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diff --git a/ppmbrighten.html b/ppmbrighten.html index d0ad0797..20d863d5 100644 --- a/ppmbrighten.html +++ b/ppmbrighten.html @@ -2,170 +2,38 @@ <html><head><title>Ppmbrighten User Manual</title></head> <body> <h1>ppmbrighten</h1> -Updated: 12 January 2019 -<br> -<a href="#index">Table Of Contents</a> +Updated: 09 August 2020 <h2>NAME</h2> -ppmbrighten - change a PPM image's Saturation and Value -<h2 id="synopsis">SYNOPSIS</h2> +ppmbrighten - replaced by pambrighten -<b>ppmbrighten</b> -[<b>-normalize</b>] -[<b>-saturation=</b>[<b>+</b>|<b>-</b><i>saturation_percent</i>]] -[<b>-value=</b>[<b>+</b>|<b>-</b><i>value_percent</i>]] -<i>ppmfile</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> +<h2>DESCRIPTION</h2> <p>This program is part of <a href="index.html">Netpbm</a>. -<p><b>ppmbrighten</b> increases or decreases the Saturation and Value -(from the HSV color space) of each pixel of a PPM image. You specify -the per centage change for each of those parameters. - -<p>You can also remap the colors of the pixels so their Values cover -the full range of possible Values. - -<p>Hue-Saturation-Value, or HSV, is one way to represent a color, like -the more well-known RGB. Hue, Saturation, and Value are numbers in -the range from 0 to 1. We always capitalize them in this document -when we mean the number from the HSV color space, especially since -"value" as a conventional English word has a much more abstract -meaning. - -<p>Value is a measure of how bright the color is, relative to some specified -maximum (the PPM format is also defined in terms of a specified maximum -brightness -- For the purposes of this program, they are the same). In -particular, it is the brightness of the brightest primary color component of -the color divided by the maximum brightness possible for a component. Zero -Value means black. White has full Value. - -<p>Hue is an indication of the secondary color with the same brightness -that most closely approximates the color. A secondary color is made -of a combination of at most two of the primary colors. - -<p>Saturation is a measure of how close the color is to the color -indicated by the Hue and Value. A lower number means more light of -the third primary color must be added to get the exact color. Full -Saturation means the color is a secondary color. Zero Saturation -means the color is gray (or black or white). Decreasing the -saturation of a color tends to make it washed out. - -<p>If it is impossible to increase the Value of a pixel by the amount you -specify (e.g. the Value is .5 and you specify +200%), <b>ppmbrighten</b> -increases it to full Value instead. +<p>Starting with Netpbm 10.86 (March 2019), <b>ppmbrighten</b> is +obsolete. Use <a href="pambrighten.html"><b>pambrighten</b></a> instead. -<p>If it is impossible to increase the Saturation of a pixel by the amount -you specify (e.g. it is already half saturated and you specify +200%), -<b>ppmbrighten</b> increases it to full Saturation instead. +<b>pambrighten</b> is mostly backward compatible with <b>ppmbrighten</b>. You +can use the <b>pambrighten</b> manual for <b>ppmbrighten</b> as long as you +ignore features that were added after Netpbm 10.86. -<p>For a simpler kind of brightening, you can use <b>pamfunc -multiplier</b> -simply to increase the brightness of each pixel by a specified per centage, -clipping each RGB component where the calculated brightness would exceed full -brightness. Thus, the brightest colors in the image would change chromaticity -in addition to not getting the specified brightness boost. -For <em>decreasing</em> brightness, <b>pamfunc</b> should do the same thing as -<b>ppmbrighten</b>. +<p>One way in which <b>pambrighten</b> is not backward compatible is that + <b>pambrighten</b> does not have a <b>-normalize</b> option. If you want + that function, use <b>pnmnorm</b> on the image before passing it to + <b>pambrighten</b>. -<p><b>ppmflash</b> does another kind of brightening. It changes the -color of each pixel to bring it a specified per centage closer to white. -This increases the value and saturation. - -<p><b>pambrighten</b> is the same as <b>ppmbrighten</b>, except that it -recognizes the various Netpbm image formats rather than treating them all as -PPM. The output format is the same as the input format and extra channels in -a PAM image (such as a transparency channel) get passed through. - -<p>If you want to modify the Hues in the image, use <b>pamhue</b>. +<p>Another backward incompatibility is that <b>pambrighten</b> produces the + same kind of output as the input, whereas <b>ppmbrighten</b> always + produces PPM. If you need PPM output, pass the results through + <b>ppmtoppm</b>. +<p><b>ppmbrighten</b> is currently implemented as a triviel program that + invokes <b>pambrighten</b>, <b>pnmnorm</b>, and <b>ppmtoppm</b>. -<h2 id="examples">EXAMPLES</h2> -<p>To double the Value of each pixel: -<pre> -ppmbrighten -value=100 -</pre> - -<p>To double the Saturation and halve the Value of each pixel: -<pre> -ppmbrighten -saturation=+100 -value=-50 -</pre> - -<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>ppmbrighten</b> recognizes the following -command line options: - -<dl> -<dt><b>-value=</b><i>value_percent</i> - -<dd>This option specifies the amount, as a per centage, by which you want -to change the Value of each pixel. It may be negative. - -<dt><b>-saturation=</b><i>value_percent</i> - -<dd>This option specifies the amount, as a per centage, by which you want -to change the Saturation of each pixel. It may be negative. - - -<dt><b>-normalize</b> - -<dd>This option causes <b>ppmbrighten</b> to normalize contrast by linearly -remapping the Values of the pixels to cover the range 0 to 1. - -<p><b>ppmbrighten</b> applies the brightening that you specify with -the <b>-value</b> option <em>after</em> the remapping. - -<p>Before Netpbm 10.14 (March 2003), your input must be from a seekable -file (not a pipe) to use <b>-normalize</b>. If it isn't, the program fails -with a bogus error message. - -</dl> - -<h2 id="seealso">SEE ALSO</h2> - -<a href="pnmnorm.html">pnmnorm</a>, -<a href="ppmdim.html">ppmdim</a>, -<a href="pamfunc.html">pamfunc</a>, -<a href="ppmflash.html">ppmflash</a>, -<a href="ppmflash.html">pambrighten</a>, -<a href="pamaltsat.html">pamaltsat</a>, -<a href="pamdepth.html">pamdepth</a>, -<a href="pnmgamma.html">pnmgamma</a>, -<a href="pamhue.html">pamhue</a>, -<a href="ppmhist.html">ppmhist</a>, -<a href="ppm.html">ppm</a> - -<h2 id="author">AUTHOR</h2> +</body> +</html> -<p>Copyright (C) 1990 by Brian Moffet. -Copyright (C) 1989 by Jef Poskanzer. -<p> -Permission to use, copy, modify, and distribute this software and its -documentation for any purpose and without fee is hereby granted, provided -that the above copyright notice appear in all copies and that both that -copyright notice and this permission notice appear in supporting -documentation. This software is provided "as is" without express or -implied warranty. -<hr> -<h2 id="index">Table Of Contents</h2> -<ul> -<li><a href="#synopsis">SYNOPSIS</a> -<li><a href="#description">DESCRIPTION</a> -<li><a href="#examples">EXAMPLES</a> -<li><a href="#options">OPTIONS</a> -<li><a href="#seealso">SEE ALSO</a> -<li><a href="#author">AUTHOR</a> -</ul> -</body> -</html> |