LaTeX Preview is working again

[chroot]

Okay guys, I added a bit of code that actively deletes stale preview images before generating new ones. That hopefully means the images will no longer be cached (by any entity -- our server, intervening proxy servers, or the browsers themselves).

Let me know if anything changes for you. Since some of you have this problem no matter what computer you use, etc., I'm worried there's actually a caching proxy server upstream of you, even if it's usually transparent.

- Warren

 

[DrGreg]

Okay guys, I added a bit of code that actively deletes stale preview images before generating new ones. That hopefully means the images will no longer be cached (by any entity -- our server, intervening proxy servers, or the browsers themselves).

Let me know if anything changes for you. Since some of you have this problem no matter what computer you use, etc., I'm worried there's actually a caching proxy server upstream of you, even if it's usually transparent.

- Warren

The problem seems to be fixed, for me at least. Thank you!

 

[Fredrik]

Okay guys, I added a bit of code that actively deletes stale preview images before generating new ones.
...
Let me know if anything changes for you.

Thank you. It's working fine for me now.

 

[Fredrik]

I just noticed another problem. Maybe it's only when I preview. I'll have to post this to find out. If I write f'(x), it appears as f single − quote(x).

$$f'(x)$$

Nope, it looks fine when I post it.

 

[chroot]

I just noticed another problem. Maybe it's only when I preview. I'll have to post this to find out. If I write f'(x), it appears as f single − quote(x).

$$f'(x)$$

Nope, it looks fine when I post it.

Fredrik,

Fixed that one too. All should be well in LaTeX-land now.

- Warren

 

[Fredrik]

Thank you. We're lucky to have you here.

 

[Unit]

$$2 + 2 = 4$$

$$2 + 2 = 5$$

 

[CompuChip]

$$2 + 2 = 5$$

That is true, modulo one.

 

[samieee]

$$\sum(A+BX_{i}-Y_{i})^2=0$$

$$\mbox{just practising}$$

 

[Jonathan Scott]

I've just given up on trying to post an answer because in preview all of my Latex stuff is showing images from a previous post ages ago and refuses to show the stuff I've entered today. I've cleared the browser cache and restarted it before trying again and that didn't help. What else can I try? For example, the following expression is displaying in preview as v²/r which I used in a post some weeks ago:

$$\frac{d\mathbf{p}}{dt} = \frac{E}{c^2} \mathbf{g} \left ( 1 + \frac{v^2}{c^2} \right )$$

Edit: When I submitted this one, the LaTeX now appears as a broken image marker.

 

[Fredrik]

Johnathan: You need to use lowercase letters for the tex tags.

Is it just me, or do we now have to refresh after every preview to get the correct latex expression to show up?

 

[sylas]

There's an ongoing problem with LaTeX used in blogs and PMs. The image files in this case have "preview" URL, and you often get the wrong image. The problem is described also in thread [post=2590434]TEX broken?[/post].

I've just checked and the problem is still there.

 

[Fredrik]

I'm not sure if you posted that to report a problem, or if it was a reply to me. I'm aware of the need to click reply and preview, to get the LaTeX to look OK when you receive a PM. But that's not what I was talking about. I've been making a bunch of posts today, and every time, the LaTeX is messed up when I preview. (Older images are displayed). It doesn't help to just click preview again. I have to click my browser's refresh button, and then the resend button that shows up. And if I make any little change, I have to repeat the procedure.

 

[dx]

Latex preview is working fine for me, but I see old images for latex in private messages and profile visitor messages.

 

[Greg Bernhardt]

Latex preview is working fine for me, but I see old images for latex in private messages and profile visitor messages.

LaTeX has never worked in PMs and PVMs

 

[fluidistic]

For the first time in more than a year, latex preview doesn't work. It shows old images though I typed new equations. I hope that when I push "Submit reply" the true images will show up.

 

[Fredrik]

For the first time in more than a year, latex preview doesn't work. It shows old images though I typed new equations. I hope that when I push "Submit reply" the true images will show up.

I'm glad it's not just me. I had that problem yesterday and the day before. Let's see if I still have it today...$$x$$, $$w$$, $$z$$. Yes, I do. (I wrote "x,y" and previewed, then I changed it to "x,w,z" and previewed again. The w shows up as y in the preview).

Edit: Trying again, after logging out and back in again. Uh...I still see a y.

 

[George Jones]

I have had problems with this today as well. A workaround is to (after a Ctrl-c for safety) refresh the composition page. Click on "Resend" in the Confirm window that opens.

 

[NeoDevin]

LaTeX doesn't work in RSS feeds. I think this is by design though...

 

[NeoDevin]

$$This is a test$$

$$This is only a test$$

Preview is not working for me, still getting old images.

