sizes of the items in these paths. + + This method walks the list of paths to each vertex, generate + the constraints and store them in a list so they can be used later + by the Simplex solver. +*/ +void QGraphicsAnchorLayoutPrivate::constraintsFromPaths(Orientation orientation) +{ + foreach (AnchorVertex *vertex, graphPaths[orientation].uniqueKeys()) + { + int valueCount = graphPaths[orientation].count(vertex); + if (valueCount == 1) + continue; + + QList<GraphPath> pathsToVertex = graphPaths[orientation].values(vertex); + for (int i = 1; i < valueCount; ++i) { + constraints[orientation] += \ + pathsToVertex[0].constraint(pathsToVertex[i]); + } + } +} + +/*! + \internal + + Create LP constraints for each anchor based on its minimum and maximum + sizes, as specified in its size hints +*/ +QList<QSimplexConstraint *> QGraphicsAnchorLayoutPrivate::constraintsFromSizeHints( + const QList<AnchorData *> &anchors) +{ + QList<QSimplexConstraint *> anchorConstraints; + for (int i = 0; i < anchors.size(); ++i) { + QSimplexConstraint *c = new QSimplexConstraint; + c->variables.insert(anchors[i], 1.0); + c->constant = anchors[i]->minSize; + c->ratio = QSimplexConstraint::MoreOrEqual; + anchorConstraints += c; + + c = new QSimplexConstraint; + c->variables.insert(anchors[i], 1.0); + c->constant = anchors[i]->maxSize; + c->ratio = QSimplexConstraint::LessOrEqual; + anchorConstraints += c; + } + + return anchorConstraints; +} + +/*! + \internal +*/ +QList< QList<QSimplexConstraint *> > +QGraphicsAnchorLayoutPrivate::getGraphParts(Orientation orientation) +{ + Q_Q(QGraphicsAnchorLayout); + + // Find layout vertices and edges for the current orientation. + AnchorVertex *layoutFirstVertex = \ + internalVertex(q, pickEdge(Qt::AnchorLeft, orientation)); + + AnchorVertex *layoutCentralVertex = \ + internalVertex(q, pickEdge(Qt::AnchorHorizontalCenter, orientation)); + + AnchorVertex *layoutLastVertex = \ + internalVertex(q, pickEdge(Qt::AnchorRight, orientation)); + + Q_ASSERT(layoutFirstVertex && layoutLastVertex); + + AnchorData *edgeL1 = NULL; + AnchorData *edgeL2 = NULL; + + // The layout may have a single anchor between Left and Right or two half anchors + // passing through the center + if (layoutCentralVertex) { + edgeL1 = graph[orientation].edgeData(layoutFirstVertex, layoutCentralVertex); + edgeL2 = graph[orientation].edgeData(layoutCentralVertex, layoutLastVertex); + } else { + edgeL1 = graph[orientation].edgeData(layoutFirstVertex, layoutLastVertex); + } + + QLinkedList<QSimplexConstraint *> remainingConstraints; + for (int i = 0; i < constraints[orientation].count(); ++i) { + remainingConstraints += constraints[orientation][i]; + } + for (int i = 0; i < itemCenterConstraints[orientation].count(); ++i) { + remainingConstraints += itemCenterConstraints[orientation][i]; + } + + QList<QSimplexConstraint *> trunkConstraints; + QSet<QSimplexVariable *> trunkVariables; + + trunkVariables += edgeL1; + if (edgeL2) + trunkVariables += edgeL2; + + bool dirty; + do { + dirty = false; + + QLinkedList<QSimplexConstraint *>::iterator it = remainingConstraints.begin(); + while (it != remainingConstraints.end()) { + QSimplexConstraint *c = *it; + bool match = false; + + // Check if this constraint have some overlap with current + // trunk variables... + foreach (QSimplexVariable *ad, trunkVariables) { + if (c->variables.contains(ad)) { + match = true; + break; + } + } + + // If so, we add it to trunk, and erase it from the + // remaining constraints. + if (match) { + trunkConstraints += c; + trunkVariables += QSet<QSimplexVariable *>::fromList(c->variables.keys()); + it = remainingConstraints.erase(it); + dirty = true; + } else { + // Note that we don't erase the constraint if it's not + // a match, since in a next iteration of a do-while we + // can pass on it again and it will be a match. + // + // For example: if trunk share a variable with + // remainingConstraints[1] and