Derives the allocation of renderer inside area if area were to be renderered in cell_area.
the gtk.CellAreaContext used to hold sizes for area.
the gtk.Widget that area is rendering on
the gtk.CellRenderer to get the allocation for
the whole allocated area for area in widget for this row
where to store the allocation for renderer
3.0
Derives the allocation of renderer inside area if area were to be renderered in cell_area.