Talk:Superellipse

Formulae now invisible on standard OS X browsers

May need tidying up to achieve formula visibility on the OS X platform. Problems may include flanking of LateX expressions with redundant white space inside <math> tags Hout (talk) 13:29, 16 September 2016 (UTC)

Not all OSX browsers, so far I have only seen the problem with Safari and Chrome. This is not limited to math markup, though - I have been seeing many many images fail to load under Safari. Perhaps we should be recommending that OSX users switch to Firefox? --Rdm (talk) 13:34, 16 September 2016 (UTC)

I don't think so - the problem is new and quickly fixed - pruning back the newly-introduced redundant spaces will restore visibility on the major browsers on that platform. If we do want to understand the etiology, then we probably need to look at the Latex -> HTML stage of the wiki software. But the experimental result is already clear. Adding that space adds nothing for the users, but does prevent significant numbers from seeing the formulae. Hout (talk) 13:42, 16 September 2016 (UTC)

Then perhaps we are seeing different problems, or different aspects of the problem, at least. Trimming those spaces does nothing for me, and I have been seeing blanks for math markup for months. --Rdm (talk) 14:31, 16 September 2016 (UTC)

Formula visibility can be consistently toggled here by introducing and removing a leading or terminating space, before or after the Latex expression, in a <math> tag:

<math>Latex</math> ⇄ <math> Latex </math>

(Chrome Version 52.0.2743.116 (64-bit), Safari Version 10.0 (12602.1.50.0.8)) Hout (talk) 14:45, 16 September 2016 (UTC)

I tried that on a preview of this Superellipse page and I could not see the rendered math even with no spaces whatsoever in the math markup. But if it makes you happy, go delete some of those spaces... --Rdm (talk) 14:49, 16 September 2016 (UTC)

I did some cursory (and somewhat shallow) web searching for problems with Chrome, LaTeX rendering --- particularly the   <math>   blank/empty rendering, and other such symptoms.   There are this and other problems that have been introduced with a new(er) version of Chrome, some have a work-a-round, but the problems are being addressed (as far as I can glean from the various articles), and, if indeed, the symptoms being seen are manifestations of the same problem(s).   I uninstalled Chrome many ages ago when I had similar problems with it's (bad) rendering of various texts and especially some fonts.   This latest go-around (here at Rosetta Code) seems to be focused on the "flanking" whitespace and the reversion of changes, and the describing of the symptom of the problem as making the formulae invisible (or more descriptive, the rendering of blanks).   Some of the changes being reverted have been around for months, leading me to believe that the problem probably lies with the recent changes to Chrome   (and I presume, Safari).   I wonder if the mere act of reverting the Rosetta Code pages to an earlier text bypassed   (in and of itself)   the problem in the newer version of Chrome?   I've asked Mr. Hout previously if he reported the problem to Chrome and/or Safari peoples to have this particular problem addressed, and I also requested a bug or tracking number to follow this problem's resolution   (nothing replied so far).   If Chrome (and/or Safari) doesn't render the LaTeX (or whatever) correctly, maybe the Rosetta Code users of those browsers might be better served if they used FireFox   (or any other browser that works)   until the problem gets fixed by the code writers of those failing/broken browsers.   -- Gerard Schildberger (talk) 17:55, 16 September 2016 (UTC)

Eyebrows duly raised :-) But never mind, as long as you do now know that introducing redundant flanking space will hide previously visible formulae from unfortunate users, and as long as you quietly check the consequences of your edits with editors who have macs (Rdm for example ?), those of use who are affected can shoulder the restoration of visibility whenever we encounter it. As for your robust expressions of confidence that the problem lies with the browsers, well, I think we both know that neither of us knows enough to be very confident of that, either. What we do now know is that the recent decline in the visibility of formulae on OS X can be easily reversed, by reversing a small aspect of your otherwise very helpful edits. Hout (talk) 19:07, 16 September 2016 (UTC)

There is no evidence that the problem lies with Safari and Chrome, and the likelihood of two entirely separate engines having simultaneously acquired identical bugs seems a little too low to really detain us for long :-) The visibility problems are not new. If you really wanted to understand what was going on, you would need to make a careful study of the output of the Wiki software's preprocessor. In the meanwhile, you can retain the value of your edits (changes in visible spacing and font sizing), and remove the damage inadvertently done to visibility in OSX Safari and Chrome (not just recent versions) by reverting the state of the math tag contents alone. There is no dishonour in having unwittingly created a problem - though it might raise an eyebrow or two if you were to resist the repair :-) Hout (talk) 18:19, 16 September 2016 (UTC)

