more complex types of skin hints ( starting with QskMargins, but more to

come )

examples/automotive/DefaultSkin.cpp

@@ -12,6 +12,7 @@
 #include <QskTextLabel.h>
 #include <QskSeparator.h>
 #include <QskColorFilter.h>
+#include <QskMargins.h>
 
 #include <QDebug>
 
@@ -109,7 +110,7 @@ void DefaultSkin::initHints()
 
     // -- push buttons
 
-    setMetric( QskPushButton::Panel | QskAspect::Padding, 10 );
+    setMargins( QskPushButton::Panel | QskAspect::Padding, 10 );
     setColor( QskPushButton::Panel, m_palette->color1 );
     setColor( QskPushButton::Text, m_palette->color3 );
     setColor( QskPushButton::Panel | QskPushButton::Pressed, m_palette->color2 );

examples/automotive/OtherSkin.cpp

@@ -12,6 +12,7 @@
 #include <QskTextLabel.h>
 #include <QskSeparator.h>
 #include <QskColorFilter.h>
+#include <QskMargins.h>
 
 #include <QDebug>
 
@@ -88,7 +89,7 @@ void OtherSkin::initHints()
     // -- push buttons
 
     setMetric( QskPushButton::Panel | QskAspect::Radius, 4 );
-    setMetric( QskPushButton::Panel | QskAspect::Padding, 8 );
+    setMargins( QskPushButton::Panel | QskAspect::Padding, 8 );
     setColor( QskPushButton::Panel, m_palette->color1 );
     setColor( QskPushButton::Text, m_palette->color3 );
     setColor( QskPushButton::Panel | QskPushButton::Pressed, m_palette->color2 );

examples/listbox/main.cpp

@@ -24,8 +24,8 @@ public:
         setMargins( QMarginsF( 15, 10, 10, 10 ) );
         setAlternatingRowColors( true );
 
-        // increasing the height of each row: usually the job of the skin !
+        // increasing the padding of each row: usually the job of the skin !
-        setMetric( Cell | Padding | HorizontalEdges, 20 );
+        setMarginsHint( Cell | Padding, QMargins( 10, 20, 10, 20 ) );
 
         populate();
 

examples/sliders/main.cpp

@@ -34,11 +34,12 @@ public:
 
         const qreal h = 30;
         const qreal w = 2.0 * h;
+        const qreal paddingW = 0.5 * w + 1;
 
         // Panel
         setMetric( Panel | Size, h );
         setMetric( Panel | Border, 1 );
-        setMetric( Panel | Padding | VerticalEdges, 0.5 * w + 1 );
+        setMarginsHint( Panel | Padding, QMarginsF( paddingW, 0, paddingW, 0 ) );
 
         setColor( Panel | Border, QskRgbValue::Grey900 );
         setColor( Panel, QskRgbValue::Grey400 );
@@ -56,7 +57,7 @@ public:
         setMetric( Handle | Border, 1 );
 
         const qreal m = qCeil( 0.5 * ( w - h ) ) + 2;
-        setMetric( Handle | Margin | VerticalEdges, -m );
+        setMarginsHint( Handle | Margin, QMarginsF( -m, 0, -m, 0 ) );
 
         for ( auto state : { NoState, Pressed } )
         {

playground/inputpanel/LineEdit.cpp

@@ -67,7 +67,7 @@ void LineEdit::updateLayout()
 {
     Inherited::updateLayout();
 
-    const auto padding = edgeMetrics( Panel, QskAspect::Padding );
+    const QMarginsF padding = marginsHint( Panel | QskAspect::Padding );
 
     Q_P( QQuickTextInput );
     p->QQuickTextInput::setLeftPadding( padding.left() );

playground/inputpanel/main.cpp

@@ -123,13 +123,13 @@ public:
         {
             using namespace QskAspect;
 
-            QFontMetricsF fm( effectiveFont( Text ) );
+            const QFontMetricsF fm( effectiveFont( Text ) );
 
             for ( auto entry : m_values )
                 m_maxWidth = qMax( m_maxWidth, fm.width( entry.first ) );
 
-            m_maxWidth += metric( Cell | Padding | LeftEdge )
+            const QMarginsF padding = marginsHint( Cell | Padding );
-                + metric( Cell | Padding | RightEdge );
+            m_maxWidth += padding.left() + padding.right();
         }
 
         return m_maxWidth;
@@ -139,9 +139,10 @@ public:
     {
         using namespace QskAspect;
 
-        return QFontMetrics( effectiveFont( Text ) ).height()
+        const QFontMetricsF fm( effectiveFont( Text ) );
-               + metric( Cell | Padding | TopEdge )
+        const QMarginsF padding = marginsHint( Cell | Padding );
-               + metric( Cell | Padding | BottomEdge );
+
+        return fm.height() + padding.top() + padding.bottom();
     }
 
     virtual QVariant valueAt( int row, int ) const override final

src/common/QskAspect.cpp

@@ -322,10 +322,7 @@ void qskDebugAspect( QDebug debug, const QMetaObject* metaObject, QskAspect::Asp
 
         switch( aspect.boxPrimitive() )
         {
-            case Margin:
-            case Padding:
             case Border:
-            case Shadow:
             {
                 if ( aspect.edge() )
                     debug << ", " << qskEnumString( "Edge", aspect.edge() );

src/common/QskAspect.h

@@ -73,12 +73,9 @@ QSK_NAMESPACE( QskAspect )
     {
         Background =     0,
 
-        Margin =         1,
-        Padding =        2,
         RadiusX =        3,
         RadiusY =        4,
         Border =         5,
-        Shadow =         6,
 
