Tk::Text - moving through hidden text

[anna_black]

Hello,

I stumbled upon a weird behaviour in Tk::Text, when trying to move with the keyboard through hidden text, and I think it might be a bug.

Consider the following code:

use strict;
use warnings;
use Tk;

my $mw = MainWindow->new(-title => "Bug?");
my $frame = $mw->Frame()
    ->pack(-side => "left", 
       -expand => 1,
       -fill => 'both');
my $text = $frame->Scrolled('Text')
    ->pack(-expand => 1,
       -fill => 'both');

my $data;
for (my $i = 1; $i <= 20; $i++) {
    $data .= "abcdefghi $i \n";
}
$text->insert('end',$data);

$text->tagConfigure("invisible",-elide => 'true');
$text->tagAdd("invisible",'7.0','13.0');

MainLoop();

If you stand on line #6, and move with the arrows down, you jump straight to line #13, as expected. Same thing when you start from #13 and move up. If you stand on line 6 and move to the right, the cursor disappears, which makes sense (even if I'd rather have it jump to #13 as well). However, if after the cursor disappears, you try to move up or down, you immediately get errors.

Is that a bug? If so, where should I report it? (CPAN?)

Thanks :)

[zentara]

It's hard to say whether it's a bug or not, but I see your problem. In the perldoc for Tk::Text, it says the text behaves as normal, but what is normal?

-elide => boolean
 Elide  specifies whether the data should be elided.  Elided data is
 not displayed and takes no space on screen,  but  further  on
behaves just as normal data.

I would say you could submit a bug report at Tk bug reports . But to be honest, the maintainer is very busy, and I wouldn't expect a quick response.

Your best option is to create a workaround, where you store the hidden ranges in an array

sub hide_text {  
   my @r = $text->tagRanges('sel'); 
   print "@r\n"; 
   return unless @r; 
   $text->tagAdd('hide',@r); 
   return;   
}

then when the cursor position is in one of those ranges, manually skip it. This would require you bind to the arrow-keys. You might also want to ask in the newsgroup comp.lang.perl.tk, where a few Tk::Text experts hang out.