use Flag enumeration to describe button position

add horizontal offset for rendering
properly extend horizontal hit area for buttons in maximize mode, padding is preserved, but Fitts law is fullfilled.

kdecoration/breezebutton.cpp

@@ -53,7 +53,7 @@ namespace Breeze
     //__________________________________________________________________
     Button::Button(QObject *parent, const QVariantList &args)
         : DecorationButton(args.at(0).value<KDecoration2::DecorationButtonType>(), args.at(1).value<Decoration*>(), parent)
-        , m_standalone(true)
+        , m_flag(FlagStandalone)
         , m_animation( new QPropertyAnimation( this ) )
     {}
 
@@ -83,7 +83,10 @@ namespace Breeze
         if (!decoration()) return;
 
         painter->save();
-        painter->translate( 0, m_verticalOffset );
+
+        // translate from offset
+        if( m_flag == FlagFirstInList ) painter->translate( m_offset );
+        else painter->translate( 0, m_offset.y() );
 
         if (type() == KDecoration2::DecorationButtonType::Menu)
         {
@@ -112,7 +115,9 @@ namespace Breeze
         all further rendering is preformed inside QRect( 0, 0, 18, 18 )
         */
         painter->translate( geometry().topLeft() );
-        painter->scale( geometry().width()/20, geometry().width()/20 );
+
+        const int width( geometry().width() - m_offset.x() );
+        painter->scale( width/20, width/20 );
         painter->translate( 1, 1 );
 
         // render background

kdecoration/breezebutton.h

@@ -52,12 +52,33 @@ namespace Breeze
         //* create
         static Button *create(KDecoration2::DecorationButtonType type, KDecoration2::Decoration *decoration, QObject *parent);
 
+        //* flag
+        enum Flag
+        {
+            FlagNone,
+            FlagStandalone,
+            FlagFirstInList,
+            FlagLastInList
+        };
+
+        //* flag
+        void setFlag( Flag value )
+        { m_flag = value; }
+
         //* standalone buttons
-        bool isStandAlone() const { return m_standalone; }
+        bool isStandAlone() const { return m_flag == FlagStandalone; }
+
+        //* offset
+        void setOffset( const QPointF& value )
+        { m_offset = value; }
+
+        //* horizontal offset, for rendering
+        void setHorizontalOffset( qreal value )
+        { m_offset.setX( value ); }
 
         //* vertical offset, for rendering
-        void setVerticalOffset( int value )
-        { m_verticalOffset = value; }
+        void setVerticalOffset( qreal value )
+        { m_offset.setY( value ); }
 
         //*@name active state change animation
         //@{
@@ -92,13 +113,13 @@ namespace Breeze
         QColor backgroundColor( void ) const;
         //@}
 
-        bool m_standalone = false;
+        Flag m_flag = FlagNone;
 
         //* active state change animation
         QPropertyAnimation *m_animation;
 
         //* vertical offset (for rendering)
-        int m_verticalOffset = 0;
+        QPointF m_offset;
 
         //* active state change opacity
         qreal m_opacity = 0;

kdecoration/breezedecoration.cpp

@@ -330,7 +330,29 @@ namespace Breeze
         foreach( const QPointer<KDecoration2::DecorationButton>& button, m_leftButtons->buttons() + m_rightButtons->buttons() )
         {
             button.data()->setGeometry( QRectF( QPoint( 0, 0 ), QSizeF( bWidth, bHeight ) ) );
-            static_cast<Button*>( button.data() )->setVerticalOffset( verticalOffset );
+            static_cast<Button*>( button.data() )->setOffset( QPointF( 0, verticalOffset ) );
+        }
+
+        if( isMaximized() )
+        {
+            // add offsets on the side buttons, to preserve padding, but satisfy Fitts law
+            const int hOffset = s->smallSpacing()*Metrics::TitleBar_SideMargin;
+            if( !m_leftButtons->buttons().isEmpty() )
+            {
+                auto button = static_cast<Button*>( m_leftButtons->buttons().front().data() );
+                button->setGeometry( QRectF( QPoint( 0, 0 ), QSizeF( bWidth + hOffset, bHeight ) ) );
+                button->setFlag( Button::FlagFirstInList );
+                button->setHorizontalOffset( hOffset );
+            }
+
+            if( !m_rightButtons->buttons().isEmpty() )
+            {
+                auto button = static_cast<Button*>( m_rightButtons->buttons().back().data() );
+                button->setGeometry( QRectF( QPoint( 0, 0 ), QSizeF( bWidth + hOffset, bHeight ) ) );
+                button->setFlag( Button::FlagLastInList );
+                button->setHorizontalOffset( hOffset );
+            }
+
         }
 
         // adjust buttons position