diff options
-rw-r--r-- | pnmcolormap.html | 21 | ||||
-rw-r--r-- | pnmquant.html | 22 | ||||
-rw-r--r-- | pnmtopng.html | 3 | ||||
-rw-r--r-- | ppmwheel.html | 65 |
4 files changed, 94 insertions, 17 deletions
diff --git a/pnmcolormap.html b/pnmcolormap.html index 9137dd68..b918dee6 100644 --- a/pnmcolormap.html +++ b/pnmcolormap.html @@ -2,7 +2,7 @@ <HTML><HEAD><TITLE>Pnmcolormap User Manual</TITLE></HEAD> <BODY> <H1>pnmcolormap</H1> -Updated: 28 October 2017 +Updated: 09 February 2019 <BR> <A HREF="#index">Table Of Contents</A> @@ -150,8 +150,8 @@ largest spread of brightness; 2) largest spread of contribution to the luminosity of the color. E.g. red is weighted much more than blue. Select among these with the <B>-spreadbrightness</B> and <B>-spreadluminosity</B> options. The default is <B>-spreadbrightness</B>. Where there are multiple -colors of the mediam magnitude, they are distributed arbitrarily among between -the suboxes. This arbitrary distribution depends upon what the system's +colors of the median magnitude, they are distributed arbitrarily among between +the subboxes. This arbitrary distribution depends upon what the system's <b>qsort</b> function does with multiple equal values, so <b>pnmcolormap</b> may produce slightly different results on different systems. @@ -161,11 +161,22 @@ colors in the box, using the above definition of "greater"; 2) the mean of the colors (each component averaged separately by brightness) in the box; 3) the mean weighted by the number of pixels of a color in the image. +<P>Select among these with the <B>-center</B>, <B>-meancolor</B>, and +<B>-meanpixel</B> options. The default is <B>-center</B>. + <P>Note that in all three methods, there may be colors in the output which do not appear in the input at all. -<P>Select among these with the <B>-center</B>, <B>-meancolor</B>, and -<B>-meanpixel</B> options. The default is <B>-center</B>. +<p>Also note that the color chosen to represent the colors in Box A the best +may also represent a color in Box B better than the color chosen to represent +the colors in Box B the best. This is true for various measures of goodness +of representation of one color by another. In particular, if you +use <b>pnmremap</b> to map the colors in the very image that you used to +create the color map to the colors in that colormap, the colors in Box B will +often map to the color <b>pnmcolormap</b> chose to represent some other box +and in fact the color <b>pnmcolormap</b> chose to represent Box B may not +appear in the <b>pnmremap</b> output at all. + <H2 id="references">REFERENCES</H2> diff --git a/pnmquant.html b/pnmquant.html index fe355a3f..61beb2de 100644 --- a/pnmquant.html +++ b/pnmquant.html @@ -2,7 +2,7 @@ <HTML><HEAD><TITLE>Pnmquant User Manual</TITLE></HEAD> <BODY> <H1>pnmquant</H1> -Updated: 09 April 2013 +Updated: 09 February 2019 <BR> <A HREF="#index">Table Of Contents</A> @@ -41,6 +41,26 @@ color map which is generated from the colors in that same input. The options have the same meaning as in those programs. See their documentation to understand <B>pnmquant</B>. +<p>You may actually get fewer than <b>ncolors</b> colors in the output because + the method <b>pnmcolormap</b> uses to choose the best set of colors for the + image is not the same as the method <b>pnmremap</b> uses to determine the + best color from the set to represent an individual color. For example, + <b>pnmcolormap</b> may include salmon in the color map as the best + representative of a pink pixel in the input and include coral in the color + map as the best representative of an actual coral pixel in the input. But + <b>pnmremap</b> is free to use any color in the color map to represent that + pink pixel and would find coral is a closer match for pink than salmon and + therefore use coral for pink. <b>pnmremap</b> might not use salmon + for <em>any</em> pixel. + +<p>This waste of a slot in the color map is a consequence of the approximate + method <b>pnmcolormap</b> uses in order to compute the color map with a + practical amount of computation. + + +<h3 id="separate">Running <b>pnmcolormap</b> and <b>pnmremap</b> Separately +</h3> + <P>It is much faster to call <B>pnmcolormap</B> and <B>pnmremap</B> directly