Single items are dragged by their origin in GAL canvas.

pcbnew/tools/edit_tool.cpp

@@ -143,14 +143,11 @@ int EDIT_TOOL::Main( TOOL_EVENT& aEvent )
             if( m_dragging )
             {
                 wxPoint movement = wxPoint( m_cursor.x, m_cursor.y ) -
-                        static_cast<BOARD_ITEM*>( selection.items.GetPickedItem( 0 ) )->GetPosition();
+                                   selection.Item<BOARD_ITEM>( 0 )->GetPosition();
 
                 // Drag items to the current cursor position
                 for( unsigned int i = 0; i < selection.items.GetCount(); ++i )
-                {
-                    BOARD_ITEM* item = static_cast<BOARD_ITEM*>( selection.items.GetPickedItem( i ) );
-                    item->Move( movement + m_offset );
-                }
+                    selection.Item<BOARD_ITEM>( i )->Move( movement );
 
                 updateRatsnest( true );
             }
@@ -160,9 +157,9 @@ int EDIT_TOOL::Main( TOOL_EVENT& aEvent )
                 editFrame->OnModify();
                 editFrame->SaveCopyInUndoList( selection.items, UR_CHANGED );
 
-                // Update dragging offset (distance between cursor and the first dragged item)
-                m_offset = static_cast<BOARD_ITEM*>( selection.items.GetPickedItem( 0 ) )->GetPosition() -
-                                                     wxPoint( m_cursor.x, m_cursor.y );
+                // Set the current cursor position to the first dragged item origin, so the
+                // movement vector could be computed later
+                m_cursor = VECTOR2I( selection.Item<BOARD_ITEM>( 0 )->GetPosition() );
                 m_dragging = true;
             }
 
@@ -312,10 +309,6 @@ int EDIT_TOOL::Rotate( TOOL_EVENT& aEvent )
 
     updateRatsnest( m_dragging );
 
-    // Update dragging offset (distance between cursor and the first dragged item)
-    m_offset = static_cast<BOARD_ITEM*>( selection.items.GetPickedItem( 0 ) )->GetPosition() -
-                                         rotatePoint;
-
     if( m_dragging )
         selection.group->ViewUpdate( KIGFX::VIEW_ITEM::GEOMETRY );
     else
@@ -366,10 +359,6 @@ int EDIT_TOOL::Flip( TOOL_EVENT& aEvent )
 
     updateRatsnest( m_dragging );
 
-    // Update dragging offset (distance between cursor and the first dragged item)
-    m_offset = static_cast<BOARD_ITEM*>( selection.items.GetPickedItem( 0 ) )->GetPosition() -
-                                         flipPoint;
-
     if( m_dragging )
         selection.group->ViewUpdate( KIGFX::VIEW_ITEM::GEOMETRY );
     else
@@ -502,7 +491,7 @@ wxPoint EDIT_TOOL::getModificationPoint( const SELECTION_TOOL::SELECTION& aSelec
 {
     if( aSelection.Size() == 1 )
     {
-        return static_cast<BOARD_ITEM*>( aSelection.items.GetPickedItem( 0 ) )->GetPosition() - m_offset;
+        return aSelection.Item<BOARD_ITEM>( 0 )->GetPosition();
     }
     else
     {

pcbnew/tools/edit_tool.h

@@ -98,9 +98,6 @@ private:
     ///> Flag determining if anything is being dragged right now
     bool m_dragging;
 
-    ///> Offset from the dragged item's center (anchor)
-    wxPoint m_offset;
-
     ///> Last cursor position (needed for getModificationPoint() to avoid changes
     ///> of edit reference point).
     VECTOR2I m_cursor;