stopping mousewheel event from happening twice in OSX

Question

I noticed mousewheel event is happening multiple times in mac osx. Can be atributed to inertia feature.

Is there a way to fix this behaviour?

(self signed ssl no

Answer 1

To have something to start with, let's make your solution shorter (therefore easier to understand & debug):

var fireEvent;
var newDelta = deltaY;
var oldDelta = null;

fireEvent = EventCheck();
oldDelta = newDelta;

function EventCheck(){
    if(oldDelta==null) return true; //(1.1)
    if(oldDelta*newDelta < 0) return true; // (1.2) if directions differ => fire event
    if(Math.abs(newDelta) fire event
    return false; // (1.4) else => don't fire;
}

As you see, it does absolutely what your code does. However, I can't understand this part of your code (which corresponds to (1.3) in my snippet):

 //check to see if the new is lower
 if (oldDelta > newDelta) {
    fireEvent = true;
 } else {
    fireEvent = false;
 }

from code provided it's unclear how deltaY is calculated. As one could assume, delta equals to endPosition - initialPosition. So, oldDelta>newDelta does not mean that the new position is lower, but that the new gap between these two values is bigger. If it's what it mean and you still use it, I suppose you try to track inertia with that. Then you should alter comparative operator (use less than, instead of greater then and vice-versa). In other words, I'd write:

if(Math.abs(newDelta)>Math.abs(oldDelta)) return true; // (1.3) 

you see, now I've used 'greater than' operator, which means: newDelta exceeds oldDelta in absolute values => it's not inertia and you can still fire the event.

Is it what you're trying to achieve or have I misinterpreted your code? If so, please explain how deltaY is calculated and what was your goal by comparing old&new Deltas. P.S. I'd suggest not to use if(isMac) in this step, while a problem can also potentially hide there.