it shares with + // remainingConstraints[0], we need a second iteration + // of the do-while loop to match both. + ++it; + } + } + } while (dirty); + + QList< QList<QSimplexConstraint *> > result; + result += trunkConstraints; + + if (!remainingConstraints.isEmpty()) { + QList<QSimplexConstraint *> nonTrunkConstraints; + QLinkedList<QSimplexConstraint *>::iterator it = remainingConstraints.begin(); + while (it != remainingConstraints.end()) { + nonTrunkConstraints += *it; + ++it; + } + result += nonTrunkConstraints; + } + + return result; +} + +/*! + \internal + + Use the current vertices distance to calculate and set the geometry of + each item. +*/ +void QGraphicsAnchorLayoutPrivate::setItemsGeometries() +{ + AnchorVertex *firstH, *secondH, *firstV, *secondV; + + foreach (QGraphicsLayoutItem *item, items) { + firstH = internalVertex(item, Qt::AnchorLeft); + secondH = internalVertex(item, Qt::AnchorRight); + firstV = internalVertex(item, Qt::AnchorTop); + secondV = internalVertex(item, Qt::AnchorBottom); + + QPointF topLeft(firstH->distance, firstV->distance); + QPointF bottomRight(secondH->distance, secondV->distance); + + item->setGeometry(QRectF(topLeft, bottomRight)); + } +} + +/*! + \internal + + Calculate the position of each vertex based on the paths to each of + them as well as the current edges sizes. +*/ +void QGraphicsAnchorLayoutPrivate::calculateVertexPositions( + QGraphicsAnchorLayoutPrivate::Orientation orientation) +{ + Q_Q(QGraphicsAnchorLayout); + QQueue<QPair<AnchorVertex *, AnchorVertex *> > queue; + QSet<AnchorVertex *> visited; + + // Get root vertex + AnchorVertex *root = graph[orientation].rootVertex(); + + qreal widgetMargin; + qreal layoutMargin; + + // Initialize the first vertex + if (orientation == Horizontal) { + widgetMargin = q->geometry().x(); + q->getContentsMargins(&layoutMargin, 0, 0, 0); + } else { + // Root position is equal to the top margin + widgetMargin = q->geometry().y(); + q->getContentsMargins(0, &layoutMargin, 0, 0); + } + root->distance = widgetMargin + layoutMargin; + visited.insert(root); + + // Add initial edges to the queue + foreach (AnchorVertex *v, graph[orientation].adjacentVertices(root)) { + queue.enqueue(qMakePair(root, v)); + } + + // Do initial calculation required by "interpolateEdge()" + setupEdgesInterpolation(orientation); + + // Traverse the graph and calculate vertex positions, we need to + // visit all pairs since each of them could have a sequential + // anchor inside, which hides more vertices. + while (!queue.isEmpty()) { + QPair<AnchorVertex *, AnchorVertex *> pair = queue.dequeue(); + AnchorData *edge = graph[orientation].edgeData(pair.first, pair.second); + + // Both vertices were interpolated, and the anchor itself can't have other + // anchors inside (it's not a complex anchor). + if (edge->type == AnchorData::Normal && visited.contains(pair.second)) + continue; + + visited.insert(pair.second); + interpolateEdge(pair.first, edge, orientation); + + QList<AnchorVertex *> adjacents = graph[orientation].adjacentVertices(pair.second); + for (int i = 0; i < adjacents.count(); ++i) { + if (!visited.contains(adjacents.at(i))) + queue.enqueue(qMakePair(pair.second, adjacents.at(i))); + } + } +} + +/*! + \internal + + Calculate interpolation parameters based on current Layout Size. + Must once before calling "interpolateEdgeSize()" for each edge. +*/ +void QGraphicsAnchorLayoutPrivate::setupEdgesInterpolation( + Orientation orientation) +{ + Q_Q(QGraphicsAnchorLayout); + qreal lower, upper, current; + + if (orientation == Horizontal) { + current = q->contentsRect().width(); + } else { + current = q->contentsRect().height(); + } + + if (current < sizeHints[orientation][Qt::PreferredSize]) { + interpolationInterval[orientation] = MinToPreferred; + lower = sizeHints[orientation][Qt::MinimumSize]; + upper = sizeHints[orientation][Qt::PreferredSize]; + } else { + interpolationInterval[orientation] = PreferredToMax; + lower = sizeHints[orientation][Qt::PreferredSize]; + upper = sizeHints[orientation][Qt::MaximumSize]; + } + + if (upper == lower) { + interpolationProgress[orientation] = 0; + } else { + interpolationProgress[orientation] = (current - lower) / (upper - lower); + } +} + +/*! + \internal + + Calculate the current Edge size based on the current Layout size and the + size the edge is supposed to have when: + + - the layout is at its minimum size. + - the layout is at its preferred size. + - the layout is at its maximum size. + + These three key values are calculated in advance using linear + programming (more expensive) or the simplification algorithm, then + subsequential resizes of the parent layout require a simple + interpolation. + + If the edge is sequential or parallel, it's possible to have more + vertices to be initalized, so it calls specialized functions that + will recurse back to interpolateEdge(). + */ +void QGraphicsAnchorLayoutPrivate::interpolateEdge(AnchorVertex *base, + AnchorData *edge, + Orientation orientation) +{ + qreal lower, upper; + + if (interpolationInterval[orientation] == MinToPreferred) { + lower = edge->sizeAtMinimum; + upper = edge->sizeAtPreferred; + } else { + lower = edge->sizeAtPreferred; + upper = edge->sizeAtMaximum; + } + + qreal edgeDistance = (interpolationProgress[orientation] * (upper - lower)) + lower; + + Q_ASSERT(edge->from == base || edge->to == base); + + if (edge->from == base) + edge->to->distance = base->distance + edgeDistance; + else + edge->from->distance = base->distance - edgeDistance; + + // Process child anchors + if (edge->type == AnchorData::Sequential) + interpolateSequentialEdges(edge->from, + static_cast<SequentialAnchorData *>(edge), + orientation); + else if (edge->type == AnchorData::Parallel) + interpolateParallelEdges(edge->from, + static_cast<ParallelAnchorData *>(edge), + orientation); +} + +void QGraphicsAnchorLayoutPrivate::interpolateParallelEdges( + AnchorVertex *base, ParallelAnchorData *data, Orientation orientation) +{ + // In parallels the boundary vertices are already calculate, we + // just need to look for sequential groups inside, because only + // them may have new vertices associated. + + // First edge + if (data->firstEdge->type == AnchorData::Sequential) + interpolateSequentialEdges(base, + static_cast<SequentialAnchorData *>(data->firstEdge), + orientation); + else if (data->firstEdge->type == AnchorData::Parallel) + interpolateParallelEdges(base, + static_cast<ParallelAnchorData *>(data->firstEdge), + orientation); + + // Second edge + if (data->secondEdge->type == AnchorData::Sequential) + interpolateSequentialEdges(base, + static_cast<SequentialAnchorData *>(data->secondEdge), + orientation); + else if (data->secondEdge->type == AnchorData::Parallel) + interpolateParallelEdges(base, + static_cast<ParallelAnchorData *>(data->secondEdge), + orientation); +} + +void QGraphicsAnchorLayoutPrivate::interpolateSequentialEdges( + AnchorVertex *base, SequentialAnchorData *data, Orientation orientation) +{ + AnchorVertex *prev = base; + + // ### I'm not sure whether this assumption is safe. If not, + // consider that m_edges.last() could be used instead (so + // at(0) would be the one to be treated specially). + Q_ASSERT(base == data->m_edges.at(0)->to || base == data->m_edges.at(0)->from); + + // Skip the last + for (int i = 0; i < data->m_edges.count() - 1; ++i) { + AnchorData *child = data->m_edges.at(i); + interpolateEdge(prev, child, orientation); + prev = child->to; + } + + // Treat the last specially, since we already calculated it's end + // vertex, so it's only interesting if it's a complex one + if (data->m_edges.last()->type != AnchorData::Normal) + interpolateEdge(prev, data->m_edges.last(), orientation); +} + +QPair<qreal, qreal> +QGraphicsAnchorLayoutPrivate::solveMinMax(QList<QSimplexConstraint *> constraints, + GraphPath