[Keith Vetter] 2003-05-04 : a simple little whizzlet simulating
rain drops on a window. Much like the old unix game rain.

[http://mini.net/sdarchive/rainstorm.jpg]

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[Jacob Levy] 05/05/2003 I keep getting error messages (in "deluge" mode mostly) about ::R(somenumber) not being there when incr is applied. The problem is probably collisions due to the ID computation based on rand(), in proc RainDrop. If ::R($id,x) already exists then we should probably go back and compute another ID.

[KPV] 05/06/2003 : thanks for the fix. I took the liberty of 
merging the code.

[Jacob Levy] 05/06/2003 Urk... the version below is (again) missing my fix...

[KPV] 05/06/2003 : true, but it contains a simpler fix

[etdxc] Sep 08 2003 : I received an error when in deluge mode.
        Wish84 has caused an error in DIBENG.DLL
Its probably something to do with my 'Windows Me' and not your code but I thought I'de let your know. Btw, can I use this code in a project I'm working on ?

[KPV] of course, everything I put on Wiki is for all to use freely.

[DKF]: Is it necessary to create and delete all those ovals?  Couldn't you use [[$w coords]] to resize them instead?  (You also leak tags; better to not set a tag and just store the id in a variable.)

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 ##+##########################################################################
 #
 # RainStorm.tcl - Simulates rain drops on a window
 # by Keith Vetter, May 2, 2003
 #
 ##+##########################################################################
 #############################################################################
 
 package require Tk

 set S(delay) 80
 set S(rain) 3
 set S(id) 0
 
 array set SIZES {0 1  1 2  2 4  3 6  4 8  5 10 6 12 7 14 8 16}
 array set DROPS {0 {Mist 500} 1 {Sprinkles 200} 2 {Shower 100}
     3 {Rain 50} 4 {Storm 25} 5 {Down\ Pour 10} 6 {Deluge 1}}
 
 wm title . "Rain Storm"
 canvas .c -relief raised -borderwidth 0 -height 500 -width 500
 scale .rain -orient h -variable S(rain) -command Rain -showvalue 0 -from 0 -to 6
 image create photo ::img::blank -width 1 -height 1
 button .about -image ::img::blank -highlightthickness 0 -command \
     [list tk_messageBox -message "Rain Storm\nby Keith Vetter, May 2003"]
 pack .c -side top -fill both -expand 1
 place .rain -in .c -relx 1 -rely 1 -anchor se
 place .about -in .c -relx 1 -rely 1 -anchor se
 bind all <Alt-c> {console show}
 
 proc Rain {args} {
     after cancel Rain
     .rain config -label [lindex $::DROPS($::S(rain)) 0]
     RainDrop
     after [lindex $::DROPS($::S(rain)) 1] Rain
 }
 proc RainDrop {{id {}}} {
     .c delete d$id
     if {$id == {}} {                            ;# New drop
         set id [incr ::S(id)]
         set ::R($id,x) [expr {round([winfo width .c] * rand())}]
         set ::R($id,y) [expr {round([winfo height .c] * rand())}]
         set ::R($id,step) -1
     } 
     set n [incr ::R($id,step)]
     if {! [info exists ::SIZES($n)]} {
         array unset ::R $id,*
     } else {
         .c create oval [box $::R($id,x) $::R($id,y) $::SIZES($n)] -tag d$id
         after $::S(delay) [list RainDrop $id]
     }
 }
 proc box {x y r} {
     return [list [expr {$x-$r}] [expr {$y-$r}] [expr {$x+$r}] [expr {$y+$r}]]
 }
 Rain
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[Category Application] | [Category Graphics] | [Category Whizzlet] | [Category Animation]