         Radius  =        7, // RadiusX | RadiusY
     };
@@ -107,6 +104,11 @@ QSK_NAMESPACE( QskAspect )
         MinimumHeight,
         MaximumWidth,
         MaximumHeight,
+
+        Margin,
+        Padding,
+        Shadow,
+
         Spacing
     };
     QSK_ENUM( MetricPrimitive )

src/common/QskMargins.cpp

@@ -0,0 +1,66 @@
+#include "QskMargins.h"
+#include <QVariant>
+
+static inline qreal qskInterpolated( qreal from, qreal to, qreal ratio )
+{
+    return from + ( to - from ) * ratio;
+}
+
+static inline QskMargins qskInterpolateMargins(
+    const QskMargins& m1, const QskMargins& m2, qreal progress )
+{
+    const qreal left = qskInterpolated( m1.left(), m2.left(), progress );
+    const qreal top = qskInterpolated( m1.top(), m2.top(), progress );
+    const qreal right = qskInterpolated( m1.right(), m2.right(), progress );
+    const qreal bottom = qskInterpolated( m1.bottom(), m2.bottom(), progress );
+
+    return QskMargins( left, top, right, bottom );
+}
+
+QskMargins QskMargins::interpolated(
+    const QskMargins& to, qreal progress ) const noexcept
+{
+    return qskInterpolateMargins( *this, to, progress );
+}
+
+QVariant QskMargins::interpolate(
+    const QskMargins& m1, const QskMargins& m2, qreal progress ) noexcept
+{
+    return QVariant::fromValue( qskInterpolateMargins( m1, m2, progress ) );
+}
+
+void QskMargins::setMarginsAt( Qt::Edges edges, qreal value ) noexcept
+{
+    if ( edges & Qt::LeftEdge )
+        setLeft( value );
+
+    if ( edges & Qt::TopEdge )
+        setTop( value );
+
+    if ( edges & Qt::RightEdge )
+        setRight( value );
+
+    if ( edges & Qt::BottomEdge )
+        setBottom( value );
+}
+
+qreal QskMargins::marginAt( Qt::Edge edge ) const noexcept
+{
+    switch( edge )
+    {
+        case Qt::LeftEdge:
+            return left();
+
+        case Qt::TopEdge:
+            return top();
+
+        case Qt::RightEdge:
+            return right();
+
+        case Qt::BottomEdge:
+            return bottom();
+    }
+
+    return 0.0;
+}
+

src/common/QskMargins.h

@@ -0,0 +1,132 @@
+/******************************************************************************
+ * QSkinny - Copyright (C) 2016 Uwe Rathmann
+ * This file may be used under the terms of the QSkinny License, Version 1.0
+ *****************************************************************************/
+
+#ifndef QSK_MARGINS_H
+#define QSK_MARGINS_H
+
+#include "QskGlobal.h"
+
+#include <QMarginsF>
+#include <Qt>
+#include <QMetaType>
+
+class QVariant;
+
+/*
+   Having a wrapper like this feels a bit stupid, but unfortunately QMarginsF
+   is not registered as Qt metatype and doing this in an external library
+   is an obvious source for conflicts with application code.
+ */
+class QSK_EXPORT QskMargins : public QMarginsF
+{
+public:
+    constexpr QskMargins() noexcept = default;
+    constexpr QskMargins( const QMarginsF& ) noexcept;
+    constexpr QskMargins( const QMargins& ) noexcept;
+
+    constexpr QskMargins( qreal left, qreal top, qreal right, qreal bottom ) noexcept;
+    constexpr QskMargins( qreal margin ) noexcept;
+    constexpr QskMargins( qreal horizontal, qreal vertical ) noexcept;
+
+    QskMargins mirrored( Qt::Orientations ) const noexcept;
+    constexpr QskMargins rotated() const noexcept;
+
+    constexpr QskMargins translated( qreal dx, qreal dy ) const noexcept;
+    constexpr QskMargins expanded( qreal dx, qreal dy ) const noexcept;
+
+    void setMargins( qreal margin ) noexcept;
+    void setMargins( qreal horizontal, qreal vertical ) noexcept;
+
+    void setMarginsAt( Qt::Edges, qreal ) noexcept;
+    qreal marginAt( Qt::Edge ) const noexcept;
+
+    constexpr qreal length( Qt::Orientation ) const noexcept;
+
+    QskMargins interpolated( const QskMargins&, qreal progress ) const noexcept;
+
+    static QVariant interpolate( const QskMargins&,
+        const QskMargins&, qreal progress ) noexcept;
+};
+
+constexpr inline QskMargins::QskMargins( qreal margin ) noexcept:
+    QskMargins( margin, margin, margin, margin )
+{
+}
+
+constexpr inline QskMargins::QskMargins( qreal horizontal, qreal vertical ) noexcept:
+    QskMargins( horizontal, vertical, horizontal, vertical )
+{
+}
+
+constexpr QskMargins::QskMargins(
+    qreal left, qreal top, qreal right, qreal bottom ) noexcept:
+    QMarginsF( left, top, right, bottom )
+{
+}
+
+constexpr inline QskMargins::QskMargins( const QMarginsF& margins ) noexcept:
+    QMarginsF( margins )
+{
+}
+
+constexpr inline QskMargins::QskMargins( const QMargins& margins ) noexcept:
+    QMarginsF( margins )
+{
+}
+
+inline void QskMargins::setMargins( qreal margin ) noexcept
+{
+    *this = QskMargins( margin );
+}
+
+inline void QskMargins::setMargins( qreal horizontal, qreal vertical ) noexcept
+{
+    *this = QskMargins( horizontal, vertical );
+}
+
+inline QskMargins QskMargins::mirrored(
+    Qt::Orientations orientations ) const noexcept
+{
+    switch( int( orientations ) )
+    {
+        case Qt::Vertical:
+            return QskMargins( left(), bottom(), right(), top() );
+
+        case Qt::Horizontal:
+            return QskMargins( right(), top(), left(), bottom() );
+
+        case Qt::Vertical | Qt::Horizontal:
+            return QskMargins( right(), bottom(), left(), top() );
+
+        default:
+            return *this;
+    }
+}
+
+constexpr inline QskMargins QskMargins::rotated() const noexcept
+{
+    return QskMargins( top(), left(), bottom(), right() );
+}
+
+constexpr inline QskMargins QskMargins::translated( qreal dx, qreal dy ) const noexcept
+{
+    return QskMargins( left() + dx, top() + dy, right() - dx, bottom() - dy );
+}
+
+constexpr QskMargins QskMargins::expanded( qreal dx, qreal dy ) const noexcept
+{
+    return QskMargins( left() + dx, top() + dy, right() + dx, bottom() + dy );
+}
+
+constexpr qreal QskMargins::length( Qt::Orientation orientation ) const noexcept
+{
+    return ( orientation == Qt::Horizontal )
+        ? ( left() + right() ) : ( top() + bottom() );
+}
+
+Q_DECLARE_TYPEINFO( QskMargins, Q_MOVABLE_TYPE );
+Q_DECLARE_METATYPE( QskMargins )
+
+#endif

src/controls/QskControl.cpp

@@ -570,13 +570,7 @@ void QskControl::setMargins( const QMarginsF& margins )
 
     if ( m != this->margins() )
     {
-        Aspect aspect = subControl | Margin;
+        setMarginsHint( subControl | Margin, m );
-
-        setMetric( aspect | LeftEdge, m.left() );
-        setMetric( aspect | TopEdge, m.top() );
-        setMetric( aspect | RightEdge, m.right() );
-        setMetric( aspect | BottomEdge, m.bottom() );
-
         resetImplicitSize();
 
         if ( m_polishOnResize || m_autoLayoutChildren )
@@ -593,7 +587,7 @@ void QskControl::resetMargins()
 
