scrolled event/bind help! 
Author Message
 scrolled event/bind help!


Is there a way to provide a callback that runs when a scrolled canvas (or
whatever) is scrolled?

I made a canvas:

$canvas = $fr_graph->Scrolled('Canvas',
                               '-scrollbars' =>  's' ,
                              '-scrollregion' => ['0',  '10', .17 * $#trace, '0'],


And, I put a graph on it:

        for (0 .. ($#trace - 1)){
                $id[$_] = $canvas->create('line',

                (blah, blah, blah...)

I created a second scrollbar for moving a 'cursor' (a vertical line) within
the graph.

I want to make the cursor visible again whenever the user scrolls away from
it - maybe put it in the middle of the visible portion of the graph whenever
the user scrolls away from the cursor.

Come to think of it is there a direct way to tell if a canvas item is
visible? I planned to check in the callback if my cursor was between the
return values of $canvas->xview.


Ron Hartikka
    Interautomation, Inc.

    Dearborn => 313-248-5401
    Mobile   => 734-216-2845

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Sat, 31 May 2003 02:04:59 GMT  
 scrolled event/bind help!
Try this!

$xscrollbar = $canvas->Subwidget('xscrollbar');

sub win_scrolling
  my ($left,$right) = $canvas->xview;


Good Luck!
Mikael Alenfalk

Mon, 02 Jun 2003 06:15:20 GMT  
 [ 2 post ] 

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