############################################################################
#
#       File:     koch.icn
#
#	Subject:  Program to demonstrate Koch curves
#
#	Author:   Stephen B. Wampler
#
#	Date:     October 14, 1992
#
############################################################################
#
#   This file is in the public domain.
#
############################################################################
#
#	Version:  1.0
#
############################################################################
#
#
#   Comments: This program shows how Koch curves work.
#
#	See the procedure 'helpmsg' for command line options
#
#	Waits for a window event before closing window
#
############################################################################
#
#  Links: glib, wopen
#
############################################################################
#
#  Requires:  Version 9 graphics and co-expressions (for glib.icn)
#
############################################################################

link glib
link wopen

global win, mono, h, w
global Window, XMAX, YMAX

procedure main (args)
    local arg, nextarg

    XMAX := YMAX := 700                 # physical screen size
    w := h := 1.0
   
    nextarg := create !args
    while arg := @nextarg do {
       if arg == ("-help"|"-h") then stop(helpmsg())
       }

    win := WOpen("label=Koch Snowflake", "width="||XMAX, "height="||YMAX)
    mono := WAttrib (win, "depth") == "1"
    Window := set_window(win, point(0,0), point(w,h),
                  viewport(point(0,0), point(XMAX, YMAX), win))

    EraseArea(win)

    Fg(win, "black")

#    koch_line(Window, point(0.25,0.25), point(0.75,0.25), 5)
#    koch_line(Window, point(0.75,0.25), point(0.50,0.67), 5)
#    koch_line(Window, point(0.50,0.67), point(0.25,0.25), 5)

    koch_line(Window, point(0.00,0.67), point(0.50,0.67), 5)
    koch_line(Window, point(0.50,0.67), point(0.25,0.25), 5)
    koch_line(Window, point(0.25,0.25), point(0.00,0.67), 5)

    koch_line(Window, point(0.25,0.25), point(0.50,0.67), 5)
    koch_line(Window, point(0.50,0.67), point(0.75,0.25), 5)
    koch_line(Window, point(0.75,0.25), point(0.25,0.25), 5)

    koch_line(Window, point(0.50,0.67), point(1.00,0.67), 5)
    koch_line(Window, point(1.00,0.67), point(0.75,0.25), 5)
    koch_line(Window, point(0.75,0.25), point(0.50,0.67), 5)

    Event(win)
    close(win)
end

procedure helpmsg()
   write("Usage: Koch")
   return
end