Re: [DOM3Events] WheelEvent and zoom

I don't think browsers should set deltaZ even when the default action is 

The spec just said that "The user's *environment* might be configured to 
associate zooming with rotation along the z-axis.".

So, zooming by Ctrl + y-axis wheel rotation is *just* a default action 
of some browsers. So, web applications should be able to handle the raw 
level action such as "Ctrl + y-axis wheel rotation" rather than 
operation for zoom.

If web application needs to handle zoom action, D3E or UI Events should 
define "zoom" event.

On 2013/09/12 22:56, Rick Byers wrote:
> Hi,
> We'd like to use the 'wheel' event in blink to communicate zoom requests
> from the user, distinct from pan (eg. on a trackpad 2-finger scroll vs.
> pinch).  The spec
> ( has a
> suggestion to use deltaZ for this:
> "The user's environment might be configured to associate vertical
> scrolling with rotation along the y-axis, horizontal scrolling with
> rotation along the x-axis, and zooming with rotation along the z-axis."
> I was looking into doing this in blink (, but it
> seems no other browser behaves this way.  IE10 and Firefox appear to
> instead use deltaY with the ctrl modifier set for zooms (pinch on a
> trackpad).  Any advice on how this should be handled?  With IE and
> Firefox already in agreement, I think it's better to follow their lead
> then to follow the suggestion in the spec.  Perhaps the suggestion
> should be updated to match implementations?
> One problem with either approach is that it's not clear how an app can
> detect that a device that supports zooming distinct from panning is
> being used.  For example, a mapping site probably wants the wheel on a
> physical mouse to control zoom (since panning can be accomplished with
> click and drag), but panning on a trackpad to pan the map instead of
> zoom it (since pinching can zoom it).  Any tips on how a UA should
> advertise that zooming is supported?  It's unfortunate, for example,
> that deltaZ isn't permitted to be undefined when not supported by the
> input device.
> Thanks,
>     Rick

Masayuki Nakano <>
Manager, Internationalization, Mozilla Japan.

Received on Friday, 13 September 2013 02:23:22 UTC