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| author | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
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| committer | giraffedata <giraffedata@9d0c8265-081b-0410-96cb-a4ca84ce46f8> | 2006-12-25 03:06:05 +0000 |
| commit | 1017cbebe5d5edd859e0fddad0a8600f509f4821 (patch) | |
| tree | 78bdf336648566f7a7d55f42837357dea3dd674c /pnmcrop.html | |
| parent | 16f2ac126651015a376eba864a3a35f738b0b25a (diff) | |
| download | netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.gz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.tar.xz netpbm-mirror-1017cbebe5d5edd859e0fddad0a8600f509f4821.zip | |
Place user guide into Subversion repository
git-svn-id: http://svn.code.sf.net/p/netpbm/code/userguide@181 9d0c8265-081b-0410-96cb-a4ca84ce46f8
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1 files changed, 188 insertions, 0 deletions
diff --git a/pnmcrop.html b/pnmcrop.html new file mode 100644 index 00000000..2d1542d5 --- /dev/null +++ b/pnmcrop.html @@ -0,0 +1,188 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML><HEAD><TITLE>Pnmcrop User Manual</TITLE></HEAD> +<BODY> +<H1>pnmcrop</H1> +Updated: 30 November 2006 +<BR> +<A HREF="#index">Table Of Contents</A> + +<H2>NAME</H2> + +pnmcrop - crop a PNM image + +<H2 id="synopsis">SYNOPSIS</H2> + +<B>pnmcrop</B> + +[<B>-white</B>|<B>-black</B>|<B>-sides</B>] + +[<B>-left</B>] + +[<B>-right</B>] + +[<B>-top</B>] + +[<B>-bottom</B>] + +[<B>-margin=</B><i>pixels</i>] + +[<B>-borderfile=</B><i>filename</i>] + +[<I>pnmfile</I>] + +<P>Minimum unique abbreviation of option is acceptable. You may use +double hyphens instead of single hyphen to denote options. You may use +white space in place of the equals sign to separate an option name +from its value. + +<H2 id="description">DESCRIPTION</H2> + +<p>This program is part of <a href="index.html">Netpbm</a>. + +<p><b>pnmcrop</b> reads a PBM, PGM, or PPM image as input, removes +borders that are the background color, and produces the same type of +image as output. + +<P>If you don't specify otherwise, <B>pnmcrop</B> assumes the +background color is whatever color the top left and right corners of +the image are and if they are different colors, something midway +between them. You can specify that the background is white or black +with the <B>-white</B> and <B>-black</B> options or make +<B>pnmcrop</B> base its guess on all four corners instead of just two +with <B>-sides</B>. + +<P>By default, <B>pnmcrop</B> chops off any stripe of background color +it finds, on all four sides. You can tell <B>pnmcrop</B> to remove +only specific borders with the <B>-left</B>, <B>-right</B>, +<B>-top</B>, and <B>-bottom</B> options. + +<p>If you want to leave some border, use the <b>-margin</b> option. It +will not only spare some of the border from cropping, but will fill in +(with what <b>pnmcrop</b> considers the background color) if necessary +to get up to that size. + +<p>If the input is a multi-image stream, <b>pnmcrop</b> processes each +one independently and produces a multi-image stream as output. It chooses +where to crop independently for each image. So if you start with a stream +of images of the same dimensions, you may end up with images of differing +dimensions. Before Netpbm 10.37 (December 2006), <b>pnmcrop</b> ignored +all input images but the first. + +<P>If you want to chop a specific amount off the side of an image, use +<B>pamcut</B>. + +<P>If you want to add different borders after removing the existing +ones, use <B>pnmcat</B> or <B>pamcomp</B>. + +<H2 id="options">OPTIONS</H2> + +<DL COMPACT> +<DT><B>-white</B> + +<DD>Take white to be the background color. <B>pnmcrop</B> removes +borders which are white. + +<DT><B>-black</B> + +<DD>Take black to be the background color. <B>pnmcrop </B> removes +borders which are black. + +<DT><B>-sides</B> + +<DD>Determine the background color from the colors of the four corners +of the input image. <B>pnmcrop</B> removes borders which are of the +background color. + +<P>If at least three of the four corners are the same color, +<B>pnmcrop </B> takes that as the background color. If not, +<B>pnmcrop</B> looks for two corners of the same color in the +following order, taking the first found as the background color: top, +left, right, bottom. If all four corners are different colors, +<B>pnmcrop</B> assumes an average of the four colors as the background +color. + +<P>The <B>-sides</B> option slows <B>pnmcrop</B> down, as it reads the +entire image to determine the background color in addition to the up +to three times that it would read it without <B>-sides</B>. + +<DT><B>-left</B> + +<DD>Remove any left border. + +<DT><B>-right</B> + +<DD>Remove any right border. + +<DT><B>-top</B> + +<DD>Remove any top border. + +<DT><B>-bottom</B> + +<DD>Remove any bottom border. + +<dt><b>-margin=</b><i>pixels</i> + +<dd>Leave <i>pixels</i> pixels of border. Expand the border to this size +if necessary. + +<p>This option was new in Netpbm 10.29 (August 2005). + +<dt><b>-borderfile=</b><i>filename</i> + +<dd>Use the image in the file named <i>filename</i> instead of the input +image to determine where the borders of the input image are. + +<p>Without this option, <b>pnmcrop</b> examines the input image and +figures out what part of the image is border and what part is +foreground (not border). With this option, <b>pnmcrop</b> finds the +borders in one image, then uses the those four border sizes (left, +right, top, bottom) in cropping a different image. + +<p>The point of this is that you may want to help <b>pnmcrop</b> to +come to a different conclusion as to where the border are by +preprocessing the input image. For example, consider an image that +has speckles of noise in its borders. <b>pnmcrop</b> isn't smart +enough to recognize these as noise; it sees them as foreground image. +So <b>pnmcrop</b> considers most of your borders to be foreground and +does not crop them off as you want. To fix this, run the image +through a despeckler such as <b>pbmclean</b> and tell <b>pnmcrop</b> +to use the despeckled version of the image as the <b>-borderfile</b> +image, but the original speckled version as the input image. That +way, you crop the borders, but retain the true foreground image, +speckles and all. + +<p>This option was new in Netpbm 10.29 (August 2005). + +<DT><B>-verbose</B> + +<DD>Print on Standard Error information about the processing, +including exactly how much is being cropped off of which sides. + +</DL> + +<H2 id="seealso">SEE ALSO</H2> + +<B><A HREF="pamcut.html">pamcut</A></B>, + +<B><A HREF="pamfile.html">pamfile</A></B>, + +<B><A HREF="pnm.html">pnm</A></B> + +<H2 id="author">AUTHOR</H2> + +Copyright (C) 1989 by Jef Poskanzer. + + +<HR> +<A NAME="index"> </A> +<H2>Table Of Contents</H2> +<UL> +<LI><A HREF="#synopsis">SYNOPSIS</A> +<LI><A HREF="#description">DESCRIPTION</A> +<LI><A HREF="#options">OPTIONS</A> +<LI><A HREF="#seealso">SEE ALSO</A> +<LI><A HREF="#author">AUTHOR</A> +</UL> +</BODY> +</HTML> |