qgridlayout.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant reason:default
 
#include "qapplication.h"
#include "qgridlayout.h"
#include "qlist.h"
#include "qsizepolicy.h"
#include "qvarlengtharray.h"
#include "qwidget.h"
 
#include "qlayoutengine_p.h"
#include "qlayout_p.h"
 
QT_BEGIN_NAMESPACE
 
struct QGridLayoutSizeTriple
{
    QSize minS;
    QSize hint;
    QSize maxS;
};
 
/*
  Three internal classes related to QGridLayout: (1) QGridBox is a
  QLayoutItem with (row, column) information and (torow, tocolumn) information; (3) QGridLayoutData is
  the internal representation of a QGridLayout.
*/
 
class QGridBox
{
public:
    QGridBox(QLayoutItem *lit) { item_ = lit; }
 
    QGridBox(const QLayout *l, QWidget *wid) { item_ = QLayoutPrivate::createWidgetItem(l, wid); }
    ~QGridBox() { delete item_; }
 
    QSize sizeHint() const { return item_->sizeHint(); }
    QSize minimumSize() const { return item_->minimumSize(); }
    QSize maximumSize() const { return item_->maximumSize(); }
    Qt::Orientations expandingDirections() const { return item_->expandingDirections(); }
    bool isEmpty() const { return item_->isEmpty(); }
 
    bool hasHeightForWidth() const { return item_->hasHeightForWidth(); }
    int heightForWidth(int w) const { return item_->heightForWidth(w); }
 
    void setAlignment(Qt::Alignment a) { item_->setAlignment(a); }
    void setGeometry(const QRect &r) { item_->setGeometry(r); }
    Qt::Alignment alignment() const { return item_->alignment(); }
    QLayoutItem *item() { return item_; }
    void setItem(QLayoutItem *newitem) { item_ = newitem; }
    QLayoutItem *takeItem() { QLayoutItem *i = item_; item_ = nullptr; return i; }
 
    int hStretch() { return item_->widget() ?
                         item_->widget()->sizePolicy().horizontalStretch() : 0; }
    int vStretch() { return item_->widget() ?
                         item_->widget()->sizePolicy().verticalStretch() : 0; }
 
private:
    friend class QGridLayoutPrivate;
    friend class QGridLayout;
 
    inline int toRow(int rr) const { return torow >= 0 ? torow : rr - 1; }
    inline int toCol(int cc) const { return tocol >= 0 ? tocol : cc - 1; }
 
    QLayoutItem *item_;
    int row, col;
    int torow, tocol;
};
 
class QGridLayoutPrivate : public QLayoutPrivate
{
    Q_DECLARE_PUBLIC(QGridLayout)
public:
    QGridLayoutPrivate();
 
    void add(QGridBox*, int row, int col);
    void add(QGridBox*, int row1, int row2, int col1, int col2);
    QSize sizeHint(int hSpacing, int vSpacing) const;
    QSize minimumSize(int hSpacing, int vSpacing) const;
    QSize maximumSize(int hSpacing, int vSpacing) const;
 
    Qt::Orientations expandingDirections(int hSpacing, int vSpacing) const;
 
    void distribute(QRect rect, int hSpacing, int vSpacing);
    inline int numRows() const { return rr; }
    inline int numCols() const { return cc; }
    inline void expand(int rows, int cols)
        { setSize(qMax(rows, rr), qMax(cols, cc)); }
    inline void setRowStretch(int r, int s)
        { expand(r + 1, 0); rStretch[r] = s; setDirty(); }
    inline void setColStretch(int c, int s)
        { expand(0, c + 1); cStretch[c] = s; setDirty(); }
    inline int rowStretch(int r) const { return rStretch.at(r); }
    inline int colStretch(int c) const { return cStretch.at(c); }
    inline void setRowMinimumHeight(int r, int s)
        { expand(r + 1, 0); rMinHeights[r] = s; setDirty(); }
    inline void setColumnMinimumWidth(int c, int s)
        { expand(0, c + 1); cMinWidths[c] = s; setDirty(); }
    inline int rowSpacing(int r) const { return rMinHeights.at(r); }
    inline int colSpacing(int c) const { return cMinWidths.at(c); }
 
    inline void setReversed(bool r, bool c) { hReversed = c; vReversed = r; }
    inline bool horReversed() const { return hReversed; }
    inline bool verReversed() const { return vReversed; }
    inline void setDirty() { needRecalc = true; hfw_width = -1; }
    inline bool isDirty() const { return needRecalc; }
    bool hasHeightForWidth(int hSpacing, int vSpacing);
    int heightForWidth(int width, int hSpacing, int vSpacing);
    int minimumHeightForWidth(int width, int hSpacing, int vSpacing);
 
    inline void getNextPos(int &row, int &col) { row = nextR; col = nextC; }
    inline int count() const { return things.size(); }
    QRect cellRect(int row, int col) const;
 
    inline QLayoutItem *itemAt(int index) const {
        if (index >= 0 && index < things.size())
            return things.at(index)->item();
        else
            return nullptr;
    }
    inline QLayoutItem *takeAt(int index) {
        Q_Q(QGridLayout);
        if (index >= 0 && index < things.size()) {
            if (QGridBox *b = things.takeAt(index)) {
                QLayoutItem *item = b->takeItem();
                if (QLayout *l = item->layout()) {
                    // sanity check in case the user passed something weird to QObject::setParent()
                    if (l->parent() == q)
                        l->setParent(nullptr);
                }
                delete b;
                return item;
            }
        }
        return nullptr;
    }
    QLayoutItem* replaceAt(int index, QLayoutItem *newitem) override
    {
        if (!newitem)
            return nullptr;
        QLayoutItem *item = nullptr;
        QGridBox *b = things.value(index);
        if (b) {
            item = b->takeItem();
            b->setItem(newitem);
        }
        return item;
    }
 
    void getItemPosition(int index, int *row, int *column, int *rowSpan, int *columnSpan) const {
        if (index >= 0 && index < things.size()) {
            const QGridBox *b =  things.at(index);
            int toRow = b->toRow(rr);
            int toCol = b->toCol(cc);
            *row = b->row;
            *column = b->col;
            *rowSpan = toRow - *row + 1;
            *columnSpan = toCol - *column +1;
        }
    }
    void deleteAll();
 
private:
    void setNextPosAfter(int r, int c);
    void recalcHFW(int w);
    void addHfwData(QGridBox *box, int width);
    void init();
    QSize findSize(int QLayoutStruct::*, int hSpacing, int vSpacing) const;
    void addData(QGridBox *b, const QGridLayoutSizeTriple &sizes, bool r, bool c);
    void setSize(int rows, int cols);
    void setupSpacings(QList<QLayoutStruct> &chain, QGridBox *grid[], int fixedSpacing,
                       Qt::Orientation orientation);
    void setupLayoutData(int hSpacing, int vSpacing);
    void setupHfwLayoutData();
    void effectiveMargins(int *left, int *top, int *right, int *bottom) const;
 