 QMarginsF QskControl::margins() const
 {
-    return edgeMetrics( QskAspect::Control, QskAspect::Margin );
+    return marginsHint( QskAspect::Control | QskAspect::Margin );
 }
 
 QRectF QskControl::contentsRect() const

src/controls/QskFocusIndicator.cpp

@@ -79,7 +79,7 @@ void QskFocusIndicator::updateFocusFrame()
 
     if ( !r.isEmpty() )
     {
-        r = r.marginsAdded( edgeMetrics( Panel, QskAspect::Padding ) );
+        r = r.marginsAdded( marginsHint( Panel | QskAspect::Padding ) );
         setGeometry( r );
     }
 

src/controls/QskHintAnimator.cpp

@@ -7,6 +7,7 @@
 #include "QskAnimationHint.h"
 #include "QskControl.h"
 #include "QskEvent.h"
+#include "QskMargins.h"
 
 #include <QObject>
 #include <QThread>
@@ -15,6 +16,12 @@
 #include <vector>
 #include <algorithm>
 
+static inline qreal qskAligned05( qreal value )
+{
+    // aligned to 0.5
+    return qRound( 2.0 * value ) / 2.0;
+}
+
 static inline bool qskCheckReceiverThread( const QObject *receiver )
 {
     /*
@@ -34,7 +41,6 @@ static inline bool qskCheckReceiverThread( const QObject *receiver )
 static inline QVariant qskAdjustedValue(
     QskAspect::Aspect aspect, const QVariant& value )
 {
-#if 1
     if( value.type() == QVariant::Double )
     {
         if ( aspect.metricPrimitive() != QskAspect::Position )
@@ -42,10 +48,17 @@ static inline QVariant qskAdjustedValue(
             // all beside QskAspect::Position are real metrics,
             // that will be aligned to the resolution of the paint device
             // so we can avoid pointless operations by rounding
-            return qRound( 2.0 * value.toReal() ) / 2.0;
+            return qskAligned05( value.toReal() );
         }
     }
-#endif
+    else if ( value.canConvert< QskMargins >() )
+    {
+        const QskMargins m = value.value< QskMargins >();
+
+        return QVariant::fromValue( 
+            QskMargins( qskAligned05( m.left() ), qskAligned05( m.top() ),
+                qskAligned05( m.right() ), qskAligned05( m.bottom() ) ) ); 
+    }
 
     return value;
 }

src/controls/QskListViewSkinlet.cpp

@@ -190,7 +190,7 @@ void QskListViewSkinlet::updateForegroundNodes(
         return;
     }
 
-    const QMarginsF margins = listView->edgeMetrics( QskListView::Cell, QskAspect::Padding );
+    const QMarginsF margins = listView->marginsHint( QskListView::Cell | QskAspect::Padding );
 
     const QRectF cr = listView->viewContentsRect();
     const QPointF scrolledPos = listView->scrollPos();

src/controls/QskScrollViewSkinlet.cpp

@@ -236,7 +236,7 @@ QRectF QskScrollViewSkinlet::scrollHandleRect(
         const auto subControlBar = QskScrollView::VerticalScrollBar;
 
         const QRectF sbRect = subControlRect( scrollView, subControlBar );
-        const auto padding = scrollView->edgeMetrics( subControlBar, QskAspect::Padding );
+        const QMarginsF padding = scrollView->marginsHint( subControlBar | QskAspect::Padding );
 
         const qreal h = scrollView->scrollableSize().height();
 
@@ -259,7 +259,7 @@ QRectF QskScrollViewSkinlet::scrollHandleRect(
         const auto subControlBar = QskScrollView::HorizontalScrollBar;
 
         const QRectF sbRect = subControlRect( scrollView, subControlBar );
-        const auto padding = scrollView->edgeMetrics( subControlBar, QskAspect::Padding );
+        const auto padding = scrollView->marginsHint( subControlBar | QskAspect::Padding );
 
         const qreal w = scrollView->scrollableSize().width();
 

src/controls/QskSimpleListBox.cpp

@@ -279,23 +279,19 @@ int QskSimpleListBox::columnCount() const
 
 qreal QskSimpleListBox::columnWidth( int col ) const
 {
-    using namespace QskAspect;
-
     if ( col >= columnCount() )
         return 0.0;
 
-    return m_data->maxTextWidth
+    const QMarginsF padding = marginsHint( Cell | QskAspect::Padding );
-           + metric( Cell | Padding | LeftEdge )
+    return m_data->maxTextWidth + padding.left() + padding.right();
-           + metric( Cell | Padding | RightEdge );
 }
 
 qreal QskSimpleListBox::rowHeight() const
 {
-    using namespace QskAspect;
+    const QMarginsF padding = marginsHint( Cell | QskAspect::Padding );
+    const QFontMetricsF fm( effectiveFont( Text ) );
 
-    return QFontMetrics( effectiveFont( Text ) ).height()
+    return fm.height() + padding.top() + padding.bottom();
-           + metric( Cell | Padding | TopEdge )
-           + metric( Cell | Padding | BottomEdge );
 }
 
 #include "moc_QskSimpleListBox.cpp"

src/controls/QskSkin.cpp

@@ -184,6 +184,16 @@ qreal QskSkin::metric( QskAspect::Aspect aspect ) const
     return m_data->hintTable.metric( aspect );
 }
 
