dystrophy has asked for the wisdom of the Perl Monks concerning the following question:

In Perl/Tk:
Is it possible to grab the current position of a scrollbar (or scrolled) and restore that position after refreshing or changing the content (EG scrolled ROText box)?

I've searched around a bit, but I haven't satisfied my curiousity.

TIA - dystrophy

Replies are listed 'Best First'.
Re: scroll position
by dystrophy (Monk) on Jan 21, 2001 at 00:54 UTC
    tye was nice enough to guide me to the solution - I had been looking under Tk::Scrollbar and Scrolled instead of Tk::Text.

    Use yview() to retreive the current position, then use yviewMoveTo($fract) to set the position.

    Now I can attempt to mess with the Perl/Tk Chatterbox Client...(no more cutting and pasting to view ancient chat)

    -dystrophy
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      You can use yview(moveto=>$fract) instead of yviewMoveTo($fract).

      Here is a convenience fix for the Perl/Tk Chatterbox Client.
      Change sub updChatterbox to:
      sub updChatterbox {
    my ($mytopchar, $myposition) = $Chatfield->yview();  # retreive sc
+roll pos
    &Status('Checking for new chat messages...');
    foreach (&getFromServer('chat')) { &printChat("$_"); }
    &Status($status_idle);
    if ($myposition == 1) {
        $Chatfield->yview(moveto=>$myposition);
    }
    else {
        $Chatfield->yview(moveto=>$mytopchar);  # restore scroll pos
    }
}

      [download]

      This allows you to scroll back and read aged chat without having the client jump to the bottom. No more cutting and pasting!!

      Update: If I had bothered to actually pay attention while browsing through the Tk CB code, I would have seen the part about $Chatfield->see('end');
      Here is a nicer fix:
          if ($myposition == 1) {
    $Chatfield->yview(moveto=>$myposition);
    }
    else {
        $Chatfield->yview(moveto=>$mytopchar);  # restore scroll pos
    }

      [download]

      -dystrophy
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