Revert "Fix (implement!) hfw/wfh in QGridLayoutEngine"

This reverts commit 62b5ef3cc1306e46a4042b14867f2f92d9a110f3.

The implementation of hfw from this patch is unfortunately not robust enough.
It doesn't manage correctly the constraints on the layouts and the cell spans.
It caused bad behaviour or regressions seen in tasks:
QTBUG-13547, QTBUG-13067, QTBUG-13549, and more

Reviewed-By: ogoffart

4 files changed, 13 insertions, 318 deletions

diff --git a/src/gui/graphicsview/qgraphicslayoutitem.cpp b/src/gui/graphicsview/qgraphicslayoutitem.cpp
index 634f68c..ad4b2b5 100644
--- a/src/gui/graphicsview/qgraphicslayoutitem.cpp
+++ b/src/gui/graphicsview/qgraphicslayoutitem.cpp
@@ -48,7 +48,6 @@
 #include "qgraphicslayoutitem.h"
 #include "qgraphicslayoutitem_p.h"
 #include "qwidget.h"
-#include "qgraphicswidget.h"
 
 #include <QtDebug>
 
@@ -140,11 +139,9 @@ QSizeF *QGraphicsLayoutItemPrivate::effectiveSizeHints(const QSizeF &constraint)
     if (!sizeHintCacheDirty && cachedConstraint == constraint)
         return cachedSizeHints;
 
-    const bool hasConstraint = constraint.width() >= 0 || constraint.height() >= 0;
-
     for (int i = 0; i < Qt::NSizeHints; ++i) {
         cachedSizeHints[i] = constraint;
-        if (userSizeHints && !hasConstraint)
+        if (userSizeHints)
             combineSize(cachedSizeHints[i], userSizeHints[i]);
     }
 
@@ -262,52 +259,6 @@ void QGraphicsLayoutItemPrivate::setSizeComponent(
     q->updateGeometry();
 }
 
-
-bool QGraphicsLayoutItemPrivate::hasHeightForWidth() const
-{
-    Q_Q(const QGraphicsLayoutItem);
-    if (isLayout) {
-        const QGraphicsLayout *l = static_cast<const QGraphicsLayout *>(q);
-        for (int i = l->count() - 1; i >= 0; --i) {
-            if (QGraphicsLayoutItemPrivate::get(l->itemAt(i))->hasHeightForWidth())
-                return true;
-        }
-    } else if (QGraphicsItem *item = q->graphicsItem()) {
-        if (item->isWidget()) {
-            QGraphicsWidget *w = static_cast<QGraphicsWidget *>(item);
-            if (w->layout()) {
-                return QGraphicsLayoutItemPrivate::get(w->layout())->hasHeightForWidth();
-            }
-        }
-    }
-    return q->sizePolicy().hasHeightForWidth();
-}
-
-bool QGraphicsLayoutItemPrivate::hasWidthForHeight() const
-{
-    // enable this code when we add QSizePolicy::hasWidthForHeight() (For 4.8)
-#if 1
-    return false;
-#else
-    Q_Q(const QGraphicsLayoutItem);
-    if (isLayout) {
-        const QGraphicsLayout *l = static_cast<const QGraphicsLayout *>(q);
-        for (int i = l->count() - 1; i >= 0; --i) {
-            if (QGraphicsLayoutItemPrivate::get(l->itemAt(i))->hasWidthForHeight())
-                return true;
-        }
-    } else if (QGraphicsItem *item = q->graphicsItem()) {
-        if (item->isWidget()) {
-            QGraphicsWidget *w = static_cast<QGraphicsWidget *>(item);
-            if (w->layout()) {
-                return QGraphicsLayoutItemPrivate::get(w->layout())->hasWidthForHeight();
-            }
-        }
-    }
-    return q->sizePolicy().hasWidthForHeight();
-#endif
-}
-
 /*!
     \class QGraphicsLayoutItem
     \brief The QGraphicsLayoutItem class can be inherited to allow your custom
diff --git a/src/gui/graphicsview/qgraphicslayoutitem_p.h b/src/gui/graphicsview/qgraphicslayoutitem_p.h
index b752e03..15cc7a5 100644
--- a/src/gui/graphicsview/qgraphicslayoutitem_p.h
+++ b/src/gui/graphicsview/qgraphicslayoutitem_p.h
@@ -65,9 +65,6 @@ class Q_AUTOTEST_EXPORT QGraphicsLayoutItemPrivate
 public:
     virtual ~QGraphicsLayoutItemPrivate();
     QGraphicsLayoutItemPrivate(QGraphicsLayoutItem *parent, bool isLayout);
-    static QGraphicsLayoutItemPrivate *get(QGraphicsLayoutItem *q) { return q->d_func();}
-    static const QGraphicsLayoutItemPrivate *get(const QGraphicsLayoutItem *q) { return q->d_func();}
-
     void init();
     QSizeF *effectiveSizeHints(const QSizeF &constraint) const;
     QGraphicsItem *parentItem() const;
@@ -76,9 +73,6 @@ public:
     enum SizeComponent { Width, Height };
     void setSizeComponent(Qt::SizeHint which, SizeComponent component, qreal value);
 
