I basically reworded some things to make it more vague and leave it more
up to implementors. Hopefully at some point we can pinpoint more what it
should be.
This e-mail doesn't really help with the "important use case" from Ian,
but there is ISSUE-84 tracking that.
===
When "mouse wheeling" occurs, the implementation must dispatch a
<code>mousemultiwheel</code> event implementing the following interface:
interface MouseMultiWheelEvent : MouseEvent {
readonly attribute long wheelDeltaX;
readonly attribute long wheelDeltaY;
readonly attribute long wheelDeltaZ;
void initMouseMultiWheelEventNS(in DOMString namespaceURI,
in DOMString typeArg,
in boolean canBubbleArg,
in boolean cancelableArg,
in views::AbstractView
viewArg,
in long detailArg,
in long screenXArg,
in long screenYArg,
in long clientXArg,
in long clientYArg,
in unsigned short
buttonArg,
in EventTarget
relatedTargetArg,
in DOMString
modifiersList,
in long wheelDeltaX,
in long wheelDeltaY,
in long wheelDeltaZ);
};
wheelDeltaX is a number indicating the distance (positive means rotated to
the right, negative means rotated to the left).
wheelDeltaY is a number indicating the distance (positive means rotated
away from user or to the right, negative means rotated towards user or to
the left).
wheelDeltaZ is a number indicating the distance (...).
The default value of wheelDeltaX, wheelDeltaY and wheelDeltaZ is 0.
UIEvent.detail must always be 0.
XXX: wheelDeltaY -> wheelDelta?
This event includes both scroll deltas. The default action of this event
is to dispatch a <code>mousewheel</code> event if the y delta is non-zero.
Besides that, its default action is to do whatever platform conventions
suggest for the wheeling behavior.
The <code>mousewheel</code> event implements the following interface:
interface MouseWheelEvent : MouseEvent {
readonly attribute long wheelDelta;
void initMouseWheelEventNS(in DOMString namespaceURI,
in DOMString typeArg,
in boolean canBubbleArg,
in boolean cancelableArg,
in views::AbstractView viewArg,
in long detailArg,
in long screenXArg,
in long screenYArg,
in long clientXArg,
in long clientYArg,
in unsigned short buttonArg,
in EventTarget
relatedTargetArg,
in DOMString modifiersList,
in long wheelDelta);
};
If the <code>mousewheel</code> event is cancelled, only the default action
for vertical wheeling is cancelled. The wheelDelta attribute is a number
indicating the distance (positive means rotated away from the user,
negative means rotated towards the user). The default value of the
wheelDelta attribute is 0.
XXX: What about UIEvent.detail?
For both <code>mousemultiwheel</code> and <code>mousewheel</code>
<code>MouseEvent.relatedNode</code> must point to the element being
wheel'd over or <code>null</code> if there is no such element. (For
example, when using some device without a pointer but with some way to
wheel you'd get that.)
===
--
Anne van Kesteren
<http://annevankesteren.nl/>
<http://www.opera.com/>
