Manual: pgmramp

Pgmramp User Manual(1)				   General Commands Manual			      Pgmramp User Manual(1)

NAME
       pgmramp - generate a grayscale ramp

SYNOPSIS
       pgmramp {-lr|-tb|-rectangle|-ellipse|-diagonal} [-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 value.

DESCRIPTION
       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 pamarith.

       The  ramp  is  linear  in brightness, not intensity.  I.e. the gamma-corrected 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 intensity, use pnmgamma	with
       pgmramp.

       Options	let  you  choose  the  shape of the ramp (left to right, inside out, etc.).  You can use pamflip to get more
       shapes.	For example, the -lr option gives you a left to right ramp and

	   $ pgmramp -lr 100 100 | pamflip -lr

       gives you a right to left ramp.

       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.

OPTIONS
       In  addition  to	 the  options common to all programs based on libnetpbm (most notably -quiet, see  Common Options ),
       pgmramp recognizes the following command line options:

       You must specify exactly one of the ramp type options.

       -lr    A left to right ramp.  Black on the left; white on the right.

       -tb    A top to bottom ramp.  Black on top; white on the bottom.

       -rectangle
	      An outside-in rectangular ramp.  It is black around the edges and white in the center.

       -ellipse
	      An outside-in elliptical ramp.  It is black around the edge and white in the center.

       -diagonal
	      A ramp from top left corner diagonally down to bottom right.  Black at the  top  left;  white  at	 the  bottom
	      right.

	      This option was new in Netpbm 10.66 (March 2014).

       -maxval=maxval
		   The maxval for the generated image.	Default is 255.

		   This option was new in Netpbm 10.1 (June 2002).  Before that, the maxval
		   is always 255.

SEE ALSO
       pamflip(1), pamarith(1), pnmgamma(1), pamseq(1), ppmrainbow(1), pamgradient(1), pgm(1)

AUTHOR
       Copyright (C) 1989 by Jef Poskanzer.

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/pgmramp.html

netpbm documentation				      15 February 2014				      Pgmramp User Manual(1)