-    bool hasHeightForWidth() const;
-    bool hasWidthForHeight() const;
-
     QSizePolicy sizePolicy;
     QGraphicsLayoutItem *parent;
 
diff --git a/src/gui/graphicsview/qgridlayoutengine.cpp b/src/gui/graphicsview/qgridlayoutengine.cpp
index 1e3addc..ae5bf90 100644
--- a/src/gui/graphicsview/qgridlayoutengine.cpp
+++ b/src/gui/graphicsview/qgridlayoutengine.cpp
@@ -545,24 +545,6 @@ QSizePolicy::Policy QGridLayoutItem::sizePolicy(Qt::Orientation orientation) con
                                            : sizePolicy.verticalPolicy();
 }
 
-/*
-  returns true if the size policy returns true for either hasHeightForWidth()
-  or hasWidthForHeight()
- */
-bool QGridLayoutItem::hasDynamicConstraint() const
-{
-    return QGraphicsLayoutItemPrivate::get(q_layoutItem)->hasHeightForWidth()
-        || QGraphicsLayoutItemPrivate::get(q_layoutItem)->hasWidthForHeight();
-}
-
-Qt::Orientation QGridLayoutItem::dynamicConstraintOrientation() const
-{
-    if (QGraphicsLayoutItemPrivate::get(q_layoutItem)->hasHeightForWidth())
-        return Qt::Vertical;
-    else //if (QGraphicsLayoutItemPrivate::get(q_layoutItem)->hasWidthForHeight())
-        return Qt::Horizontal;
-}
-
 QSizePolicy::ControlTypes QGridLayoutItem::controlTypes(LayoutSide /* side */) const
 {
     return q_layoutItem->sizePolicy().controlType();
@@ -631,14 +613,7 @@ QRectF QGridLayoutItem::geometryWithin(qreal x, qreal y, qreal width, qreal heig
         qreal cellWidth = width;
         qreal cellHeight = height;
 
-        QSize constraint;
-        if (hasDynamicConstraint()) {
-            if (dynamicConstraintOrientation() == Qt::Vertical)
-                constraint.setWidth(cellWidth);
-            else
-                constraint.setHeight(cellHeight);
-        }
-        QSizeF size = effectiveMaxSize(constraint).boundedTo(QSizeF(cellWidth, cellHeight));
+        QSizeF size = effectiveMaxSize().boundedTo(QSizeF(cellWidth, cellHeight));
         width = size.width();
         height = size.height();
 
@@ -700,13 +675,13 @@ void QGridLayoutItem::insertOrRemoveRows(int row, int delta, Qt::Orientation ori
     Note that effectiveSizeHint does not take sizePolicy into consideration,
     (since it only evaluates the hints, as the name implies)
 */
-QSizeF QGridLayoutItem::effectiveMaxSize(const QSizeF &constraint) const
+QSizeF QGridLayoutItem::effectiveMaxSize() const
 {
-    QSizeF size = constraint;
+    QSizeF size;
     bool vGrow = (sizePolicy(Qt::Vertical) & QSizePolicy::GrowFlag) == QSizePolicy::GrowFlag;
     bool hGrow = (sizePolicy(Qt::Horizontal) & QSizePolicy::GrowFlag) == QSizePolicy::GrowFlag;
     if (!vGrow || !hGrow) {
-        QSizeF pref = layoutItem()->effectiveSizeHint(Qt::PreferredSize, constraint);
+        QSizeF pref = layoutItem()->effectiveSizeHint(Qt::PreferredSize);
         if (!vGrow)
             size.setHeight(pref.height());
         if (!hGrow)
@@ -714,7 +689,7 @@ QSizeF QGridLayoutItem::effectiveMaxSize(const QSizeF &constraint) const
     }
 
     if (!size.isValid()) {
-        QSizeF maxSize = layoutItem()->effectiveSizeHint(Qt::MaximumSize, constraint);
+        QSizeF maxSize = layoutItem()->effectiveSizeHint(Qt::MaximumSize);
         if (size.width() == -1)
             size.setWidth(maxSize.width());
         if (size.height() == -1)
@@ -1035,7 +1010,6 @@ void QGridLayoutEngine::invalidate()
     q_cachedEffectiveLastRows[Ver] = -1;
     q_cachedDataForStyleInfo.invalidate();
     q_cachedSize = QSizeF();
-    q_cachedConstraintOrientation = UnknownConstraint;
 }
 
 static void visualRect(QRectF *geom, Qt::LayoutDirection dir, const QRectF &contentsRect)
@@ -1100,13 +1074,10 @@ QRectF QGridLayoutEngine::cellRect(const QLayoutStyleInfo &styleInfo,
 }
 
