You can assign a separate color for each data point, line segment, or label in
your plot. lc rgbcolor variable tells the program to read RGB color
information for each line in the data file. This requires a corresponding
additional column in the using specifier. The extra column is interpreted as
a 24-bit packed RGB triple. If the value is provided directly in the data file
it is easiest to give it as a hexadecimal value (see rgbcolor (p. )).
Alternatively, the using specifier can contain an expression that evaluates
to a 24-bit RGB color as in the example below.
Text colors are similarly set using tc rgbcolor variable.
Example:
# Place colored points in 3D at the x,y,z coordinates corresponding to
# their red, green, and blue components
rgb(r,g,b) = 65536 * int(r) + 256 * int(g) + int(b)
splot "data" using 1:2:3:(rgb($1,$2,$3)) with points lc rgb variable