Initial import from the monolithic Qt.

This is the beginning of revision history for this module. If you want to look at revision history older than this, please refer to the Qt Git wiki for how to use Git history grafting. At the time of writing, this wiki is located here: http://qt.gitorious.org/qt/pages/GitIntroductionWithQt If you have already performed the grafting and you don't see any history beyond this commit, try running "git log" with the "--follow" argument. Branched from the monolithic repo, Qt master branch, at commit 896db169ea224deb96c59ce8af800d019de63f12
author: Qt by Nokia <qt-info@nokia.com> 2011-04-27 12:05:43 +0200
committer: axis <qt-info@nokia.com> 2011-04-27 12:05:43 +0200
commit: 38be0d13830efd2d98281c645c3a60afe05ffece (patch)
tree: 6ea73f3ec77f7d153333779883e8120f82820abe /src/gui/kernel/qlayoutengine.cpp
1 files changed, 436 insertions, 0 deletions
diff --git a/src/gui/kernel/qlayoutengine.cpp b/src/gui/kernel/qlayoutengine.cpp
new file mode 100644
index 00000000000..fdabd8ae1fa
--- /dev/null
+++ b/src/gui/kernel/qlayoutengine.cpp
@@ -0,0 +1,436 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** 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.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qlayout.h"
+#include "private/qlayoutengine_p.h"
+
+#include "qvector.h"
+#include "qwidget.h"
+
+#include <qlist.h>
+#include <qalgorithms.h>
+
+#include <qdebug.h>
+
+QT_BEGIN_NAMESPACE
+
+//#define QLAYOUT_EXTRA_DEBUG
+
+typedef qint64 Fixed64;
+static inline Fixed64 toFixed(int i) { return (Fixed64)i * 256; }
+static inline int fRound(Fixed64 i) {
+    return (i % 256 < 128) ? i / 256 : 1 + i / 256;
+}
+
+/*
+  This is the main workhorse of the QGridLayout. It portions out
+  available space to the chain's children.
+
+  The calculation is done in fixed point: "fixed" variables are
+  scaled by a factor of 256.
+
+  If the layout runs "backwards" (i.e. RightToLeft or Up) the layout
+  is computed mirror-reversed, and it's the caller's responsibility
+  do reverse the values before use.
+
+  chain contains input and output parameters describing the geometry.
+  count is the count of items in the chain; pos and space give the
+  interval (relative to parentWidget topLeft).
+*/
+void qGeomCalc(QVector<QLayoutStruct> &chain, int start, int count,
+               int pos, int space, int spacer)
+{
+    int cHint = 0;
+    int cMin = 0;
+    int cMax = 0;
+    int sumStretch = 0;
+    int sumSpacing = 0;
+
+    bool wannaGrow = false; // anyone who really wants to grow?
+    //    bool canShrink = false; // anyone who could be persuaded to shrink?
+
+    bool allEmptyNonstretch = true;
+    int pendingSpacing = -1;
+    int spacerCount = 0;
+    int i;
+
+    for (i = start; i < start + count; i++) {
+        QLayoutStruct *data = &chain[i];
+
+        data->done = false;
+        cHint += data->smartSizeHint();
+        cMin += data->minimumSize;
+        cMax += data->maximumSize;
+        sumStretch += data->stretch;
+        if (!data->empty) {
+            /*
+                Using pendingSpacing, we ensure that the spacing for the last
+                (non-empty) item is ignored.
