[ui-events] MouseEvent details

I think we need to do two things here.

1. Move everything from MouseEvent into the UI Events specification.
as a distinct definition does not work.

2. Define offsetX and offsetY as algorithms whose input is the target
node. In particular they are not initialized like the other
attributes, they are computed on getting. This is observable if you
create a synthetic MouseEvent and dispatch it. (CSSOM View does not
get this detail.) Conversely, offsetX and offsetY should not appear in
the initialization dictionary for this event.

This matters in particular for the shadow tree case where we mutate
the target, but do not want to mutate offsetX and offsetY as that
would require further event-specific caching.

The subject prefix [D4E] is suggested in the UI Events draft, but I
think that is in error now.

UI Events: https://dvcs.w3.org/hg/d4e/raw-file/tip/source_respec.htm


Received on Tuesday, 12 February 2013 15:07:44 UTC