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diff --git a/doc/groff.html.node/Output-Language-Compatibility.html b/doc/groff.html.node/Output-Language-Compatibility.html new file mode 100644 index 0000000..4ad971f --- /dev/null +++ b/doc/groff.html.node/Output-Language-Compatibility.html @@ -0,0 +1,103 @@ +<!DOCTYPE html> +<html> +<!-- Created by GNU Texinfo 7.0.3, https://www.gnu.org/software/texinfo/ --> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"> +<!-- This manual documents GNU troff version 1.23.0. + +Copyright © 1994-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with no +Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A +copy of the license is included in the section entitled "GNU Free +Documentation License". --> +<title>Output Language Compatibility (The GNU Troff Manual)</title> + +<meta name="description" content="Output Language Compatibility (The GNU Troff Manual)"> +<meta name="keywords" content="Output Language Compatibility (The GNU Troff Manual)"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta name="viewport" content="width=device-width,initial-scale=1"> + +<link href="index.html" rel="start" title="Top"> +<link href="Request-Index.html" rel="index" title="Request Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="gtroff-Output.html" rel="up" title="gtroff Output"> +<link href="Intermediate-Output-Examples.html" rel="prev" title="Intermediate Output Examples"> +<style type="text/css"> +<!-- +ul.mark-bullet {list-style-type: disc} +--> +</style> + + +</head> + +<body lang="en"> +<div class="subsection-level-extent" id="Output-Language-Compatibility"> +<div class="nav-panel"> +<p> +Previous: <a href="Intermediate-Output-Examples.html" accesskey="p" rel="prev">Intermediate Output Examples</a>, Up: <a href="gtroff-Output.html" accesskey="u" rel="up"><code class="code">gtroff</code> Output</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Request-Index.html" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<h4 class="subsection" id="Output-Language-Compatibility-1">6.1.4 Output Language Compatibility</h4> + +<p>The intermediate output language of <abbr class="acronym">AT&T</abbr> <code class="code">troff</code> was +first documented in <cite class="cite">A Typesetter-independent TROFF</cite>, by Brian +Kernighan, and by 1992 the <abbr class="acronym">AT&T</abbr> <code class="code">troff</code> manual was +updated to incorprate a description of it. +</p> +<p>The GNU <code class="code">troff</code> intermediate output format is compatible with this +specification except for the following features. +</p> +<ul class="itemize mark-bullet"> +<li>The classical quasi-device independence is not yet implemented. + +</li><li>The old hardware was very different from what we use today. So the +<code class="code">groff</code> devices are also fundamentally different from the ones +in <abbr class="acronym">AT&T</abbr> <code class="code">troff</code>. For example, the <abbr class="acronym">AT&T</abbr> +PostScript device is called <code class="code">post</code> and has a resolution of only 720 +units per inch, suitable for printers 20 years ago, while <code class="code">groff</code>’s +<code class="code">ps</code> device has a resolution of 72000 units per inch. Maybe, by +implementing some rescaling mechanism similar to the classical +quasi-device independence, <code class="code">groff</code> could emulate <abbr class="acronym">AT&T</abbr>’s +<code class="code">post</code> device. + +</li><li>The B-spline command ‘<samp class="samp">D~</samp>’ is correctly handled by the intermediate +output parser, but the drawing routines aren’t implemented in some of +the postprocessor programs. + +</li><li>The argument of the commands ‘<samp class="samp">s</samp>’ and ‘<samp class="samp">x H</samp>’<!-- /@w --> has the +implicit unit scaled point ‘<samp class="samp">z</samp>’ in <code class="code">gtroff</code>, while +<abbr class="acronym">AT&T</abbr> <code class="code">troff</code> has point (‘<samp class="samp">p</samp>’). This isn’t an +incompatibility but a compatible extension, for both units coincide for +all devices without a <code class="code">sizescale</code> parameter in the <samp class="file">DESC</samp> +file, including all postprocessors from <abbr class="acronym">AT&T</abbr> and +<code class="code">groff</code>’s text devices. The few <code class="code">groff</code> devices with a +<code class="code">sizescale</code> parameter either do not exist for <abbr class="acronym">AT&T</abbr> +<code class="code">troff</code>, have a different name, or seem to have a different +resolution. So conflicts are very unlikely. + +</li><li>The position changing after the commands ‘<samp class="samp">Dp</samp>’, ‘<samp class="samp">DP</samp>’, and +‘<samp class="samp">Dt</samp>’ is illogical, but as old versions of <code class="code">gtroff</code> used this +feature it is kept for compatibility reasons. + + +</li></ul> + + + +</div> +<hr> +<div class="nav-panel"> +<p> +Previous: <a href="Intermediate-Output-Examples.html">Intermediate Output Examples</a>, Up: <a href="gtroff-Output.html"><code class="code">gtroff</code> Output</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Request-Index.html" title="Index" rel="index">Index</a>]</p> +</div> + + + +</body> +</html> |