From now on dragged widgets will be re-aligned on drop. They will find the nearest hotspot of the group they are dropped into, and calculate an offset so they will align to the hotspot and yet remain where they were dropped.

code/nel/include/nel/gui/interface_element.h

@@ -518,6 +518,15 @@ namespace NLGUI
 			_YReal += y;
 		}
 
+		/// Retrieves the coordinates of the specified hotspot
+		void getHSCoords( const THotSpot &hs, sint32 &x, sint32 &y ) const;
+
+		/// Tells which hotspot is the closest to the specified element
+		void getClosestHotSpot( const CInterfaceElement *other, THotSpot &hs );
+
+		/// Aligns the element to the other element specified
+		void alignTo( CInterfaceElement *other );
+
 	protected:
 
 		bool editorSelected;

code/nel/src/gui/interface_element.cpp

@@ -1594,6 +1594,97 @@ namespace NLGUI
 		}
 	}
 
+	void CInterfaceElement::getHSCoords( const THotSpot &hs, sint32 &x, sint32 &y ) const
+	{
+		x = _XReal;
+		y = _YReal;
+
+		if( ( hs & Hotspot_Mx ) != 0 )
+			y += _HReal / 2;
+		else
+		if( ( hs & Hotspot_Tx ) != 0 )
+			y += _HReal;
+
+
+		if( ( hs & Hotspot_xM ) != 0 )
+			x += _WReal / 2;
+		else
+		if( ( hs & Hotspot_xR ) != 0 )
+			x += _WReal;
+	}
+
+	void CInterfaceElement::getClosestHotSpot( const CInterfaceElement *other, THotSpot &hs )
+	{
+		/// Iterate over the following hotspots, calculate the distance and store the closest
+
+
+		static THotSpot hslist[] =
+		{
+			Hotspot_BL,
+			Hotspot_BR,
+			Hotspot_MM,
+			Hotspot_TL,
+			Hotspot_TR
+		};
+
+		int c = sizeof( hslist ) / sizeof( THotSpot );
+
+		int x,y,ox,oy,vx,vy;
+		float d;
+		float closestd = 9999999.0f;
+		THotSpot closestHS = Hotspot_TR;
+
+		for( int i = 0; i < c; i++ )
+		{
+			other->getHSCoords( hslist[ i ], ox, oy );
+			getHSCoords( hslist[ i ], x, y );
+
+			// Make a vector between the two hotspots
+			vx = x - ox;
+			vy = y - oy;
+
+			// Calculate length
+			d = sqrt( pow( vx, 2.0f ) + pow( vy, 2.0f ) );
+
+			// If these hotspots are the closest, store the hotspot
+			if( d < closestd )
+			{
+				closestd = d;
+				closestHS = hslist[ i ];
+			}
+		}
+
+		hs = closestHS;
+	}
+
+	void CInterfaceElement::alignTo( CInterfaceElement *other )
+	{
+		if( other == this )
+			return;
+
+		// Check which hotspot is the closest
+		THotSpot hs;
+		other->getClosestHotSpot( this, hs );
+
+		// Get the hotspot coordinates
+		sint32 x, y, ox, oy;
+		getHSCoords( hs, x, y );
+		other->getHSCoords( hs, ox, oy );
+
+		// Calculate the difference between the hotspot we found and our current position,
+		sint32 dx = ox - x;
+		sint32 dy = oy - y;
+
+		// This difference is our offset, so we remain in the same position
+		setX( -1 * dx );
+		setY( -1 * dy );
+
+		setPosRef( hs );
+		setParentPosRef( hs );
+
+		invalidateCoords();
+	}
+
 	CStringMapper* CStringShared::_UIStringMapper = NULL;
 
 

code/nel/src/gui/widget_manager.cpp

@@ -2683,7 +2683,8 @@ namespace NLGUI
 			e->setParentSize( g );
 			g->addElement( e );
 
-			e->setName( "==MARKED==" );
+			e->alignTo( g );
+			//e->setName( "==MARKED==" );
 
 			draggedElement = NULL;