[OpenLayers-Dev] iPhone javascript events

[Tim Schaub]

Hey Andrew-

Your efforts on this front are appreciated.  I'd encourage you to work 
with a sandbox that is a copy of the trunk.  If you keep your sandbox up 
to date with changes from the trunk, it will be easier to eventually 
create patches for the trunk.

See the FAQ for details on creating and using a sandbox [1].

What you are experimenting with is very similar to how others have 
gotten OpenLayers working on the iPhone.  For inspiration, it may help 
to poke around the iOL library:

http://projects.opengeo.org/mobile/browser/IOL/trunk/lib

For OpenLayers 3.0, we'd like to be able to support more (browser) 
environments at a deeper level.  In the end, you shouldn't have to 
modify handlers, controls, or (especially) Events.js.

Keep us posted on your efforts,
Tim

[1] 
http://trac.openlayers.org/wiki/FrequentlyAskedQuestions#HowdoIcreatemyownsandboxintheSVNrepository

On 7/13/10 6:01 PM, Andrew Marks wrote:
> 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
>
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-- 
Tim Schaub
OpenGeo - http://opengeo.org
Expert service straight from the developers.