set ::secs_togo 0
proc countdown_start { } {
countdown_reset
countdown_continue
}
proc countdown_continue { } {
.c itemconfigure face -fill white
draw_hands
if !$::secs_togo {
.start configure -text "Start" -command countdown_start
.c itemconfigure face -fill green
bell
return
}
.start configure -text "Pause" -command countdown_pause
incr ::secs_togo -1
after 1000 countdown_continue
}
proc countdown_pause { } {
catch {after cancel countdown_continue}
.c itemconfigure face -fill blue
.start configure -text "Continue" -command countdown_continue
}
proc countdown_reset { } {
catch {after cancel countdown_continue}
set ::secs_togo [expr $::seconds+60*$::minutes]
.c itemconfigure face -fill $::bg
.start configure -text "Start" -command countdown_start
draw_hands
}
proc draw_hand { hand angle decorations } {
set end_xy [get_xy $hand $angle]
eval .c create line $::size $::size $end_xy $decorations
}
proc end_coordinate {hand difference} {
set length [expr {$hand == "seconds" ? .9 : .8}]
set hand_length [expr $::size * $length]
return [expr $::size + $hand_length * $difference]
}
proc get_xy { hand angle } {
return [list [end_coordinate $hand [expr sin($angle)]] \
[end_coordinate $hand [expr -cos($angle)]]]
}
proc draw_hands {} {
set seconds $::secs_togo
catch {.c delete withtag hands}
set twopi 6.283185
set seconds_angle [expr $seconds * $twopi / 60.]
draw_hand seconds $seconds_angle "-width 1 -tags hands"
set minutes_angle [expr $seconds_angle / 60.]
draw_hand minutes $minutes_angle \
"-width 2 -capstyle projecting -arrow last -tags hands"
}
proc init {} {
catch {destroy .c}
set ::size 30
set full_diameter [expr 2 * $::size]
canvas .c -width $full_diameter -height $full_diameter
button .start -text "Start" -command countdown_start
button .reset -text "Reset" -command countdown_reset
label .l -text "mm:ss"
spinbox .m -textvariable ::minutes -width 2 -justify right \
-from 0 -to 59 -validate key -vcmd {expr "%P<0||%P>59?0:1"}
spinbox .s -textvariable ::seconds -width 2 -justify right \
-from 0 -to 59 -validate key -vcmd {expr "%P<0||%P>59?0:1"}
set ::bg [.c cget -background]
grid .l .m .s -sticky ew
grid .c - -
grid .start - .reset -sticky ew
set border 2
set diameter [expr 2 * $::size - $border]
.c create oval $border $border $diameter $diameter \
-fill $::bg -outline black -tag face
}
# Example usage:
init