Mouse selection support

[dsseng]

TODO:

• Multiple selections created by mouse using modifier keys
• Double-clicking to select words (will probably need to add extra vars to state for counting)
• Select lines by dragging on the left side
• Automatically switch view if clicked out of the current view
• Pick items from menus using mouse (may be out of scope)

[archseer]

I think you can skip the double-clicking, it doesn't seem to be present on kakoune at least, not sure about vim.

[cessen]

Really looking forward to this!

I agree that double-click is probably not needed. If I want to select a bunch of words with the mouse, I'll probably just add cursors at each word with modifier-click, and then use a keyboard command to expand to word boundaries. That way it's "click, click, click, hotkey" rather than "click-click, click-click, click-click".

Similarly for selecting a range of lines: I'd probably just drag the selection to encompass the lines I want, and then hit X to expand to line boundaries. That also frees up clicking in the gutter for other things (not entirely sure what those would be, but maybe things related to debugging or version control).

[dsseng]

Similarly for selecting a range of lines: I'd probably just drag the selection to encompass the lines I want, and then hit X to expand to line boundaries. That also frees up clicking in the gutter for other things (not entirely sure what those would be, but maybe things related to debugging or version control).

You're right. If anyone wished that feature, right click can be used, but IMO that can be fully dropped really.

[dsseng]

I've split out verify_screen_coords, but looks like there's no way to switch views from event handler. Looking for advice on how to do that the best.

[archseer]

switch views from event handler

You can do this by setting cx.editor.tree.focus = view.id.

[pickfire]

For an initial implementation I think we can merge this step by step rather than all at once. Just left click is good enough as the first step. I think we can have them as separate PR?

[dsseng]

Currently there's some work on view switching also, but that can be sent in another PR if it succeeds.

[dsseng]

View switching is done locally. Should I push it here or do that later?

[archseer]

Yeah include it, I'd like to wait for at least @cessen's review too

[dsseng]

Now two TODOs are left for another PR:

• Multiple selections created by mouse using modifier keys
• Pick items from menus using mouse (may be out of scope)

[archseer]

• Multiple selections created by mouse using modifier keys

This shouldn't be too hard. If shift is pressed, instead of making a new selection clone the old one then use selection.push to add a new range. It will automatically become the new primary one, so the dragging code needs no changes.

I'd also like to see this behavior be configurable, if mouse = false in the config then the events should just not get enabled (I personally don't use the mouse and will disable it to reduce the amount of incoming crossterm events)

The menu one isn't necessary and I think it's better to skip for term.

[dsseng]

Maybe it would be nice to have a runtime command to change mouse behavior?

[Omnikar]

Is it intended for drag-selection to create multiple cursors, or is that a bug?

[pickfire]

Is it intended for drag-selection to create multiple cursors?

Not by default but probably possible with some combinations like ctrl. Like ctrl + drag a few stuff.

[dsseng]

Alt+Click makes a new cursor. Drag is a bit broken atm, see #509 (comment)

[archseer]

Looking better now, a couple more changes

[cessen]

Looks good to me! I also tested locally, and everything seems to work great.

(I think we could use some more thorough tests, including e.g. CJK characters, graphemes, etc. but I can make a PR for that later myself. The basics are there.)

Note: the lint failures in the recent CI run are due to #525, not this PR.

[cessen]

@sh7dm
If you rebase on current master now, the lints should pass.

[archseer]

Great work! I followed up with some refactoring (6bb744a, 62eb8c6)

[dsseng]

Huge thanks to all the reviewers for the great help!

[cessen]

Great work, @sh7dm! Thanks for taking the time and effort for this!