Ppmwheel User Manual(1) General Commands Manual Ppmwheel User Manual(1) NAME ppmwheel - make a PPM image of a color wheel SYNOPSIS ppmwheel diameter [{-huevalue | -huesaturation}] [-maxval=N] DESCRIPTION This program is part of Netpbm(1). ppmwheel produces a PPM image of a color wheel of the specified diame- ter inside a white square just large enough to hold it. The color wheel is based on the HSV color model. Hues are distributed angularly around the circle and the values and saturations are dis- tributed radially. You can generate three kinds of color wheel: • Hue-value: Select this with a -huevalue option. 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. 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. • Hue-saturation: Select this with a -huesaturation option. 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. • Ppmcirc: Select this by not specifying any other wheel type op- tion. The saturation is 100% everywhere. The value is a strange func- tion 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 dis- tance 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 ppmwheel from its inception in 2003 to 2019. ARGUMENTS You must specify one non-option argument: the radius of the color wheel in pixels. This is also the height and width of the output image. OPTIONS In addition to the options common to all programs based on libnetpbm (most notably -quiet, see Common Options ⟨index.html#commonoptions⟩ ), ppmwheel recognizes the following command line options: -huevalue This selects a hue-value color wheel. This option was new in Netpbm 10.86 (March 2019). -huesaturation This selects a hue-saturation color wheel. This option was new in Netpbm 10.86 (March 2019). -maxval=N This selects the maxval for the image. The default is 255. This option was new in Netpbm 10.86 (March 2019). SEE ALSO ppmcie(1), ppmrainbow(1), ppm(1) HISTORY ppmwheel was added to Netpbm in Release 10.14 (March 2003). AUTHOR Copyright (C) 1995 by Peter Kirchgessner 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/ppmwheel.html netpbm documentation 03 February 2019 Ppmwheel User Manual(1)
Generated by dwww version 1.15 on Sun Jun 30 20:48:26 CEST 2024.