Pgmramp User Manual(0) Pgmramp User Manual(0)
pgmramp - generate a grayscale ramp
pgmramp -lr|-tb|-rectangle|-ellipse -maxval=maxval width height
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
This program is part of Netpbm(1).
Generates a graymap of the specified size containing a black-to-white
ramp. These ramps are useful for multiplying with other images, using
The ramp is linear in brightness, not intensity. I.e. the gamma-cor-
rected sample values in the PGM rise linearly with distance from the
corner of the image. If you want a ramp that is linear in light inten-
sity, use pnmgamma with pgmramp.
To generate a simple ramp of all the values from 0 to maxval, and not
necessarily a graphic image, use pamseq(1).
ppmrainbow does something similar to what pgmramp does, but for color.
The image fades between two colors of your choice.
You must specify exactly one of the ramp type options.
-lr A left to right ramp.
-tb A top to bottom ramp.
An outside-in rectangular ramp. It is black around the edges
and white in the center.
An outside-in elliptical ramp. It is black around the edge and
white in the center.
The maxval for the generated image. Default is 255.
This option did not exist before June 2002. Before, the
pamarith(1), pnmgamma(1), pamseq(1), ppmrainbow(1), pamgradient(1),
Copyright (C) 1989 by Jef Poskanzer.
netpbm documentation 04 June 2002 Pgmramp User Manual(0)
Man(1) output converted with