Keith Vetter 2004-01-30 : Here's a fun, simple little animation of a rotating fan. You can vary the speed, direction, number and color of the blades and the size.
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#
# Fan.tcl - draws rotating fan blades
# by Keith Vetter, Jan 30, 2004
package require Tk
array set S {title Fan angle 0 increment 2 delay 1
bg \#FCCA04 color black colors 0 blades 3 speed 2}
set colors [list red yellow green blue cyan purple violet white black]
if {$tcl_platform(platform) == "unix"} {set S(delay) 10}
proc DoDisplay {} {
wm title . $::S(title)
canvas .c -relief raised -height 250 -width 250 -bg $::S(bg) -bd 2
label .lspeed -text "Speed:"
scale .sspeed -orient horizontal -showvalue 0 -variable S(speed) \
-command Speed -from -20 -to 20
label .lblades -text "Blades:"
scale .sblades -orient horizontal -showvalue 0 -variable S(blades) \
-command DrawFan -from 1 -to 20
checkbutton .colors -text "C" -font {Helvetica 6 bold} \
-indicatoron 0 -variable S(colors) -command [list DrawFan 1]
button .about -text "?" -font {Helvetica 6 bold} \
-command [list tk_messageBox -title "About $::S(title)" \
-message "$::S(title)\nby Keith Vetter, January 2004"]
grid .c - - -row 0 -sticky news
grid .lspeed .sspeed .colors -sticky ew
grid .lblades .sblades .about -sticky ew
grid rowconfigure . 0 -weight 1
grid columnconfigure . 1 -weight 1
bind all <Key-F2> {console show}
bind .c <Configure> {ReCenter %W %h %w}
update
DrawFan 1
}
proc DrawFan {{arg 0}} {
global S colors
set a [expr {360.0 / $S(blades)}] ; set b [expr {$a / 2}] ;# Blade positions
if {$arg} {
.c delete all
set clen [llength $::colors]
for {set i 0} {$i < $S(blades)} {incr i} {
set color [expr {! $S(colors) ? $S(color) \
: [lindex $colors [expr {int($clen*rand())}]]}]
.c create arc $S(size1) -tag blade$i -fill $color -outline $color \
-start [expr {$S(angle) + $i*$a}] -extent $b
}
.c create oval $S(size2) -tag outer -fill $S(bg) -outline $S(bg)
.c create oval $S(size3) -tag inner -fill $S(color) -outline $S(color)
} else { ;# Here to just update position
for {set i 0} {$i < $S(blades)} {incr i} {
.c itemconfig blade$i -start [expr {$S(angle) + $i * $a}] -extent $b
}
}
}
# Recenter -- keeps 0,0 at the center of the canvas during resizing
proc ReCenter {W h w} { ;# Called by configure event
set h2 [expr {$h / 2}] ; set w2 [expr {$w / 2}]
$W config -scrollregion [list -$w2 -$h2 $w2 $h2]
set s [expr {($h2 < $w2 ? $h2 : $w2) * .75}];# Blade size
set ::S(size1) [list -$s -$s $s $s]
set s [expr {$s / 4}] ;# Middle circle
set ::S(size2) [list -$s -$s $s $s]
set s [expr {$s / 2}] ;# Inner circle
set ::S(size3) [list -$s -$s $s $s]
DrawFan -1
}
proc Speed {val} {
foreach old $::S(increment) ::S(increment) [expr {$val / 4.0}] break
if {! $old} Go
}
proc Go {} {
foreach aid [after info] {after cancel $aid};# Be safe
if {$::S(increment) == 0} return
set ::S(angle) [expr {$::S(angle) + $::S(increment)}]
DrawFan
after $::S(delay) Go
}
DoDisplay
GoSS to work well with Unix you should not use after with an argument < 10, because that's the max granularity of the timer of many unix-like operating systems (notably Linux >= 2.6 should perform better, having the HZ macro set to 1000 instead of 100). Otherwise X server events will speed-up the Fun when you move the cursor, press keys and so on.
KPV Okay, I added code to set S(delay) to 10 if tcl_platform(platform) equals "unix".