    int rr;
    int cc;
    QList<QLayoutStruct> rowData;
    QList<QLayoutStruct> colData;
    QList<QLayoutStruct> *hfwData;
    QList<int> rStretch;
    QList<int> cStretch;
    QList<int> rMinHeights;
    QList<int> cMinWidths;
    QList<QGridBox *> things;
 
    int hfw_width;
    int hfw_height;
    int hfw_minheight;
    int nextR;
    int nextC;
 
    int horizontalSpacing;
    int verticalSpacing;
    int leftMargin;
    int topMargin;
    int rightMargin;
    int bottomMargin;
 
    uint hReversed : 1;
    uint vReversed : 1;
    uint needRecalc : 1;
    uint has_hfw : 1;
    uint addVertical : 1;
};
 
void QGridLayoutPrivate::effectiveMargins(int *left, int *top, int *right, int *bottom) const
{
    int l = leftMargin;
    int t = topMargin;
    int r = rightMargin;
    int b = bottomMargin;
#ifdef Q_OS_MAC
    int leftMost = INT_MAX;
    int topMost = INT_MAX;
    int rightMost = 0;
    int bottomMost = 0;
 
    QWidget *w = nullptr;
    const int n = things.count();
    for (int i = 0; i < n; ++i) {
        QGridBox *box = things.at(i);
        QLayoutItem *itm = box->item();
        w = itm->widget();
        if (w) {
            bool visualHReversed = hReversed != (w->layoutDirection() == Qt::RightToLeft);
            QRect lir = itm->geometry();
            QRect wr = w->geometry();
            if (box->col <= leftMost) {
                if (box->col < leftMost) {
                    // we found an item even closer to the margin, discard.
                    leftMost = box->col;
                    if (visualHReversed)
                        r = rightMargin;
                    else
                        l = leftMargin;
                }
                if (visualHReversed) {
                    r = qMax(r, wr.right() - lir.right());
                } else {
                    l = qMax(l, lir.left() - wr.left());
                }
            }
            if (box->row <= topMost) {
                if (box->row < topMost) {
                    // we found an item even closer to the margin, discard.
                    topMost = box->row;
                    if (vReversed)
                        b = bottomMargin;
                    else
                        t = topMargin;
                }
                if (vReversed)
                    b = qMax(b, wr.bottom() - lir.bottom());
                else
                    t = qMax(t, lir.top() - wr.top());
            }
            if (box->toCol(cc) >= rightMost) {
                if (box->toCol(cc) > rightMost) {
                    // we found an item even closer to the margin, discard.
                    rightMost = box->toCol(cc);
                    if (visualHReversed)
                        l = leftMargin;
                    else
                        r = rightMargin;
                }
                if (visualHReversed) {
                    l = qMax(l, lir.left() - wr.left());
                } else {
                    r = qMax(r, wr.right() - lir.right());
                }
 
            }
            if (box->toRow(rr) >= bottomMost) {
                if (box->toRow(rr) > bottomMost) {
                    // we found an item even closer to the margin, discard.
                    bottomMost = box->toRow(rr);
                    if (vReversed)
                        t = topMargin;
                    else
                        b = bottomMargin;
                }
                if (vReversed)
                    t = qMax(t, lir.top() - wr.top());
                else
                    b = qMax(b, wr.bottom() - lir.bottom());
            }
        }
    }
 
#endif
    if (left)
        *left = l;
    if (top)
        *top = t;
    if (right)
        *right = r;
    if (bottom)
        *bottom = b;
}
 
QGridLayoutPrivate::QGridLayoutPrivate()
{
    addVertical = false;
    setDirty();
    rr = cc = 0;
    nextR = nextC = 0;
    hfwData = nullptr;
    hReversed = false;
    vReversed = false;
    horizontalSpacing = -1;
    verticalSpacing = -1;
}
 
void QGridLayoutPrivate::deleteAll()
{
    while (!things.isEmpty())
        delete things.takeFirst();
    delete hfwData;
}
 
bool QGridLayoutPrivate::hasHeightForWidth(int hSpacing, int vSpacing)
{
    setupLayoutData(hSpacing, vSpacing);
    return has_hfw;
}
 
/*
  Assumes that setupLayoutData() has been called, and that
  qGeomCalc() has filled in colData with appropriate values.
*/
void QGridLayoutPrivate::recalcHFW(int w)
{
    /*
      Go through all children, using colData and heightForWidth()
      and put the results in hfwData.
    */
    if (!hfwData)
        hfwData = new QList<QLayoutStruct>(rr);
    setupHfwLayoutData();
    QList<QLayoutStruct> &rData = *hfwData;
 
    int h = 0;
    int mh = 0;
    for (int r = 0; r < rr; r++) {
        int spacing = rData.at(r).spacing;
        h += rData.at(r).sizeHint + spacing;
        mh += rData.at(r).minimumSize + spacing;
    }
 
    hfw_width = w;
    hfw_height = qMin(QLAYOUTSIZE_MAX, h);
    hfw_minheight = qMin(QLAYOUTSIZE_MAX, mh);
}
 
int QGridLayoutPrivate::heightForWidth(int w, int hSpacing, int vSpacing)
{
    setupLayoutData(hSpacing, vSpacing);
    if (!has_hfw)
        return -1;
    int left, top, right, bottom;
    effectiveMargins(&left, &top, &right, &bottom);
 
    int hMargins = left + right;
    if (w - hMargins != hfw_width) {
        qGeomCalc(colData, 0, cc, 0, w - hMargins);
        recalcHFW(w - hMargins);
    }
    return hfw_height + top + bottom;
}
 
int QGridLayoutPrivate::minimumHeightForWidth(int w, int hSpacing, int vSpacing)
{
    (void)heightForWidth(w, hSpacing, vSpacing);
    if (!has_hfw)
        return -1;
    int top, bottom;
    effectiveMargins(nullptr, &top, nullptr, &bottom);
    return hfw_minheight + top + bottom;
}
 
