Hi Daniel. Thanks for sharing this plugin with the community. I have troubles trying to make the plugin work. I installed it correctly together with the dependency and configured the Atto bar to display it. However, the button does not appear. I was trying to debug and the reason is that the function initializer() returns after this: if (typeof MathJax === 'undefined' && !this.get('filteractive')) Any idea what might be reason for this? The description page does not mention any special setup needed and the TinyMCE variant of the plugin work well on the same site.

Turning TeX filter on and off does not make any difference.

Hello David,
Thanks for looking at this. Have you tried it with the MathJax filter on? This is necessary if MathJax is not enabled in the theme head. The line you found is making this check.
This behaviour is different than the TinyMCE plugin for some historical reasons. The TinyMCE plugin was started in Moodle 2.4, and has a setting for a MathJax url to load if it is not available in the header, and loads it into an iframe header. Since MathJax was added to the core in 2.7 with the Atto, this plugin uses the filter instead of the one in the TinyMCE plugin to load MathJax. I could remove the restriction to allow using the Mathslate even when the MathJax filter is not enabled, but I am not sure if that might represent a security problem of some kind. A checkbox setting may be needed.
It also may be good to consider a plugin set for dependencies. Currently this plugin depends on the TinyMCE one where the bulk of the yui code is. However, I am assuming eventually that TinyMCE or yui support will be removed and this will no longer make sense.

I updated the description to include this.

That was the issue indeed. Thanks for updating the description Daniel. You are cleared to land now, welcome to the plugins directory!

So far I've been unable to get the button to show up in Atto in Moodle 2.9. TinyMCE works fine though.

Hi Matthew, Did you add 'mathslate' to Atto toolbar settings to position the button? The step is necessary in Atto, but not TinyMCE.

I was unaware it was unnecessary in TinyMCE so I put it in both configurations. I've tried adding it in many areas of the editor and it doesn't show up. I've turned the mathjax filter on, off. I've setup a local copy of MathJax, used the CDN. Still can't get the MathSlate icon to show up in Atto.

Is the core Atto equation editor appearing with MathJax filter on and TeX notation turned off? Does that editor display correctly? This should tell you whether MathJax is working.
If the core editor works, the check javascript console in you browsers tools menu to see if there is a helpful error message.

The editor displays correctly with the core Atto editor. Also, just found out that mathslate button does show up in Atto if the default equation editor button in enabled.

Thanks Matthew. I am able to reproduce this now. MathJax filter is not loading MathJax if the equation editor is not enabled. I will try to update this soon.

Matthew, I updated with a new release that loads MathJax when the equation editor is disabled.

Works like a charm now. Thanks Daniel

The description of the last version mentions a prototype that supports Moodle 2.6. Which version of the plugin is this?

Great job!

The is a branch for 2.5 in the github repo https://github.com/dthies/moodle-atto_mathslate/archive/MOODLE_25_STABLE.zip. I think that this will work with 2.6 if Atto is installed as an addon, but it has been a long time since I tried it.