than to run <B>pnmquant</B>. You save the overhead of the Perl interpreter and creating two extra processes. <B>pnmquant</B> is diff --git a/pnmtopng.html b/pnmtopng.html index d2f07a68..d808766b 100644 --- a/pnmtopng.html +++ b/pnmtopng.html @@ -140,7 +140,8 @@ with "unrecognized option," fall back to the old syntax. <DD> Enables scaling of maxvalues of more then 65535 to 16 bit. Since this means loss of image data, <b>pnmtopng</b> does not do it by - default. <DT><B>-interlace</B> + default. +<DT><B>-interlace</B> <DD> Creates an interlaced PNG file (Adam7). <DT><B>-alpha=</b><i>filename</i> diff --git a/ppmwheel.html b/ppmwheel.html index ff62a609..3328cf7b 100644 --- a/ppmwheel.html +++ b/ppmwheel.html @@ -2,7 +2,7 @@ <HTML><HEAD><TITLE>Ppmwheel User Manual</TITLE></HEAD> <BODY> <H1>ppmwheel</H1> -Updated: 13 January 2019 +Updated: 03 February 2019 <BR> <A HREF="#index">Table Of Contents</A> @@ -13,6 +13,9 @@ ppmwheel - make a PPM image of a color wheel <B>ppmwheel</B> <I>diameter</I> +[{<b>-huevalue</b> | <b>-huesaturation</b>}] +[<b>-maxval=</b><I>N</I>] + <H2 id="description">DESCRIPTION</H2> @@ -21,19 +24,60 @@ ppmwheel - make a PPM image of a color wheel <p><b>ppmwheel</b> produces a PPM image of a color wheel of the specified diameter inside a white square just large enough to hold it. -<p>The color wheel is based on the HSV color model. Hues are -distributed angularly around the circle and the values are distributed -radially and the saturation is 100% everywhere. The values are zero at -the center, increasing linearly to maximum at the edge. The maximum value -corresponds to the maxval of the PPM image. +<p>The color wheel is based on the HSV color model. Hues are distributed + angularly around the circle and the values and saturations are distributed + radially. + +<p>You can generate three kinds of color wheel: +<ul> + <li>Hue-value: Select this with a <b>-huevalue</b> option. + <p>The saturation is 100% everywhere. The value goes from zero to 100% + linearly, from the center of the wheel to the edge. So the center is black. + + <p>Hence, the image consists of all of the secondary colors based on the + red, green, and blue primary colors. A secondary color is one that is + composed of light of at most two of the three primary colors. + + <li>Hue-saturation: Select this with a <b>-huesaturation</b> option. + <p>The value is 100% everywhere. The saturation goes from zero to 100% + linearly, from the center of the wheel to the edge. So the center is white. + + <li>Ppmcirc: Select this by not specifying any other wheel type option. + <p>The saturation is 100% everywhere. The value is a strange function of + the distance from the center, increasing as the square root of the distance + until halfway out, then decreasing as the 8th root of the distance the rest + of the way. We don't know what the point of this is, but it is what the + program Ppmcirc by Peter Kirchgessner in 1995 does, and was the only option + in <b>ppmwheel</b> from its inception in 2003 to 2019. + +</ul> + + +<H2 id="arguments">ARGUMENTS</H2> -<p>Hence, the image consists of all of the secondary colors based on the red, -green, and blue primary colors. A secondary color is one that is composed of -light of at most two of the three primary colors. +<p>You must specify one non-option argument: the radius of the color wheel +in pixels. +<p>This is also the height and width of the output image. + + <H2 id="options">OPTIONS</H2> -<P>None. +<dl> + <dt><b>-huevalue</b> + <dd>This selects a hue-value color wheel. + <p>This option was new in Netpbm 10.86 (March 2019). + + <dt><b>-huesaturation</b> + <dd>This selects a hue-saturation color wheel. + <p>This option was new in Netpbm 10.86 (March 2019). + + <dt><b>-maxval=</b><i>N</i> + <dd>This selects the maxval for the image. The default is 255. + <p>This option was new in Netpbm 10.86 (March 2019). + +</dl> + <H2 id="seealso">SEE ALSO</H2> @@ -55,6 +99,7 @@ Copyright (C) 1995 by Peter Kirchgessner <UL> <LI><A HREF="#synopsis">SYNOPSIS</A> <LI><A HREF="#description">DESCRIPTION</A> +<LI><A HREF="#arguments">ARGUMENTS</A> <LI><A HREF="#options">OPTIONS</A> <LI><A HREF="#seealso">SEE ALSO</A> <LI><A HREF="#history">HISTORY</A> |