ref: d5e2fd9028687dfc18c0ac1b249ccec38ab075f6
dir: /sys/lib/postscript/prologues/shade.ps/
%
% Shading support - primarily for ASCII file translators.
%
/grays [0.98 0.9 0.75 0.6] def
/setshade {
/level exch def
level 0 le {
/textgray 0 def
/backgray 1 def
}{
/backgray level grays length gt
{/textgray 1 def 0}
{/textgray 0 def grays level 1 sub get}
ifelse def
} ifelse
textgray setgray
/dY1 0 def
/dY2 0 def
} bind def
/drawrvbox {
/x2 exch charwidth mul def
/x1 exch charwidth mul def
x1 x2 lt {
dup % expects y on top
/y1 exch linespace mul def
/y2 y1 def
dY1 0 eq dY2 0 eq and {
currentfont /FontBBox get aload pop
160 sub
currentfont /FontMatrix get dtransform /dY2 exch def pop
100 add
currentfont /FontMatrix get dtransform /dY1 exch def pop
} if
/y1 y1 dY1 add def
/y2 y2 dY2 add def
backgray setgray
newpath
x1 y1 moveto
x2 y1 lineto
x2 y2 lineto
x1 y2 lineto
closepath fill
} if
textgray setgray
} bind def