+void QskSkin::setMargins( QskAspect::Aspect aspect, const QskMargins& margins )
+{
+    m_data->hintTable.setMargins( aspect, margins );
+}
+
+QskMargins QskSkin::margins( QskAspect::Aspect aspect ) const
+{
+    return m_data->hintTable.margins( aspect );
+}
+
 void QskSkin::setAnimation(
     QskAspect::Aspect aspect, QskAnimationHint animation )
 {

src/controls/QskSkin.h

@@ -28,6 +28,7 @@ class QskAnimationHint;
 class QskSkinHintTable;
 
 class QVariant;
+class QskMargins;
 
 class QSK_EXPORT QskSkin : public QObject
 {
@@ -65,6 +66,9 @@ public:
     void setMetric( QskAspect::Aspect, qreal metric );
     qreal metric( QskAspect::Aspect ) const;
 
+    void setMargins( QskAspect::Aspect, const QskMargins& );
+    QskMargins margins( QskAspect::Aspect ) const;
+
     void setAnimation( QskAspect::Aspect, QskAnimationHint );
     QskAnimationHint animation( QskAspect::Aspect ) const;
 

src/controls/QskSkinHintTable.h

@@ -8,6 +8,7 @@
 
 #include "QskGlobal.h"
 #include "QskAspect.h"
+#include "QskMargins.h"
 #include "QskAnimationHint.h"
 
 #include <QVariant>
@@ -31,6 +32,9 @@ public:
     void setMetric( QskAspect::Aspect, qreal metric );
     qreal metric( QskAspect::Aspect ) const;
 
+    void setMargins( QskAspect::Aspect, const QskMargins& );
+    QskMargins margins( QskAspect::Aspect ) const;
+
     void setAnimation( QskAspect::Aspect, QskAnimationHint animation );
     QskAnimationHint animation( QskAspect::Aspect ) const;
 
@@ -100,6 +104,16 @@ inline qreal QskSkinHintTable::metric( QskAspect::Aspect aspect ) const
     return skinHint( aspect | QskAspect::Metric ).toReal();
 }
 
+inline void QskSkinHintTable::setMargins( QskAspect::Aspect aspect, const QskMargins& margins )
+{
+    setSkinHint( aspect | QskAspect::Metric, QVariant::fromValue( margins ) );
+}
+
+inline QskMargins QskSkinHintTable::margins( QskAspect::Aspect aspect ) const
+{
+    return skinHint( aspect | QskAspect::Metric ).value< QskMargins >();
+}
+
 inline void QskSkinHintTable::setAnimation(
     QskAspect::Aspect aspect, QskAnimationHint animation )
 {

src/controls/QskSkinRenderer.cpp

@@ -208,7 +208,7 @@ static inline QskAspect::Edge qskRotateEdge( QskAspect::Edge edge, int count )
 QMarginsF QskSkinRenderer::margins( const QskSkinnable* skinnable,
     QskAspect::Subcontrol subControl, int rotation )
 {
-    const QMarginsF m = skinnable->edgeMetrics( subControl, QskAspect::Margin );
+    const QMarginsF m = skinnable->marginsHint( subControl | QskAspect::Margin );
     return qskRotatedMargins( m, rotation );
 }
 
@@ -250,10 +250,10 @@ QskBoxOptions QskSkinRenderer::boxOptions( const QskSkinnable* skinnable,
     QskBoxOptions options; 
 
     options.borders = qskRotatedMargins( 
-        skinnable->edgeMetrics( subControl, Border ), rotation );
+        skinnable->borderMetrics( subControl ), rotation );
 
     options.shadows = qskRotatedMargins(
-        skinnable->edgeMetrics( subControl, Shadow ), rotation );
+        skinnable->marginsHint( subControl | Shadow ), rotation );
 
     const auto leftEdge = qskRotateEdge( LeftEdge, rotation );
     const auto topEdge = qskRotateEdge( TopEdge, rotation );

src/controls/QskSkinnable.cpp

@@ -11,6 +11,7 @@
 #include "QskSkinHintTable.h"
 #include "QskSkinlet.h"
 #include "QskAnimationHint.h"
+#include "QskMargins.h"
 #include "QskHintAnimator.h"
 #include "QskControl.h"
 #include "QskColorFilter.h"
@@ -256,12 +257,22 @@ qreal QskSkinnable::metric( QskAspect::Aspect aspect, QskSkinHintStatus* status
     return effectiveHint( aspect | QskAspect::Metric, status ).toReal();
 }
 
-QMarginsF QskSkinnable::edgeMetrics( QskAspect::Subcontrol subControl,
+void QskSkinnable::setMarginsHint( QskAspect::Aspect aspect, const QMarginsF& margins )
-    QskAspect::BoxPrimitive primitive ) const
+{
+    m_data->hintTable.setMargins( aspect, margins );
+}
+
+QMarginsF QskSkinnable::marginsHint(
+    QskAspect::Aspect aspect, QskSkinHintStatus* status ) const
+{
+    return effectiveHint( aspect | QskAspect::Metric, status ).value< QskMargins >();
+}
+
+QMarginsF QskSkinnable::borderMetrics( QskAspect::Subcontrol subControl ) const
 {
     using namespace QskAspect;
 
-    const Aspect aspect = subControl | primitive;
+    const Aspect aspect = subControl | Border;
 
     return QMarginsF(
         metric( aspect | LeftEdge ),
@@ -523,28 +534,30 @@ static inline QMarginsF qskMarginsInner( const QskSkinnable* skinnable,
     qreal top = skinnable->metric( aspect | Border | TopEdge );
     qreal bottom = skinnable->metric( aspect | Border | BottomEdge );
 
