Input Interaction: only consider selection at edge if directed towards it

[ellatrix]

Closes #12322

Description

An alternative to #13638. I chose to make the selection direction check inside isVerticalEdge, as we do the same for isHorizontalEdge. Still needs tests.

How has this been tested?

Screenshots

Types of changes

Checklist:

• My code is tested.
• My code follows the WordPress code style.
• My code follows the accessibility standards.
• My code has proper inline documentation.
• I've included developer documentation if appropriate.

[aduth]

Generally, this is great.

There's one small imperfection by the logic, and it's OS-specific as well. Per #13638 (comment) , the behavior of Shift+Up in a non-collapsed selection in a line of a text in non-macOS environments is that it should expand to the previous line (or in our case, if in the first line of a paragraph and a block preceded it, triggering multi-selection). Right now, the behavior is that nothing happens. Effectively in this scenario, I think it might be correct to say that it is at the vertical edge, even if the selection is non-collapsed.

That being said, what exists here is a huge improvement all the same, so I'd like to see it merged.

[aduth]

Love the dedication to the 80 column 👍

[ellatrix]

@aduth Thanks for the review! I'll have a look into the issue you're describing, maybe we can fix it separately.

[ellatrix]

@aduth Looking at your GIF, it seems like a consecutive shift+arrowUp press would trigger multi-block selection? The behaviour is slightly different, but you can still select blocks?

[ellatrix]

Or am I missing something that would block multi-block selection after these steps?

[aduth]

The specific point I'm trying to make could do for a better / different animation, I think.

Essentially: Everywhere except macOS, if an uncollapsed selection exists within a single line, the effect of pressing ArrowUp (with Shift held) should be to expand the selection to the previous line.

In terms of blocks, that may mean triggering a multi-selection. Or, at the very least, it's contradictory to the idea here that a vertical edge traversal can never occur with an uncollapsed selection.

[ellatrix]

@aduth I think I slowly get what you mean. It would be good to have an issue with the steps to reproduce the issue, and what you'd expect to happen vs what happens now in master. After playing on macOS a bit, it does seem strange that the OS completely disregards the selection direction when using the keyboard after having set it with a pointer device.

[aduth]

I created an issue at #14463 . Noting that it's improved a bit more from what I was observing, as a result of the changes from #14453, but still not quite as expected.