QSize QGridLayoutPrivate::findSize(int QLayoutStruct::*size, int hSpacing, int vSpacing) const
{
    QGridLayoutPrivate *that = const_cast<QGridLayoutPrivate*>(this);
    that->setupLayoutData(hSpacing, vSpacing);
 
    int w = 0;
    int h = 0;
 
    for (int r = 0; r < rr; r++)
        h += rowData.at(r).*size + rowData.at(r).spacing;
    for (int c = 0; c < cc; c++)
        w += colData.at(c).*size + colData.at(c).spacing;
 
    w = qMin(QLAYOUTSIZE_MAX, w);
    h = qMin(QLAYOUTSIZE_MAX, h);
 
    return QSize(w, h);
}
 
Qt::Orientations QGridLayoutPrivate::expandingDirections(int hSpacing, int vSpacing) const
{
    QGridLayoutPrivate *that = const_cast<QGridLayoutPrivate*>(this);
    that->setupLayoutData(hSpacing, vSpacing);
    Qt::Orientations ret;
 
    for (int r = 0; r < rr; r++) {
        if (rowData.at(r).expansive) {
            ret |= Qt::Vertical;
            break;
        }
    }
    for (int c = 0; c < cc; c++) {
        if (colData.at(c).expansive) {
            ret |= Qt::Horizontal;
            break;
        }
    }
    return ret;
}
 
QSize QGridLayoutPrivate::sizeHint(int hSpacing, int vSpacing) const
{
    return findSize(&QLayoutStruct::sizeHint, hSpacing, vSpacing);
}
 
QSize QGridLayoutPrivate::maximumSize(int hSpacing, int vSpacing) const
{
    return findSize(&QLayoutStruct::maximumSize, hSpacing, vSpacing);
}
 
QSize QGridLayoutPrivate::minimumSize(int hSpacing, int vSpacing) const
{
    return findSize(&QLayoutStruct::minimumSize, hSpacing, vSpacing);
}
 
void QGridLayoutPrivate::setSize(int r, int c)
{
    if ((int)rowData.size() < r) {
        int newR = qMax(r, rr * 2);
        rowData.resize(newR);
        rStretch.resize(newR);
        rMinHeights.resize(newR);
        for (int i = rr; i < newR; i++) {
            rowData[i].init();
            rowData[i].maximumSize = 0;
            rowData[i].pos = 0;
            rowData[i].size = 0;
            rStretch[i] = 0;
            rMinHeights[i] = 0;
        }
    }
    if ((int)colData.size() < c) {
        int newC = qMax(c, cc * 2);
        colData.resize(newC);
        cStretch.resize(newC);
        cMinWidths.resize(newC);
        for (int i = cc; i < newC; i++) {
            colData[i].init();
            colData[i].maximumSize = 0;
            colData[i].pos = 0;
            colData[i].size = 0;
            cStretch[i] = 0;
            cMinWidths[i] = 0;
        }
    }
 
    if (hfwData && (int)hfwData->size() < r) {
        delete hfwData;
        hfwData = nullptr;
        hfw_width = -1;
    }
    rr = r;
    cc = c;
}
 
void QGridLayoutPrivate::setNextPosAfter(int row, int col)
{
    if (addVertical) {
        if (col > nextC || (col == nextC && row >= nextR)) {
            nextR = row + 1;
            nextC = col;
            if (nextR >= rr) {
                nextR = 0;
                nextC++;
            }
        }
    } else {
        if (row > nextR || (row == nextR && col >= nextC)) {
            nextR = row;
            nextC = col + 1;
            if (nextC >= cc) {
                nextC = 0;
                nextR++;
            }
        }
    }
}
 
void QGridLayoutPrivate::add(QGridBox *box, int row, int col)
{
    expand(row + 1, col + 1);
    box->row = box->torow = row;
    box->col = box->tocol = col;
    things.append(box);
    setDirty();
    setNextPosAfter(row, col);
}
 
void QGridLayoutPrivate::add(QGridBox *box, int row1, int row2, int col1, int col2)
{
    if (Q_UNLIKELY(row2 >= 0 && row2 < row1))
        qWarning("QGridLayout: Multi-cell fromRow greater than toRow");
    if (Q_UNLIKELY(col2 >= 0 && col2 < col1))
        qWarning("QGridLayout: Multi-cell fromCol greater than toCol");
    if (row1 == row2 && col1 == col2) {
        add(box, row1, col1);
        return;
    }
    expand(qMax(row1, row2) + 1, qMax(col1, col2) + 1);
    box->row = row1;
    box->col = col1;
 
    box->torow = row2;
    box->tocol = col2;
 
    things.append(box);
    setDirty();
    if (col2 < 0)
        col2 = cc - 1;
 
    setNextPosAfter(row2, col2);
}
 
void QGridLayoutPrivate::addData(QGridBox *box, const QGridLayoutSizeTriple &sizes, bool r, bool c)
{
    const QWidget *widget = box->item()->widget();
 
    if (box->isEmpty() && widget)
        return;
 
    if (c) {
        QLayoutStruct *data = &colData[box->col];
        if (!cStretch.at(box->col))
            data->stretch = qMax(data->stretch, box->hStretch());
        data->sizeHint = qMax(sizes.hint.width(), data->sizeHint);
        data->minimumSize = qMax(sizes.minS.width(), data->minimumSize);
 
        qMaxExpCalc(data->maximumSize, data->expansive, data->empty, sizes.maxS.width(),
                    box->expandingDirections() & Qt::Horizontal, box->isEmpty());
    }
    if (r) {
        QLayoutStruct *data = &rowData[box->row];
        if (!rStretch.at(box->row))
            data->stretch = qMax(data->stretch, box->vStretch());
        data->sizeHint = qMax(sizes.hint.height(), data->sizeHint);
        data->minimumSize = qMax(sizes.minS.height(), data->minimumSize);
 
        qMaxExpCalc(data->maximumSize, data->expansive, data->empty, sizes.maxS.height(),
                    box->expandingDirections() & Qt::Vertical, box->isEmpty());
    }
}
 
static void initEmptyMultiBox(QList<QLayoutStruct> &chain, int start, int end)
{
    for (int i = start; i <= end; i++) {
        QLayoutStruct *data = &chain[i];
        if (data->empty && data->maximumSize == 0) // truly empty box
            data->maximumSize = QWIDGETSIZE_MAX;
        data->empty = false;
    }
}
 
static void distributeMultiBox(QList<QLayoutStruct> &chain, int start, int end, int minSize,
                               int sizeHint, QList<int> &stretchArray, int stretch)
{
    int i;
    int w = 0;
    int wh = 0;
    int max = 0;
 
    for (i = start; i <= end; i++) {
        QLayoutStruct *data = &chain[i];
        w += data->minimumSize;
        wh += data->sizeHint;
        max += data->maximumSize;
        if (stretchArray.at(i) == 0)
            data->stretch = qMax(data->stretch, stretch);
 
        if (i != end) {
            int spacing = data->spacing;
            w += spacing;
            wh += spacing;
            max += spacing;
        }
    }
 
