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6.5 KiB
Tcl

# anilabel.tcl --
#
# This demonstration script creates a toplevel window containing
# several animated label widgets.
if {![info exists widgetDemo]} {
error "This script should be run from the \"widget\" demo."
}
package require Tk
set w .anilabel
catch {destroy $w}
toplevel $w
wm title $w "Animated Label Demonstration"
wm iconname $w "anilabel"
positionWindow $w
label $w.msg -font $font -wraplength 4i -justify left -text "Four animated labels are displayed below; each of the labels on the left is animated by making the text message inside it appear to scroll, and the label on the right is animated by animating the image that it displays."
pack $w.msg -side top
## See Code / Dismiss buttons
set btns [addSeeDismiss $w.buttons $w]
pack $btns -side bottom -fill x
# Ensure that this this is an array
array set animationCallbacks {}
## This callback is the core of how to do animation in Tcl/Tk; all
## animations work in basically the same way, with a procedure that
## uses the [after] command to reschedule itself at some point in the
## future. Of course, the details of how to update the state will vary
## according to what is being animated.
proc RotateLabelText {w interval} {
global animationCallbacks
# Schedule the calling of this procedure again in the future
set animationCallbacks($w) [after $interval RotateLabelText $w $interval]
# We do marquee-like scrolling text by chopping characters off the
# front of the text and sticking them on the end.
set text [$w cget -text]
set newText [string range $text 1 end][string index $text 0]
$w configure -text $newText
}
## A helper procedure to start the animation happening.
proc animateLabelText {w text interval} {
global animationCallbacks
# Install the text into the widget
$w configure -text $text
# Schedule the start of the animation loop
set animationCallbacks($w) [after $interval RotateLabelText $w $interval]
# Make sure that the animation stops and is cleaned up after itself
# when the animated label is destroyed. Note that at this point we
# cannot manipulate the widget itself, as that has already died.
bind $w <Destroy> {
after cancel $animationCallbacks(%W)
unset animationCallbacks(%W)
}
}
## Next, a similar pair of procedures to animate a GIF loaded into a
## photo image.
proc SelectNextImageFrame {w interval} {
global animationCallbacks
set animationCallbacks($w) \
[after $interval SelectNextImageFrame $w $interval]
set image [$w cget -image]
# The easy way to animate a GIF!
set idx -1
scan [$image cget -format] "GIF -index %d" idx
if {[catch {
# Note that we get an error if the index is out of range
$image configure -format "GIF -index [incr idx]"
}]} then {
$image configure -format "GIF -index 0"
}
}
proc animateLabelImage {w imageData interval} {
global animationCallbacks
# Create a multi-frame GIF from base-64-encoded data
set image [image create photo -format GIF -data $imageData]
# Install the image into the widget
$w configure -image $image
# Schedule the start of the animation loop
set animationCallbacks($w) \
[after $interval SelectNextImageFrame $w $interval]
# Make sure that the animation stops and is cleaned up after itself
# when the animated label is destroyed. Note that at this point we
# cannot manipulate the widget itself, as that has already died.
# Also note that this script is in double-quotes; this is always OK
# because image names are chosen automatically to be simple words.
bind $w <Destroy> "
after cancel \$animationCallbacks(%W)
unset animationCallbacks(%W)
rename $image {}
"
}
# Make some widgets to contain the animations
labelframe $w.left -text "Scrolling Texts"
labelframe $w.right -text "GIF Image"
pack $w.left $w.right -side left -padx 10 -pady 10 -expand yes
# This method of scrolling text looks far better with a fixed-width font
label $w.left.l1 -bd 4 -relief ridge -font fixedFont
label $w.left.l2 -bd 4 -relief groove -font fixedFont
label $w.left.l3 -bd 4 -relief flat -font fixedFont -width 18
pack $w.left.l1 $w.left.l2 $w.left.l3 -side top -expand yes -padx 10 -pady 10 -anchor w
# Don't need to do very much with this label except turn off the border
label $w.right.l -bd 0
pack $w.right.l -side top -expand yes -padx 10 -pady 10
# This is a base-64-encoded animated GIF file.
set tclPoweredData {
R0lGODlhKgBAAPQAAP//////zP//AP/MzP/Mmf/MAP+Zmf+ZZv+ZAMz//8zM
zMyZmcyZZsxmZsxmAMwzAJnMzJmZzJmZmZlmmZlmZplmM5kzM2aZzGZmzGZm
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YWlsbHkuY29tACH5BAVkAAEALAAAAAAqAEAAAAX+YCCOZEkyTKM2jOm66yPP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KaWRHeTZEJF8SqLDn/hhsOeQgBbqAh6DGqronxeARUIIACH5BAUeAAAALAUA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}
# Finally, set up the text scrolling animation
animateLabelText $w.left.l1 "* Slow Animation *" 300
animateLabelText $w.left.l2 "* Fast Animation *" 80
animateLabelText $w.left.l3 "This is a longer scrolling text in a widget that will not show the whole message at once. " 150
animateLabelImage $w.right.l $tclPoweredData 100