Perl/Tk - display "%completed" at the bottom

[MoshiachNow]

Hi,

How would I display "%completed" at the very bottom (grey)of my main window during the progress of the main loop ?

Thanks

Long live king Moshiach !

http://www.7for70.com/

 

[Kirsle]

Check out Tk::StatusBar:

http://search.cpan.org/~zabel/Tk-StatusBar-0.04/lib/Tk/StatusBar.pm

It adds a status bar widget to the bottom of your window, which I think is what you're looking for.

You can then put in a progress bar and a % completed widget too.

my $sb = $mw->StatusBar;

$sb->addProgressBar (
   -length  => 60,
   -anchor  => 'left',
   -from    => 0,
   -to      => 100, # 0 - 100%
   -variable => \$progress,
);

my $textProg = $sb->addLabel (
   -width   => 20,
   -anchor  => 'left',
   -text    => '0% completed', # we'll update this widget later
);

# your main loop to update $progress
while (1) {
   select (undef,undef,undef,0.01);
   $mw->update;

   # update $progress
   if ($progress < 100) { # less than 100%
      $progress += 5; # 5% at a time...
      # and the progress bar updates instantly

      # update the text widget too
      $textProg->configure (-text => "$progress\% completed");
   }
}

There's not much you can do about the text widget because it contains both a variable AND text that isn't involved in the variable. If you want, you can do -textvariable on the label and then just do

$text = "$progress\% completed";

and the label widget will update with that too.

Note:

Tk::StatusBar isn't a standard Tk widget, but it's not hard to install either. A quick and simple way: on the CPAN page, right-click "View Source" and do "Save Target As", and save it to C:\perl\site\lib\Tk\StatusBar.pm (assuming that's the path to your Perl lib where Tk's modules are)

 

[MoshiachNow]

Thanks a lot !

What it's this thing actually doing :

select (undef,undef,undef,0.01);

?

Long live king Moshiach !

http://www.7for70.com/

 

[MoshiachNow]

P.S.

-anchor => 'w',


it did not acccept " -anchor => 'left',


Long live king Moshiach !

http://www.7for70.com/

 

[Kirsle]

Ah, thanks for catching that one.

The select command is the only way I know of to have a sleep of a non-integer value. The sleep() command takes integers only, so that sleep(.5) rounds off to sleep(0) which doesn't sleep at all (it would be the same as int(.5) = 0)

From perlfunc:

http://search.cpan.org/perldoc?perlfunc

select RBITS,WBITS,EBITS,TIMEOUT

This calls the select(2) system call with the bit masks specified, which can be constructed using fileno and vec, along these lines:

$rin = $win = $ein = '';
vec($rin,fileno(STDIN),1) = 1;
vec($win,fileno(STDOUT),1) = 1;
$ein = $rin | $win;

If you want to select on many filehandles you might wish to write a subroutine:

sub fhbits {
my(@fhlist) = split(' ',$_[0]);
my($bits);
for (@fhlist) {
vec($bits,fileno($_),1) = 1;
}
$bits;
}
$rin = fhbits('STDIN TTY SOCK');

The usual idiom is:

($nfound,$timeleft) =
select($rout=$rin, $wout=$win, $eout=$ein, $timeout);

or to block until something becomes ready just do this

$nfound = select($rout=$rin, $wout=$win, $eout=$ein, undef);

Most systems do not bother to return anything useful in $timeleft, so calling select() in scalar context just returns $nfound.

Any of the bit masks can also be undef. The timeout, if specified, is in seconds, which may be fractional. Note: not all implementations are capable of returning the $timeleft. If not, they always return $timeleft equal to the supplied $timeout.

You can effect a sleep of 250 milliseconds this way:

select(undef, undef, undef, 0.25);

Note that whether select gets restarted after signals (say, SIGALRM) is implementation-dependent. See also perlport for notes on the portability of select.

On error, select behaves like the select(2) system call : it returns -1 and sets $!.

Note: on some Unixes, the select(2) system call may report a socket file descriptor as "ready for reading", when actually no data is available, thus a subsequent read blocks. It can be avoided using always the O_NONBLOCK flag on the socket. See select(2) and fcntl(2) for further details.

WARNING: One should not attempt to mix buffered I/O (like read or <FH>) with select, except as permitted by POSIX, and even then only on POSIX systems. You have to use sysread instead.

 

[MoshiachNow]

Thanks for education !

Long live king Moshiach !

http://www.7for70.com/