file

set palette file is basically a set palette defined (<gradient>) where <gradient> is read from a datafile. Select four columns (gray,R,G,B) or three columns (R,G,B) via the using specifier. In the three column case, the line number will be used as gray. The gray range is automatically rescaled to [0,1]. The file is read as a normal data file, so all datafile modifiers can be used. Please note that R might actually be H if HSV color space is selected.

Use show palette gradient to display the gradient.

Examples:

Read in a palette of RGB triples each in range [0,255]:

      set palette file 'some-palette' using ($1/255):($2/255):($3/255)

Equidistant rainbow (blue-green-yellow-red) palette:

      set palette model RGB file "-"
      0 0 1
      0 1 0
      1 1 0
      1 0 0
      e

Binary palette files are supported as well, see binary general. Example: put 64 triplets of R,G,B doubles into file palette.bin and load it by

      set palette file "palette.bin" binary record=64 using 1:2:3