 QSizeF QGridLayoutEngine::sizeHint(const QLayoutStyleInfo &styleInfo, Qt::SizeHint which,
-                                   const QSizeF &constraint) const
+                                   const QSizeF & /* constraint */) const
 {
     ensureColumnAndRowData(styleInfo);
 
-    if (hasDynamicConstraint())
-        return dynamicallyConstrainedSizeHint(which, constraint);
-
     switch (which) {
     case Qt::MinimumSize:
         return QSizeF(q_totalBoxes[Hor].q_minimumSize, q_totalBoxes[Ver].q_minimumSize);
@@ -1404,11 +1375,7 @@ void QGridLayoutEngine::fillRowData(QGridLayoutRowData *rowData, const QLayoutSt
                         box = &multiCell.q_box;
                         multiCell.q_stretch = itemStretch;
                     }
-                    // Items with constraints are not included in the orientation that
-                    // they are constrained (since it depends on the hfw/constraint function).
-                    // They must be combined at a later stage.
-                    if (!item->hasDynamicConstraint() || orientation != item->dynamicConstraintOrientation())
-                        box->combine(item->box(orientation));
+                    box->combine(item->box(orientation));
 
                     if (effectiveRowSpan == 1) {
                         QSizePolicy::ControlTypes controls = item->controlTypes(top);
@@ -1565,138 +1532,6 @@ void QGridLayoutEngine::ensureColumnAndRowData(const QLayoutStyleInfo &styleInfo
     q_cachedDataForStyleInfo = styleInfo;
 }
 
