OSD zoom controls are hidden from 768px to 1279px

[LlGC-jop]

UV version:

 universalviewer@<version>

I'm submitting a:

• bug report => please fork one of these codesandbox examples with a repro of your issue and include a link to it below
• feature request => please use the user stories repo
• support request => Please do not submit support requests here, use stackoverflow

Current behavior:

If using the viewer on a device with a screen size somewhere between 768px and 1279px wide there are no zoom control buttons available.

While this is bit of an edge case, and it's almost 100% likely that a device with that screen size is some form of touch device, we have had enquiries about the lack of zoom from users who weren't familiar with pinching to zoom.

Expected behavior:

Some form of button should ideally be available.

Adjusting the media query to show the normal OSD buttons would probably be pointless, as these are triggered on hover, which a touch device doesn't really do.

So perhaps a couple of extra buttons in the footer, next to share and download? Or maybe the top left of the header?

Steps to reproduce:

1. Load the viewer examples, either on a tablet or desktop with device simulation
2. Set resolution to between 768 and 1279
3. Try and zoom in without tapping/pinching