oracular (3) Term::Twiddle.3pm.gz
NAME
Term::Twiddle - Twiddles a thingy while-u-wait
SYNOPSIS
use Term::Twiddle;
my $spinner = new Term::Twiddle;
$spinner->start;
system('tar', '-xvf', 'some_phat_tarfile.tar');
$spinner->stop;
$spinner->random; ## makes it appear to really struggle at times!
$spinner->start;
&some_long_function();
$spinner->stop;
DESCRIPTION
Always fascinated by the spinner during FreeBSD's loader bootstrap, I wanted to capture it so I could
view it any time I wanted to--and I wanted to make other people find that same joy I did. Now, anytime
you or your users have to wait for something to finish, instead of twiddling their thumbs, they can watch
the computer twiddle its thumbs.
During Twiddling
Once the twiddler/spinner is in motion you need to do something (e.g., unpack a tar file, call some long
function, etc.). You can do almost anything in between start and stop as long as there are no sleep calls
in there (unless the process has been forked, as in a Perl system call). From Time::HiRes:
Use of interval timers may interfere with alarm(), sleep(), and
usleep(). In standard-speak the "interaction is unspecified",
which means that anything may happen: it may work, it may not.
Try not to do any terminal I/O while the twiddler is going (unless you don't mind dragging the twiddler
around with your cursor).
Spinner Methods
new Creates a new Twiddle object:
my $spinner = new Term::Twiddle;
Optionally initializes the Twiddle object:
## a moderately paced spinner
my $spinner = new Term::Twiddle( { rate => 0.075 } );
start
Starts the twiddler twiddling:
$spinner->start;
stop
Stops the twiddler:
$spinner->stop;
thingy
Creates a new thingy. The argument is a reference to a list of strings to print (usually single
characters) so that animation looks good. The default spinner sequence looks like this:
$spinner->thingy( [ "\\", "|", "/", "-" ] );
an arrow could be done like this:
$spinner->thingy( [
"---->",
" ----->",
" ----->",
" ----->",
" ----->|",
" ---->|",
" --->|",
" -->|",
" ->|",
" >|",
" |",
" "]);
Look at the test.pl file for this package for more fun thingy ideas.
rate
Changes the rate at which the thingy is changing (e.g., spinner is spinning). This is the time to
wait between thingy characters (or "frames") in seconds. Fractions of seconds are supported. The
default rate is 0.175 seconds.
$spinner->rate(0.075); ## faster!
probability
Determines how likely it is for each step in the thingy's motion to change rate of change. That is,
each time the thingy advances in its sequence, a random number from 1 to 100 is generated. If
probability is set, it is compared to the random number. If the probability is greater than or equal
to the randomly generated number, then a new rate of change is randomly computed (between 0 and 0.2
seconds).
In short, if you want the thingy to change rates often, set probability high. Otherwise set it low.
If you don't want the rate to change ever, set it to 0 (zero). 0 is the default.
## half of all sequence changes will result in a new rate of change
$spinner->probability(50);
$spinner->start;
do_something;
$spinner->stop;
The purpose of this is to create a random rate of change for the thingy, giving the impression that
whatever the user is waiting for is certainly doing a lot of work (e.g., as the rate slows, the
computer is working harder, as the rate increases, the computer is working very fast. Either way your
computer looks good!).
random
Invokes the probability method with the argument specified. If no argument is specified, 25 is the
default value. This is meant as a short-cut for the probability method.
$spinner->random;
stream
Select an alternate stream to print on. By default, STDOUT is printed to.
$spinner->stream(*STDERR);
Alternative Spinner Methods
Since version 2.70, Term::Twiddle objects support a couple of new spinners that aren't so "plain". 2.70
includes a bounceing ball and a swishing object (that's the best name I could think to call it).
The following methods are used to activate and customize these new spinners.
type
Use this method to set the type of spinner. The default type (no type) is whatever thingy is set to.
Two other currently supported types are bounce, and swish. These may be set in the constructor:
my $sp = new Term::Twiddle({ type => 'bounce' });
$sp->start;
or you can set it with this type method:
my $sp = new Term::Twiddle;
$sp->type('bounce');
There is currently no way to add new types without some hacking (it's on the "to do" list).
width
This method is only used when type is undefined (i.e., a normal spinner). width determines how wide
the bounce or swish objects go. width may be set in the constructor:
my $sp = new Term::Twiddle({ type => 'bounce', width => 60 });
$sp->start;
or you can set it with this width method:
my $sp = new Term::Twiddle({ type => 'swish' });
$sp->width(74);
delay
Determines the speed of motion of the object. Usually the default is fine (and each object has its
own default delay option for optimal aesthetics).
EXAMPLES
Show the user something while we unpack the archive:
my $sp = new Term::Twiddle;
$sp->random;
$sp->start;
system('tar', '-zxf', '/some/tarfile.tar.gz');
$sp->stop;
Show the user a bouncing ball while we modify their configuration file:
my $sp = new Term::Twiddle( { type => 'bounce' } );
$sp->start;
## there must not be any 'sleep' calls in this!
do_config_stuff();
$sp->stop;
AUTHOR
Scott Wiersdorf, <scott@perlcode.org>
CAVEATS
• Prolly won't run on platforms lacking setitimer. Will run on Cygwin/Win32 (reported by Zak
Zebrowski--thanks!).
•
ACKNOWLEDGEMENTS
• Thanks to Tom Christiansen for the timer code (found lurking in an old FAQ somewhere). He probably
never had an idea that it would be part of one of the most useful modules on CPAN ;o)
The timer code has since been replaced by Time::HiRes's setitimer function, but it is good to thank
Mr. Christiansen for his goodness to Perl anyway.
• "Drew" (drew@drewtaylor.com) from rt.cpan.org for suggesting the removal of 'use warnings' for the
faithful 5.005 users.
• Orignal swishing motion filched from Term::ReadKey's test.pl by Kenneth Albanowski
(kjahds@kjahds.com). Danke!
SEE ALSO
perl.