Beefy Boxes and Bandwidth Generously Provided by pair Networks
XP is just a number

Re^4: getting visible area of Tk::Scrolled?

by halley (Prior)
on Sep 19, 2011 at 20:42 UTC ( #926802=note: print w/replies, xml ) Need Help??

in reply to Re^3: getting visible area of Tk::Scrolled?
in thread getting visible area of Tk::Scrolled?

Thanks again for your help, BrowserUk. This is the heart of a drag-an-item handler, so that when dragging near the edge of the scrollable canvas, the canvas automatically scrolls more into view. Otherwise the user must drop, scroll, and grab the item again.

# move all associated items... $c->move($group, $dx, $dy); # consider moving the visible area in the scrollregion my @corners = $c->get_corners(); my @bb = $c->bbox($group); if ($bb[0] < $corners[0]) { $c->xviewScroll(-1, 'units'); } if ($bb[1] < $corners[1]) { $c->yviewScroll(-1, 'units'); } if ($bb[2] >= $corners[2]) { $c->xviewScroll(+1, 'units'); } if ($bb[3] >= $corners[3]) { $c->yviewScroll(+1, 'units'); }

Without starting any timers or anything, it's a little chunky, but it's pretty useful and dead simple.

[ e d @ h a l l e y . c c ]

Log In?

What's my password?
Create A New User
Node Status?
node history
Node Type: note [id://926802]
Discipulus there are none so deaf as those who will not hear..
Discipulus who do not want to ear
[Corion]: marto: No, I haven't seen anything either and I'm not sure if learning-by- osmosis will work here
[marto]: I've experienced the behavior LanX described, outsourcing really opens your eyes to the situation :)
[Discipulus]: ;=)

How do I use this? | Other CB clients
Other Users?
Others chilling in the Monastery: (6)
As of 2017-03-30 07:10 GMT
Find Nodes?
    Voting Booth?
    Should Pluto Get Its Planethood Back?

    Results (353 votes). Check out past polls.