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funct: cut_line <0=open> -- cut open contour w/list
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keyboard equivalent: none

The "LINE" button (lower right), performs a
connected line segment cut of the surface using
the current ordered list of surface marks.

This can be used to make relaxation cuts when
flattening hemispheres or surface fragments, or
can be used to touch up an already cut label.

N.B.: First, be sure to clear any surface marks
with a R-click in the surface display window.

N.B.: if you are making a large, elaborate cut,
do it in stages so you can use (one-step) UNDO,
in case you make a stray click..

Then mark a series of surface vertices by
left-clicking each in turn.  A middle-click on
any already-selected vertex will remove it from
the ordered list before the cut.  Clicking "LINE"
then disconnects edges intersecting the line
segments identified by successive pairs of
vertices.

Use "UNDO" button to undo previous cut (tcl
funct: restore_ripflags 1).

Use "INIT" button to go back to the initial
read-in state of the surface, which may have
already had some hidden vertices (tcl funct:
restore_ripflags 2).

Use "ALL" button to show all vertices (tcl funct:
clear_ripflags).

If only one vertex is selected, "LINE" removes a
single vertex.

See "PTS" to more generally edit (cut/restore)
lists of single vertices.