+    const QMarginsF padding = skinnable->marginsHint( aspect | Padding );
+
     const qreal w = size.width() - 0.5 * ( left + right );
     const qreal h = size.height() - 0.5 * ( top + bottom );
 
     left += qskMax(
         qskPaddingInner( skinnable, aspect | RadiusX | TopLeftCorner, w ),
         qskPaddingInner( skinnable, aspect | RadiusX | BottomLeftCorner, w ),
-        (qreal) skinnable->metric( aspect | Padding | LeftEdge ) );
+        padding.left() );
 
     right += qskMax(
         qskPaddingInner( skinnable, aspect | RadiusX | TopRightCorner, w ),
         qskPaddingInner( skinnable, aspect | RadiusX | BottomRightCorner, w ),
-        (qreal)skinnable->metric( aspect | Padding | RightEdge ) );
+        padding.right() );
 
     top += qskMax(
         qskPaddingInner( skinnable, aspect | RadiusY | TopLeftCorner, h ),
         qskPaddingInner( skinnable, aspect | RadiusY | TopRightCorner, h ),
-        (qreal)skinnable->metric( aspect | Padding | TopEdge ) );
+        padding.top() );
 
     bottom += qskMax(
         qskPaddingInner( skinnable, aspect | RadiusY | BottomLeftCorner, h ),
         qskPaddingInner( skinnable, aspect | RadiusY | BottomRightCorner, h ),
-        (qreal)skinnable->metric( aspect | Padding | BottomEdge ) );
+        padding.bottom() );
 
     return QMarginsF( left, top, right, bottom );
 }
@@ -561,28 +574,30 @@ static inline QMarginsF qskMarginsOuter( const QskSkinnable* skinnable,
     qreal top = skinnable->metric( aspect | Border | TopEdge );
     qreal bottom = skinnable->metric( aspect | Border | BottomEdge );
 
+    const QMarginsF padding = skinnable->marginsHint( aspect | Padding );
+
     const qreal w = size.width() + 0.5 * ( left + right );
     const qreal h = size.height() + 0.5 * ( top + bottom );
 
     left += qskMax(
         qskPaddingOuter( skinnable, aspect | RadiusX | TopLeftCorner, w ),
         qskPaddingOuter( skinnable, aspect | RadiusX | BottomLeftCorner, w ),
-        (qreal)skinnable->metric( aspect | Padding | LeftEdge ) );
+        padding.left() );
 
     right += qskMax(
         qskPaddingOuter( skinnable, aspect | RadiusX | TopRightCorner, w ),
         qskPaddingOuter( skinnable, aspect | RadiusX | BottomRightCorner, w ),
-        (qreal)skinnable->metric( aspect | Padding | RightEdge ) );
+        padding.right() );
 
     top += qskMax(
         qskPaddingOuter( skinnable, aspect | RadiusY | TopLeftCorner, h ),
         qskPaddingOuter( skinnable, aspect | RadiusY | TopRightCorner, h ),
-        (qreal)skinnable->metric( aspect | Padding | TopEdge ) );
+        padding.top() );
 
     bottom += qskMax(
         qskPaddingOuter( skinnable, aspect | RadiusY | BottomLeftCorner, h ),
         qskPaddingOuter( skinnable, aspect | RadiusY | BottomRightCorner, h ),
-        (qreal)skinnable->metric( aspect | Padding | BottomEdge ) );
+        padding.bottom() );
 
     return QMargins( left, top, right, bottom );
 }

src/controls/QskSkinnable.h

@@ -76,12 +76,15 @@ public:
     void setMetric( QskAspect::Aspect, qreal metric );
     qreal metric( QskAspect::Aspect, QskSkinHintStatus* = nullptr ) const;
 
+    void setMarginsHint( QskAspect::Aspect, const QMarginsF& );
+    QMarginsF marginsHint( QskAspect::Aspect, QskSkinHintStatus* = nullptr ) const;
+
     void setFlagHint( QskAspect::Aspect, int flag );
     int flagHint( QskAspect::Aspect ) const;
 
     template< typename T > T flagHint( QskAspect::Aspect, T = T() ) const;
 
-    QMarginsF edgeMetrics( QskAspect::Subcontrol, QskAspect::BoxPrimitive ) const;
+    QMarginsF borderMetrics( QskAspect::Subcontrol ) const;
 
     void setFontRole( QskAspect::Aspect, int role );
     int fontRole( QskAspect::Aspect ) const;

src/controls/QskSliderSkinlet.cpp

@@ -15,7 +15,7 @@
 static QMarginsF qskMargins(
     const QskSlider* slider, QskAspect::Subcontrol subControl )
 {
-    QMarginsF m = slider->edgeMetrics( subControl, QskAspect::Margin );
+    QMarginsF m = slider->marginsHint( subControl | QskAspect::Margin );
 
     if ( slider->orientation() == Qt::Vertical )
         m = QMarginsF( m.top(), m.right(), m.bottom(), m.left() );
@@ -26,8 +26,8 @@ static QMarginsF qskMargins(
 static QMarginsF qskPadding(
     const QskSlider* slider, QskAspect::Subcontrol subControl )
 {
-    QMarginsF m = slider->edgeMetrics( subControl, QskAspect::Padding )
+    QMarginsF m = slider->marginsHint( subControl | QskAspect::Padding )
-        + slider->edgeMetrics( subControl, QskAspect::Border );
+        + slider->borderMetrics( subControl );
 
     if ( slider->orientation() == Qt::Vertical )
         m = QMarginsF( m.top(), m.right(), m.bottom(), m.left() );

src/controls/QskSubWindowSkinlet.cpp

@@ -134,12 +134,11 @@ qreal QskSubWindowSkinlet::titleBarHeight( const QskSubWindow* subWindow ) const
         return 0;
 
     const QFontMetricsF fm( subWindow->effectiveFont( QskSubWindow::TitleBar ) );
+    const QMarginsF margins = subWindow->marginsHint( QskSubWindow::TitleBar | Padding );
 
-    qreal height = fm.height()
+    const qreal height = fm.height() + margins.top() + margins.bottom();
-        + subWindow->metric( QskSubWindow::TitleBar | Padding | TopEdge )
+    const qreal minHeight = subWindow->metric( QskSubWindow::TitleBar | MinimumHeight );
-        + subWindow->metric( QskSubWindow::TitleBar | Padding | BottomEdge );
 
-    qreal minHeight = subWindow->metric( QskSubWindow::TitleBar | MinimumHeight );
     return qMax( height, minHeight);
 }
 

src/controls/QskVariantAnimator.cpp

@@ -5,6 +5,7 @@
 
 #include "QskVariantAnimator.h"
 #include "QskColorFilter.h"
+#include "QskMargins.h"
 
