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variable: $colscalerectflag -- toggle rect/disk
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default: 0 (off)

The "bar" or "rect" or "off" button (upper right)
toggles the state of the lower right display
window color scale inset between 3 states:

 (1) disk color scale (phase is angle if
     non-integral angle_cycles and radius if
     intergral angle_cycles).

 (2) rectangular phase color scale inset
     (x-axis is phase, y-axis is significance)

 (3) off

Use $fullpolrectflag ("ful" in [fn]-F3 interface)
to toggle half/full phase range of rect with
non-integral $angle_cycles.

In state (1), the disk represents the the color
saturation for complex amplitude input of
2.0*fmid (i.e., fully saturated).  To see a range
of saturations, use state (2).

In state (2), the bottom of the rectangular phase
color scale represents the color saturation for a
complex amplitude input of zero.  The top of the
rectangle starts out representing a complex
amplitude input of 2.0*fmid.  The top limit can
be reset with the entry to the right of "bar"
(just above "fthresh").

N.B.: the effects of the stat mask are not
represented in the rect/disk insets (with the
rectangle, a 3D volume would be required to
represent colors for all different combinations
of phase, amplitude, and stat).