path) +{ + QSimplex simplex; + simplex.setConstraints(constraints); + + // Obtain the objective constraint + QSimplexConstraint objective; + QSet<AnchorData *>::const_iterator iter; + for (iter = path.positives.constBegin(); iter != path.positives.constEnd(); ++iter) + objective.variables.insert(*iter, 1.0); + + for (iter = path.negatives.constBegin(); iter != path.negatives.constEnd(); ++iter) + objective.variables.insert(*iter, -1.0); + + simplex.setObjective(&objective); + + // Calculate minimum values + qreal min = simplex.solveMin(); + + // Save sizeAtMinimum results + QList<QSimplexVariable *> variables = simplex.constraintsVariables(); + for (int i = 0; i < variables.size(); ++i) { + AnchorData *ad = static_cast<AnchorData *>(variables[i]); + ad->sizeAtMinimum = ad->result; + } + + // Calculate maximum values + qreal max = simplex.solveMax(); + + // Save sizeAtMaximum results + for (int i = 0; i < variables.size(); ++i) { + AnchorData *ad = static_cast<AnchorData *>(variables[i]); + ad->sizeAtMaximum = ad->result; + } + + return qMakePair<qreal, qreal>(min, max); +} + +void QGraphicsAnchorLayoutPrivate::solvePreferred(QList<QSimplexConstraint *> constraints) +{ + QList<AnchorData *> variables = getVariables(constraints); + QList<QSimplexConstraint *> preferredConstraints; + QList<QSimplexVariable *> preferredVariables; + QSimplexConstraint objective; + + // Fill the objective coefficients for this variable. In the + // end the objective function will be + // + // z = n * (A_shrink + B_shrink + ...) + (A_grower + B_grower + ...) + // + // where n is the number of variables that have + // slacks. Note that here we use the number of variables + // as coefficient, this is to mark the "shrinker slack + // variable" less likely to get value than the "grower + // slack variable". + + // This will fill the values for the structural constraints + // and we now fill the values for the slack constraints (one per variable), + // which have this form (the constant A_pref was set when creating the slacks): + // + // A + A_shrinker - A_grower = A_pref + // + for (int i = 0; i < variables.size(); ++i) { + AnchorData *ad = static_cast<AnchorData *>(variables[i]); + if (ad->skipInPreferred) + continue; + + QSimplexVariable *grower = new QSimplexVariable; + QSimplexVariable *shrinker = new QSimplexVariable; + QSimplexConstraint *c = new QSimplexConstraint; + c->variables.insert(ad, 1.0); + c->variables.insert(shrinker, 1.0); + c->variables.insert(grower, -1.0); + c->constant = ad->prefSize; + + preferredConstraints += c; + preferredVariables += grower; + preferredVariables += shrinker; + + objective.variables.insert(grower, 1.0); + objective.variables.insert(shrinker, variables.size()); + } + + + QSimplex *simplex = new QSimplex; + simplex->setConstraints(constraints + preferredConstraints); + simplex->setObjective(&objective); + + // Calculate minimum values + simplex->solveMin(); + + // Save sizeAtPreferred results + for (int i = 0; i < variables.size(); ++i) { + AnchorData *ad = static_cast<AnchorData *>(variables[i]); + ad->sizeAtPreferred = ad->result; + } + + // Make sure we delete the simplex solver -before- we delete the + // constraints used by it. + delete simplex; + + // Delete constraints and variables we created. + qDeleteAll(preferredConstraints); + qDeleteAll(preferredVariables); +} + +#ifdef QT_DEBUG +void QGraphicsAnchorLayoutPrivate::dumpGraph() +{ + QFile file(QString::fromAscii("anchorlayout.dot")); + if (!file.open(QIODevice::WriteOnly | QIODevice::Text | QIODevice::Truncate)) + qWarning("Could not write to %s", file.fileName().toLocal8Bit().constData()); + + QString str = QString::fromAscii("digraph anchorlayout {\nnode [shape=\"rect\"]\n%1}"); + QString dotContents = graph[0].serializeToDot(); + dotContents += graph[1].serializeToDot(); + file.write(str.arg(dotContents).toLocal8Bit()); + + file.close(); +} +#endif + +QT_END_NAMESPACE |