[Ruby/Tk example] Feedback [incr Widget] -- take 2

[Morton Goldberg]

This is my second take on the progress indicator example. Perhaps
it's more interesting because it uses a TkTimer (aka TkAfter) to step
the progress bar.

Puts up a window containing a progress bar and a button. Clicking on
the button, disables it and starts stepping the progress bar. When
the progress bar has filled, the button is re-enabled and the whole
thing can be repeated until you're bored out of your mind

<code>
#! /usr/bin/ruby -w
# Author: Morton Goldberg
#
# Date: September 6, 2006
#
# Progress Indicator 2

require 'tk'
require 'tkextlib/iwidgets'

DEBUG = []

begin
# Build a window containing a progress indicator and a button.
root = TkRoot.new {title 'Ruby/Tk Progress Indicator'}
fb = Tk::Iwidgets::Feedback.new(root) {
steps 20
labeltext "Click the Button"
barcolor 'red'
barheight 20
troughcolor 'gray90'
}
fb.component_widget('trough').
configure('relief'=>'ridge', 'borderwidth'=>4)
fb.component_widget('bar').
configure('relief'=>'sunken', 'borderwidth'=>5)
fb.pack('fill'=>'x', 'padx'=>15, 'pady'=>10)
btn = TkButton.new(root) {
text "Do Something"
command {btn.action}
}
btn.pack('pady'=>10)
btn.instance_variable_set@fb, fb)
# Starts the timer going when the button is clicked.
def btn.action
self.state = 'disable' # Strange -- explicit receiver required
# Set the timer to trigger at 200 m-sec intervals, once for each
# progress step.
$timer = TkTimer.start(200, @fb.steps) {@fb.update}
end
fb.instance_variable_set@btn, btn)
# Run on each timer tick.
def fb.update
labeltext = "Doing Something ..."
step
# loop_rest returns remaining trigger intervals.
unless $timer.loop_rest > 1
labeltext = "Click the Button"
reset
@btn.state = 'normal'
end
end

# Set initial window geometry; i.e., size and placement.
win_w, win_h = 300, 160
# root.minsize(win_w, win_h)
win_l = (TkWinfo.screenwidth('.') - win_w) / 2
root.geometry("#{win_w}x#{win_h}+#{win_l}+50")

# Set resize permissions.
root.resizable(false, false)

# Make Cmnd+Q work as expected.
root.bind('Command-q') {Tk.root.destroy}

Tk.mainloop
ensure
puts DEBUG unless DEBUG.empty?
end
</code>

Regards, Morton