[Tugindia] Query on printing with 'screens'

[Dr C. K. Raju]

> Date: Thu, 27 Nov 2008 20:28:05 +0530> From: cordeiroderek at gmail.com> > Dr C. K. Raju wrote:> >> > > Is this what you are saying: that half-tone screen information present in the postscipt file is not properly converted to pdf unless you use Distiller? > > 
 
> I could rephrase my question as follows:> if a package like poligraf.sty can include commands like \mirror to > create postscript files which are mirrored, is there any package that > adds halftone screen information? Or is there any work around?
That's finally a specific question that admits a specific answer. I don't have the Latex Graphics Companion with me, but check it out, the first few pages (ten at the most) should provide an answer on halftoning suggested by Knuth long ago, and also by Adrian Clark. This should also exist on the Tex Archives somewhere. 
 
The other work around is to throw in half-toning information into the postscript file. You could use Ghostscript or simply add the following code (from Practical Postscript). Remember that you must first redefine the frequency and angle you want. 
 
%!PS HALFTONES
%%Title: HalftoneBlock
%%Creator: Practical PostScript
/asyouwere save def
/F { findfont exch scalefont setfont} def
/screen
{ { dup mul exch dup mul add 1.0 exch sub } setscreen } def % empty brace %
/htbox
{ newpath 5 0 moveto 0 50 rlineto 147 0 rlineto 0 −50 rlineto closepath
gsave 0.7 setgray 120 45 screen fill grestore 0 setgray
0.1 setlinewidth stroke } def
gsave
145 100 translate htbox
137 25 moveto −1 1 scale 1 setgray
24 /Times−Bold F
(LetterPress) show
−134 12 moveto
10 /Times−Bold F
(Makes a Good Impression) show
grestore
gsave
/Pixels 256 string def % reserve some memory %
/wedge { translate scale 106 45 screen image } def % frequency and angle %
0 1 255 { Pixels exch dup put } for % go from 0 pixel to 255 one at a time %
256 1 8 [ 256 0 0 1 0 0 ] { Pixels } % 256 pixels long x 1 high; reading 8 bits %
160 25 160 10 wedge % scales: translates %
grestore
showpage
asyouwere restore
 
 
 
Best, 
 
C. K. Raju
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