秒錶

stopwatch.tcl

set seconds {}
set timetext 00:00:00
set id {}
ttk::label .time -textvariable timetext -font {Arial 32}
ttk::button .reset -text 清零 -command reset
ttk::button .start -text 計時 -command {
	reset
	set seconds -1
	setSeconds
}
proc setSeconds {} {
	set ::id [after 1000 setSeconds]
	incr ::seconds
}
proc reset {} {
	if {$::id != {}} {
		after cancel $::id
	}
	set ::id {}
	set ::seconds 0
}
trace add variable seconds write updateTime
proc updateTime {args} {
	set ::timetext [clock format $::seconds -gmt 7 -format %H:%M:%S]
}
pack .time .reset .start