Restore Mouse Wheel In PanZoom

Restore Mouse Wheel In PanZoom

The default zoom behavior bound to mouse wheel was doing scaled translation
that didn't play well with the rest of the pan/zoom math. This overrides the
default behavior and fires a standard YUI zoom synthetic event. We are then 
able to manually apply the delta and manage scale/translate ourselves.

https://code.launchpad.net/~bcsaller/juju-gui/scrollwheel/+merge/143003

(do not edit description out of merge proposal)

[bcsaller, 2013-01-11 23:55:49]

Please take a look.

[matthew.scott, 2013-01-14 17:00:26]

The code looks good, but there are a few interaction problems that I'd at least
like input on from Ben+others.

1 - as below, the focus call is happening before the container is placed in the
DOM, so it's not having any effect.  Can either get rid of it, or move it to
after line 550 in app.js, after showView('login'), or within showView's callback
function.

2 - Scrollwheel doesn't work if the mouse is over a service or relation. I can't
remember if this was the case previously or not, too, so it may be safe to
ignore this).

3 - Zooming with the scroll-wheel zooms from the origin (that is, translate is
not updated in the transform).  While I don't like this, it may be acceptable,
depending on what London/others say.  Two ways around it are a) the
d3.behavior.zoom way, which is to scroll from the mouse's location (which
d3.mouse(<rect element> can provide) or b) scroll from the center of the rect,
which is visible in the old _fire_zoom method on line 1210 back in
http://bazaar.launchpad.net/~juju-gui/juju-gui/trunk/revision/275#app/views/t...

What does everyone think?  I don't really have any issues other than these, and
if they're non-issues, that's fine too.

https://codereview.appspot.com/7099046/diff/1/app/views/login.js
File app/views/login.js (right):

https://codereview.appspot.com/7099046/diff/1/app/views/login.js#newcode74
app/views/login.js:74:
this.get('container').one('input[type=password]').focus();
At this point, the container has not been added to the DOM, so this line is not
having the desired effect.  Tested with chrome debugger with 

Y.one('#login-column') === null

[matthew.scott, 2013-01-14 17:10:25]

Additionally, it appears that panning is no longer working.  This is one I don't
think we can live without.

[bcsaller, 2013-01-14 17:54:28]

Pan, wow, didn't even notice that I was so focused on getting the zoom working.
Thanks, I'll look into it.

[benji, 2013-01-14 20:14:29]

Other than some unnecessary parenthesis, this looks great.

https://codereview.appspot.com/7099046/diff/1/app/views/topology/panzoom.js
File app/views/topology/panzoom.js (right):

https://codereview.appspot.com/7099046/diff/1/app/views/topology/panzoom.js#n...
app/views/topology/panzoom.js:99: evt.scale = (topo.get('scale') + delta);
The unnecessary parentheses are... unnecessary. :)

[bcsaller, 2013-01-15 20:32:19]

*** Submitted:

Restore Mouse Wheel In PanZoom

The default zoom behavior bound to mouse wheel was doing scaled translation
that didn't play well with the rest of the pan/zoom math. This overrides the
default behavior and fires a standard YUI zoom synthetic event. We are then 
able to manually apply the delta and manage scale/translate ourselves.

R=
CC=
https://codereview.appspot.com/7099046