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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 des-
       ignate 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  multi-
       plying with other images, using pamarith.

       The  ramp  is linear in brightness, not intensity.  I.e. the gamma-corrected sample values in the PGM rise lin-
       early with distance from the corner of the image.  If you want a ramp that is linear in  light  intensity,  use
       pnmgamma with pgmramp.

       To  generate  a  simple  ramp of all the values from 0 to maxval, and not necessarily a graphic image, use pam-
       seq(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)