+proc notecrossings {id lo hi corner} {
+ global oldtodo crossings cornercrossings
+
+ for {set i $lo} {[incr i] < $hi} {} {
+ set p [lindex $oldtodo $i]
+ if {$p == {}} continue
+ if {$i == $corner} {
+ if {![info exists cornercrossings($id)]
+ || [lsearch -exact $cornercrossings($id) $p] < 0} {
+ lappend cornercrossings($id) $p
+ }
+ if {![info exists cornercrossings($p)]
+ || [lsearch -exact $cornercrossings($p) $id] < 0} {
+ lappend cornercrossings($p) $id
+ }
+ } else {
+ if {![info exists crossings($id)]
+ || [lsearch -exact $crossings($id) $p] < 0} {
+ lappend crossings($id) $p
+ }
+ if {![info exists crossings($p)]
+ || [lsearch -exact $crossings($p) $id] < 0} {
+ lappend crossings($p) $id
+ }
+ }
+ }
+}
+