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diff --git a/pamtotiff.html b/pamtotiff.html index f5f849a1..0b482e0a 100644 --- a/pamtotiff.html +++ b/pamtotiff.html @@ -2,7 +2,7 @@ <HTML><HEAD><TITLE>Pamtotiff User Manual</TITLE></HEAD> <BODY> <H1>pamtotiff</H1> -Updated: 03 December 2008 +Updated: 17 April 2014 <BR> <A HREF="#index">Table Of Contents</A> @@ -69,10 +69,46 @@ ignored all but the first Netpbm image in the input stream. <h3 id="output">The Output File</h3> -<P>The output goes to Standard Output. <b>pamtotiff</b> approaches -this output file differently from Unix and Netpbm convention. This is due -entirely to <b>pamtotiff</b>'s use of the TIFF library to do all -TIFF output. +<P>By default, the output goes to Standard Output. Alternatively, you can +specify an output file with the <b>-output</b> option and <b>pamtotiff</b> +will write its output directly to that file. + +<p>Because of the way the TIFF library (which <b>pamtotiff</b> uses) works, +when the program writes to Standard Output, it generates the entire TIFF image +in a temporary file and then copies it to Standard Output; you may see +negative performance effects of this. + +<p>The <b>-output</b> method avoids the performance effects of the copy +through the temporary file, but there are restrictions on the output file: it +must be seekable and it must be readable. The program fails if it is not. +With Standard Output, neither of those restrictions applies. + +<p>With <b>-output</b>, if the file already exists and has data in it, +<b>pamtotiff</b> appends the image to the existing TIFF file. (A TIFF file +may contain multiple images). + +<p>By default, <b>pamtotiff</b> creates the file named by <b>-output</b> if it +does not already exist. But if you also specify <b>-append</b>, the program +fails if the file named by <b>-output</b> does not already exist. + +<p>Before Netpbm 10.67 (June 2014), there is no <b>-output</b> option and +Standard Output must be seekable. So pipes are out. + +<p>Before Netpbm 10.67 (June 2014), you could append to Standard Output. See +below. The current program does not have the ability; you must +use <b>-output</b> to append to an existing TIFF file. + +<p>The difference above means current <b>pamtotiff</b> is actually not +backward compatible, which is a rare thing for Netpbm. But it's a good thing +because the previous function was very strange and probably hardly ever +exploited. + + +<h4 id="oldoutput">Old Versions</h4> + +<p>As alluded to above, <b>pamtotiff</b> does output very differently +in releases before 10.67. The following describes the old function, +which is unusual both for Netpbm and for Unix programs in general. <ul> <li>The output file must be seekable. <b>pamtotiff</b> does not @@ -330,6 +366,29 @@ an IMAGEWIDTH tag that gives the actual width of the image. <p><b>-tag</b> was new in Netpbm 10.31 (December 2005). +<h3 id="outputoptions">Output</h3> + +<p>See <a href="output">The Output File</a>. + +<p><b>-output</b> names the output file. Without this option +<b>pamtotiff</b> writes to Standard Output. + +<p>The <b>-append</b> option tells <b>pamtotiff</b> only to append to the file +named by <b>output</b>; not create it. Without this option, the program +creates the file it does not already exist. But even then, if the file does +already exist, the program appends the image to what is in the file already. +(A TIFF file may contain multiple images). + +<p><b>-append</b> has no effect if you don't also specify <b>-output</b>. + +<p>Before Netpbm 10.67 (June 2014), <b>-append</b> means something rather +different: it means to append the image to the output TIFF file (which is +always Standard Output in 10.67) instead of replacing its contents. + +<p><b>-append</b> was new in Netpbm 10.27 (March 2005). + + + <h3 id="other">Other</h3> <P>You can use the <B>-rowsperstrip</B> option to set the number of @@ -337,12 +396,6 @@ rows (scanlines) in each strip of data in the output file. By default, the output file has the number of rows per strip set to a value that will ensure each strip is no more than 8 kilobytes long. -<p>The <b>-append</b> option tells <b>pamtotiff</b> to add images to -the existing output file (a TIFF file may contain multiple images) -instead of the default, which is to replace the output file. - -<p><b>-append</b> was new in Netpbm 10.27 (March 2005). - <H2 id="notes">NOTES</H2> @@ -512,7 +565,10 @@ Author: Patrick J. Naughton (<A HREF="mailto:naughton@wind.sun.com">naughton@win <LI><A HREF="#synopsis">SYNOPSIS</A> <LI><A HREF="#description">DESCRIPTION</A> <ul> - <li><a href="#outputfile">The Output File</a> + <li><a href="#output">The Output File</a> + <ul> + <li><a href="#oldoutput">Old Versions</a> + </ul> <li><a href="#library">TIFF Capability</a> </ul> <LI><A HREF="#options">OPTIONS</A> @@ -524,6 +580,7 @@ Author: Patrick J. Naughton (<A HREF="mailto:naughton@wind.sun.com">naughton@win <li><a href="#fillorder">Fill Order</a> <li><a href="#colorspacer">Color Space</a> <li><a href="#extratags">Extra Tags</a> + <li><a href="#outputoptions">Output</a> <li><a href="#other">Other</a> </ul> <LI><A HREF="#notes">NOTES</A> |