miscellaneous update

git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@1352 9d0c8265-081b-0410-96cb-a4ca84ce46f8

1 files changed, 30 insertions, 11 deletions

diff --git a/pnmtops.html b/pnmtops.html
index 46e7088a..4c47317a 100644
--- a/pnmtops.html
+++ b/pnmtops.html
@@ -91,7 +91,7 @@ value from a DSC point of view).
 http://http://www.tailrecursive.org/postscript/eps.html</a>.
 
 <p>Many of the ideas in <b>pnmtops</b> come from Dirk Krause's <b>bmeps</b>.
-See <a href="#seealso">SEE ALSO</a>
+See <a href="#seealso">SEE ALSO</a>.
 
 <H2 id="options">OPTIONS</H2>
 
@@ -221,6 +221,28 @@ bunch of adjacent pixels are all the same.  But without
 all the green values, then all the blue values, so long runs appear
 wherever there are long stretches of the same color.
 
+<p>Here is an explanation by Jef Poskanzer of why he invented the
+<b>-rle</b> option:
+
+<blockquote>
+I just spent a few hours modifying my pbmtops filter to produce run length
+encoded PostScript output.  The results are not spectacular for me - yes, the
+files are smaller, but the printing times are about the same.  But I'm
+printing over the network.  If you were stuck with the serial line, this would
+be a big win.  I've appended a sample program generated by my filter.  If
+anyone sees ways to improve the code, please let me know, I'm not much of a
+PostScript hacker.  This version of pbmtops will be distributed to
+comp.sources.misc and expo.lcs.mit.edu sometime in October. - Jef
+</blockquote>
+
+<p>This is
+from <a href="http://www.lngpstscrpt.tk/re-postscript-run-length-encoding-again">a
+forum about Postscript</a>, extracted in October 2010.  Jef added -rle in
+August 1988.  In those days, RS-232 lines (referred to a &quot;serial&quot; in
+the quotation) were typically 9600bps.  2400 bps lines were still around.
+What the quotation calls &quot;the network&quot; is probably a 10 Mbps
+ethernet connection.
+
 <dt><b>-flate</b>
 
 <dd>This option tells <b>pnmtops</b> to use &quot;flate&quot;
@@ -236,13 +258,6 @@ same as PNG).
 <p>Before Netpbm 10.32 (February 2006), you could not specify <b>-rle</b>
 and <b>-flate</b> together.
 
-<p>This sometimes produces what is probably an incorrect image -- one
-that is missing the lower rows.  This appears to be an implementation
-problem in the flate compressor, but we don't know what it is.  We
-also don't know on which images it has the problem.  (January 2007).
-We provide <a href="flatebug.png">an example</a> of an image with which
-<b>pnmtops</b> appears to have the problem.  (Convert it to PGM with
-<b>pngtopam</b> and feed that to <b>pnmtops</b>).
 
 <dt><b>-ascii85</b>
 
@@ -397,14 +412,18 @@ input -- only from PNG input).
 <B><A HREF="pbmtopsg3.html">pbmtopsg3</A></B>,
 <B><A HREF="ppmtopgm.html">ppmtopgm</A></B>,
 
-<H2 id="author">AUTHOR</H2>
+
+<h2 id="history">HISTORY</h2>
 
 <p>Copyright (C) 1989, 1991 by Jef Poskanzer.
 
 <p>Modified November 1993 by Wolfgang Stuerzlinger, <A
 HREF="mailto:wrzl@gup.uni-linz.ac.at">wrzl@gup.uni-linz.ac.at</A>
 
-<HR>
+<p>The program was originally <b>pbmtops</b>.  It became <b>pgmtops</b> in
+October 1988 and was merged with <b>ppmtops</b> to form <b>pnmtops</b> in
+January 1991.  <b>ppmtops</b> came into being some time before September 1989.
+
 <H2 id="index">Table Of Contents</H2>
 <UL>
 <LI><A HREF="#synopsis">SYNOPSIS</A>
@@ -412,7 +431,7 @@ HREF="mailto:wrzl@gup.uni-linz.ac.at">wrzl@gup.uni-linz.ac.at</A>
 <LI><A HREF="#options">OPTIONS</A>
 <LI><A HREF="#limitations">LIMITATIONS</A>
 <LI><A HREF="#seealso">SEE ALSO</A>
-<LI><A HREF="#author">AUTHOR</A>
+<LI><A HREF="#history">HISTORY</A>
 </UL>
 </BODY>
 </HTML>