> sure, a giant floating "+" in a circle in notes app on a mobile device is alright CTA to add a new note
No, it’s not, because it floats over the actual content, which means that the user can neither see nor interact with the content under it. Of course, no one carefully designs the rest of the UI to make sure that content doesn’t get stuck under the floating button.
It’s remarkably common for some floating UI element to obscure the bottom portion of something scrollable. You can’t work around this by scrolling because, if the region in question is on the screen at all, it’s at the bottom.
Even Mobile Safari messes this up on occasion — sometimes the URL bar at the bottom obscures the bottom of a page, and, while one can temporarily reveal it by dragging up, the content rubber-bands right back down when the user lets go.
A small amount of searching suggests that dvh and svh have semantics on Mobile Safari that are, at best, confusing.
But I think this misses the point. Mobile Safari has a heuristically auto-hiding “toolbar”, and the heuristic is far from perfect, and the toolbar overlays the content, and Safari tries to offer some features that maybe let webpages move their content out of the way when hidden. And the result works poorly sometimes.
Fundamentally, doing a good job of having a control sitting on the section of the screen that shows content and mitigating the risk that the control obscures the content is hard.
No, it’s not, because it floats over the actual content, which means that the user can neither see nor interact with the content under it. Of course, no one carefully designs the rest of the UI to make sure that content doesn’t get stuck under the floating button.