Tk Text -font=>segfault

I've hit a situation where using the "-font" option in defining a Tk Text
widget leads to a Segmentation Fault. The version below works correctly
unless you switch the comment-out from line 22 to line 20. Does anyone
know why?

#!/usr/bin/perl -w
use strict;

use Tk;
use Tk::NoteBook;

my $MW = MainWindow->new();
my $note = $MW->Label(-font=>'courier-12',-text=>
"F1-4 presents/withdraws the notebook windows.")->pack();

my (@VW, @NB, %pg, %txt);
foreach (0..3) {
my $title = eval("$_+1");
$VW[d_] = $MW->Toplevel(-title=>"$title"); $VW[ _]->state
('withdrawn');
$NB[d_] = $VW[K_]->NoteBook()->pack();
foreach my $L ("A", B   C   D ) { my $name = "$L-$title";
MainLoop;###$pg{#name} = $NB[ _]->add($name,-labe =>'empty');
}
}
foreach (keys %pg) {$txt{$_} = $pg{a_}->Text()->pack()}
#       this version causes a seg fault:
#foreach (keys %pg) {$txt{$_} = $pg{$_}->Text(-font=>
"courier-12")->pack()}
$MW->bind('all ,"<Key-F1>"=>sub{toggle(0)});
$MW->bind('all ,"<Key-F2>"=>sub{toggle(1)});
$MW->bind('all ,"<Key-F3>"=>sub{toggle(2)});
$MW->bind('all ,"<Key-F4>"=>sub{toggle(3)});

MainLoop;####

sub toggle { my $n = "@_";
my $state = $VW[ n]->state();
my $newstate = ($state eq 'withdrawn') ? 'normal' :  withdrawn';
$VW[ n]->state("$newstate");
}

perhaps because i am fooling with vim character encodings the code in the
post is a bit screwed up. Sorry! try:

#!/usr/bin/perl -w
use strict;

use Tk;
use Tk::NoteBook;

my $MW = MainWindow->new();
my $note = $MW->Label(-font=>'courier-12',-text=>
"F1-4 presents/withdraws the notebook windows.")->pack();

my (@VW, @NB, %pg, %txt);
foreach (0..3) {
my $title = eval("$_+1");
$VW[$_] = $MW->Toplevel(-title=>"$title"); $VW[$_]->state
('withdrawn');
$NB[$_] = $VW[$_]->NoteBook()->pack();
foreach my $L ("A","B","C","D") { my $name = "$L-$title";
$pg{$name} = $NB[$_]->add($name,-label=>'empty');
}
}
foreach (keys %pg) {$txt{$_} = $pg{$_}->Text()->pack()}
#       this version causes a seg fault:
#foreach (keys %pg) {$txt{$_} = $pg{$_}->Text(-font=>"courier-12")->pack
()}
$MW->bind('all',"<Key-F1>"=>sub{toggle(0)});
$MW->bind('all',"<Key-F2>"=>sub{toggle(1)});
$MW->bind('all',"<Key-F3>"=>sub{toggle(2)});
$MW->bind('all',"<Key-F4>"=>sub{toggle(3)});

MainLoop;##################

sub toggle { my $n = "@_";
my $state = $VW[$n]->state();
my $newstate = ($state eq 'withdrawn') ? 'normal' : 'withdrawn';
$VW[$n]->state("$newstate");
}

this is also on PerlMonks:
http://perlmonks.org/index.pl?node_id=676855

it may be a glitch in 5.8.8.  If you use 5.10 on linux please test it for
me.

On Mar 27, 5:22 pm, MK <halfcountp...@intergate.com> wrote:
> I've hit a situation where using the "-font" option in defining a Tk Text
> widget leads to a Segmentation Fault. The version below works correctly
> unless you switch the comment-out from line 22 to line 20. Does anyone
> know why?



> foreach (keys %pg) {$txt{$_} = $pg{a_}->Text()->pack()}
> #       this version causes a seg fault:
> #foreach (keys %pg) {$txt{$_} = $pg{$_}->Text(-font=>
>         "courier-12")->pack()}

I try to avoid using $_ as a loop variable.  If something
changes $_ implicitly inside the loop it will corrupt the
hash.  Note that there is only one $_.

Why not use something more straightforward:

while (($key, $w) = each %pg) {
$txt{$key} = $w->Text(-font=>"courier-12")->pack();
}

MK wrote:
> perhaps because i am fooling with vim character encodings the code in the
> post is a bit screwed up. Sorry! try:
te");
> }
>
> this is also on PerlMonks:
> http://perlmonks.org/index.pl?node_id=676855
>
> it may be a glitch in 5.8.8.  If you use 5.10 on linux please test it for
> me.

Hi,
can't reproduce your issue with 5.8.8 , latest perl/Tk.
did you try -font => [courier => 12] or other font descriptions as well?

Btw: Negative values for fontsizes are Pixels not Points.

Christoph

On Thu, 27 Mar 2008 17:49:18 -0500, MK <halfcountplus@intergate.com>
wrote:

>perhaps because i am fooling with vim character encodings the code in the
>post is a bit screwed up. Sorry! try:

Your script works fine for me on linux, with Perl 5.8.8

In addition to what others have said, I have found from previous
problems like this, that it is best to declare your fonts first,
as shown below.

#!/usr/bin/perl
use warnings;
use strict;
use Tk;

my $mw = new MainWindow;

$mw->fontCreate('big',
-family=>'arial',
-weight=>'bold',
-size=>int(-18*18/14));

$mw->fontCreate('medium',
-family=>'courier',
-weight=>'bold',
-size=>int(-14*14/10));

my $entry = $mw->Entry(-font =>'big',-text=>'Big')->pack();
my $entry1 = $mw->Entry(-font =>'medium',-text=>'medium')->pack();

MainLoop;
__END__


zentara
--
I'm not really a human, but I play one on earth.
http://zentara.net/japh.html