Public Sub Flip()
On Error Resume Next
Dim l_undUndo As cMultiUndoEntry, l_brsBrush As Fury2Brush
Dim l_undTileUndo As cTileUndoEntry, l_undBlockingUndo As cBlockingUndoEntry, l_undObjectUndo As cObjectUndoEntry, l_undPropertyUndo As cPropertyUndoEntry
Dim l_lyrLayer As Fury2MapLayer, l_sprSprite As Fury2Sprite, l_araArea As Fury2Area, l_lngLines As Long
Dim l_lnLines() As FLine, l_intTile As Integer
Dim l_lngX As Long, l_lngY As Long
    BeginProcess "Flipping..."
    Set l_undUndo = New cMultiUndoEntry

    For Each l_araArea In Map.Areas
        Set l_undPropertyUndo = New cPropertyUndoEntry
        With l_undPropertyUndo
            .MethodName = "Y"
            Set .Object = l_araArea
            .Value = l_araArea.Y
        End With
        l_undUndo.Entries.Add l_undPropertyUndo
        l_araArea.Y = Map.MaxY - l_araArea.Y - l_araArea.Height
    Next l_araArea

    For Each l_sprSprite In Map.Sprites
        Set l_undPropertyUndo = New cPropertyUndoEntry
        With l_undPropertyUndo
            .MethodName = "Y"
            Set .Object = l_sprSprite
            .Value = l_sprSprite.Y
        End With
        l_undUndo.Entries.Add l_undPropertyUndo
        l_sprSprite.Y = Map.MaxY - l_sprSprite.Y
    Next l_sprSprite

    For Each l_lyrLayer In Map.Layers
        Set l_undTileUndo = New cTileUndoEntry
        With l_undTileUndo
            .X = 0
            .Y = 0
            .Layer = l_lyrLayer.Index
            Set .Map = Map
            Set .Brush = New Fury2Brush
            .Brush.Grab Map, l_lyrLayer.Index, 0, 0, l_lyrLayer.Width, l_lyrLayer.Height, , , True
        End With
        l_undUndo.Entries.Add l_undTileUndo
        With l_lyrLayer
            If Not .Prerendered Then
                For l_lngY = 0 To (.Height - 1) \ 2
                    For l_lngX = 0 To .Width - 1
                        l_intTile = .Tile(l_lngX, l_lngY)
                        .Tile(l_lngX, l_lngY) = .Tile(l_lngX, (.Height - 1) - l_lngY)
                        .Tile(l_lngX, (.Height - 1) - l_lngY) = l_intTile
                    Next l_lngX
                Next l_lngY
            End If
        End With
        Set l_undBlockingUndo = New cBlockingUndoEntry
        With l_undBlockingUndo
            .Layer = l_lyrLayer.Index
            .Lines = l_lyrLayer.CollisionLines
            Set .Map = Map
        End With
        l_undUndo.Entries.Add l_undBlockingUndo
        With l_lyrLayer
            l_lnLines = .CollisionLines
            For l_lngLines = LBound(l_lnLines) To UBound(l_lnLines)
                With l_lnLines(l_lngLines)
                    .Start.Y = Map.MaxY - .Start.Y
                    .end.Y = Map.MaxY - .end.Y
                End With
            Next l_lngLines
            .CollisionLines = l_lnLines
        End With
    Next l_lyrLayer

    m_colUndo.Add l_undUndo
    m_colRedo.Clear
    If m_colUndo.Count > c_lngUndoStackLength Then
        m_colUndo.Remove 1
    End If
    EndProcess
    Redraw
End Sub