sub readPPM(f$)
	local ff, x, y, t$, dcol$, wid, hei

	if f$ = "" print "No PPM file name indicate." : return false

	ff = open (f$, "rb")
	if not ff print "File ", f$, " not found."  : return false

	input #ff t$, wid, hei, dcol$

	if t$ = "P6" then
		open window wid, hei
	
		for x = 0 to hei - 1
		 	for y = 0 to wid - 1
		 		color peek(#ff), peek(#ff), peek(#ff)
		 		dot y, x
		 	next y
		next x
		
		close #ff
	else
		print "File is NOT PPM P6 type." : return false
	end if
	
	return true
end sub