1.16.1.1 rgbcolor variable

Most plot commands assign a single color (linetype) to each element of the plot. If there are multiple plots on a single graph, the default color (linetype) is incremented sequentially. You can instead assign a separate color for each data point, line segment, or label based on additional information in the input data file. This is indicated by the colorspec keyword ‘variable‘.

‘lc rgbcolor variable‘ tells the program to use a 24-bit RGB color from a separate column 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. These are most easily specified as hexidecimal values (see ‘rgbcolor‘). 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