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-rw-r--r--library/demos/pendulum.tcl72
1 files changed, 36 insertions, 36 deletions
diff --git a/library/demos/pendulum.tcl b/library/demos/pendulum.tcl
index d344d8d..4fff99a 100644
--- a/library/demos/pendulum.tcl
+++ b/library/demos/pendulum.tcl
@@ -10,7 +10,7 @@ if {![info exists widgetDemo]} {
package require Tk
set w .pendulum
-catch {destroy $w}
+destroy $w
toplevel $w
wm title $w "Pendulum Animation Demonstration"
wm iconname $w "pendulum"
@@ -34,7 +34,7 @@ canvas $w.c -width 320 -height 200 -background white -bd 2 -relief sunken
$w.c create text 5 5 -anchor nw -text "Click to Adjust Bob Start Position"
# Coordinates of these items don't matter; they will be set properly below
$w.c create line 0 25 320 25 -tags plate -fill grey50 -width 2
-$w.c create oval 155 20 165 30 -tags pivot -fill grey50 -outline {}
+$w.c create oval 155 20 165 30 -tags pivot -fill grey50 -outline ""
$w.c create line 1 1 1 1 -tags rod -fill black -width 3
$w.c create oval 1 1 2 2 -tags bob -fill yellow -outline black
pack $w.c -in $w.p.l1 -fill both -expand true
@@ -45,7 +45,7 @@ pack $w.c -in $w.p.l1 -fill both -expand true
canvas $w.k -width 320 -height 200 -background white -bd 2 -relief sunken
$w.k create line 160 200 160 0 -fill grey75 -arrow last -tags y_axis
$w.k create line 0 100 320 100 -fill grey75 -arrow last -tags x_axis
-for {set i 90} {$i>=0} {incr i -10} {
+for {set i 90} {$i >= 0} {incr i -10} {
# Coordinates of these items don't matter; they will be set properly below
$w.k create line 0 0 1 1 -smooth true -tags graph$i -fill grey$i
}
@@ -55,7 +55,7 @@ $w.k create text 0 0 -anchor ne -text "\u03b4\u03b8" -tags label_dtheta
pack $w.k -in $w.p.l2 -fill both -expand true
# Initialize some variables
-set points {}
+set points [list]
set Theta 45.0
set dTheta 0.0
set pi 3.1415926535897933
@@ -68,22 +68,22 @@ set home 160
# the pendulum from the length of the pendulum rod and its angle, the
# length and angle are computed in reverse from the given location
# (which is taken to be the centre of the pendulum bob.)
-proc showPendulum {canvas {at {}} {x {}} {y {}}} {
+proc showPendulum {canvas {at ""} {x ""} {y ""}} {
global Theta dTheta pi length home
- if {$at eq "at" && ($x!=$home || $y!=25)} {
+ if {($at eq "at") && (($x != $home) || ($y != 25))} {
set dTheta 0.0
set x2 [expr {$x - $home}]
set y2 [expr {$y - 25}]
- set length [expr {hypot($x2, $y2)}]
- set Theta [expr {atan2($x2, $y2) * 180/$pi}]
+ set length [expr { hypot ($x2, $y2)}]
+ set Theta [expr { ( ( atan2 ($x2, $y2) ) * 180) / $pi}]
} else {
- set angle [expr {$Theta * $pi/180}]
- set x [expr {$home + $length*sin($angle)}]
- set y [expr {25 + $length*cos($angle)}]
+ set angle [expr {($Theta * $pi) / 180}]
+ set x [expr {$home + ($length * ( sin ($angle)))}]
+ set y [expr {25 + ($length * ( cos ($angle)))}]
}
$canvas coords rod $home 25 $x $y
$canvas coords bob \
- [expr {$x-15}] [expr {$y-15}] [expr {$x+15}] [expr {$y+15}]
+ [expr {$x - 15}] [expr {$y - 15}] [expr {$x + 15}] [expr {$y + 15}]