    if (max < minSize) { // implies w < minSize
        /*
          We must increase the maximum size of at least one of the
          items. qGeomCalc() will put the extra space in between the
          items. We must recover that extra space and put it
          somewhere. It does not really matter where, since the user
          can always specify stretch factors and avoid this code.
        */
        qGeomCalc(chain, start, end - start + 1, 0, minSize);
        int pos = 0;
        for (i = start; i <= end; i++) {
            QLayoutStruct *data = &chain[i];
            int nextPos = (i == end) ? minSize : chain.at(i + 1).pos;
            int realSize = nextPos - pos;
            if (i != end)
                realSize -= data->spacing;
            if (data->minimumSize < realSize)
                data->minimumSize = realSize;
            if (data->maximumSize < data->minimumSize)
                data->maximumSize = data->minimumSize;
            pos = nextPos;
        }
    } else if (w < minSize) {
        qGeomCalc(chain, start, end - start + 1, 0, minSize);
        for (i = start; i <= end; i++) {
            QLayoutStruct *data = &chain[i];
            if (data->minimumSize < data->size)
                data->minimumSize = data->size;
        }
    }
 
    if (wh < sizeHint) {
        qGeomCalc(chain, start, end - start + 1, 0, sizeHint);
        for (i = start; i <= end; i++) {
            QLayoutStruct *data = &chain[i];
            if (data->sizeHint < data->size)
                data->sizeHint = data->size;
        }
    }
}
 
static QGridBox *&gridAt(QGridBox *grid[], int r, int c, int cc,
                         Qt::Orientation orientation = Qt::Vertical)
{
    if (orientation == Qt::Horizontal)
        qSwap(r, c);
    return grid[(r * cc) + c];
}
 
void QGridLayoutPrivate::setupSpacings(QList<QLayoutStruct> &chain, QGridBox *grid[],
                                       int fixedSpacing, Qt::Orientation orientation)
{
    Q_Q(QGridLayout);
    int numRows = rr;       // or columns if orientation is horizontal
    int numColumns = cc;    // or rows if orientation is horizontal
 
    if (orientation == Qt::Horizontal) {
        qSwap(numRows, numColumns);
    }
 
    QStyle *style = nullptr;
    if (fixedSpacing < 0) {
        if (QWidget *parentWidget = q->parentWidget())
            style = parentWidget->style();
    }
 
    for (int c = 0; c < numColumns; ++c) {
        QGridBox *previousBox = nullptr;
        int previousRow = -1;       // previous *non-empty* row
 
        for (int r = 0; r < numRows; ++r) {
            if (chain.at(r).empty)
                continue;
 
            QGridBox *box = gridAt(grid, r, c, cc, orientation);
            if (previousRow != -1 && (!box || previousBox != box)) {
                int spacing = fixedSpacing;
                if (spacing < 0) {
                    QSizePolicy::ControlTypes controlTypes1 = QSizePolicy::DefaultType;
                    QSizePolicy::ControlTypes controlTypes2 = QSizePolicy::DefaultType;
                    if (previousBox)
                        controlTypes1 = previousBox->item()->controlTypes();
                    if (box)
                        controlTypes2 = box->item()->controlTypes();
 
                    if ((orientation == Qt::Horizontal && hReversed)
                            || (orientation == Qt::Vertical && vReversed))
                        qSwap(controlTypes1, controlTypes2);
 
                    if (style)
                        spacing = style->combinedLayoutSpacing(controlTypes1, controlTypes2,
                                             orientation, nullptr, q->parentWidget());
                } else {
                    if (orientation == Qt::Vertical) {
                        QGridBox *sibling = vReversed ? previousBox : box;
                        if (sibling) {
                            if (sibling->item()->isEmpty()) {
                                spacing = 0;
                            } else {
                                QWidget *wid = sibling->item()->widget();
                                if (wid)
                                    spacing = qMax(spacing, sibling->item()->geometry().top() - wid->geometry().top());
                            }
                        }
                    }
                }
 
                if (spacing > chain.at(previousRow).spacing)
                    chain[previousRow].spacing = spacing;
            }
 
            previousBox = box;
            previousRow = r;
        }
    }
}
 
//#define QT_LAYOUT_DISABLE_CACHING
 
void QGridLayoutPrivate::setupLayoutData(int hSpacing, int vSpacing)
{
    Q_Q(QGridLayout);
 
#ifndef QT_LAYOUT_DISABLE_CACHING
    if (!needRecalc)
        return;
#endif
    has_hfw = false;
    int i;
 
    for (i = 0; i < rr; i++) {
        rowData[i].init(rStretch.at(i), rMinHeights.at(i));
        rowData[i].maximumSize = rStretch.at(i) ? QLAYOUTSIZE_MAX : rMinHeights.at(i);
    }
    for (i = 0; i < cc; i++) {
        colData[i].init(cStretch.at(i), cMinWidths.at(i));
        colData[i].maximumSize = cStretch.at(i) ? QLAYOUTSIZE_MAX : cMinWidths.at(i);
    }
 
    int n = things.size();
    QVarLengthArray<QGridLayoutSizeTriple> sizes(n);
 
    bool has_multi = false;
 
    /*
        Grid of items. We use it to determine which items are
        adjacent to which and compute the spacings correctly.
    */
    QVarLengthArray<QGridBox *> grid(rr * cc);
    memset(grid.data(), 0, rr * cc * sizeof(QGridBox *));
 
    /*
        Initialize 'sizes' and 'grid' data structures, and insert
        non-spanning items to our row and column data structures.
    */
    for (i = 0; i < n; ++i) {
        QGridBox * const box = things.at(i);
        sizes[i].minS = box->minimumSize();
        sizes[i].hint = box->sizeHint();
        sizes[i].maxS = box->maximumSize();
 
        if (box->hasHeightForWidth())
            has_hfw = true;
 
        if (box->row == box->toRow(rr)) {
            addData(box, sizes[i], true, false);
        } else {
            initEmptyMultiBox(rowData, box->row, box->toRow(rr));
            has_multi = true;
        }
 
        if (box->col == box->toCol(cc)) {
            addData(box, sizes[i], false, true);
        } else {
            initEmptyMultiBox(colData, box->col, box->toCol(cc));
            has_multi = true;
        }
 
        for (int r = box->row; r <= box->toRow(rr); ++r) {
            for (int c = box->col; c <= box->toCol(cc); ++c) {
                gridAt(grid.data(), r, c, cc) = box;
            }
        }
    }
 
    setupSpacings(colData, grid.data(), hSpacing, Qt::Horizontal);
    setupSpacings(rowData, grid.data(), vSpacing, Qt::Vertical);
 
