man.postnix Miscellaneous man pages of Plan 9 related material

     CMAP(9.6)                                               CMAP(9.6)

     NAME
          cmap - color map format

     DESCRIPTION
          A color map is a 256x3-byte translation table for color
          values.  In a monochrome picture, pixel values index the
          color map to yield red, green and blue, like this:

               uchar cmap[256][3];
               red = cmap[pixel][0];
               green = cmap[pixel][1];
               blue = cmap[pixel][2];

          In a full-color picture, the color map is, in effect, three
          intensity-compensation tables: cmap[red][0] maps red chan-
          nels, cmap[green][1] maps green channels and cmap[blue][2]
          maps blue channels.

          A color map file is just a 768-byte file containing the
          color map, stored in the order implied by the declaration of
          cmap above.

     Page 1                       Plan 9             (printed 11/6/25)