+            */
+            if (pendingSpacing >= 0) {
+                sumSpacing += pendingSpacing;
+                ++spacerCount;
+            }
+            pendingSpacing = data->effectiveSpacer(spacer);
+        }
+        wannaGrow = wannaGrow || data->expansive || data->stretch > 0;
+        allEmptyNonstretch = allEmptyNonstretch && !wannaGrow && data->empty;
+    }
+
+    int extraspace = 0;
+
+    if (space < cMin + sumSpacing) {
+        /*
+          Less space than minimumSize; take from the biggest first
+        */
+
+        int minSize = cMin + sumSpacing;
+
+        // shrink the spacers proportionally
+        if (spacer >= 0) {
+            spacer = minSize > 0 ? spacer * space / minSize : 0;
+            sumSpacing = spacer * spacerCount;
+        }
+
+        QList<int> list;
+
+        for (i = start; i < start + count; i++)
+            list << chain.at(i).minimumSize;
+
+        qSort(list);
+
+        int space_left = space - sumSpacing;
+
+        int sum = 0;
+        int idx = 0;
+        int space_used=0;
+        int current = 0;
+        while (idx < count && space_used < space_left) {
+            current = list.at(idx);
+            space_used = sum + current * (count - idx);
+            sum += current;
+            ++idx;
+        }
+        --idx;
+        int deficit = space_used - space_left;
+
+        int items = count - idx;
+        /*
+         * If we truncate all items to "current", we would get "deficit" too many pixels. Therefore, we have to remove
+         * deficit/items from each item bigger than maxval. The actual value to remove is deficitPerItem + remainder/items
+         * "rest" is the accumulated error from using integer arithmetic.
+        */
+        int deficitPerItem = deficit/items;
+        int remainder = deficit % items;
+        int maxval = current - deficitPerItem;
+
+        int rest = 0;
+        for (i = start; i < start + count; i++) {
+            int maxv = maxval;
+            rest += remainder;
+            if (rest >= items) {
+                maxv--;
+                rest-=items;
+            }
+            QLayoutStruct *data = &chain[i];
+            data->size = qMin(data->minimumSize, maxv);
+            data->done = true;
+        }
+    } else if (space < cHint + sumSpacing) {
+        /*
+          Less space than smartSizeHint(), but more than minimumSize.
+          Currently take space equally from each, as in Qt 2.x.
+          Commented-out lines will give more space to stretchier
+          items.
+        */
+        int n = count;
+        int space_left = space - sumSpacing;
+        int overdraft = cHint - space_left;
+
+        // first give to the fixed ones:
+        for (i = start; i < start + count; i++) {
+            QLayoutStruct *data = &chain[i];
+            if (!data->done
+                 && data->minimumSize >= data->smartSizeHint()) {
+                data->size = data->smartSizeHint();
+                data->done = true;
+                space_left -= data->smartSizeHint();
+                // sumStretch -= data->stretch;
+                n--;
+            }
+        }
+        bool finished = n == 0;
+        while (!finished) {
+            finished = true;
+            Fixed64 fp_over = toFixed(overdraft);
+            Fixed64 fp_w = 0;
+
+            for (i = start; i < start+count; i++) {
+                QLayoutStruct *data = &chain[i];
+                if (data->done)
+                    continue;
+                // if (sumStretch <= 0)
+                fp_w += fp_over / n;
+                // else
+                //    fp_w += (fp_over * data->stretch) / sumStretch;
+                int w = fRound(fp_w);
+                data->size = data->smartSizeHint() - w;
+                fp_w -= toFixed(w); // give the difference to the next
+                if (data->size < data->minimumSize) {
+                    data->done = true;
+                    data->size = data->minimumSize;
+                    finished = false;
+                    overdraft -= data->smartSizeHint() - data->minimumSize;
+                    // sumStretch -= data->stretch;
+                    n--;
+                    break;
+                }
+            }
+        }
+    } else { // extra space
+        int n = count;
+        int space_left = space - sumSpacing;
+        // first give to the fixed ones, and handle non-expansiveness
+        for (i = start; i < start + count; i++) {
+            QLayoutStruct *data = &chain[i];
+            if (!data->done
+                && (data->maximumSize <= data->smartSizeHint()
+                    || (wannaGrow && !data->expansive && data->stretch == 0)
+                    || (!allEmptyNonstretch && data->empty &&
+                        !data->expansive && data->stretch == 0))) {
+                data->size = data->smartSizeHint();
+                data->done = true;
+                space_left -= data->size;
+                sumStretch -= data->stretch;
+                n--;
+            }
+        }
+        extraspace = space_left;
+
+        /*
+          Do a trial distribution and calculate how much it is off.
+          If there are more deficit pixels than surplus pixels, give
+          the minimum size items what they need, and repeat.
