The color scheme, i.e. the gradient of the smooth color with min_z and max_z values of pm3d's palette, is drawn in a color box unless `unset colorbox`.
set colorbox
set colorbox {
{ vertical | horizontal }
{ default | user }
{ origin x, y }
{ size x, y }
{ front | back }
{ noborder | bdefault | border [line style] }
}
show colorbox
unset colorbox
Color box position can be `default` or `user`. If the latter is specified the values as given with the origin and size subcommands are used. The box can be drawn after (`front`) or before (`back`) the graph or the surface.
The orientation of the color gradient can be switched by options `vertical` and `horizontal`.
`origin x, y` and `size x, y` are used only in combination with the `user` option. The x and y values are interpreted as screen coordinates by default, and this is the only legal option for 3D plots. 2D plots, including splot with `set view map`, allow any coordinate system to be specified. Try for example:
set colorbox horiz user origin .1,.02 size .8,.04
which will draw a horizontal gradient somewhere at the bottom of the graph.
border turns the border on (this is the default). `noborder` turns the border off. If an positive integer argument is given after border, it is used as a line style tag which is used for drawing the border, e.g.:
set style line 2604 linetype -1 linewidth .4
set colorbox border 2604
will use line style `2604`, a thin line with the default border color (-1) for drawing the border. `bdefault` (which is the default) will use the default border line style for drawing the border of the color box.
The axis of the color box is called `cb` and it is controlled by means of the usual axes commands, i.e. `set/unset/show` with cbrange, `[m]cbtics`, `format cb`, `grid [m]cb`, cblabel, and perhaps even cbdata, `[no]cbdtics`, `[no]cbmtics`.
`set colorbox` without any parameter switches the position to default. `unset colorbox` resets the default parameters for the colorbox and switches the colorbox off.
See also help for pm3d, palette, pm3d, and `set style line`.