Re: Support viewBox in CSS

I have a simple use case: I want to use the <picture> element for art
direction, but I also want to ensure space is reserved in the layout before
the images are downloaded, to avoid a disorienting page jump for the user
once they load.

The only way you can achieve both of these (art direction + reserving space
in layout) right now is by ditching the <picture> element to instead use
two imgs, each wrapped with a the famous "padding bottom" hack to reserve
spacing whilst they load. It's not pretty :-(

I think page jumping is one of the worst UX problems on the web. It's not
the case that authors can fix it easily, they have to reach for hacks like
the padding bottom trick. Take the simple use case of a fluid img—there is
no simple way to preserve space of the correct aspect ratio, so most
content authors don't. Thus, page jumping prevails.

I would love to see more movement on this.