+          Otherwise give to the maximum size items, and repeat.
+
+          Paul Olav Tvete has a wonderful mathematical proof of the
+          correctness of this principle, but unfortunately this
+          comment is too small to contain it.
+        */
+        int surplus, deficit;
+        do {
+            surplus = deficit = 0;
+            Fixed64 fp_space = toFixed(space_left);
+            Fixed64 fp_w = 0;
+            for (i = start; i < start + count; i++) {
+                QLayoutStruct *data = &chain[i];
+                if (data->done)
+                    continue;
+                extraspace = 0;
+                if (sumStretch <= 0)
+                    fp_w += fp_space / n;
+                else
+                    fp_w += (fp_space * data->stretch) / sumStretch;
+                int w = fRound(fp_w);
+                data->size = w;
+                fp_w -= toFixed(w); // give the difference to the next
+                if (w < data->smartSizeHint()) {
+                    deficit +=  data->smartSizeHint() - w;
+                } else if (w > data->maximumSize) {
+                    surplus += w - data->maximumSize;
+                }
+            }
+            if (deficit > 0 && surplus <= deficit) {
+                // give to the ones that have too little
+                for (i = start; i < start+count; i++) {
+                    QLayoutStruct *data = &chain[i];
+                    if (!data->done && data->size < data->smartSizeHint()) {
+                        data->size = data->smartSizeHint();
+                        data->done = true;
+                        space_left -= data->smartSizeHint();
+                        sumStretch -= data->stretch;
+                        n--;
+                    }
+                }
+            }
+            if (surplus > 0 && surplus >= deficit) {
+                // take from the ones that have too much
+                for (i = start; i < start + count; i++) {
+                    QLayoutStruct *data = &chain[i];
+                    if (!data->done && data->size > data->maximumSize) {
+                        data->size = data->maximumSize;
+                        data->done = true;
+                        space_left -= data->maximumSize;
+                        sumStretch -= data->stretch;
+                        n--;
+                    }
+                }
+            }
+        } while (n > 0 && surplus != deficit);
+        if (n == 0)
+            extraspace = space_left;
+    }
+
+    /*
+      As a last resort, we distribute the unwanted space equally
+      among the spacers (counting the start and end of the chain). We
+      could, but don't, attempt a sub-pixel allocation of the extra
+      space.
+    */
+    int extra = extraspace / (spacerCount + 2);
+    int p = pos + extra;
+    for (i = start; i < start+count; i++) {
+        QLayoutStruct *data = &chain[i];
+        data->pos = p;
+        p += data->size;
+        if (!data->empty)
+            p += data->effectiveSpacer(spacer) + extra;
+    }
+
+#ifdef QLAYOUT_EXTRA_DEBUG
+    qDebug() << "qGeomCalc" << "start" << start <<  "count" << count <<  "pos" << pos
+             <<  "space" << space <<  "spacer" << spacer;
+    for (i = start; i < start + count; ++i) {
+        qDebug() << i << ':' << chain[i].minimumSize << chain[i].smartSizeHint()
+                 << chain[i].maximumSize << "stretch" << chain[i].stretch
+                 << "empty" << chain[i].empty << "expansive" << chain[i].expansive
+                 << "spacing" << chain[i].spacing;
+        qDebug() << "result pos" << chain[i].pos << "size" << chain[i].size;
+    }
+#endif
+}
+
+Q_GUI_EXPORT QSize qSmartMinSize(const QSize &sizeHint, const QSize &minSizeHint,