 // Even if we don't use the standard Qt animation system we
 // use its registry of interpolators: why adding our own ...
@@ -16,6 +17,7 @@
 static void qskRegisterInterpolator()
 {
     qRegisterAnimationInterpolator<QskColorFilter>( QskColorFilter::interpolate );
+    qRegisterAnimationInterpolator<QskMargins>( QskMargins::interpolate );
 }
 
 Q_CONSTRUCTOR_FUNCTION( qskRegisterInterpolator )

src/skins/material/QskMaterialSkin.cpp

@@ -25,6 +25,7 @@
 #include <QskFunctions.h>
 #include <QskRgbValue.h>
 #include <QskAnimationHint.h>
+#include <QskMargins.h>
 #include <QskSkinlet.h>
 
 #if 1
@@ -149,7 +150,7 @@ void QskMaterialSkin::initCommonHints()
 
     const ColorPalette& pal = m_data->palette;
 
-    setMetric( Control | Padding, 4 );
+    setMargins( Control | Padding, 4 );
 
     setColor( Control | Background, pal.baseColor );
     setColor( Control | Border, pal.darker200 );
@@ -189,7 +190,7 @@ void QskMaterialSkin::initFocusIndicatorHints()
     const ColorPalette& pal = m_data->palette;
 
     setMetric( Q::Panel | Border, 2 );
-    setMetric( Q::Panel | Padding, 5 );
+    setMargins( Q::Panel | Padding, 5 );
     setColor( Q::Panel | Border, pal.accentColor );
 }
 
@@ -229,8 +230,8 @@ void QskMaterialSkin::initPageIndicatorHints()
     setMetric( Q::Highlighted | Radius, 6 );
 #endif
 
-    setMetric( Q::Panel | Margin, 0 );
+    setMargins( Q::Panel | Margin, 0 );
-    setMetric( Q::Panel | Padding, 0 );
+    setMargins( Q::Panel | Padding, 0 );
     setMetric( Q::Panel | Border, 0 );
     setColor( Q::Panel | Background, 0 );
 
@@ -250,16 +251,17 @@ void QskMaterialSkin::initPushButtonHints()
     setSkinHint( Q::Text | QskAspect::FontRole, ButtonFontRole );
     setSkinHint( Q::Text | QskAspect::Alignment, Qt::AlignCenter );
 
+    const QskMargins margin( 4, 3 );
+    const QskMargins padding( 10, 6 );
+
     {
         const auto aspect = Q::Panel;
 
-        setMetric( aspect | Radius, 2.0f );
+        setMetric( aspect | Radius, 2 );
 
-        setMetric( aspect | Padding | HorizontalEdges, 6.0f );
+        setMargins( aspect | Margin, margin );
-        setMetric( aspect | Padding | VerticalEdges, 10.0f );
+        setMargins( aspect | Padding, padding );
-
+        setMargins( aspect | Shadow, 0 );
-        setMetric( aspect | Margin | HorizontalEdges, 3.0f );
-        setMetric( aspect | Margin | VerticalEdges, 4.5f );
 
         setMetric( aspect | Spacing, 4 );
     }
@@ -269,30 +271,20 @@ void QskMaterialSkin::initPushButtonHints()
     {
         const auto aspect = Q::Panel | state;
 
-        setMetric( aspect | Padding | TopEdge, 4.0f );
+        setMargins( aspect | Margin, margin.translated( 0, -margin.top() ) );
-        setMetric( aspect | Padding | BottomEdge, 8.0f );
+        setMargins( aspect | Padding, padding.translated( 0, -2 ) );
-
+        setMargins( aspect | Shadow, QskMargins( 4, -1.0, 4, 5.0 ) );
-        setMetric( aspect | Margin | TopEdge, 0.0f );
-        setMetric( aspect | Margin | BottomEdge, 6.0f );
-
-        setMetric( aspect | Shadow | VerticalEdges, 4.5f );
-        setMetric( aspect | Shadow | TopEdge, -1.0f );
-        setMetric( aspect | Shadow | BottomEdge, 5.0f );
     }
 
-    // Hover (or normal for touch)
     for ( const auto state :
         { Q::Hovered, Q::Checked | Q::Checkable
           | Q::Hovered, Q::Checkable | Q::Hovered } )
     {
-        const auto aspect = Q::Panel | Shadow | state;
+        const auto aspect = Q::Panel | state;
-
+        setMargins( aspect | Shadow, QskMargins( 2, 2, 2, 4 ) );
-        setMetric( aspect | VerticalEdges, 2.5f );
-        setMetric( aspect | TopEdge, 1.5f );
-        setMetric( aspect | BottomEdge, 3.0f );
     }
 
-    setMetric( Q::Panel | Q::Flat | Shadow, 0 );
+    setMargins( Q::Panel | Q::Flat | Shadow, 0 );
 
     setAnimation( Q::Panel | Color, qskDuration );
     setAnimation( Q::Panel | Margin | Metric, qskDuration );
@@ -355,27 +347,15 @@ void QskMaterialSkin::initDialogButtonHints()
 
     setMetric( Q::Panel | Radius, 2.0f );
 
-    setMetric( Q::Panel | Padding | HorizontalEdges, 6.0f );
+    setMargins( Q::Panel | Margin, QskMargins( 3, 4.5 ) );
-    setMetric( Q::Panel | Padding | VerticalEdges, 10.0f );
+    setMargins( Q::Panel | Padding, QskMargins( 10, 6 ) );
-
-    setMetric( Q::Panel | Margin | HorizontalEdges, 3.0f );
-    setMetric( Q::Panel | Margin | VerticalEdges, 4.5f );
 
     setMetric( Q::Panel | Spacing, 4 );
 