    /*
        Insert multicell items to our row and column data structures.
        This must be done after the non-spanning items to obtain a
        better distribution in distributeMultiBox().
    */
    if (has_multi) {
        for (i = 0; i < n; ++i) {
            QGridBox * const box = things.at(i);
 
            if (box->row != box->toRow(rr))
                distributeMultiBox(rowData, box->row, box->toRow(rr), sizes[i].minS.height(),
                                   sizes[i].hint.height(), rStretch, box->vStretch());
            if (box->col != box->toCol(cc))
                distributeMultiBox(colData, box->col, box->toCol(cc), sizes[i].minS.width(),
                                   sizes[i].hint.width(), cStretch, box->hStretch());
        }
    }
 
    for (i = 0; i < rr; i++)
        rowData[i].expansive = rowData.at(i).expansive || rowData.at(i).stretch > 0;
    for (i = 0; i < cc; i++)
        colData[i].expansive = colData.at(i).expansive || colData.at(i).stretch > 0;
 
    q->getContentsMargins(&leftMargin, &topMargin, &rightMargin, &bottomMargin);
 
    needRecalc = false;
}
 
void QGridLayoutPrivate::addHfwData(QGridBox *box, int width)
{
    QList<QLayoutStruct> &rData = *hfwData;
    if (box->hasHeightForWidth()) {
        int hint = box->heightForWidth(width);
        rData[box->row].sizeHint = qMax(hint, rData.at(box->row).sizeHint);
        rData[box->row].minimumSize = qMax(hint, rData.at(box->row).minimumSize);
    } else {
        QSize hint = box->sizeHint();
        QSize minS = box->minimumSize();
        rData[box->row].sizeHint = qMax(hint.height(), rData.at(box->row).sizeHint);
        rData[box->row].minimumSize = qMax(minS.height(), rData.at(box->row).minimumSize);
    }
}
 
/*
  Similar to setupLayoutData(), but uses heightForWidth(colData)
  instead of sizeHint(). Assumes that setupLayoutData() and
  qGeomCalc(colData) has been called.
*/
void QGridLayoutPrivate::setupHfwLayoutData()
{
    QList<QLayoutStruct> &rData = *hfwData;
    for (int i = 0; i < rr; i++) {
        rData[i] = rowData.at(i);
        rData[i].minimumSize = rData[i].sizeHint = rMinHeights.at(i);
    }
 
    for (int pass = 0; pass < 2; ++pass) {
        for (int i = 0; i < things.size(); ++i) {
            QGridBox *box = things.at(i);
            int r1 = box->row;
            int c1 = box->col;
            int r2 = box->toRow(rr);
            int c2 = box->toCol(cc);
            int w = colData.at(c2).pos + colData.at(c2).size - colData.at(c1).pos;
 
            if (r1 == r2) {
                if (pass == 0)
                    addHfwData(box, w);
            } else {
                if (pass == 0) {
                    initEmptyMultiBox(rData, r1, r2);
                } else {
                    QSize hint = box->sizeHint();
                    QSize min = box->minimumSize();
                    if (box->hasHeightForWidth()) {
                        int hfwh = box->heightForWidth(w);
                        if (hfwh > hint.height())
                            hint.setHeight(hfwh);
                        if (hfwh > min.height())
                            min.setHeight(hfwh);
                    }
                    distributeMultiBox(rData, r1, r2, min.height(), hint.height(),
                                       rStretch, box->vStretch());
                }
            }
        }
    }
    for (int i = 0; i < rr; i++)
        rData[i].expansive = rData.at(i).expansive || rData.at(i).stretch > 0;
}
 
void QGridLayoutPrivate::distribute(QRect r, int hSpacing, int vSpacing)
{
    Q_Q(QGridLayout);
    bool visualHReversed = hReversed;
    QWidget *parent = q->parentWidget();
    if (parent && parent->isRightToLeft())
        visualHReversed = !visualHReversed;
 
    setupLayoutData(hSpacing, vSpacing);
 
    int left, top, right, bottom;
    effectiveMargins(&left, &top, &right, &bottom);
    r.adjust(+left, +top, -right, -bottom);
 
    qGeomCalc(colData, 0, cc, r.x(), r.width());
    QList<QLayoutStruct> *rDataPtr;
    if (has_hfw) {
        recalcHFW(r.width());
        qGeomCalc(*hfwData, 0, rr, r.y(), r.height());
        rDataPtr = hfwData;
    } else {
        qGeomCalc(rowData, 0, rr, r.y(), r.height());
        rDataPtr = &rowData;
    }
    QList<QLayoutStruct> &rData = *rDataPtr;
    int i;
 
    bool reverse = ((r.bottom() > rect.bottom()) || (r.bottom() == rect.bottom()
                                                     && ((r.right() > rect.right()) != visualHReversed)));
    int n = things.size();
    for (i = 0; i < n; ++i) {
        QGridBox *box = things.at(reverse ? n-i-1 : i);
        int r2 = box->toRow(rr);
        int c2 = box->toCol(cc);
 
        int x = colData.at(box->col).pos;
        int y = rData.at(box->row).pos;
        int x2p = colData.at(c2).pos + colData.at(c2).size; // x2+1
        int y2p = rData.at(r2).pos + rData.at(r2).size;    // y2+1
        int w = x2p - x;
        int h = y2p - y;
 
        if (visualHReversed)
            x = r.left() + r.right() - x - w + 1;
        if (vReversed)
            y = r.top() + r.bottom() - y - h + 1;
 
        box->setGeometry(QRect(x, y, w, h));
    }
}
 
QRect QGridLayoutPrivate::cellRect(int row, int col) const
{
    if (row < 0 || row >= rr || col < 0 || col >= cc)
        return QRect();
 
    const QList<QLayoutStruct> *rDataPtr;
    if (has_hfw && hfwData)
        rDataPtr = hfwData;
    else
        rDataPtr = &rowData;
    return QRect(colData.at(col).pos, rDataPtr->at(row).pos,
                 colData.at(col).size, rDataPtr->at(row).size);
}
 
/*!
    \class QGridLayout
 
    \brief The QGridLayout class lays out widgets in a grid.
 
    \ingroup geomanagement
    \inmodule QtWidgets
 
    QGridLayout takes the space made available to it (by its parent
    layout or by the parentWidget()), divides it up into rows and
    columns, and puts each widget it manages into the correct cell.
 
    Columns and rows behave identically; we will discuss columns, but
    there are equivalent functions for rows.
 
    Each column has a minimum width and a stretch factor. The minimum
    width is the greatest of that set using setColumnMinimumWidth() and the
    minimum width of each widget in that column. The stretch factor is
    set using setColumnStretch() and determines how much of the available
    space the column will get over and above its necessary minimum.
 
    Normally, each managed widget or layout is put into a cell of its
    own using addWidget(). It is also possible for a widget to occupy
    multiple cells using the row and column spanning overloads of
    addItem() and addWidget(). If you do this, QGridLayout will guess
    how to distribute the size over the columns/rows (based on the
    stretch factors).
 
