QskScrollArea respecting dynamic constraints

examples/thumbnails/main.cpp

@@ -164,9 +164,15 @@ int main( int argc, char* argv[] )
     new QskPushButton( "Push Me", buttonBox );
     new QskPushButton( "Push Me", buttonBox );
 
+    auto iconGrid = new IconGrid();
+
+    // don't allow to shrink the iconGrid
+    iconGrid->setSizePolicy( QskSizePolicy::MinimumExpanding,
+        QskSizePolicy::MinimumExpanding );
+
     auto scrollArea = new ScrollArea( box );
     scrollArea->setMargins( QMarginsF( 25, 25, 5, 5 ) );
-    scrollArea->setScrolledItem( new IconGrid() );
+    scrollArea->setScrolledItem( iconGrid );
 
     auto focusIndicator = new QskFocusIndicator();
     focusIndicator->setBoxBorderColorsHint( QskFocusIndicator::Panel, Qt::darkRed );

src/common/QskSizePolicy.h

@@ -24,10 +24,12 @@ class QSK_EXPORT QskSizePolicy
   public:
     enum Flag
     {
-        GrowFlag = 1,
+        GrowFlag   = 1 << 0,
-        ExpandFlag = 2,
+        ExpandFlag = 1 << 1,
-        ShrinkFlag = 4,
+        ShrinkFlag = 1 << 2,
-        IgnoreFlag = 8
+        IgnoreFlag = 1 << 3,
+
+        ConstrainedFlag = IgnoreFlag
     };
 
     enum Policy
@@ -39,7 +41,7 @@ class QSK_EXPORT QskSizePolicy
         MinimumExpanding = GrowFlag | ExpandFlag,
         Expanding = GrowFlag | ShrinkFlag | ExpandFlag,
         Ignored = ShrinkFlag | GrowFlag | IgnoreFlag,
-        Constrained = IgnoreFlag
+        Constrained = ConstrainedFlag
     };
 
     Q_ENUM( Flag )

src/controls/QskScrollArea.cpp

@@ -16,48 +16,6 @@ QSK_QT_PRIVATE_BEGIN
 #include <private/qquickwindow_p.h>
 QSK_QT_PRIVATE_END
 
-static QSizeF qskAdjustedSize( const QQuickItem* item, const QSizeF& targetSize )
-{
-    using namespace QskLayoutConstraint;
-
-    QSizeF sz = effectiveConstraint( item, Qt::PreferredSize );
-
-    qreal w = sz.width();
-    qreal h = sz.height();
-
-    if ( targetSize != sz )
-    {
-        const QSizeF minSize = effectiveConstraint( item, Qt::MinimumSize );
-        const QSizeF maxSize = effectiveConstraint( item, Qt::MaximumSize );
-
-        const auto policy = sizePolicy( item );
-
-        if ( targetSize.width() > w )
-        {
-            if ( policy.horizontalPolicy() & QskSizePolicy::GrowFlag )
-                w = qMin( maxSize.width(), targetSize.width() );
-        }
-        else if ( targetSize.width() < w )
-        {
-            if ( policy.horizontalPolicy() & QskSizePolicy::ShrinkFlag )
-                w = qMax( minSize.width(), w );
-        }
-
-        if ( targetSize.height() > h )
-        {
-            if ( policy.verticalPolicy() & QskSizePolicy::GrowFlag )
-                h = qMin( maxSize.height(), targetSize.height() );
-        }
-        else if ( targetSize.height() < h )
-        {
-            if ( policy.verticalPolicy() & QskSizePolicy::ShrinkFlag )
-                h = qMax( minSize.height(), h );
-        }
-    }
-
-    return QSizeF( w, h );
-}
-
 namespace
 {
     class ViewportClipNode final : public QQuickDefaultClipNode
@@ -485,7 +443,7 @@ void QskScrollArea::adjustItem()
                 moment we ignore this and start with a simplified code.
              */
 #endif
-            auto newSize = qskAdjustedSize( item, rect.size() );
+            const auto newSize = QskLayoutConstraint::adjustedSize( item, rect.size() );
             item->setSize( newSize );
         }
 

src/controls/QskScrollView.cpp

@@ -628,50 +628,54 @@ QPointF QskScrollView::boundedScrollPos( const QPointF& pos ) const
 
