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  CUPS PostScript file specification for CUPS.

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<H1 CLASS="title">Generating PostScript for CUPS</H1>

<h2 class='title'><a name='INTRODUCTION'>Introduction</a></h2>

<p>This document describes how to generate PostScript output for
CUPS and is largely based on the <a
href="http://partners.adobe.com/public/developer/en/ps/5001.DSC_Spec.pdf">
Adobe TechNote #5001: PostScript Language Document Structuring
Conventions Specification Version 3.0</a>. While CUPS can
generally print any PostScript file, following the rules in the
Adobe TechNote and this document will ensure that your PostScript
output will work reliably.</p>

<blockquote><b>Note:</b> While PostScript is currently the
de-facto standard print job file format/language for UNIX-based
applications, it is slowly being phased out in favor of Adobe's
Portable Document Format ("PDF") which offers many advantages
over PostScript. OS X uses PDF as the primary print job file
format and Linux is making the transition. Both PostScript and
PDF are complex formats, and we highly recommend using high-level
toolkits whenever possible to create your print jobs.</blockquote>

<h3>Anatomy of a PostScript File</h3>

<p>PostScript files are ASCII text files starting with a header
line (<tt>%!PS-Adobe-3.0</tt>) followed by a combination of
comment lines starting with the percent sign (<tt>%</tt>) and
PostScript code lines. The lines themselves should not exceed 255
characters to conform to the DSC. The following short PostScript
file produces a box with a smiley face in it:</p>

<pre class="command">
%!PS-Adobe-3.0
%%BoundingBox: 36 36 576 756
%%Pages: 1
%%LanguageLevel: 2
%%EndComments
%%BeginSetup
% this is where fonts would be embedded
%%EndSetup
%%Page: (1) 1
%%BeginPageSetup
% this is where page-specific features would be specified
%%EndPageSetup
% Draw a black box around the page
0 setgray
1 setlinewidth
36 36 540 720 rectstroke

% Draw a two inch blue circle in the middle of the page
0 0 1 setrgbcolor
306 396 144 0 360 arc closepath fill

% Draw two half inch yellow circles for eyes
1 1 0 setrgbcolor
252 432 36 0 360 arc closepath fill
360 432 36 0 360 arc closepath fill

% Draw the smile
1 setlinecap
18 setlinewidth
306 396 99 200 340 arc stroke

% Print it!
showpage
%%EOF
</pre>

<div class="figure"><table summary="Sample PostScript File Output">
<caption>Figure 1: <a name="FIGURE_1">Sample PostScript File Output</a></caption>
<tr><td align="center"><img src="../images/smiley.jpg"
width="445" height="570" alt="Sample PostScript File Output"></td></tr>
</table></div>


<h2><a name='OPTIONS'>Embedding Printer Options</a></h2>

<p>There are two main strategies for embedding printer options in PostScript
files. The first is to list CUPS options using the <code>%cupsJobTicket</code>
comment:</p>

<pre>
%!PS-Adobe-3.0
%cupsJobTicket: media=A4 sides=two-sided-long-edge
%cupsJobTicket: PrinterOption=foo PrinterOption2=bar
...
%%EndComments
</pre>

<p>CUPS options apply to the entire job. To apply options to individual pages,
use the <code>%%IncludeFeature</code> comment instead:</p>

<pre>
%%Page: label 123
%%BeginPageSetup
%%IncludeFeature: *PageSize A4
%%IncludeFeature: *PrinterOption Foo
%%IncludeFeature: *PrinterOption2 Bar
%%EndPageSetup
...
</pre>


<h2><a name='FONTS'>Embedding Fonts and Text</a></h2>

<p>Always embed the fonts used by your print job, and for best performance
embed the fonts and character encodings in the setup section of the PostScript
file. Type 1 and Type 3 fonts are supported by all PostScript printers, while
Type 42 (TrueType) and CID fonts are supported by most level 2 and all level 3
PostScript printers. Binary font files should always be converted to the
corresponding ASCII (hex) encoding to avoid problems when printing over
interfaces that do not support binary PostScript.</p>


<h2><a name='IMAGES'>Embedding Images</a></h2>

<p>The <code>image</code> operator should be used to embed images in PostScript
files. Always use ASCII hex or Base-85 encoding for the image data to avoid
problems when printing over interfaces that do not support binary PostScript.
In most cases, the Base-85 encoding and compression filters can be used to
embed images with very little, if any, increase in data size.</p>

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