KUIWidget := Object clone do (
        /* parent & children here are used only for layout */
        parent := nil
        children := List clone

        bbox := Box clone
        parentcenter := Point clone
        center := Point clone
        offset := Point clone

        zlayer := 0

        img := Image clone
        img size := method(
                return Point clone set(width, height)
        )
        _calculateBbox := method(
                e := try(
                        parentBbox := parent bbox
                )
                e catch (
                        parentBbox := Box clone set(Point clone, Point clone)
                )
                bboxOrigin := ((parentBbox origin) + ((parentBbox size)*(parentcenter))) + offset
                bboxSize := Point clone set (img width, img height)
                self bbox := Box clone set(bboxOrigin, bboxSize)
                return bbox
        )

        size := method( return bbox size )

        _calculateSize := method ( return size )

        calculateBbox := method(
                _calculateBbox
                children foreach(c, c ?calculateBbox)
        )
        calculateSize := method(
                children foreach(c, c ?calculateSize)
                _calculateSize
        )
        setParent := method(p,
                self parent := p
                p children append(self)
        )
)
KUIContainer := KUIWidget clone do (
        widgetLint := method(
                if(self children size < 1,
                        self children foreach(c,
                                if(c zlayer <= self zlayer, c zlayer := (self zlayer + 1))
                        )
                        self children foreach(c, c ?widgetLint)
                        self children foreach(c,
                                self bbox := self bbox Union(c bbox)
                        )
                )
                return bbox
        )
        _calculateBbox := method(
                resend
                widgetLint
                return bbox
        )
)
x := KUIWidget clone
x offset set(10, 20)
y := KUIContainer clone
y setParent(x)
y offset set(10, 20)

"Initial bbox for" println
"X:" println
x bbox println
"Y:" println
y bbox println
"Recalculating..." println
x calculateBbox
"New bbox for" println
"X:" println
x bbox println
"Y:" println
y bbox println