menu 1 [scan-image]

global [b-on]

; calls the main programs
to scan-image
	initialize
	start-scan
end


; initialize on-off variables, speed, direction, and picture size
to initialize

	setpower 8

	a, thisway
	b, thisway
	c, thisway

	setb-on 1

end


; start scanning at northwest corner of picture
; start stippling
; continues scanning rest of image
to start-scan
	launch [start-stipple]
	loop [
		if (b-on < 10) [b, thisway on
				waituntil [switch 10]
				b, off
				move-vertically
				b, thatway on
				waituntil [switch 9]
				b, off
				move-vertically]
	]
end

; moves motor a vertically
to move-vertically
	ifelse (switch 8) [stop-scan]
			   [a, onfor 10 a, off]
end


to stop-scan
	setb-on 10
	b, rd onfor 10
	a, thatway on 
	waituntil [switch 7]
	a, off
	b, thatway on
	waituntil [switch 9]
	b, off
	;stoprules
end

to start-stipple
	loop [
		ifelse (b-on < 9) [adjust-stipple]
				  [end-stipple]
	]
end


; determines darkness of image
to image-darkness
	output sensor 0
end


; adjusts stippling speed
to adjust-stipple
	say image-darkness
	if (image-darkness < 101) [resett]
	if (image-darkness > 100) [stipple 1]
end


to stipple :speed
	c, onfor 2 thisway
	c, onfor :speed thatway
end

to end-stipple
	c, onfor 2 thisway
	;stoprules 
	c, off 
end