latex typesetting in jsxgraph

[Peter Johnston]

Hello,

I have the following piece of latex code to label a vector in a jsxgraph extension function:

{size:'none',name:'\\[\\underline{v}\\]'} (this is part of a point definition)

This produces an underlined letter "v" in a latex math font.

However when I use

{size:'none',name:'\\[\\underline{v}_{\\perp}\\]'}

to indicate the perpendicular component of v, I get the following string on my image: \[\underline{v}\perp\] (note that the string \perp\] looks like a subscript in my image.

I was wondering what it is that I have missed.

Thanks,

Peter.

[Christian Lawson-Perfect]

Can you give me a link to a question that shows this behaviour, please?

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[Peter Johnston]

Thanks Christian,

I'm not sure how to do this, but from the firefox address window I have:

https://numbas.mathcentre.ac.uk/question/42544/projecting-vectors/

Please let me know if this helps.

Thanks,

Peter.

[Peter Johnston]

I found the answer to my own query (amazingly I had already used it once before!!!)

One needs to include the lines:

// option to use mathjax to render latex
JXG.Options.text.useMathJax = true;

(well at least the second line) at the top of the function definition.

Peter.

[Christian Lawson-Perfect]

Glad you sorted it. I suppose the extension should turn that option on by default.

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[Peter Johnston]

I have now discovered a weirdness introduced by the JXG option as listed below. It seems to screw up the latex typesetting in the statement of the problem and the advice section. For example $\underline{u}$ produces the letter u typeset in latex math font, but the underline is almost a full line of text underneath the letter. I am still working with example entitled "Projecting Vectors".

Thanks,

Peter.

[Peter Johnston]

Hello,

I would like to follow up this weirdness some more.

I have created and assigned (through a SCORM file under BlackBoard) a quiz for my students where the question involving the JXG option mentioned below has been included. My students intermittently get the result as shown in fig1.png. Here the latex typesetting is not rendered and the numerical variables are not displayed. Does this imply that there is something missing on their computers? Having said that, I have not be able to reproduce the same problem on my own computer using firefox, chrome and safari, as well as several other computers. The only time I did reproduce the error was in our university library common computing area (Windows 10 under firefox and chrome). However, here, it did not happen all the time. I could shut down the quiz and restart it and it would be fine, but then I shut that down, restart again and the error came back.

Now, going back to the original question which prompted this discussion. Fig2.png shows the effect of including the JXG option line

JXG.Options.text.useMathJax = true;

in the extension code for a Numbas test run. The figure shows the advice section of the question. Note that the latex is typeset correctly in the graph, but the latex in the advice text is not correctly typeset. Fig3.png shows a similar figure generated with the JXG option line removed, also for a Numbas test run. Here the latex in the graph is not typeset correctly, but it is in the advice text. To make things more complicated, fig4.png shows a similar figure that was generated using the final quiz that I developed, downloaded as a SCORM file and uploaded to blackboard at our university. Here, both the graph and the advice latex are typeset correctly.

This is all very confusing to me. It is more than a little frustrating for my students. If anyone has any insights or any suggestions to make things clearer, that would be great. Is it a matter of a bad browser version? missing or incorrectly installed software (eg javascript)? Or is it something more fundamental.

Thanks very much,

Peter.

[Christian Lawson-Perfect]

I've come back to this, and I can't reproduce the problem in Firefox. Did you fix it? If not, I'll need to test with more browsers.

[Peter Johnston]

Dear Christian,

Thanks for your reply. I have only just got back to this problem myself.

It would appear that if I use the option 

JXG.Options.text.useMathJax = true;

in my JXG function under the extensions and scripts tab, then the latex is rendered correctly in the figure generated. However, this affects the behaviour of the subsequent latex typesetting in the normal advice section.

If I set the above option to false, then the latex is not correctly typeset in the figure, but the remaining advice text is fine.

Any thoughts?

Regards,

Peter.

Associate Professor Peter Johnston (FAustMS, FIMA)

School of Environment and Science

Griffith University | Nathan | QLD 4111 | Technology (N44) Room 3.19
T +61 7 373 57748| F +61 7 373 57656 Email p.joh...@griffith.edu.au

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Sent: Monday, 24 June 2019 5:53 PM
To: numbas...@googlegroups.com <numbas...@googlegroups.com>
Subject: Re: latex typesetting in jsxgraph

 

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[Christian Lawson-Perfect]

Peter, I think I've finally worked this out!

MathJax has a queue system, written before JS Promises were a thing, to let you ask for elements to be typeset without hanging the whole page.

It lets you create your own queues, so I'd set up Numbas to make its own queue for typesetting elements. It turns out that MathJax doesn't try to resolve race conditions between queues, so JSXGraph was using the standard queue and having its work overridden by the Numbas one shortly after. I've made Numbas use the standard MathJax queue, and it all now seems to render properly. Phew!

To view this discussion on the web, visit https://groups.google.com/d/msgid/numbas-users/SYYP282MB0864E254B6CAA6A5B0E271E6C8E50%40SYYP282MB0864.AUSP282.PROD.OUTLOOK.COM.

[Peter Johnston]

Thanks Christian,

That is great news.

I enjoyed the EAMS conference presentations.

Regards,

Peter.

Associate Professor Peter Johnston (FAustMS, FIMA)

School of Environment and Science

Griffith University | Nathan | QLD 4111 | Technology (N44) Room 3.19
T +61 7 373 57748| F +61 7 373 57656 Email p.joh...@griffith.edu.au

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From: numbas...@googlegroups.com <numbas...@googlegroups.com> on behalf of Christian Lawson-Perfect <christia...@gmail.com>

Sent: Thursday, 2 July 2020 11:13 PM

To view this discussion on the web, visit https://groups.google.com/d/msgid/numbas-users/CAEMHSOifFSPZs3bXcRXK_5UbEFECfzY0J-5%3DEEu_EFugbeAb4w%40mail.gmail.com.