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diff --git a/pambrighten.html b/pambrighten.html new file mode 100644 index 00000000..14102cd0 --- /dev/null +++ b/pambrighten.html @@ -0,0 +1,160 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 3.2//EN"> +<HTML><HEAD><TITLE>Pambrighten User Manual</TITLE></HEAD> +<BODY> +<H1>pambrighten</H1> +Updated: 12 January 2019 +<BR> +<A HREF="#index">Table Of Contents</A> + +<H2>NAME</H2> +pambrighten - change a PPM image's Saturation and Value + +<H2 id="synopsis">SYNOPSIS</H2> + +<b>pambrighten</b> +[<b>-saturation=</b>[<b>+</b>|<b>-</b><i>saturation_percent</i>]] +[<b>-value=</b>[<b>+</b>|<b>-</b><i>value_percent</i>]] +<i>netpbmfile</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>pambrighten</b> increases or decreases the Saturation and Value +(from the HSV color space) of each pixel of a Netpbm image. You specify +the percentage 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>The output format is the same as the input format and any extra channels, +such as transparency, are passed through. + +<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 Netpbm formats are 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>pambrighten</b> +increases it to full Value 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>pambrighten</b> increases it to full Saturation instead. + +<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 percentage, +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>pambrighten</b>. + +<p><b>ppmflash</b> does another kind of brightening. It changes the color of +each pixel to bring it a specified percentage closer to white. This increases +the value and saturation. + +<p><b>pambrighten</b> is the same as <b>pambrighten</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>. + + +<H2 id="examples">EXAMPLES</H2> +<p>To double the Value of each pixel: +<pre> +pambrighten -value=100 +</pre> + +<p>To double the Saturation and halve the Value of each pixel: +<pre> +pambrighten -saturation=+100 -value=-50 +</pre> + +<H2 id="options">OPTIONS</H2> + +<DL> +<DT><b>-value=</b><i>value_percent</i> + +<DD>This option specifies the amount, as a percentage, 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 percentage, by which you want to +change the Saturation of each pixel. It may be negative. + +</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="pamaltsat.html">pamaltsat</A>, +<A HREF="pmbrighten.html">ppmbrighten</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="history">HISTORY</H2> + +<P><B>pambrighten</B> was new in Netphm 10.86 (March 2019). It was a +PAM conversion of the much older <b>ppmbrighten</b>. + + +<H2 id="author">AUTHOR</H2> + +<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="#history">HISTORY</A> +<LI><A HREF="#author">AUTHOR</A> +</UL> +</BODY> +</HTML> |