-    setMetric( Q::Panel | Q::Pressed | Padding | TopEdge, 4.0f );
+    setMargins( Q::Panel | Q::Pressed | Margin, QskMargins( 3, 0, 3, 6 ) );
-    setMetric( Q::Panel | Q::Pressed | Padding | BottomEdge, 8.0f );
+    setMargins( Q::Panel | Q::Pressed | Padding, QskMargins( 10, 4, 10, 8 ) );
-
+    setMargins( Q::Panel | Q::Pressed | Shadow, QskMargins( 4.5, -1, 4.5, 5 ) );
-    setMetric( Q::Panel | Q::Pressed | Margin | TopEdge, 0.0f );
+    setMargins( Q::Panel | Q::Hovered | Shadow, QskMargins( 2.5, 1.5, 2.5, 3 ) );
-    setMetric( Q::Panel | Q::Pressed | Margin | BottomEdge, 6.0f );
-
-    setMetric( Q::Panel | Q::Pressed | Shadow | VerticalEdges, 4.5f );
-    setMetric( Q::Panel | Q::Pressed | Shadow | TopEdge, -1.0f );
-    setMetric( Q::Panel | Q::Pressed | Shadow | BottomEdge, 5.0f );
-
-    setMetric( Q::Panel | Q::Hovered | Shadow | VerticalEdges, 2.5f );
-    setMetric( Q::Panel | Q::Hovered | Shadow | TopEdge, 1.5f );
-    setMetric( Q::Panel | Q::Hovered | Shadow | BottomEdge, 3.0f );
 
     setAnimation( Q::Panel | Color, qskDuration );
     setAnimation( Q::Panel | Margin | Metric, qskDuration );
@@ -414,12 +394,12 @@ void QskMaterialSkin::initSliderHints()
 
     setMetric( Q::Panel | Size, dim );
     setMetric( Q::Panel | Border, 0 );
-    setMetric( Q::Panel | Padding | VerticalEdges, 0.5 * dim );
+    setMargins( Q::Panel | Padding, QskMargins( 0.5 * dim, 0 ) );
 
     for ( auto subControl : { Q::Groove, Q::Fill } )
     {
         setMetric( subControl | Border, 0 );
-        setMetric( subControl | Padding, 0 );
+        setMargins( subControl | Padding, 0 );
         setMetric( subControl | Size, 5 );
         setMetric( subControl | Radius, 0 );
     }
@@ -516,7 +496,7 @@ void QskMaterialSkin::initInputPanelHints()
     // frame
     setMetric( Q::KeyFrame | Border, 2 );
     setMetric( Q::KeyFrame | Radius, 4 );
-    setMetric( Q::KeyFrame | Margin, 2 );
+    setMargins( Q::KeyFrame | Margin, 2 );
 
     setColor( Q::KeyFrame, pal.baseColor );
     setColor( Q::KeyFrame | Q::Pressed, pal.accentColor );
@@ -556,7 +536,7 @@ void QskMaterialSkin::initScrollViewHints()
     for ( auto subControl : { Q::HorizontalScrollBar, Q::VerticalScrollBar } )
     {
         setMetric( subControl | Size, 12 );
-        setMetric( subControl | Padding, 0 );
+        setMargins( subControl | Padding, 0 );
     }   
     
     setMetric( Q::HorizontalScrollHandle | MinimumWidth, qskDpiScaled( 40.0 ) );
@@ -564,7 +544,7 @@ void QskMaterialSkin::initScrollViewHints()
 
     for ( auto subControl : { Q::HorizontalScrollHandle, Q::VerticalScrollHandle } )
     {
-        setMetric( subControl | Margin, 0 );
+        setMargins( subControl | Margin, 0 );
         setMetric( subControl | Radius, 3 );
         setMetric( subControl | Border, 1 );
 
@@ -591,8 +571,7 @@ void QskMaterialSkin::initListViewHints()
     const ColorPalette& pal = m_data->palette;
 
     // padding for each cell
-    setMetric( Q::Cell | Padding | HorizontalEdges, 8 );
+    setMargins( Q::Cell | Padding, QskMargins( 4, 8 ) );
-    setMetric( Q::Cell | Padding | VerticalEdges, 4 );
 
     setAnimation( Q::CellSelected | Color, qskDuration );
     setAnimation( Q::TextSelected | Color, qskDuration );
@@ -616,7 +595,7 @@ void QskMaterialSkin::initSubWindowHints()
     // panel
 
     setMetric( Q::Panel | Border, 2 );
-    setMetric( Q::Panel | Padding, 10 );
+    setMargins( Q::Panel | Padding, 10 );
 
     setColor( Q::Panel | Border | LeftEdge | TopEdge, pal.lighter125 );
     setColor( Q::Panel | Border | RightEdge | BottomEdge, pal.darker200 );

src/skins/squiek/QskSquiekSkin.cpp

@@ -25,6 +25,7 @@
 #include <QskFunctions.h>
 #include <QskRgbValue.h>
 #include <QskAnimationHint.h>
+#include <QskMargins.h>
 #include <QskSkinlet.h>
 
 static const int qskDuration = 200;
@@ -173,7 +174,7 @@ void QskSquiekSkin::initCommonHints()
 
     const ColorPalette& pal = m_data->palette;
 
-    setMetric( Control | Padding, 4 );
+    setMargins( Control | Padding, 4 );
 
     setColor( Control | Background, pal.lighter135 );
     setColor( Control | Border, pal.darker200 );
@@ -210,7 +211,7 @@ void QskSquiekSkin::initFocusIndicatorHints()
 
     setMetric( Q::Panel | Border, 2 );
     setMetric( Q::Panel | Radius, 4 );
-    setMetric( Q::Panel | Padding, 5 );
+    setMargins( Q::Panel | Padding, 5 );
 
     setColor( Q::Panel | Border, pal.highlighted );
 }
@@ -242,8 +243,8 @@ void QskSquiekSkin::initPageIndicatorHints()
     setMetric( Q::Highlighted | Size, 8 );
     setMetric( Q::Highlighted | Radius, 4 );
 
-    setMetric( Q::Panel | Margin, 0 );
+    setMargins( Q::Panel | Margin, 0 );
-    setMetric( Q::Panel | Padding, 0 );
+    setMargins( Q::Panel | Padding, 0 );
     setMetric( Q::Panel | Border, 0 );
     setColor( Q::Panel | Background, 0 );
 
@@ -264,7 +265,7 @@ void QskSquiekSkin::initPushButtonHints()
     setMetric( Q::Panel | Border | HorizontalEdges, 2 );
     setMetric( Q::Panel | Border | VerticalEdges, 1 );
 
-    setMetric( Q::Panel | Padding, 10 );
+    setMargins( Q::Panel | Padding, 10 );
     setMetric( Q::Panel | Spacing, 4 );
 
     setSkinHint( Q::Text | Q::Disabled | Style, Qsk::Sunken );
@@ -307,7 +308,7 @@ void QskSquiekSkin::initDialogButtonHints()
     setMetric( Q::Panel | Border | HorizontalEdges, 2 );
     setMetric( Q::Panel | Border | VerticalEdges, 1 );
 
