[OpenLayers-Dev] iPhone javascript events

[Andrew Marks]

Hello,

    I would like to start a discussion about the proper inclusion of
special iphone-safari javascript events into OpenLayers.  I am
attempting to add touch pan and zoom support to OpenLayers and while I
am doing it, I might as well do it in a way that is correct and can be
used by others.  I'll talk about what I have done what I plan to do.  I
am working with 2.9.1 (maybe I should work with trunk?)

What I have done: (Made touch map panning work)

First I added "touchstart", "touchend", "touchmove" to BROWSER_EVENTS in
Events.js
I then had to modify OpenLayers.Events.getMousePosition because the
position information in the touch events is in a different location,
specifically under "targetTouches" or "changedTouches" in the event. 
Here is the code, added just before original return statement of
getMousePosition:

        if (evt.type.match(/touch/)) {
            var touches = evt.targetTouches;
            if (touches.length < 1) {
                touches = evt.changedTouches;
            }
            return new OpenLayers.Pixel(
            (touches[0].pageX + this.element.scrolls[0]) -
this.element.offsets[0]
                         - this.element.lefttop[0],
            (touches[0].pageY + this.element.scrolls[1]) -
this.element.offsets[1]
                         - this.element.lefttop[1]
            );
        }
        return new ...

I then added three methods to OpenLayers.Handler.Drag:
    touchstart: function (evt) {
        evt.button = 1; //Pretend to be a left click.
        return this.mousedown(evt);
    },

    touchmove: function(evt) {
        return this.mousemove(evt);
    },

    touchend: function(evt) {
        return this.mouseup(evt);
    },

And now touch panning is working.

What I plan to do next is look at gesture events, specifically pinching
to zoom in and out.

I welcome all feedback to ensure this is done correctly.  If I am going
about it incorrectly, let me know.

Thanks for your time,
    Andrew Marks