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
              maxval was
                   always 255.


       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)

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