    To remove a widget from a layout, call removeWidget(). Calling
    QWidget::hide() on a widget also effectively removes the widget
    from the layout until QWidget::show() is called.
 
    This illustration shows a fragment of a dialog with a five-column,
    three-row grid (the grid is shown overlaid in magenta):
 
    \image qgridlayout.png A grid layout
 
    Columns 0, 2 and 4 in this dialog fragment are made up of a
    QLabel, a QLineEdit, and a QListBox. Columns 1 and 3 are
    placeholders made with setColumnMinimumWidth(). Row 0 consists of three
    QLabel objects, row 1 of three QLineEdit objects and row 2 of
    three QListBox objects. We used placeholder columns (1 and 3) to
    get the right amount of space between the columns.
 
    Note that the columns and rows are not equally wide or tall. If
    you want two columns to have the same width, you must set their
    minimum widths and stretch factors to be the same yourself. You do
    this using setColumnMinimumWidth() and setColumnStretch().
 
    If the QGridLayout is not the top-level layout (i.e. does not
    manage all of the widget's area and children), you must add it to
    its parent layout when you create it, but before you do anything
    with it. The normal way to add a layout is by calling
    addLayout() on the parent layout.
 
    Once you have added your layout you can start putting widgets and
    other layouts into the cells of your grid layout using
    addWidget(), addItem(), and addLayout().
 
    QGridLayout also includes two margin widths:
    the \l{getContentsMargins()}{contents margin} and the spacing().
    The contents margin is the width of the reserved space along each
    of the QGridLayout's four sides. The spacing() is the width of the
    automatically allocated spacing between neighboring boxes.
 
    The default contents margin values are provided by the
    \l{QStyle::pixelMetric()}{style}. The default value Qt styles specify
    is 9 for child widgets and 11 for windows. The spacing defaults to the same as
    the margin width for a top-level layout, or to the same as the
    parent layout.
 
    \sa QBoxLayout, QStackedLayout, {Layout Management}, {Basic Layouts Example}
*/
 
 
/*!
    Constructs a new QGridLayout with parent widget, \a parent.  The
    layout has one row and one column initially, and will expand when
    new items are inserted.
 
    The layout is set directly as the top-level layout for \a parent.
    There can be only one top-level layout for a widget. It is returned
    by QWidget::layout().
 
    If \a parent is \nullptr, then you must insert this grid layout
    into another layout, or set it as a widget's layout using
    QWidget::setLayout().
 
    \sa QWidget::setLayout()
*/
QGridLayout::QGridLayout(QWidget *parent)
    : QLayout(*new QGridLayoutPrivate, nullptr, parent)
{
    Q_D(QGridLayout);
    d->expand(1, 1);
}
 
/*!
\internal (mostly)
 
Sets the positioning mode used by addItem(). If \a orient is
Qt::Horizontal, this layout is expanded to \a n columns, and items
will be added columns-first. Otherwise it is expanded to \a n rows and
items will be added rows-first.
*/
 
void QGridLayout::setDefaultPositioning(int n, Qt::Orientation orient)
{
    Q_D(QGridLayout);
    if (orient == Qt::Horizontal) {
        d->expand(1, n);
        d->addVertical = false;
    } else {
        d->expand(n,1);
        d->addVertical = true;
    }
}
 
 
/*!
    Destroys the grid layout. Geometry management is terminated if
    this is a top-level grid.
 
    The layout's widgets aren't destroyed.
*/
QGridLayout::~QGridLayout()
{
    Q_D(QGridLayout);
    d->deleteAll();
}
 
/*!
    \property QGridLayout::horizontalSpacing
    \brief the spacing between widgets that are laid out side by side
    \since 4.3
 
    If no value is explicitly set, the layout's horizontal spacing is
    inherited from the parent layout, or from the style settings for
    the parent widget.
 
    \sa verticalSpacing, QStyle::pixelMetric(), {QStyle::}{PM_LayoutHorizontalSpacing}
*/
void QGridLayout::setHorizontalSpacing(int spacing)
{
    Q_D(QGridLayout);
    d->horizontalSpacing = spacing;
    invalidate();
}
 
int QGridLayout::horizontalSpacing() const
{
    Q_D(const QGridLayout);
    if (d->horizontalSpacing >= 0) {
        return d->horizontalSpacing;
    } else {
        return qSmartSpacing(this, QStyle::PM_LayoutHorizontalSpacing);
    }
}
 
/*!
    \property QGridLayout::verticalSpacing
    \brief the spacing between widgets that are laid out on top of each other
    \since 4.3
 
    If no value is explicitly set, the layout's vertical spacing is
    inherited from the parent layout, or from the style settings for
    the parent widget.
 
    \sa horizontalSpacing, QStyle::pixelMetric(), {QStyle::}{PM_LayoutHorizontalSpacing}
*/
void QGridLayout::setVerticalSpacing(int spacing)
{
    Q_D(QGridLayout);
    d->verticalSpacing = spacing;
    invalidate();
}
 
int QGridLayout::verticalSpacing() const
{
    Q_D(const QGridLayout);
    if (d->verticalSpacing >= 0) {
        return d->verticalSpacing;
    } else {
        return qSmartSpacing(this, QStyle::PM_LayoutVerticalSpacing);
    }
}
 
/*!
    This function sets both the vertical and horizontal spacing to
    \a spacing.
 
    \sa setVerticalSpacing(), setHorizontalSpacing()
*/
void QGridLayout::setSpacing(int spacing)
{
    Q_D(QGridLayout);
    d->horizontalSpacing = d->verticalSpacing = spacing;
    invalidate();
}
 
/*!
    If the vertical spacing is equal to the horizontal spacing,
    this function returns that value; otherwise it return -1.
 
    \sa setSpacing(), verticalSpacing(), horizontalSpacing()
*/
int QGridLayout::spacing() const
{
    int hSpacing = horizontalSpacing();
    if (hSpacing == verticalSpacing()) {
        return hSpacing;
    } else {
        return -1;
    }
}
 
/*!
    Returns the number of rows in this grid.
*/
int QGridLayout::rowCount() const
{
    Q_D(const QGridLayout);
    return d->numRows();
}
 
/*!
    Returns the number of columns in this grid.
*/
int QGridLayout::columnCount() const
{
    Q_D(const QGridLayout);
    return d->numCols();
}
 
/*!
    \reimp
*/
QSize QGridLayout::sizeHint() const
{
    Q_D(const QGridLayout);
    QSize result(d->sizeHint(horizontalSpacing(), verticalSpacing()));
    int left, top, right, bottom;
    d->effectiveMargins(&left, &top, &right, &bottom);
    result += QSize(left + right, top + bottom);
    return result;
}
 
