Pamhue User Manual(1) General Commands Manual Pamhue User Manual(1)
NAME
pamhue - change a Netpbm image's hues
SYNOPSIS
pamhue [-huechange=[degrees]] filename
Minimum unique abbreviation of option is acceptable. You may use dou-
ble 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.
DESCRIPTION
This program is part of Netpbm(1).
pamhue shifts the hue of every pixel in an image by the same amount.
If the image is in a black and white or grayscale format, the image is
fully desaturated, so the hue is meaningless and pamhue leaves the im-
age unchanged.
Hue-Saturation-Value, or HSV, is one way to represent a color, like the
more well-known RGB. Hue is an indication of the secondary color with
the same brightness that most closely approximates the color. A sec-
ondary color is made of a combination of at most two of the primary
colors.
In the HSV model, hue is an angular position on the color wheel.
With pamhue, you indicate an angle by which to change all the hues in
the image; for example you can say move it 60 degrees clockwise. That
would change all red pixels to yellow and all yellow pixels to green,
etc.
To modify the saturation and value components of the colors, use pam-
brighten.
EXAMPLES
To shift the color of each pixel 120 degrees clockwise:
pamhue -huechange=120
To shift the color of each pixel 120 degrees counterclockwise:
pamhue -huechange=-120
OPTIONS
In addition to the options common to all programs based on libnetpbm
(most notably -quiet, see
Common Options ⟨index.html#commonoptions⟩ ), pamhue recognizes the
following command line option:
-huechange=degrees
This option specifies the amount to shift each color. It is in
degrees, with positive meaning clockwise and negative meaning
counterclockwise. It may be fractional and may be more than a
full revolution.
This option is mandatory.
HISTORY
pamhue was new in Netpbm 10.86 (March 2019).
SEE ALSO
pambrighten(1), ppmflash(1), ppmhist(1), ppm(1)
AUTHOR
Copyright (C) 2018 by Willem van Schaik. Copyright (C) 1990 by Brian
Moffet. Copyright (C) 1989 by Jef Poskanzer.
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted, pro-
vided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in sup-
porting documentation. This software is provided "as is" without ex-
press or implied warranty.
DOCUMENT SOURCE
This manual page was generated by the Netpbm tool 'makeman' from HTML
source. The master documentation is at
http://netpbm.sourceforge.net/doc/pamhue.html
netpbm documentation 07 January 2018 Pamhue User Manual(1)
Generated by dwww version 1.15 on Sat Jun 29 02:21:14 CEST 2024.