Day Clock

dayclock.tcl

package require Tk

wm title . "Dayclock"
wm geometry . 200x225

canvas .clock
pack .clock

set expired_slice [.clock create arc 1 1 200 200 \
                       -start 225 -extent -270 -fill red]

set remaining_slice [.clock create arc 1 1 200 200 \
                         -start 225 -extent 0 -fill green]

set label [.clock create text 100 200 -text ""]

.clock create arc 1 1 200 200 -start 315 -extent 270

set start_hour 9
set end_hour 18
set duration [expr {$end_hour - $start_hour}]

proc unpad {value} {
    if {$value == 0} {
        return 0
    } else {
        return [regsub {^0+} $value {}]
    }
}

proc round2 {value} {
    return [expr {round($value * 100.0) / 100.0}]
}

proc draw_slices {} {
    global start_hour end_hour duration label expired_slice remaining_slice
    set hour [unpad [clock format [clock seconds] -format %H]]
    set minute [unpad [clock format [clock seconds] -format %M]]

    set total_range [expr {60.0 * $duration}]
    set frac_hour [expr {($hour - $start_hour) + $minute/60.0}]

    if {$frac_hour >= $start_hour && $frac_hour <= $end_hour} {
        set expired_start 225
        set expired_angle [expr {($frac_hour / $duration) * 270}]
        set remaining_start [expr {$expired_start - $expired_angle}]
        set remaining_angle [expr {270 - $expired_angle}]

        set hours_left [expr {$duration - $frac_hour}]
        .clock itemconfigure $label -text "[round2 $hours_left] remaining"
    } else {
        set expired_start 225
        set expired_angle 270
        set remaining_start 225
        set remaining_angle 0

        .clock itemconfigure $label -text "No time remaining"
    }

    .clock itemconfigure $expired_slice -start $expired_start -extent -$expired_angle
    .clock itemconfigure $remaining_slice -start $remaining_start -extent -$remaining_angle

    after 15000 draw_slices
}

draw_slices