+                                 const QSize &minSize, const QSize &maxSize,
+                                 const QSizePolicy &sizePolicy)
+{
+    QSize s(0, 0);
+
+    if (sizePolicy.horizontalPolicy() != QSizePolicy::Ignored) {
+        if (sizePolicy.horizontalPolicy() & QSizePolicy::ShrinkFlag)
+            s.setWidth(minSizeHint.width());
+        else
+            s.setWidth(qMax(sizeHint.width(), minSizeHint.width()));
+    }
+
+    if (sizePolicy.verticalPolicy() != QSizePolicy::Ignored) {
+        if (sizePolicy.verticalPolicy() & QSizePolicy::ShrinkFlag) {
+            s.setHeight(minSizeHint.height());
+        } else {
+            s.setHeight(qMax(sizeHint.height(), minSizeHint.height()));
+        }
+    }
+
+    s = s.boundedTo(maxSize);
+    if (minSize.width() > 0)
+        s.setWidth(minSize.width());
+    if (minSize.height() > 0)
+        s.setHeight(minSize.height());
+
+    return s.expandedTo(QSize(0,0));
+}
+
+Q_GUI_EXPORT QSize qSmartMinSize(const QWidgetItem *i)
+{
+    QWidget *w = ((QWidgetItem *)i)->widget();
+    return qSmartMinSize(w->sizeHint(), w->minimumSizeHint(),
+                            w->minimumSize(), w->maximumSize(),
+                            w->sizePolicy());
+}
+
+Q_GUI_EXPORT QSize qSmartMinSize(const QWidget *w)
+{
+    return qSmartMinSize(w->sizeHint(), w->minimumSizeHint(),
+                            w->minimumSize(), w->maximumSize(),
+                            w->sizePolicy());
+}
+
+Q_GUI_EXPORT QSize qSmartMaxSize(const QSize &sizeHint,
+                                 const QSize &minSize, const QSize &maxSize,
+                                 const QSizePolicy &sizePolicy, Qt::Alignment align)
+{
+    if (align & Qt::AlignHorizontal_Mask && align & Qt::AlignVertical_Mask)
+        return QSize(QLAYOUTSIZE_MAX, QLAYOUTSIZE_MAX);
+    QSize s = maxSize;
+    QSize hint = sizeHint.expandedTo(minSize);
+    if (s.width() == QWIDGETSIZE_MAX && !(align & Qt::AlignHorizontal_Mask))
+        if (!(sizePolicy.horizontalPolicy() & QSizePolicy::GrowFlag))
+            s.setWidth(hint.width());
+
+    if (s.height() == QWIDGETSIZE_MAX && !(align & Qt::AlignVertical_Mask))
+        if (!(sizePolicy.verticalPolicy() & QSizePolicy::GrowFlag))
+            s.setHeight(hint.height());
+
+    if (align & Qt::AlignHorizontal_Mask)
+        s.setWidth(QLAYOUTSIZE_MAX);
+    if (align & Qt::AlignVertical_Mask)
+        s.setHeight(QLAYOUTSIZE_MAX);
+    return s;
+}
+
+Q_GUI_EXPORT QSize qSmartMaxSize(const QWidgetItem *i, Qt::Alignment align)
+{
+    QWidget *w = ((QWidgetItem*)i)->widget();
+
+    return qSmartMaxSize(w->sizeHint().expandedTo(w->minimumSizeHint()), w->minimumSize(), w->maximumSize(),
+                            w->sizePolicy(), align);
+}
+
+Q_GUI_EXPORT QSize qSmartMaxSize(const QWidget *w, Qt::Alignment align)
+{
+    return qSmartMaxSize(w->sizeHint().expandedTo(w->minimumSizeHint()), w->minimumSize(), w->maximumSize(),
+                            w->sizePolicy(), align);
+}
+
+Q_GUI_EXPORT int qSmartSpacing(const QLayout *layout, QStyle::PixelMetric pm)
+{
+    QObject *parent = layout->parent();
+    if (!parent) {
+        return -1;
+    } else if (parent->isWidgetType()) {
+        QWidget *pw = static_cast<QWidget *>(parent);
+        return pw->style()->pixelMetric(pm, 0, pw);
+    } else {
+        return static_cast<QLayout *>(parent)->spacing();
+    }
+}
+
+QT_END_NAMESPACE
author	Qt by Nokia <qt-info@nokia.com>	2011-04-27 12:05:43 +0200
committer	axis <qt-info@nokia.com>	2011-04-27 12:05:43 +0200
commit	38be0d13830efd2d98281c645c3a60afe05ffece (patch)
tree	6ea73f3ec77f7d153333779883e8120f82820abe /src/gui/kernel/qlayoutengine.cpp