-QSizeF QGridLayoutEngine::dynamicallyConstrainedSizeHint(Qt::SizeHint which,
-                                                         const QSizeF &constraint) const
-{
-    Q_ASSERT(hasDynamicConstraint());
-    if (constraint.width() < 0 && constraint.height() < 0) {
-        // Process the hfw / wfh items that we did not process in fillRowData()
-        const Qt::Orientation constraintOrient = constraintOrientation();
-
-        QGridLayoutRowData rowData = constraintOrient == Qt::Vertical ? q_rowData : q_columnData;
-        for (int i = q_items.count() - 1; i >= 0; --i) {
-            QGridLayoutItem *item = q_items.at(i);
-            if (item->hasDynamicConstraint()) {
-                QGridLayoutBox box = item->box(constraintOrient);
-                QGridLayoutBox &rowBox = rowData.boxes[item->firstRow(constraintOrient)];
-                rowBox.combine(box);
-            }
-        }
-
-        QGridLayoutBox totalBoxes[2];
-        if (constraintOrient == Qt::Vertical) {
-            totalBoxes[Hor] = q_columnData.totalBox(0, columnCount());
-            totalBoxes[Ver] = rowData.totalBox(0, rowCount());
-        } else {
-            totalBoxes[Hor] = rowData.totalBox(0, columnCount());
-            totalBoxes[Ver] = q_rowData.totalBox(0, rowCount());
-        }
-        return QSizeF(totalBoxes[Hor].q_sizes(which), totalBoxes[Ver].q_sizes(which));
-    }
-
-
-    Q_ASSERT(constraint.width() >= 0 || constraint.height() >= 0);
-    q_xx.resize(columnCount());
-    q_yy.resize(rowCount());
-    q_widths.resize(columnCount());
-    q_heights.resize(rowCount());
-    q_descents.resize(rowCount());
-
-
-    const Qt::Orientation orientation = constraintOrientation();
-    QGridLayoutRowData *colData;
-    QGridLayoutRowData constrainedRowData;
-    QGridLayoutBox *totalBox;
-    qreal *sizes;
-    qreal *pos;
-    qreal *descents;
-    qreal targetSize;
-    qreal cCount;
-    qreal rCount;
-
-    if (orientation == Qt::Vertical) {
-        // height for width
-        colData = &q_columnData;
-        totalBox = &q_totalBoxes[Hor];
-        sizes = q_widths.data();
-        pos = q_xx.data();
-        descents = 0;
-        targetSize = constraint.width();
-        cCount = columnCount();
-        rCount = rowCount();
-        constrainedRowData = q_rowData;
-    } else {
-        // width for height
-        colData = &q_rowData;
-        totalBox = &q_totalBoxes[Ver];
-        sizes = q_heights.data();
-        pos = q_yy.data();
-        descents = q_descents.data();
-        targetSize = constraint.height();
-        cCount = rowCount();
-        rCount = columnCount();
-        constrainedRowData = q_columnData;
-    }
-    colData->calculateGeometries(0, cCount, targetSize, pos, sizes, descents, *totalBox);
-    for (int i = q_items.count() - 1; i >= 0; --i) {
-        QGridLayoutItem *item = q_items.at(i);
-
-        if (item->hasDynamicConstraint()) {
-            const qreal size = sizes[item->firstColumn(orientation)];
-            QGridLayoutBox box = item->box(orientation, size);
-            QGridLayoutBox &rowBox = constrainedRowData.boxes[item->firstRow(orientation)];
-            rowBox.combine(box);
-        }
-    }
-    const qreal newSize = constrainedRowData.totalBox(0, rCount).q_sizes(which);
-
-    return (orientation == Qt::Vertical) ? QSizeF(targetSize, newSize) : QSizeF(newSize, targetSize);
-}
-
-
-/**
-   returns false if the layout has contradicting constraints (i.e. some items with a horizontal
-   constraint and other items with a vertical constraint)
- */
-bool QGridLayoutEngine::ensureDynamicConstraint() const
-{
-    if (q_cachedConstraintOrientation == UnknownConstraint) {
-        for (int i = q_items.count() - 1; i >= 0; --i) {
-            QGridLayoutItem *item = q_items.at(i);
-            if (item->hasDynamicConstraint()) {
-                Qt::Orientation itemConstraintOrientation = item->dynamicConstraintOrientation();
-                if (q_cachedConstraintOrientation == UnknownConstraint) {
-                    q_cachedConstraintOrientation = itemConstraintOrientation;
-                } else if (q_cachedConstraintOrientation != itemConstraintOrientation) {
-                    q_cachedConstraintOrientation = UnfeasibleConstraint;
-                    qWarning("QGridLayoutEngine: Unfeasible, cannot mix horizontal and"
-                             " vertical constraint in the same layout");
-                    return false;
-                }
-            }
-        }
-        if (q_cachedConstraintOrientation == UnknownConstraint)
-            q_cachedConstraintOrientation = NoConstraint;
-    }
-    return true;
-}
-
-bool QGridLayoutEngine::hasDynamicConstraint() const
-{
-    if (!ensureDynamicConstraint())
-        return false;
-    return q_cachedConstraintOrientation != NoConstraint;
-}
-
-/*
- * return value is only valid if hasConstraint() returns true
- */
-Qt::Orientation QGridLayoutEngine::constraintOrientation() const
-{
-    (void)ensureDynamicConstraint();
-    return (Qt::Orientation)q_cachedConstraintOrientation;
-}
-
 void QGridLayoutEngine::ensureGeometries(const QLayoutStyleInfo &styleInfo,
                                          const QSizeF &size) const
 {
@@ -1709,74 +1544,10 @@ void QGridLayoutEngine::ensureGeometries(const QLayoutStyleInfo &styleInfo,
     q_widths.resize(columnCount());
     q_heights.resize(rowCount());
     q_descents.resize(rowCount());
-
-
-    Qt::Orientation orientation = Qt::Vertical;
-    if (hasDynamicConstraint())
-        orientation = constraintOrientation();
-
-    /*
-      In order to do hfw we need to first distribute the columns, then the rows.
-      In order to do wfh we need to first distribute the rows, then the columns.
-
-      If there is no constraint, the order of distributing the rows or columns first is irrelevant.
-      We choose horizontal just to keep the same behaviour as before (however, there shouldn't
-      be any behaviour difference).
- */
-
-    QGridLayoutRowData *colData;
-    QGridLayoutRowData rowData;
-    qreal *widths;
-    qreal *heights;
-    qreal *xx;
-    qreal *yy;
-    qreal *xdescents = 0;
-    qreal *ydescents = 0;
-    qreal cCount;
-    qreal rCount;
-    QSizeF oSize = size;
-    if (orientation == Qt::Vertical) {
-        // height for width
-        colData = &q_columnData;
-        rowData = q_rowData;
-        widths = q_widths.data();
-        heights = q_heights.data();
-        xx = q_xx.data();
-        yy = q_yy.data();
-        cCount = columnCount();
-        rCount = rowCount();
-        ydescents = q_descents.data();
-    } else {
-        // width for height
-        colData = &q_rowData;
-        rowData = q_columnData;
-        widths = q_heights.data();
-        heights = q_widths.data();
-        xx = q_yy.data();
-        yy = q_xx.data();
-        cCount = rowCount();
-        rCount = columnCount();
-        xdescents = q_descents.data();
-        oSize.transpose();
-    }
-
-    colData->calculateGeometries(0, cCount, oSize.width(), xx, widths,
-                                 xdescents, q_totalBoxes[orientation == Qt::Horizontal]);
-    for (int i = q_items.count() - 1; i >= 0; --i) {
-        QGridLayoutItem *item = q_items.at(i);
-        const int col = item->firstColumn(orientation);
-        const int row = item->firstRow(orientation);
-        if (item->hasDynamicConstraint()) {
-            const qreal sz = widths[col];
-            QGridLayoutBox box = item->box(orientation, sz);
-            rowData.boxes[row].combine(box);
-        }
-    }
-
-    QGridLayoutBox &totalBox = q_totalBoxes[orientation == Qt::Vertical];
-    totalBox = rowData.totalBox(0, rCount);
-    rowData.calculateGeometries(0, rCount, oSize.height(), yy, heights,
-                                 ydescents, totalBox);
+    q_columnData.calculateGeometries(0, columnCount(), size.width(), q_xx.data(), q_widths.data(),
+                                     0, q_totalBoxes[Hor]);
+    q_rowData.calculateGeometries(0, rowCount(), size.height(), q_yy.data(), q_heights.data(),
+                                  q_descents.data(), q_totalBoxes[Ver]);
 
