the GtkCellAreaContext used to hold sizes for @area.
the GtkWidget that @area is rendering on
the whole allocated area for @area in @widget for this row
the x position
the y position
where to store the inner allocated area of the returned cell renderer
the GtkCellRenderer at @x and @y.
Gets the GtkCellRenderer at @x and @y coordinates inside @area and optionally returns the full cell allocation for it inside @cell_area.