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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 /libnetpbm.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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diff --git a/libnetpbm.html b/libnetpbm.html new file mode 100644 index 00000000..f835376d --- /dev/null +++ b/libnetpbm.html @@ -0,0 +1,83 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML> +<HEAD> +<TITLE>Libnetpbm manual</TITLE> +<META NAME="manual_section" CONTENT="3"> +</HEAD> +<BODY> +<H1>libnetpbm</H1> +Updated: December 2003 +<BR> +<?makeman .SH NAME ?> +<?makeman libnetpbm \- general introduction to the netpbm library ?> +<?makeman .SH DESCRIPTION ?> + +<p><b>libnetpbm</b> is a C programming library for reading, writing, and +manipulating Netpbm images. It also contains a few general graphics +manipulation tools, but it is not intended to be a graphics tools +library. For graphics tools, Netpbm expects you to run the Netpbm +programs. From a C program, the <b>libnetpbm</b> function +<b>pm_system()</b> makes this easy. However, since it creates a +process and execs a program, this may be too heavyweight for some +applications. + +<p>To use <b>libnetpbm</b> services in your C program, #include the +<b>pam.h</b> interface header file. For historical reasons, you can +also get by in some cases with <b>pbm.h</b>, <b>pgm.h</b>, +<b>ppm.h</b>, or <b>pnm.h</b>, but there's really no point to that +anymore. + +<p>The <b>libnetpbm</b> functions are divided into these categories: +<ul> +<li>PBM functions. These have names that start with <b>pbm</b> and work +only on PBM images. +<li>PGM functions. These have names that start with <b>pgm</b> and work +only on PGM images. +<li>PPM functions. These have names that start with <b>ppm</b> and work +only on PPM images. +<li>PNM functions. These have names that start with <b>pnm</b> and work on +PBM, PGM, and PPM images. +<li>PAM functions. These also have names that start with <b>pnm</b> and +work on all the Netpbm image types. +<li>PM functions. These are utility functions that aren't specific to any +particular image format. +</ul> + +<p>For new programming, you rarely need to concern yourself with the +PBM, PGM, PPM, and PNM functions, because the newer PAM functions do +the same thing and are easier to use. For certain processing of +bi-level images, the PBM functions are significantly more efficient, +though. + +<p><b>libnetpbm</b> has a backward compatibility feature that means a +function designed to read one format can read some others too, +converting on the fly. In particular, a function that reads a PGM +image will also read a PBM image, but converts it as it reads it so +that for programming purposes, it is a PGM image. Similarly, a +function that reads PPM can read PBM and PGM as well. And a function +that reads PBM, PGM, or PPM can read a PAM that has an equivalent +tuple type. + +<p>For each of the five classes of <b>libnetpbm</b> image processing +functions, <b>libnetpbm</b> has in in-memory representation for a +pixel, a row, and a whole image. Do not confuse this format with the +actual image format, as you would see in a file. The <b>libnetpbm</b> +in-memory format is designed to make programming very easy. It is +sometimes extremely inefficient, even more than the actual image +format. For example, a pixel that a PPM image represents with 3 +bytes, <b>libnetpbm</b>'s PAM functions represent with 16 bytes. A +pixel in a PBM image is represented by a single bit, but the PNM +functions represent that pixel in memory with 96 bits. + +<p>See <a href="libnetpbm_ug.html">Libnetpbm User's Manual</a> for the +basics on using <b>libnetpbm</b> in a program. + +<p>You can look up the reference information for a particular function +in <a href="libnetpbm_dir.html">The libnetpbm Directory</a>. + +<P>Before Netpbm release 10 (June 2002), this library was split into +four: libpbm, libpgm, libppm, and libpnm. That's largely the reason +for the multiple sets of functions and scattered documentation. + +</BODY> +</HTML> |