ppmrainbow(1) General Commands Manual ppmrainbow(1)NAME
ppmrainbow - Generate a rainbow
SYNOPSIS
ppmrainbow [-width=number] [-height=number]
[-tmpdir=directory] [-verbose] color ...
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 equals signs between an option name and its value.
DESCRIPTION
ppmrainbow generates a PPM image that fades from one color to another to another from left to right, like a rainbow. The colors are those
you specify on the command line, in that order. The first color is added again on the right end of the image.
If you want a vertical or other non-horizontal rainbow, run the output through pnmrotate.
One use for such a rainbow is to compose it with another image under an alpha mask in order to add a rainbow area to another image. In
fact, you can make rainbow-colored text by using pbmtext, pnmcomp, and ppmrainbow.
OPTIONS -width number
The width in pixels of the output image.
Default is 600.
-height number
The height in pixels of the output image.
Default is 8.
-tmpdir
The directory specification of the directory ppmrainbow is to use for temporary files.
Default is the value of the TMPDIR environment variable, or /tmp if TMPDIR is not set.
-verbose
Print the "commands" (invocations of other Netpbm programs) that ppmrainbow uses to create the image.
SEE ALSO ppmmake(1), pnmcomp(1), pbmtext(1), ppmfade(1), ppm(5).
AUTHOR
Arjen Bax wrote ppmrainbow in June 2001 and contributed it to the Netpbm package. Bryan Henderson wrote this man page in July 2001.
1 July 2001 ppmrainbow(1)
Check Out this Related Man Page
ppmcolors(1) General Commands Manual ppmcolors(1)NAME
ppmcolors - generate a color map of all colors of a certain maxval
SYNOPSIS
ppmcolors [-maxval=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 value.
DESCRIPTION
ppmcolors generates a PPM color map containing all the colors representable 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 colors 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 plus black).
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.
OPTIONS -maxval=maxval
This is the maxval of the generated color map. Default is 5.
SEE ALSO pnmdepth(1), pnmcolormap(1), ppmcie(1), ppmrainbow(1), pgmramp(1), ppm(5)AUTHOR
By Bryan Henderson, December 2001.
Contributed to the public domain.
20 December 2001 ppmcolors(1)
What is the point of this? Whenever I close my shell it appends to the history file without adding this. I have never seen it overwrite my history file.
# When the shell exits, append to the history file instead of overwriting it
shopt -s histappend (3 Replies)