Pgmramp User Manual(0)					Pgmramp User Manual(0)



NAME
       pgmramp - generate a grayscale ramp


SYNOPSIS
       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
       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-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.



OPTIONS
       You must specify exactly one of the ramp type options.


       -lr    A left to right ramp.


       -tb    A top to bottom ramp.


       -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.


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

		   This	 option	 did  not exist before June 2002.  Before, the
	      maxval was
		   always 255.





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



AUTHOR
       Copyright (C) 1989 by Jef Poskanzer.



netpbm documentation		 04 June 2002		Pgmramp User Manual(0)