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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.3//EN">
<html><head><title>Asciitopgm User Manual</title></head>
<body>
<h1>asciitopgm</h1>
Updated: 20 January 2011
<br>
<a href="#index">Table Of Contents</a>
<h2>NAME</h2>
asciitopgm - convert ASCII graphics into a PGM
<h2 id="synopsis">SYNOPSIS</h2>
<b>asciitopgm</b>
[<b>-d</b> <i>divisor</i>] <i>height</i> <i>width</i> [<i>asciifile</i>]
<h2 id="description">DESCRIPTION</h2>
<p>This program is part of <a href="index.html">Netpbm</a>.
<p><b>asciitopgm</b> reads ASCII data as input and produces a PGM image
with pixel values which are an approximation of the
"brightness" of the ASCII characters, assuming
black-on-white printing. In other words, a capital M is very dark, a
period is very light, and a space is white.
<p>Obviously, <b>asciitopgm</b> assumes a certain font in assigning
a brightness value to a character.
<p><b>asciitopgm</b> considers ASCII control characters to be all white. For
a lower case character, It assigns a special brightnesses which has nothing to
do with what it looks like printed.
<b>asciitopgm</b> takes the ASCII character code from the lower 7 bits
of each input byte. But it warns you if the most significant bit of
any input byte is not zero.
<p>The output image is <i>height</i> pixels high by <i>width</i> pixels wide,
truncating and padding with white on the right and bottom as necessary.
<p>The <i>divisor</i> value is an integer (decimal) by which the
blackness of an input character is divided. You can use this to
adjust the brightness of the output: for example, if the image is too
bright, increase the divisor.
<p>In a sort of reminiscence of Fortran line printer carriage control,
where a line starts with <b>+</b> (plus), <b>asciitopgm</b> combines it
with the previous row of output instead of generating a new row. This
allows a larger range of gray values. (In Fortran carriage control, the
first character of every line sent to the printer tells how much to advance
the paper, with <b>+</b> meaning not at all, so that the rest of the
characters on the line overstrike the ones already on the paper. What
<b>asciitopgm</b> does is rather different in that <b>asciitopgm</b> does not
reserve the first character of every line that way. If the first character is
anything but <b>+</b>, <b>asciitopgm</b> considers it just to be first
character of the image.
<p>If you're looking for something that creates an image of text,
with that text specified in ASCII, that is something quite different.
Use <b>pbmtext</b> for that.
<h2 id="options">OPTIONS</h2>
<p>In addition to the options common to all programs based on libnetpbm
(most notably <b>-quiet</b>, see <a href="index.html#commonoptions">
Common Options</a>), <b>asciitopgm</b> recognizes the following
command line option:
<dl compact>
<dt><b>-d</b> <i>divisor</i>
<dd>Specify the value by which the blackness of an input character is
divided. This is an integer value. Default value is 1. Larger
values produce darker output images.
</dl>
<h2 id="seealso">SEE ALSO</h2>
<a href="pbmtoascii.html">pbmtoascii</a>,
<a href="pbmtext.html">pbmtext</a>,
<a href="pgm.html">pgm</a>
<h2 id="author">AUTHOR</h2>
Wilson H. Bent. Jr. (<a href="mailto:whb@usc.edu">whb@usc.edu</a>)
<hr>
<h2 id="index">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>
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