ppmcolors – generate a color map of all colors of a certain maxval
All options can be abbreviated to their shortest unique prefix. You
may use two hyphens instead of one to designate an option. You may use
either white space or an equals sign between an option name and its
ppmcolors generates a PPM color map containing all the colors repre‐
sentable with a certain maxval.
A PPM color map is a regular PPM image that is used by some programs to
define a set of colors.
ppmcolors generates a one row PPM image that contains one pixel of each
color representable by the maxval you choose. The maxval of the PPM
image is that maxval. Note that you can change the maxval of the color
map by running the output of ppmcolors through pnmdepth. As long as
the new maxval is a multiple of the original, the resulting set of col‐
ors will be identical. If the new maxval is not a multiple, the
resulting set of colors will be slightly different.
When you select a maxval of 5 (which is the default), you get a color
map of the set of “web safe” colors as defined by Netscape. Most web
browsers guarantee that they can produce at least these 216 colors (215
pnmcolormap is another program to generate a color map. It chooses a
set of colors designed to represent the colors in a specified image (or
simply the set of all the colors in that image, if you choose).
pgmramp performs a similar function for PGM images.
This is the maxval of the generated color map. Default is 5.
By Bryan Henderson, December 2001.
20 December 2001 ppmcolors