 

[Gokul43201]

NOTE: This is not about preview or latex in PMs/VMs etc.

Inline latex seems to be somewhat broken:

[ tex ]\dot \theta[ /tex ] = $$\dot \theta$$

[ itex ]\dot \theta [ /itex ] = $\dot \theta$

However, [ itex ]\dot x \dot k[ /itex ] = $\dot x \dot k$

So it seems that with inline tex things like superscripts, dots, overlines, hats, and vector symbols do not show up over tall characters (like theta or k), but work for short characters (like x). This didn't happen before.

 

[Fredrik]

That problem has been around for a long time Gokul, but since you're retired staff with over 10K posts, I guess you've been here much longer than that. Another problem with itex (example: $\mathbb R$) is that it changes the distance to the next line. You would often get better results with tex tags actually. And I'll just type a few more words to make sure that there's at least one line of text below the math expression.

 

[DrGreg]

NOTE: This is not about preview or latex in PMs/VMs etc.

Inline latex seems to be somewhat broken:

[ tex ]\dot \theta[ /tex ] = $$\dot \theta$$

[ itex ]\dot \theta [ /itex ] = $\dot \theta$

However, [ itex ]\dot x \dot k[ /itex ] = $\dot x \dot k$

So it seems that with inline tex things like superscripts, dots, overlines, hats, and vector symbols do not show up over tall characters (like theta or k), but work for short characters (like x). This didn't happen before.

It seems that the top row of pixels is missing in itex.

[noparse]$\sqrt{X}$[/noparse] = $\sqrt{X}$
[noparse]$$\sqrt{X}$$[/noparse] = $$\sqrt{X}$$

(By the way, this message didn't preview correctly either, the same image was displayed for both the tex and itex.)

EDIT: the final version still seems to be wrong, the tex and itex seem to be identical. They are both displaying the top row of pixels missing on my computer.

 

[dx]

EDIT: the final version still seems to be wrong, the tex and itex seem to be identical. They are both displaying the top row of pixels missing on my computer.

tex : $$\sqrt{\alpha \beta \gamma}$$

itex : $\sqrt{\alpha \beta \gamma}$

Top row seems to be fine.

 

[NeoDevin]

$\sqrt{iTeX}$
$$\sqrt{TeX}$$

Problem only seems to happen with tall enough characters.

 

[Fredrik]

They are both displaying the top row of pixels missing on my computer.

That seems to be an issue with the noparse tags, not with tex or itex. I have noticed before that noparse doesn't always work as advertised.

 

[Gokul43201]

That problem has been around for a long time Gokul, but since you're retired staff with over 10K posts, I guess you've been here much longer than that. Another problem with itex (example: $\mathbb R$) is that it changes the distance to the next line. You would often get better results with tex tags actually. And I'll just type a few more words to make sure that there's at least one line of text below the math expression.

Thanks for the pointer, Fredrik. I've definitely noticed the line-spacing issue, but oddly, never noticed the other problem until now. And I find it hard to believe that I've only ever used dots or vectors on tall symbols within tex tags and never with itex (but I guess that's possible)!

 

[Dickfore]

The LaTeX preview does not work for me. When I hit the Preview Post button, I see my old equations. What is the solution?

 

[DrGreg]

The LaTeX preview does not work for me. When I hit the Preview Post button, I see my old equations. What is the solution?

Use your browser's command to refresh the window after the "Preview Post" has gone wrong. See post #53.

By the way, does anyone know if chroot is aware of this problem?

 

[chroot]

I'm aware of it, I just can't tell if it's something going on on the server end, or the client end. Nothing on the site itself has changed, so it's either something caused by a downstream provider (i.e. a caching proxy server), something in some newer version of a browser, or...

I will do some poking around to gather some evidence of these hypotheses.

- Warren

 

[Fredrik]

I'm using Firefox 3.6.3 on Windows 7, but I just tried it with Internet Explorer 8.0.7600.16385 on the same computer, and it has the same problem. The refresh/resend workaround works in IE too.

 

[Gokul43201]

Likewise with Firefox 3.0 on OS X.

 

[Dickfore]

In Google Chrome on Windows Vista too.

$$\int_{-\infty}^{\infty}{\int_{-\infty}^{\infty}{e^{\textup{i} \, k \, (x - x')} \, f(x') dx' \, \frac{dk}{2\pi}}} = f(x)$$

 

[Saladsamurai]

Test1

$$\int_0^\infty e^{-x}\,dx$$Nope. Problem exists using Google Chrome on OSX too.

 

[Mentallic]

I also use google chrome, and I can vouch for Saladsamurai that preview only works sometimes (better than before though).