Safari and Chrome are not two entirely separate engines;   WebKit is an open source browser engine for rendering web pages that is used in Safari and it had been used in Chrome, but Google currently incorporates (I don't know the date) a WebKit fork/offshoot of WebKit with software named "Blink", so there is some commonality of code, of which and how much, I do not know.   I don't know enough about Wiki's software pre-processor or even where to find/view the output of same, let alone make a careful study of its output, nor would I suggest that someone study that as a means of resolving a problem (or trying to find out the location of where the problem is).   That is way beyond my capabilities and time availabilities.   Since I don't see the non-rendering (the "invisibility" that you see) with the web-browsers that I have installed), it wouldn't behoove me or Rosetta Code to make further changes in removing whitespace in specific areas as I can't see the results (the failures) that you're seeing with your browsers).   I don't believe that I introduced (even unwittingly) a problem, but as I see it, you most likely have uncovered a problem in the way LaTeX is rendering whitespace in the browser(s) that you're using.   I'll never accuse anyone of introducing a problem just because my browser fails in handling (rendering) whitespace.   I've been web-searching for Chrome's (rendering of LaTeX and other stuff) problems, and there seems to be enough discussion on issues related to these types of issues.   -- Gerard Schildberger (talk) 18:53, 16 September 2016 (UTC)

That evidence might be inadequate, or not conclusive, and maybe even superficial, but it's not zero, either. Meanwhile, the mechanism for working around the problem (adding space or deleting space and - generally speaking - reverting to older versions) seems ad hoc (which probably means we do not understand what is going on well enough to be drawing conclusions yet).

That said, I do not see any problem, yet, with using this ad-hoc mechanism to fix the rendering of math markup. If it was breaking something else significant, though, let's hear about that.

I should add that I see this problem with safari version 8.0.8, so it's apparently a long-standing issue. (Which should not be surprising. I saw work happening on a different browser bug something over ten years after I reported the problem.) --Rdm (talk) 19:00, 16 September 2016 (UTC)

Thanks. Restoring the formula code to the pre June 4 version has restored its visibility here. Are you seeing the same ? Hout (talk) 15:19, 16 September 2016 (UTC)

It does work for me, now, also. --Rdm (talk) 15:22, 16 September 2016 (UTC)

Toggling flanking space now proves sufficient to toggle formula visibility in OSX Chrome and Safari, but it looks as if some of Gerard's other spacing edits can also suppress visibility in the same contexts. In short, lost formula visibility can more consistently be restored by simply reverting the contents of the math tags to their state on the last date before the TOC spacing edits were undertaken. Hout (talk) 16:33, 16 September 2016 (UTC)

I don't understand what you mean by "looks like".   It either does or doesn't.   Could you be more specific what those contexts are before you lay blame on "other spacing edits"?   I don't understand what TOC spacing has to do with this.   I've been adding whitespace before the TOC for over a year and a half now.   In a recent change, both whitespace and the use of a bigger font via   <big>   were reverted.   It can't be symptomatic that both would be causing the problem(s).   -- Gerard Schildberger (talk) 17:55, 16 September 2016 (UTC)

It does. Visibility is restored in most cases by simply deleting the flanking spaces which you introduced, but in other cases this does not prove sufficient. It does, however, prove sufficient to revert the context of the Math tags to the state they were in before you undertook the edits. I don't know how many other tasks are affected – I just noticed the same problem with Binomial Coefficients, but it's certainly possible that a trail of formulae have been losing their visibility to some users for over a year now. I have been aware of the patchy visibility, and had a sense that invisibility was a growing problem, but I hadn't previously taken the time to pin it down. Hout (talk) 18:04, 16 September 2016 (UTC)

You should be able to identify what other elements of your edits are toggling formula visibility by a process of elimination.

Introducing the the HTML entity &nbsp; seems like one candidate that might be worth checking. The broader picture is, however, clear - visibility is always restored by reverting your spacing edits en masse, and is usually, but not always, restored by only reverting the flanking spaces in math tags. Experiment is the only source of knowledge, and even then Nature reveals her secrets reluctantly :-) Hout (talk) 18:43, 16 September 2016 (UTC)