/*!
    \reimp
*/
QSize QGridLayout::minimumSize() const
{
    Q_D(const QGridLayout);
    QSize result(d->minimumSize(horizontalSpacing(), verticalSpacing()));
    int left, top, right, bottom;
    d->effectiveMargins(&left, &top, &right, &bottom);
    result += QSize(left + right, top + bottom);
    return result;
}
 
/*!
    \reimp
*/
QSize QGridLayout::maximumSize() const
{
    Q_D(const QGridLayout);
 
    QSize s = d->maximumSize(horizontalSpacing(), verticalSpacing());
    int left, top, right, bottom;
    d->effectiveMargins(&left, &top, &right, &bottom);
    s += QSize(left + right, top + bottom);
    s = s.boundedTo(QSize(QLAYOUTSIZE_MAX, QLAYOUTSIZE_MAX));
    if (alignment() & Qt::AlignHorizontal_Mask)
        s.setWidth(QLAYOUTSIZE_MAX);
    if (alignment() & Qt::AlignVertical_Mask)
        s.setHeight(QLAYOUTSIZE_MAX);
    return s;
}
 
/*!
    \reimp
*/
bool QGridLayout::hasHeightForWidth() const
{
    return const_cast<QGridLayout*>(this)->d_func()->hasHeightForWidth(horizontalSpacing(), verticalSpacing());
}
 
/*!
    \reimp
*/
int QGridLayout::heightForWidth(int w) const
{
    Q_D(const QGridLayout);
    QGridLayoutPrivate *dat = const_cast<QGridLayoutPrivate *>(d);
    return dat->heightForWidth(w, horizontalSpacing(), verticalSpacing());
}
 
/*!
    \reimp
*/
int QGridLayout::minimumHeightForWidth(int w) const
{
    Q_D(const QGridLayout);
    QGridLayoutPrivate *dat = const_cast<QGridLayoutPrivate *>(d);
    return dat->minimumHeightForWidth(w, horizontalSpacing(), verticalSpacing());
}
 
/*!
    \reimp
*/
int QGridLayout::count() const
{
    Q_D(const QGridLayout);
    return d->count();
}
 
 
/*!
    \reimp
*/
QLayoutItem *QGridLayout::itemAt(int index) const
{
    Q_D(const QGridLayout);
    return d->itemAt(index);
}
 
/*!
    \since 4.4
 
    Returns the layout item that occupies cell (\a row, \a column), or
    \nullptr if the cell is empty.
 
    \sa getItemPosition(), indexOf()
*/
QLayoutItem *QGridLayout::itemAtPosition(int row, int column) const
{
    Q_D(const QGridLayout);
    int n = d->things.size();
    for (int i = 0; i < n; ++i) {
        QGridBox *box = d->things.at(i);
        if (row >= box->row && row <= box->toRow(d->rr)
                && column >= box->col && column <= box->toCol(d->cc)) {
            return box->item();
        }
    }
    return nullptr;
}
 
/*!
    \reimp
*/
QLayoutItem *QGridLayout::takeAt(int index)
{
    Q_D(QGridLayout);
    return d->takeAt(index);
}
 
/*!
  Returns the position information of the item with the given \a index.
 
  The variables passed as \a row and \a column are updated with the position of the
  item in the layout, and the \a rowSpan and \a columnSpan variables are updated
  with the vertical and horizontal spans of the item.
 
  \sa itemAtPosition(), itemAt()
*/
void QGridLayout::getItemPosition(int index, int *row, int *column, int *rowSpan, int *columnSpan) const
{
    Q_D(const QGridLayout);
    d->getItemPosition(index, row, column, rowSpan, columnSpan);
}
 
 
/*!
    \reimp
*/
void QGridLayout::setGeometry(const QRect &rect)
{
    Q_D(QGridLayout);
    if (d->isDirty() || rect != geometry()) {
        QRect cr = alignment() ? alignmentRect(rect) : rect;
        d->distribute(cr, horizontalSpacing(), verticalSpacing());
        QLayout::setGeometry(rect);
    }
}
 
/*!
    Returns the geometry of the cell with row \a row and column \a column
    in the grid. Returns an invalid rectangle if \a row or \a column is
    outside the grid.
 
    \warning in the current version of Qt this function does not
    return valid results until setGeometry() has been called, i.e.
    after the parentWidget() is visible.
*/
QRect QGridLayout::cellRect(int row, int column) const
{
    Q_D(const QGridLayout);
    return d->cellRect(row, column);
}
 
/*!
    \reimp
*/
void QGridLayout::addItem(QLayoutItem *item)
{
    Q_D(QGridLayout);
    int r, c;
    d->getNextPos(r, c);
    addItem(item, r, c);
}
 
/*!
    Adds \a item at position \a row, \a column, spanning \a rowSpan
    rows and \a columnSpan columns, and aligns it according to \a
    alignment. If \a rowSpan and/or \a columnSpan is -1, then the item
    will extend to the bottom and/or right edge, respectively. The
    layout takes ownership of the \a item.
 
    \warning Do not use this function to add child layouts or child
    widget items. Use addLayout() or addWidget() instead.
*/
void QGridLayout::addItem(QLayoutItem *item, int row, int column, int rowSpan, int columnSpan, Qt::Alignment alignment)
{
    Q_D(QGridLayout);
    QGridBox *b = new QGridBox(item);
    b->setAlignment(alignment);
    d->add(b, row, (rowSpan < 0) ? -1 : row + rowSpan - 1, column, (columnSpan < 0) ? -1 : column + columnSpan - 1);
    invalidate();
}
 
/*!
    Adds the given \a widget to the cell grid at \a row, \a column. The
    top-left position is (0, 0) by default.
 
    The alignment is specified by \a alignment. The default
    alignment is 0, which means that the widget fills the entire cell.
 
*/
void QGridLayout::addWidget(QWidget *widget, int row, int column, Qt::Alignment alignment)
{
    Q_D(QGridLayout);
    if (!d->checkWidget(widget))
        return;
    if (Q_UNLIKELY(row < 0 || column < 0)) {
        qWarning("QGridLayout: Cannot add %s/%s to %s/%s at row %d column %d",
                 widget->metaObject()->className(), widget->objectName().toLocal8Bit().data(),
                 metaObject()->className(), objectName().toLocal8Bit().data(), row, column);
        return;
    }
    addChildWidget(widget);
    QWidgetItem *b = QLayoutPrivate::createWidgetItem(this, widget);
    addItem(b, row, column, 1, 1, alignment);
}
 
/*!
    \overload
 
    This version adds the given \a widget to the cell grid, spanning
    multiple rows/columns. The cell will start at \a fromRow, \a
    fromColumn spanning \a rowSpan rows and \a columnSpan columns. The
    \a widget will have the given \a alignment.
 
