Section Header
    + name := EDGE;
    - comment := "Sub prototype for BITMAP.polygone";
Section Inherit
    - parent_object:OBJECT :=
Section Public
Make.
    + y:INTEGER;
    + x:INTEGER;
    + width:INTEGER;
    + dx:INTEGER;
        REAL_24_8
    + is_down:BOOLEAN;
    + is_point:BOOLEAN;
    - x0:INTEGER <-
    - y0:INTEGER <-
    - x1:INTEGER <-
    - y1:INTEGER <-
    + next_y:EDGE;
    + prev_x:EDGE;
        doubly linked list
    + next_x:EDGE;
Function.
    - make (xx,yy:INTEGER) add inc:INTEGER <-
        Flat.
    - make (xx,yy:INTEGER) to (xx1,yy1:INTEGER) <-
        Line.
    - set_next_x new:EDGE <-
    - set_prev_x new:EDGE <-
    - set_next_y new:EDGE <-
    - add old_root:EDGE :EDGE <-
        Double link and sort with X.
    - next_line old_root:EDGE :EDGE <-
        Remove double link.
    - new_step <-