     q_cachedSize = size;
 }
diff --git a/src/gui/graphicsview/qgridlayoutengine_p.h b/src/gui/graphicsview/qgridlayoutengine_p.h
index 580af7e..9ac9a8e 100644
--- a/src/gui/graphicsview/qgridlayoutengine_p.h
+++ b/src/gui/graphicsview/qgridlayoutengine_p.h
@@ -91,14 +91,6 @@ enum LayoutSide {
     Bottom
 };
 
-enum {
-    NoConstraint,
-    HorizontalConstraint,
-    VerticalConstraint,
-    UnknownConstraint,      // need to update cache
-    UnfeasibleConstraint    // not feasible, it be has some items with Vertical and others with Horizontal constraints
-};
-
 template <typename T>
 class QLayoutParameter
 {
@@ -278,10 +270,6 @@ public:
     inline void setAlignment(Qt::Alignment alignment) { q_alignment = alignment; }
 
     QSizePolicy::Policy sizePolicy(Qt::Orientation orientation) const;
-
-    bool hasDynamicConstraint() const;
-    Qt::Orientation dynamicConstraintOrientation() const;
-
     QSizePolicy::ControlTypes controlTypes(LayoutSide side) const;
     QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const;
     QGridLayoutBox box(Qt::Orientation orientation, qreal constraint = -1.0) const;
@@ -292,7 +280,7 @@ public:
     void setGeometry(const QRectF &rect);
     void transpose();
     void insertOrRemoveRows(int row, int delta, Qt::Orientation orientation = Qt::Vertical);
-    QSizeF effectiveMaxSize(const QSizeF &constraint) const;
+    QSizeF effectiveMaxSize() const;
 
 #ifdef QT_DEBUG
     void dump(int indent = 0) const;
@@ -384,14 +372,6 @@ public:
                     int column, int rowSpan, int columnSpan) const;
     QSizeF sizeHint(const QLayoutStyleInfo &styleInfo, Qt::SizeHint which,
                     const QSizeF &constraint) const;
-
-    // heightForWidth / widthForHeight support
-    QSizeF dynamicallyConstrainedSizeHint(Qt::SizeHint which, const QSizeF &constraint) const;
-    bool ensureDynamicConstraint() const;
-    bool hasDynamicConstraint() const;
-    Qt::Orientation constraintOrientation() const;
-
-
     QSizePolicy::ControlTypes controlTypes(LayoutSide side) const;
     void transpose();
     void setVisualDirection(Qt::LayoutDirection direction);
@@ -425,7 +405,6 @@ private:
     // Lazily computed from the above user input
     mutable int q_cachedEffectiveFirstRows[NOrientations];
     mutable int q_cachedEffectiveLastRows[NOrientations];
-    mutable quint8 q_cachedConstraintOrientation : 2;
 
     // Layout item input
     mutable QLayoutStyleInfo q_cachedDataForStyleInfo;