Introduce _breeze_menu_is_top property for drawing menus

This property, when set, will cause menus to drop their top border + their top corner rounding.

kstyle/breezehelper.cpp

@@ -594,14 +594,22 @@ namespace Breeze
     //______________________________________________________________________________
     void Helper::renderMenuFrame(
         QPainter* painter, const QRect& rect,
-        const QColor& color, const QColor& outline, bool roundCorners ) const
+        const QColor& color, const QColor& outline, bool roundCorners, bool isTopMenu ) const
     {
 
 
+        painter->save();
+
         // set brush
         if( color.isValid() ) painter->setBrush( color );
         else painter->setBrush( Qt::NoBrush );
 
+        // We simulate being able to independently adjust corner radii by
+        // setting a clip region and then extending the rectangle beyond it.
+        if ( isTopMenu ) {
+            painter->setClipRect( rect );
+        }
+
         if( roundCorners )
         {
 
@@ -609,6 +617,8 @@ namespace Breeze
             QRectF frameRect( rect );
             qreal radius( frameRadius( PenWidth::NoPen ) );
 
+            if( isTopMenu ) frameRect.adjust(0, -radius, 0, 0);
+
             // set pen
             if( outline.isValid() )
             {
@@ -626,6 +636,8 @@ namespace Breeze
 
             painter->setRenderHint( QPainter::Antialiasing, false );
             QRect frameRect( rect );
+            if( isTopMenu ) frameRect.adjust(0, 1, 0, 0);
+
             if( outline.isValid() )
             {
 
@@ -638,6 +650,8 @@ namespace Breeze
 
         }
 
+        painter->restore();
+
     }
 
     //______________________________________________________________________________

kstyle/breezehelper.h

@@ -171,7 +171,7 @@ namespace Breeze
         void renderSidePanelFrame( QPainter*, const QRect&, const QColor& outline, Side ) const;
 
         //* menu frame
-        void renderMenuFrame( QPainter*, const QRect&, const QColor& color, const QColor& outline, bool roundCorners = true ) const;
+        void renderMenuFrame( QPainter*, const QRect&, const QColor& color, const QColor& outline, bool roundCorners = true, bool isTopMenu = false ) const;
 
         //* button frame
         void renderButtonFrame( QPainter*, const QRect&, const QColor& color, const QColor& outline, const QColor& shadow, bool focus, bool sunken ) const;

kstyle/breezepropertynames.cpp

@@ -19,5 +19,6 @@ namespace Breeze
     const char PropertyNames::alteredBackground[] = "_breeze_altered_background";
     const char PropertyNames::highlightNeutral[] = "_kde_highlight_neutral";
     const char PropertyNames::noSeparator[] = "_breeze_no_separator";
+    const char PropertyNames::isTopMenu[] = "_breeze_menu_is_top";
 
 }

kstyle/breezepropertynames.h

@@ -22,6 +22,7 @@ namespace Breeze
         static const char alteredBackground[];
         static const char highlightNeutral[];
         static const char noSeparator[];
+        static const char isTopMenu[];
     };
 
 }

kstyle/breezestyle.cpp

@@ -3748,6 +3748,7 @@ namespace Breeze
 
         const auto& palette( option->palette );
         const bool hasAlpha( _helper->hasAlphaChannel( widget ) );
+        const bool isTopMenu( widget != nullptr && widget->property(PropertyNames::isTopMenu).toBool() );
         auto background( _helper->frameBackgroundColor( palette ) );
         auto outline( _helper->frameOutlineColor( palette ) );
 
@@ -3761,7 +3762,7 @@ namespace Breeze
             outline = _helper->alphaColor( palette.color( QPalette::WindowText ), 0.25 );
         }
 
-        _helper->renderMenuFrame( painter, option->rect, background, outline, hasAlpha );
+        _helper->renderMenuFrame( painter, option->rect, background, outline, hasAlpha, isTopMenu );
 
         painter->restore();
         
@@ -4822,7 +4823,7 @@ namespace Breeze
             Sides sides;
             if( !menuItemOption->menuRect.isNull() )
             {
-                if( rect.top() <= menuItemOption->menuRect.top() ) sides |= SideTop;
+                if( rect.top() <= menuItemOption->menuRect.top() && !(widget && widget->property(PropertyNames::isTopMenu).toBool()) ) sides |= SideTop;
                 if( rect.bottom() >= menuItemOption->menuRect.bottom() ) sides |= SideBottom;
                 if( rect.left() <= menuItemOption->menuRect.left() ) sides |= SideLeft;
                 if( rect.right() >= menuItemOption->menuRect.right() ) sides |= SideRight;