Zoom problems on mobile devices

https://groups.google.com/d/topic/mathjax-users/9HFG2Btm4OU/discussion

Hello,

I ran into a strange error - I was testing my MathJax rendered content on an ipad with meta tag

and I have the problem that I can not zoom (put two fingers on the screen and expand) when both fingers are on MathJax rendered content. It works when one finger is on a non rendered area.

I tried this on mathjax.org as well, same problem here.

I modified my config to be very restrict, taking out the mathmenu, the zoom, only using systemfonts and everything that would put an event on the content, but with no sucess. (I attached my configuration)

What could be the problem here? (or even better: the solution :))

I thought about the following:

-problems with position:relative;

• problem for the webkit browser because mathjax is rendered after the page is loaded
• are there hidden events you can not control over the config file.

It would be great if someone has some suggestions to look at and possible bugfixes.

You can test the behavior on www.mathjax.org

Best regards stephan c.

---

I am able to reproduce the issue. MathJax's "double-tap-and-hold" is implemented by checking for a double-tap (two successive taps in close succession) where the second is held down. I suspect that the pinch is coming as two separate tap events in close succession, and since you hold to pinch or stretch, it is triggering MathJax's menu code.

I will check into it further and see about a work-around. For now, you can disable the double-tap checking by using

<script type="text/x-mathjax-config">
MathJax.Hub.Register.StartupHook("MathEvents Ready",function () {
  MathJax.Extension.MathEvents.Touch.delay = -1;
});
</script>

This is prevent MathJax from trapping the double-taps and should make pinching work properly again.

Davide

NOTE: This has been fixed as of MathJax v2.1