-    setMetric( Q::Panel | Padding, 10 );
+    setMargins( Q::Panel | Padding, 10 );
     setMetric( Q::Panel | Spacing, 4 );
 
     setMetric( Q::Panel | MinimumWidth, qskDpiScaled( 75.0 ) );
@@ -339,23 +340,15 @@ void QskSquiekSkin::initTabButtonHints()
 
     setMetric( Q::Panel | Radius | TopCorners, 3 );
     setMetric( Q::Panel | Border | LeftEdge | TopEdge | RightEdge, 1 );
-    setMetric( Q::Panel | Padding | VerticalEdges, 10 );
+    setMargins( Q::Panel | Padding, QskMargins( 10, 4 ) );
-    setMetric( Q::Panel | Padding | HorizontalEdges, 4 );
     setMetric( Q::Panel | MinimumWidth, 30 );
     setMetric( Q::Panel | MinimumHeight, 16 );
 
     for ( const auto state : { NoState } )
-    {
+        setMargins( Q::Panel | Margin | state, QskMargins( -1, 2, -1, 0 ) );
-        setMetric( Q::Panel | Margin | TopEdge | state, 2 );
-        setMetric( Q::Panel | Margin | BottomEdge | state, 0 );
-        setMetric( Q::Panel | Margin | VerticalEdges | state, -1 );
-    }
 
     for ( const auto state : { Q::Checked, Q::Checked | Q::Pressed } )
-    {
+        setMargins( Q::Panel | Margin | state, QskMargins( -1, 0, -1, -1 ) );
-        setMetric( Q::Panel | Margin | TopEdge | state, 0 );
-        setMetric( Q::Panel | Margin | BottomEdge | state, -1 );
-    }
 
     setSkinHint( Q::Text | QskAspect::Alignment, Qt::AlignCenter );
 #if 0
@@ -393,13 +386,12 @@ void QskSquiekSkin::initSliderHints()
     setMetric( Q::Panel | Size, dim ); 
     setMetric( Q::Panel | Border, 0 );
 
-    setMetric( Q::Panel | Padding | HorizontalEdges, 0 );
+    setMargins( Q::Panel | Padding, QskMargins( 0.5 * dim, 0 ) );
-    setMetric( Q::Panel | Padding | VerticalEdges, 0.5 * dim );
 
     for ( auto subControl : { Q::Groove, Q::Fill } )
     {
         setMetric( subControl | Border, 0 );
-        setMetric( subControl | Padding, 0 );
+        setMargins( subControl | Padding, 0 );
         setMetric( subControl | Size, 0.3 * dim );
         setMetric( subControl | Radius, 0.1 * dim );
     }
@@ -427,8 +419,11 @@ void QskSquiekSkin::initTabBarHints()
     using namespace QskAspect;
     using Q = QskTabBar;
 
-    for ( auto aspect : { Radius, Border, Padding, Margin } )
+    setMetric( Q::Panel | Radius, 0 );
-        setMetric( Q::Panel | aspect, 0 );
+    setMetric( Q::Panel | Border, 0 );
+
+    setMargins( Q::Panel | Margin, 0 );
+    setMargins( Q::Panel | Padding, 0 );
 
     setColor( Q::Panel | Background, 0 );
 }
@@ -461,7 +456,7 @@ void QskSquiekSkin::initInputPanelHints()
     // frame
     setMetric( Q::KeyFrame | Border, 2 );
     setMetric( Q::KeyFrame | Radius, 4 );
-    setMetric( Q::KeyFrame | Margin, 2 );
+    setMargins( Q::KeyFrame | Margin, 2 );
 
     setAnimation( Q::KeyFrame | Color, qskDuration ); 
     setAnimation( Q::KeyFrame | Color | Border, qskDuration );
@@ -494,13 +489,13 @@ void QskSquiekSkin::initScrollViewHints()
     for ( auto subControl : { Q::HorizontalScrollBar, Q::VerticalScrollBar } )
     {
         setMetric( subControl | Size, 8 );
-        setMetric( subControl | Padding, 0 );
+        setMargins( subControl | Padding, 0 );
-        setMetric( subControl | Margin, 0 );
+        setMargins( subControl | Margin, 0 );
     }
 
     for ( auto subControl : { Q::HorizontalScrollHandle, Q::VerticalScrollHandle } )
     {
-        setMetric( subControl | Margin, 0 );
+        setMargins( subControl | Margin, 0 );
         setMetric( subControl | Radius, 3 );
         setMetric( subControl | Border, 1 );
 
@@ -523,8 +518,7 @@ void QskSquiekSkin::initListViewHints()
     const ColorPalette& pal = m_data->palette;
 
     // padding for each cell
-    setMetric( Q::Cell | Padding | HorizontalEdges, 8 );
+    setMargins( Q::Cell | Padding, QskMargins( 4, 8 ) );
-    setMetric( Q::Cell | Padding | VerticalEdges, 4 );
 
     setAnimation( Q::CellSelected | Color, qskDuration );
     setAnimation( Q::TextSelected | Color, qskDuration );
@@ -544,7 +538,7 @@ void QskSquiekSkin::initSubWindowHints()
     const ColorPalette& pal = m_data->palette;
 
     setMetric( Q::Panel | Border, 2 );
-    setMetric( Q::Panel | Padding, 10 );
+    setMargins( Q::Panel | Padding, 10 );
     setMetric( Q::TitleBar | Border, 2 );
 
     setSkinHint( Q::TitleBar | FontRole, int( QskSkin::TinyFont ) );

src/src.pro

@@ -37,6 +37,7 @@ HEADERS += \
     common/QskFunctions.h \
     common/QskGlobal.h \
     common/QskGradient.h \
+    common/QskMargins.h \
     common/QskModule.h \
     common/QskNamespace.h \
     common/QskObjectCounter.h \
@@ -49,6 +50,7 @@ SOURCES += \
     common/QskCorner.cpp \
     common/QskFunctions.cpp \
     common/QskGradient.cpp \
+    common/QskMargins.cpp \
     common/QskModule.cpp \
     common/QskObjectCounter.cpp \
     common/QskSizePolicy.cpp \