Re: displaying of Tk::Optionmenu

listmail <[email protected]> writes:

> A Tk::Optionmenu typically displays it’s drop down list for its options 
> just below the drop down selector. When the Tk::Optionmenu is located 
> close to the bottom of the screen (such as near the windows taskbar) and 
> the option list is too long to have room to display its list below the 
> drop down select, it will display the list upwards which ends up 
> overlapping the menu selector. I suppose the display portion could be 
> something that is handled by the window manger and not necessarily 
> Tk::Optionmen/Tk::Menubutton etc.
> 
> I would like to have it start displaying the contents from the top of 
> the drop down selector and move upward when the list is too long to 
> display downward. One of the main reasons for this is that is easy for 
> the end user to accidentaly select the wrong option when it overlaps and 
> draws itself under the current mouse position as well. Can anyone give 
> me a clue as to how I could get things work as I describe? Does this 
> problem exist in the more recent versions of Tk?
> 

Yes, the problem still exists, and it seems to be existent in current
Tcl/Tk versions, too. Under Unix/X11, there is a similar problem with
application menus in Tk (I am not sure if the problem is also under
Windows, maybe there native menus will be used).

To workaround this problem, you can drop the following lines into your
script. I originally wrote it for the Unix menu problem, but it seems
to also solve the Optionmenu problem.


{
package Tk::Menu;
use Tk::Menu;
my $orig_menu_post;
BEGIN {
    $orig_menu_post = \&Tk::Menu::post;
}
if ($Tk::VERSION < 805) {
    *post = sub {
	my($self, $x, $y) = @_;
	if ($y + $self->reqheight > $self->screenheight) {
	    my $pointery = $self->pointery;
	    $y = $pointery - 10 - $self->reqheight;
	    if ($y < 0) {
		$y = 0;
	    }
	}
	$orig_menu_post->($self, $x, $y);
    };
}
}



Regards,
        Slaven

-- 
Slaven Rezic - slaven <at> rezic <dot> de
  BBBike - route planner for cyclists in Berlin
  WWW version:                           http://www.bbbike.de
  Perl/Tk version for Unix and Windows:  http://bbbike.sourceforge.net
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