Project Euler Forum

I occasionally log in to PE to read some of the archived problems while on my commute to work. For at least a week, no LaTeX has been rendering on mobile at all so I have to check out the HTML to see what was supposed to have rendered in place of all the blank spaces in the problem descriptions, or wait until I’m next to a computer. Similarly, I can only see plain text and code in the solutions forums for any of the old problems that I’ve solved. No LaTeX seems to be rendered on mobile if present in a solution.

I'm not able to reproduce that issue on my mobile. Do you get the same results in a standard browser? Are you running an unusual browser? The fact that you are able to log in to the site is most perplexing. The issue seems to be related to the content security policy I have setup which will block content if your browser is sending or interfering with the headers. In particular, it might be blocking the JavaScript from the CDN necessary for MathJax. Have you activated an unusual setting in developer mode? Are you using a third party plug-in? Are you running anti-virus software that could be interfering with the security headers?

I’m using the safari browser on iPhone with Google as the default search engine, although I routinely use private browsing. I haven’t used any mobile browser extensions recently. I don’t believe that I’m using any unusual developer settings as I haven’t tinkered with those in almost a year, and I only started having this issue recently. Since you mentioned MathJax I visited mathjax.org, and interestingly I have the same rendering issue when I view the typography samples in the CommonHTML rendering mode, but not when I switch to viewing them in SVG mode.

This sounds like a Safari issue. I believe it is related to the way that it aggressively handles optimisation due to temporary network conditions or low power mode. In this case, it sounds like it is blocking the required font. I'm assuming you're not running in private mode?

I've added a small change to the configuration file to delay the media delivery by 50ms for CHTML. Please let me know if this helps.

I was running it in private mode each time I tried it, but I just logged in to check and it’s the same without private browsing. Right now it continues to have the same issues with rendering. If it helps, the LaTeX rendering on webpages like https://en.wikipedia.org/wiki/Hölder%27s_inequality and https://artofproblemsolving.com/wiki/in ... 7s_Theorem seem to work fine.

Looking at the AoPS, they use an older version of MathJax (version 3) and are forcing SVG rendering too. I'm not sure how Wikipedia handle their mathematics, but they are also being rendered as images.

I'm currently at school at the moment, so it's difficult to do much more right now. I've increased the delay to 100ms, but I'm a little unsure about this approach as it affects everyone. See if that helps. It might be we just have to accept that Safari on mobile sucks!

It doesn't look like Safari is in a particularly cooperative mood, so you may as well do away with the media delays. It was worth a try though, so thank you. I'll default to accessing PE from my PC.

I've just made a pretty major change by switching from CHTML to SVG. This clearly provides better support for iOS Safari/WebKit browsers and hopefully greater all-round consistency in rendering (not relying on web fonts or CSS), but it might be too much of a trade-off in terms of processing large pages of equations. We'll have to monitor this. Can you check if this change causes your mobile to render correctly now?

I just logged in and the LaTeX is rendering correctly now. Thank you very much.