Adjusts the dimensions to use pixel boundaries to prevent antialiasing
for some of the key preview and longpress popups, and adjusts horizontal
positioning of key preview to center more precisely, for iOS.
Fixes#5929.
Fixes#6381.
This fixes four separate issues with the longpress popups and key
previews:
1. The key preview was offset by a couple of pixels (unreported issue).
2. The background 'shim' did not cover the key caps, which caused them
to look startlingly white when the rest of the background greyed
down (#5929).
3. The popup menu was incorrectly wrapping to two rows due to sizing
model mismatches (#6381).
4. The popup menu would be realigned incorrectly for the in-app
keyboard, when moving it to keep it in the keyboard area (#5929).
Fixes#5831.
iOS 15 has a significant crashing bug whereby use of a canvas element
completely crashes the browser in some contexts. In particular, we have
observed this when using a WKWebView in a keyboard extension without
'Allow Full Access' switched on.
Keyman uses canvas element to draw a nice looking key preview (key tip)
on iPhones. This is a critical issue for Keyman for iPhone. Keyman for
iPad is not affected because the iPad version does not use key previews.
The resolution here is to remove use of the canvas drawing for key tips
and use a simplified pure HTML/CSS shape. I have not conditioned this
fix on platform; I have currently opted to apply this to all platforms.
This issue will be reported to Apple for resolution. The issue applies
so far to iOS 15.0, 15.1.
Fixes three issues:
* longpress positioning for inlined OSK views where not all elements
may be in the offset hierarchy; impacts particularly where an inlined
OSK may be within a flex-box.
* Tweaks position of keytip, to take into account the offsetTop of the
key element.
* Inverts test for display of longpress callout, matching Keyman 14.
