[Web][Android][iOS] UX: Make subkeys easier to press by making touch targets much, MUCH bigger (Fitts's Law)

[eddieantonio]

Is your feature request related to a problem? Please describe.

I like being able to access lesser-used characters by pressing and holding a key, and selecting the character I want via a subkey. However, selecting those small sub keys is rather small.

Sometimes I select try to select the leftmost subkey and overshoot:

Sometimes I select try to select the rightmost subkey and overshoot:

Sometimes I select slightly above the short little subkey array:

Describe the solution you'd like What I think would be nice, is if the touch target of the leftmost key extended infinitely to the left; likewise, the touch target of the rightmost key should extended infinitely to the right; and all keys' touch targets should extend to the very top of the keyboard. To cancel the press-and-hold of the menu, you would let go on or below the original key. Bigger targets are easier to press. Infinite targets are impossible not to press.

Describe alternatives you've considered

Instead of extending the touch key infinitely, it may extend dramatically to the sides of the visible key; at a certain point selecting far enough from the key, it should cancel.

Product context

• OS: Android (iOS would be affected too).

Additional context

This matches the behaviour in SwiftKey. Gboard extends the touch targets infinitely to the right, extends the targets a bit upwards, and a bit to the left; however, after a certain point to the left, you are no longer selecting subkeys in Gboard.

[mcdurdin]

We'll aim to get this into 13.0; given it is not a bug we need to focus on addressing bugs at this time for 12.0.

[jahorton]

Related to #1025, though the two are distinct. I'd recommend addressing them both together when the time comes.