 Qt::Orientations QskScrollView::scrollableOrientations() const
 {
+    // layoutRect ???
     const QRectF vr = contentsRect();
 
-    Qt::ScrollBarPolicy policyV = m_data->verticalScrollBarPolicy;
+    auto policyVertical = m_data->verticalScrollBarPolicy;
-    Qt::ScrollBarPolicy policyH = m_data->horizontalScrollBarPolicy;
+    auto policyHorizontal = m_data->horizontalScrollBarPolicy;
 
-    if ( policyV == Qt::ScrollBarAsNeeded )
+    if ( policyVertical == Qt::ScrollBarAsNeeded )
     {
-        qreal h = vr.height();
+        qreal height = vr.height();
-        if ( policyH == Qt::ScrollBarAlwaysOn )
-            h -= metric( HorizontalScrollBar | QskAspect::Size );
 
-        if ( m_data->scrollableSize.height() > h )
+        if ( policyHorizontal == Qt::ScrollBarAlwaysOn )
-            policyV = Qt::ScrollBarAlwaysOn;
+            height -= metric( HorizontalScrollBar | QskAspect::Size );
+
+        if ( m_data->scrollableSize.height() > height )
+            policyVertical = Qt::ScrollBarAlwaysOn;
     }
 
-    if ( policyH == Qt::ScrollBarAsNeeded )
+    if ( policyHorizontal == Qt::ScrollBarAsNeeded )
     {
-        qreal w = vr.width();
+        qreal width = vr.width();
-        if ( policyV == Qt::ScrollBarAlwaysOn )
-            w -= metric( VerticalScrollBar | QskAspect::Size );
 
-        if ( m_data->scrollableSize.width() > w )
+        if ( policyVertical == Qt::ScrollBarAlwaysOn )
+            width -= metric( VerticalScrollBar | QskAspect::Size );
+
+        if ( m_data->scrollableSize.width() > width )
         {
-            policyH = Qt::ScrollBarAlwaysOn;
+            policyHorizontal = Qt::ScrollBarAlwaysOn;
 
             // we have to check the vertical once more
 
-            if ( ( policyV == Qt::ScrollBarAsNeeded ) &&
+            if ( ( policyVertical == Qt::ScrollBarAsNeeded ) &&
                  ( m_data->scrollableSize.height() >
                      vr.height() - metric( HorizontalScrollBar | QskAspect::Size ) ) )
             {
-                policyV = Qt::ScrollBarAlwaysOn;
+                policyVertical = Qt::ScrollBarAlwaysOn;
             }
         }
     }
 
-    Qt::Orientations o;
+    Qt::Orientations orientations;
-    if ( policyH == Qt::ScrollBarAlwaysOn )
-        o |= Qt::Horizontal;
 
-    if ( policyV == Qt::ScrollBarAlwaysOn )
+    if ( policyHorizontal == Qt::ScrollBarAlwaysOn )
-        o |= Qt::Vertical;
+        orientations |= Qt::Horizontal;
 
-    return o;
+    if ( policyVertical == Qt::ScrollBarAlwaysOn )
+        orientations |= Qt::Vertical;
+
+    return orientations;
 }
 
 #include "moc_QskScrollView.cpp"

src/controls/QskScrollViewSkinlet.cpp

@@ -54,6 +54,7 @@ QRectF QskScrollViewSkinlet::subControlRect(
 
     if ( subControl == QskScrollView::Panel )
     {
+        // layoutRect ???
         return scrollView->contentsRect();
     }
 

src/layouts/QskLayoutConstraint.cpp

@@ -39,6 +39,23 @@ static inline bool qskHasHintFor( const QQuickItem* item, const char* method )
     return false;
 }
 
