[HJG] This program simulates the candles burning down on an advent-wreath, 
and keeps track of statistics, such as how many times each candle was lit,
and how many times each advent was celebrated.
So you can try to maximize the usage you might get out of a set of candles...
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 #!/bin/sh
 # Restart with tcl: -*- mode: tcl; tab-width: 4; -*- \
  exec wish $0 ${1+"$@"}

 # http://wiki.tcl.tk/20479 - advent10.tcl - 2008-12-20
 # Simulate an advent-wreath: select which candles to light, press button to burn

 # Todo: 
 # * variable number of candles/checkbuttons/stats-displays
 # * click on candle to toggle checkbox
 # * delete+redraw --> itemconfig
 # * use grid for positioning the candles
 # * log to console
 # * candleflames + animation
 # * Options:
 # ** initial length of candles
 # ** candle-colors
 # ...

  package require Tk

  global Prg

  set Prg(Title)    "Advent-Wreath"
  set Prg(Version)  "v1.0"
  set Prg(Date)     "2008-12-13"
  set Prg(Author)   "Hans-Joachim Gurt"
  set Prg(Contact)  [string map -nocase {: @ ! .} gurt:gmx!de]
  set Prg(About)    "Simulate an advent-wreath: select which candles to light, press button to burn one slice."


  proc Init {w t} {
  #: Init. variables, draw all candles.

    global candle len active stat

    for { set i 1 } { $i <= $candle(maxC) } { incr i 1 } {
      set len($i) $candle(hC)
      set active($i) 0
      set stat(c$i)  0
      set stat(a$i)  0
      DrawCandle $w $i
    }
    set active(1) 1
  }


  proc DrawCandle {w nr} {
  #: Draw one of the candles / calculate its position on the canvas.

    global candle len stat

    set  c   red2
    set  ww [expr { $candle(sC) + $candle(wC) } ]
    set  x1 [expr { $candle(sC) + ($nr-1) * $ww } ]
    set  x2 $x1
    incr x2 $candle(wC)

    set  y1 [expr { $candle(hC) + 50 } ]
    set  y2 [expr { $y1 - $len($nr) } ]

  # Candle:
    .cv create rect   $x1 $y1  $x2 $y2  -width 1 -fill $candle(cC)  -tag "c$nr"

  # Holder:
     incr x1 -5
     incr x2  5
     set  y2 $y1
     incr y1 10
    .cv create rect   $x1 $y1  $x2 $y2  -width 1 -fill gold  -tag "c$nr"
  }


  proc Burn {w nr} {
  #: Burn one slice of selected candles + update statistics.

    global candle len active stat

    set ok  1
    set adv 0
    for { set i 1 } { $i <= $candle(maxC) } { incr i 1 } {
      if  $active($i) {
        if { $::len($i) < $::candle(bC) } { set ok 0; bell; }
        incr adv 1
      }
    }

    if $ok {
      incr stat(a$adv) 1
      for { set nr 1 } { $nr <= $candle(maxC) } { incr nr 1 } {
        if  $active($nr) {
          set ::len($nr)  [expr { $::len($nr) - $::candle(bC) } ]
          $w delete "c$nr"
          DrawCandle $w $nr
          incr stat(c$nr) 1
        }
      }
    }
  }


#---+----1----+----2----+----3----+----4----+----5----+----6----+----7--

  wm title . $Prg(Title)
  if {[file exists  advent.ico]} {
    wm iconbitmap . advent.ico
  }

  frame .f1                ;# display
  frame .f2                ;# buttons
  frame .f3                ;# candle-stats
  frame .f4                ;# advent-stats
  pack .f1 .f2 .f3 .f4

# Candle-attributes: totalnumber, height,width, spacing, burn, color
  array set candle { maxC 4   hC 125   wC 50   sC 50   bC 10   cC red2 }

  for { set i 1 } { $i <= $candle(maxC) } { incr i 1 } {
    checkbutton .cb$i  -variable active($i) -text $i
    entry       .ec$i  -textvar stat(c$i) -width 5 -state readonly
    entry       .ea$i  -textvar stat(a$i) -width 5 -state readonly
  }

  set maxY [expr { $candle(hC) + 100 } ]
  set maxX [expr { $candle(maxC) * ($candle(wC) + $candle(sC)) + 50 } ]

  canvas  .cv -width $maxX -height $maxY  -bg white
  pack    .cv -in .f1

  button  .bN -text "New"   -command { Init .cv "Canvas" }
  button  .b1 -text "Burn"  -command { Burn .cv 1 }
  pack .bN   .cb1 .cb2 .cb3 .cb4 .b1  -in .f2  -side left -padx 2

  label   .lab1 -text "Candle burnt:" -width 14
  label   .lab2 -text "Advent:"       -width 14
  label   .lab0 -text " "              -width 16
  label   .lab9 -text " "              -width 16
  pack .lab1 .ec1 .ec2 .ec3 .ec4 .lab0  -in .f3  -side left -padx 2
  pack .lab2 .ea1 .ea2 .ea3 .ea4 .lab9  -in .f4  -side left -padx 2

  Init .cv "Canvas"
  focus -force .

 # Debug:
  bind .  <F1>     { console show }
  bind .  <Escape> { source $argv0 }

  if 0 {
  proc int x  { expr int($x) }
  bind .cv <Motion> {wm title . "[int [%W canvasx %x]],[int [%W canvasy %y]]=[.cv find withtag current]"}
  }

 #catch {console show}
 #catch {wm withdraw .}

#.
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Not all planned features are implemented yet, but I wanted this to get out before christmas...

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[Category Graphics] - [Category Toys]