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% Test a tilted halftone screen.
/dot0
% The following screen algorithm is used by permission of the author.
{ 1 add 180 mul cos 1 0.08 add mul exch 2 add 180 mul cos
1 0.08 sub mul add 2 div % (C) 1989 Berthold K.P. Horn
} bind def
/dot1
{ dup mul exch dup mul add 1 exch sub
} bind def
/dot2
{ exch abs exch abs 2 copy le { exch } if
exch 1 sub dup mul exch dup mul add 1 exch sub
} bind def
72 72 scale
0 setlinewidth
/tiles {
0 1 7
{ /y exch def
0 1 7
{ /x exch def
x y moveto
1 0 rlineto 0 1 rlineto -1 0 rlineto closepath
gsave y 8 mul x add 63 div setgray fill grestore
0 setgray stroke
} for
} for
} bind def
gsave
2.3 -22 /dot0 load setscreen
currentscreen pop == pop
tiles showpage
grestore
gsave
2.3 22 /dot1 load setscreen
currentscreen pop == pop
tiles showpage
grestore
gsave
2.3 45 /dot1 load setscreen
currentscreen pop == pop
tiles showpage
grestore
gsave
2.3 45 /dot2 load setscreen
currentscreen pop == pop
tiles showpage
grestore
quit
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