file

set palette file is basically a set palette defined (<gradient>) where <gradient> is read from a datafile or datablock. The color values may be provided either as a single 24-bit packed RGB integer (1 or 2 using columns) or as three separate fractional R, G, B components (3 or 4 using columns). If no explicit gray value is provided in the first input column, the line number is used; this generates equal spacing along the color axis.

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 "-" using 1:2:3
      0 0 1
      0 1 0
      1 1 0
      1 0 0
      e

Same thing using explicit gray intervals and packed RGB values:

      set palette model RGB file "-" using 1:2
      1  0x0000ff
      2  0x00ff00
      3  0xffff00
      4  0xff0000
      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