+static inline qreal qskAdjustedValue( QskSizePolicy::Policy policy, qreal value, qreal targetValue )
+{
+    if ( targetValue > value )
+    {
+        if ( policy & QskSizePolicy::GrowFlag )
+            return targetValue;
+    }
+    else if ( targetValue < value )
+    {
+        if ( policy & QskSizePolicy::ShrinkFlag )
+            return targetValue;
+    }
+
+    return value;
+}
+
+
 bool QskLayoutConstraint::hasDynamicConstraint( const QQuickItem* item )
 {
     if ( const QskControl* control = qobject_cast< const QskControl* >( item ) )
@@ -141,3 +158,68 @@ QskSizePolicy QskLayoutConstraint::sizePolicy( const QQuickItem* item )
 
     return QskSizePolicy( QskSizePolicy::Preferred, QskSizePolicy::Preferred );
 }
+
+QSizeF QskLayoutConstraint::boundedSize( const QQuickItem* item, const QSizeF& size )
+{
+    const auto minSize = effectiveConstraint( item, Qt::MinimumSize );
+    const auto maxSize = effectiveConstraint( item, Qt::MaximumSize );
+
+    qreal width = size.width();
+    qreal height = size.height();
+
+    if ( ( minSize.width() >= 0 ) && ( minSize.width() > width ) )
+        width = minSize.width();
+
+    if ( ( minSize.height() >= 0 ) && ( minSize.height() > height ) )
+        height = minSize.height();
+
+    if ( ( maxSize.width() >= 0 ) && ( maxSize.width() < width ) )
+        width = maxSize.width();
+
+    if ( ( maxSize.height() >= 0 ) && ( maxSize.height() < height ) )
+        height = maxSize.height();
+
+    return QSizeF( width, height );
+}
+
+QSizeF QskLayoutConstraint::adjustedSize( const QQuickItem* item, const QSizeF& targetSize )
+{
+    const auto policy = sizePolicy( item );
+
+    const auto boundedSize = QskLayoutConstraint::boundedSize( item, targetSize );
+    const auto preferredSize = effectiveConstraint( item, Qt::PreferredSize );
+
+    qreal w;
+    qreal h;
+
+    if ( policy.horizontalPolicy() == QskSizePolicy::Constrained )
+    {
+        h = qskAdjustedValue( policy.verticalPolicy(),
+            preferredSize.height(), boundedSize.height() );
+
+        w = widthForHeight( item, h );
+
+        if ( w < boundedSize.height() )
+            w = boundedSize.height();
+    }
+    else if ( policy.verticalPolicy() == QskSizePolicy::Constrained )
+    {
+        w = qskAdjustedValue( policy.horizontalPolicy(),
+            preferredSize.width(), boundedSize.width() );
+
+        h = heightForWidth( item, w );
+
+        if ( h < boundedSize.height() )
+            h = boundedSize.height();
+    }
+    else
+    {
+        w = qskAdjustedValue( policy.horizontalPolicy(),
+            preferredSize.width(), boundedSize.width() );
+
+        h = qskAdjustedValue( policy.verticalPolicy(),
+            preferredSize.height(), boundedSize.height() );
+    }
+
+    return QSizeF( w, h );
+}

src/layouts/QskLayoutConstraint.h

@@ -24,6 +24,11 @@ namespace QskLayoutConstraint
     QSK_EXPORT QSizeF effectiveConstraint( const QQuickItem*, Qt::SizeHint );
     QSK_EXPORT QskSizePolicy sizePolicy( const QQuickItem* );
 
+    // bounded by Qt::MinimumSize/Qt::MaximumSize
+    QSK_EXPORT QSizeF boundedSize( const QQuickItem*, const QSizeF& );
+
+    QSK_EXPORT QSizeF adjustedSize( const QQuickItem*, const QSizeF& );
+
     // QGridLayoutEngine internally uses FLT_MAX
     const qreal unlimited = std::numeric_limits< float >::max();
 }