    If \a rowSpan and/or \a columnSpan is -1, then the widget will
    extend to the bottom and/or right edge, respectively.
 
*/
void QGridLayout::addWidget(QWidget *widget, int fromRow, int fromColumn,
                            int rowSpan, int columnSpan, Qt::Alignment alignment)
{
    Q_D(QGridLayout);
    if (!d->checkWidget(widget))
        return;
    int toRow = (rowSpan < 0) ? -1 : fromRow + rowSpan - 1;
    int toColumn = (columnSpan < 0) ? -1 : fromColumn + columnSpan - 1;
    addChildWidget(widget);
    QGridBox *b = new QGridBox(this, widget);
    b->setAlignment(alignment);
    d->add(b, fromRow, toRow, fromColumn, toColumn);
    invalidate();
}
 
/*!
    \fn void QGridLayout::addWidget(QWidget *widget)
 
    \overload
    \internal
*/
 
/*!
    Places the \a layout at position (\a row, \a column) in the grid. The
    top-left position is (0, 0).
 
    The alignment is specified by \a alignment. The default
    alignment is 0, which means that the widget fills the entire cell.
 
    A non-zero alignment indicates that the layout should not grow to
    fill the available space but should be sized according to
    sizeHint().
 
 
    \a layout becomes a child of the grid layout.
*/
void QGridLayout::addLayout(QLayout *layout, int row, int column, Qt::Alignment alignment)
{
    Q_D(QGridLayout);
    if (!d->checkLayout(layout))
        return;
    if (!adoptLayout(layout))
        return;
    QGridBox *b = new QGridBox(layout);
    b->setAlignment(alignment);
    d->add(b, row, column);
}
 
/*!
  \overload
    This version adds the layout \a layout to the cell grid, spanning multiple
    rows/columns. The cell will start at \a row, \a column spanning \a
    rowSpan rows and \a columnSpan columns.
 
    If \a rowSpan and/or \a columnSpan is -1, then the layout will extend to the bottom
    and/or right edge, respectively.
*/
void QGridLayout::addLayout(QLayout *layout, int row, int column,
                                      int rowSpan, int columnSpan, Qt::Alignment alignment)
{
    Q_D(QGridLayout);
    if (!d->checkLayout(layout))
        return;
    if (!adoptLayout(layout))
        return;
    QGridBox *b = new QGridBox(layout);
    b->setAlignment(alignment);
    d->add(b, row, (rowSpan < 0) ? -1 : row + rowSpan - 1, column, (columnSpan < 0) ? -1 : column + columnSpan - 1);
}
 
/*!
    Sets the stretch factor of row \a row to \a stretch. The first row
    is number 0.
 
    The stretch factor is relative to the other rows in this grid.
    Rows with a higher stretch factor take more of the available
    space.
 
    The default stretch factor is 0. If the stretch factor is 0 and no
    other row in this table can grow at all, the row may still grow.
 
    \sa rowStretch(), setRowMinimumHeight(), setColumnStretch()
*/
void QGridLayout::setRowStretch(int row, int stretch)
{
    Q_D(QGridLayout);
    d->setRowStretch(row, stretch);
    invalidate();
}
 
/*!
    Returns the stretch factor for row \a row.
 
    \sa setRowStretch()
*/
int QGridLayout::rowStretch(int row) const
{
    Q_D(const QGridLayout);
    return d->rowStretch(row);
}
 
/*!
    Returns the stretch factor for column \a column.
 
    \sa setColumnStretch()
*/
int QGridLayout::columnStretch(int column) const
{
    Q_D(const QGridLayout);
    return d->colStretch(column);
}
 
/*!
    Sets the stretch factor of column \a column to \a stretch. The first
    column is number 0.
 
    The stretch factor is relative to the other columns in this grid.
    Columns with a higher stretch factor take more of the available
    space.
 
    The default stretch factor is 0. If the stretch factor is 0 and no
    other column in this table can grow at all, the column may still
    grow.
 
    An alternative approach is to add spacing using addItem() with a
    QSpacerItem.
 
    \sa columnStretch(), setRowStretch()
*/
void QGridLayout::setColumnStretch(int column, int stretch)
{
    Q_D(QGridLayout);
    d->setColStretch(column, stretch);
    invalidate();
}
 
 
 
/*!
    Sets the minimum height of row \a row to \a minSize pixels.
 
    \sa rowMinimumHeight(), setColumnMinimumWidth()
*/
void QGridLayout::setRowMinimumHeight(int row, int minSize)
{
    Q_D(QGridLayout);
    d->setRowMinimumHeight(row, minSize);
    invalidate();
}
 
/*!
    Returns the minimum width set for row \a row.
 
    \sa setRowMinimumHeight()
*/
int QGridLayout::rowMinimumHeight(int row) const
{
    Q_D(const QGridLayout);
    return d->rowSpacing(row);
}
 
/*!
    Sets the minimum width of column \a column to \a minSize pixels.
 
    \sa columnMinimumWidth(), setRowMinimumHeight()
*/
void QGridLayout::setColumnMinimumWidth(int column, int minSize)
{
    Q_D(QGridLayout);
    d->setColumnMinimumWidth(column, minSize);
    invalidate();
}
 
/*!
    Returns the column spacing for column \a column.
 
    \sa setColumnMinimumWidth()
*/
int QGridLayout::columnMinimumWidth(int column) const
{
    Q_D(const QGridLayout);
    return d->colSpacing(column);
}
 
/*!
    \reimp
*/
Qt::Orientations QGridLayout::expandingDirections() const
{
    Q_D(const QGridLayout);
    return d->expandingDirections(horizontalSpacing(), verticalSpacing());
}
 
/*!
    Sets the grid's origin corner, i.e. position (0, 0), to \a corner.
*/
void QGridLayout::setOriginCorner(Qt::Corner corner)
{
    Q_D(QGridLayout);
    d->setReversed(corner == Qt::BottomLeftCorner || corner == Qt::BottomRightCorner,
                   corner == Qt::TopRightCorner || corner == Qt::BottomRightCorner);
}
 
/*!
    Returns the corner that's used for the grid's origin, i.e. for
    position (0, 0).
*/
Qt::Corner QGridLayout::originCorner() const
{
    Q_D(const QGridLayout);
    if (d->horReversed()) {
        return d->verReversed() ? Qt::BottomRightCorner : Qt::TopRightCorner;
    } else {
        return d->verReversed() ? Qt::BottomLeftCorner : Qt::TopLeftCorner;
    }
}
 
/*!
    \reimp
*/
void QGridLayout::invalidate()
{
    Q_D(QGridLayout);
    d->setDirty();
    QLayout::invalidate();
}
 
QT_END_NAMESPACE
 
#include "moc_qgridlayout.cpp"