-------------------------------------------
var,funct (left-click): read col LUT
  set val2rgblut <infile>
  read_val2rgblut
-------------------------------------------

The "R" button on the "lut:" entry line reads the
color lookup table (LUT) from file whose name is
current value of $val2rgblut (entry to left).  If
$complexvalflag not set to 1 ("cpx" is
unclicked), the "R" button will reset the
colscale to 12 (real-valued LUT).

If $complexvalflag is set to 1 ("cpx" is clicked),
then the "R" button will reset the color scale to
14 (complex LUT for phase).  In this case, it
expects to read a color LUT file whose first
column ranges from 0.0 to 1.0 (and which usually
wraps -- i.e., color for 0.0 equals color for
1.0).  Complex phase LUT first column values
below 0.0 or above 1.0 are ignored.

The *display* of complex color LUT is affected by
$revphaseflag and $angle_offset (but not by
$angle_cycles).  Since the state of the variables
$revphaseflag, $angle_offset, and $angle_cycles
is incorporated into the phase color LUT at the
time the LUT file was written, to restore that
appearance, unset revphaseflag (unlick "rev") and
set $angle_offset to 0.0.

The setting of $angle_cycles will be ignored for
phase LUT display, except to determine whether
the colorscale disk is displayed as
"eccentricity" (integer angle_cycles) or "polar
angle" (floating point angle_cycles).
