Disappearing minus sign (scaling problem with SVG fonts).

[grahamandrewsmith]

Issue Summary

We are using MathJax as part of a platform for setting exams for our calculus students. Recently, the minus sign has started disappearing on certain browsers at certain zoom levels. This would appear to be a problem with the SVG fonts.

Steps to Reproduce:

This can be seen, for example, on the following page at 50% zoom on Chrome.

https://arquimedes.nce.ufrj.br/calculo1/prova/diagnostic.php

Observe that the \leq sign is also incorrectly displayed at 80% zoom.

Technical details:

• MathJax Version: https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-svg.js
• Client OS: Windows 10
• Browser: Chrome 87.0.4280.141

Supporting information:

Below follow some examples.

Line C of Question 3 of the following file.

Second, Third and Seventh Equations of the following file.

Third equation of the following file.

[Acfboy]

I also encountered this problem

[dpvc]

If this is in Chrome (or another browser that uses Blink, e.g., Opera or recent Edge browsers), we have heard reports of recent version of Chrome not showing minus and plus properly when the math is scaled. This is apparently a Chrome bug, and turning off hardware acceleration seems to resolve the issue for those who have reported it.

https://www.technipages.com/google-chrome-enable-disable-hardware-acceleration-mode

If you are using SVG output, you could also consider changing to CHTML output, as that uses a different rendering process that might work better for you.

[adamma1024]

By the way, two months ago, I find the same problem and read Chrome's Bugs report. I told to test engineer it's Chrome's bug, but he still thinks it's my fault, lol 🤣

[adamma1024]

And now, I revert SVG to Img to resolve this problem

[bsmarsh333]

It appears this my have been fixed in Chrome 88. https://bugs.chromium.org/p/chromium/issues/detail?id=1159852

Can anyone confirm that was experiencing the issue previously?

[oliveras]

@bsmarsh333 I just updated Chrome to 88 and found that the SVG rendered the negative sign correctly for me now (when they did not before). Of course, take this as a sample size of one.

[dpvc]

@oliveras and @bsmarsh333, thanks for sharing the information you have found. That is very valuable, and I hope others are able to confirm your results as well.