Only center slide after images have loaded

[joeyates]

When slides contain images, the images often have not loaded when the page is centred. This results in images appearing partially off screen.

[joeyates]

I believe this fixes #154

[binford2k]

I'm not able to replicate this. I even set my network to simulate a terrible link and watch an image take four seconds to progressively render, and it was still centered. Can you share more details about what would be causing what you see? Are you using very large images that don't fit on-screen?

I don't see side effects in this code, so I may merge it anyway, but I'd like to believe that we're solving a real problem here.

[joeyates]

I have the presentation on Heroku, here is slide 5: https://software-libera-tutti.herokuapp.com/#5

I've switch the Heroku deploy back to HEAD and I see the image cut off.

Example:

Locally, I get the same result against HEAD. If I check what's happening in showoff.js, I can see that the page height is being calculated before the image has loaded.

If I use my branch, page height is calculated after the image has loaded. As a result, the title appears higher on the page and the whole image is visible.

[binford2k]

Interesting. I still cannot replicate it locally, but I can see it happen on your presentation. Thanks for the update.

[joeyates]

Thanks for that.

Just for completeness' sake, here's the text of the slide:

!SLIDE

# programma

![Firefox Window](Firefox-Window.png)