}
showPendulum $w.c
@@ -92,12 +92,12 @@ showPendulum $w.c
# respect to time.)
proc showPhase {canvas} {
global Theta dTheta points psw psh
- lappend points [expr {$Theta+$psw}] [expr {-20*$dTheta+$psh}]
+ lappend points [expr {$Theta + $psw}] [expr {(-20 * $dTheta) + $psh}]
if {[llength $points] > 100} {
set points [lrange $points end-99 end]
}
- for {set i 0} {$i<100} {incr i 10} {
- set list [lrange $points end-[expr {$i-1}] end-[expr {$i-12}]]
+ for {set i 0} {$i < 100} {incr i 10} {
+ set list [lrange $points end-[expr {$i - 1}] end-[expr {$i - 12}]]
if {[llength $list] >= 4} {
$canvas coords graph$i $list
}
@@ -126,16 +126,16 @@ bind $w.c <ButtonRelease-1> {
}
bind $w.c <Configure> {
%W coords plate 0 25 %w 25
- set home [expr %w/2]
- %W coords pivot [expr $home-5] 20 [expr $home+5] 30
+ set home [expr {%w / 2}]
+ %W coords pivot [expr {$home - 5}] 20 [expr {$home + 5}] 30
}
bind $w.k <Configure> {
- set psh [expr %h/2]
- set psw [expr %w/2]
- %W coords x_axis 2 $psh [expr %w-2] $psh
- %W coords y_axis $psw [expr %h-2] $psw 2
- %W coords label_dtheta [expr $psw-4] 6
- %W coords label_theta [expr %w-6] [expr $psh+4]
+ set psh [expr {%h / 2}]
+ set psw [expr {%w / 2}]
+ %W coords x_axis 2 $psh [expr {%w - 2}] $psh
+ %W coords y_axis $psw [expr {%h - 2}] $psw 2
+ %W coords label_dtheta [expr {$psw - 4}] 6
+ %W coords label_theta [expr {%w - 6}] [expr {$psh + 4}]
}
# This procedure is the "business" part of the simulation that does
@@ -143,7 +143,7 @@ bind $w.k <Configure> {
# pendulum.
proc recomputeAngle {} {
global Theta dTheta pi length
- set scaling [expr {3000.0/$length/$length}]
+ set scaling [expr {(3000.0 / $length) / $length}]
# To estimate the integration accurately, we really need to
# compute the end-point of our time-step. But to do *that*, we
@@ -157,22 +157,22 @@ proc recomputeAngle {} {
# But my math skills are not good enough to solve this!
# first estimate
- set firstDDTheta [expr {-sin($Theta * $pi/180)*$scaling}]
+ set firstDDTheta [expr {- ( sin (($Theta * $pi) / 180) ) * $scaling}]
set midDTheta [expr {$dTheta + $firstDDTheta}]
- set midTheta [expr {$Theta + ($dTheta + $midDTheta)/2}]
+ set midTheta [expr {$Theta + (($dTheta + $midDTheta) / 2)}]
# second estimate
- set midDDTheta [expr {-sin($midTheta * $pi/180)*$scaling}]
- set midDTheta [expr {$dTheta + ($firstDDTheta + $midDDTheta)/2}]
- set midTheta [expr {$Theta + ($dTheta + $midDTheta)/2}]
+ set midDDTheta [expr {- ( sin (($midTheta * $pi) / 180) ) * $scaling}]
+ set midDTheta [expr {$dTheta + (($firstDDTheta + $midDDTheta) / 2)}]
+ set midTheta [expr {$Theta + (($dTheta + $midDTheta) / 2)}]
# Now we do a double-estimate approach for getting the final value
# first estimate
- set midDDTheta [expr {-sin($midTheta * $pi/180)*$scaling}]
+ set midDDTheta [expr {- ( sin (($midTheta * $pi) / 180) ) * $scaling}]
set lastDTheta [expr {$midDTheta + $midDDTheta}]
- set lastTheta [expr {$midTheta + ($midDTheta + $lastDTheta)/2}]
+ set lastTheta [expr {$midTheta + (($midDTheta + $lastDTheta) / 2)}]
# second estimate
- set lastDDTheta [expr {-sin($lastTheta * $pi/180)*$scaling}]
- set lastDTheta [expr {$midDTheta + ($midDDTheta + $lastDDTheta)/2}]
- set lastTheta [expr {$midTheta + ($midDTheta + $lastDTheta)/2}]
+ set lastDDTheta [expr {- ( sin ( ($lastTheta * $pi) / 180) ) * $scaling}]
+ set lastDTheta [expr {$midDTheta + (($midDDTheta + $lastDDTheta) / 2)}]
+ set lastTheta [expr {$midTheta + (($midDTheta + $lastDTheta) / 2)}]
# Now put the values back in our globals
set dTheta $lastDTheta
set Theta $lastTheta
@@ -180,11 +180,11 @@ proc recomputeAngle {} {
# This method ties together the simulation engine and the graphical
# display code that visualizes it.
-proc repeat w {
+proc repeat {w} {
global animationCallbacks
# Simulate
- recomputeAngle
+ recomputeAngle
# Update the display
showPendulum $w.c
generated by cgit v0.12 at 2025-09-01 19:55:28 (GMT)