[vim] fix fat cursor for non-monospace fonts

[krydos]

This pull request should fix #3256

(non monospace font and header size is different from other portion of a text)

I don't think it's good idea to check if vim mode is enabled directly in cursorCoords but I don't really see the better way.

Could somebody help me with better solution?

Thanks

[marijnh]

Making a core method work differently when the vim mode is enabled in order to be able to use it in a way it isn't intended to is way too dodgy. Maybe see if you can use charCoords instead.

[krydos]

@marijnh, do you mean I should update drawSelectionCursor to call charCoords somewhere next to cursorCoords? If so, that makes sense and feels better. I'll try.

[krydos]

Ok, new change feels much better. We don't touch measurement functions at all now. drawSelectionCursor function is the only affected by the change and the change itself is related to how the cursor is drawn.

@marijnh thanks for the advice

[marijnh]

The core library shouldn't know anything about the vim mode, so testing for it like this doesn't seem like a good idea.

There seems to already be logic in keymap/vim.js that sets a bookmark with a cm-animate-fat-cursor class. But somehow it is only firing in visual mode. I don't know the code well enough to figure out why that is, but it seems that an approach like that (having the vim mode use markText to display its visual cursor) would be the way to do this.

[krydos]

@marijnh you're right about cm-animate-fat-cursor, but that part in visual mode doesn't update the cursor width. It just draws one more "fake cursor" and hides the actual cursor.
The actual cursor isn't well-shaped even in visual mode.

I agree that check for vim mode in code library doesn't look well.

Vim mode assigns cm-fat-cursor class to the wrapper element so we can check that I think.

Not sure how better it is but at least we don't directly check for vim mode. It also means that any addon/keymap that wants to use fat cursor will work fine after this change is merged.

[marijnh]

Hm, that's still a bit of a hack, but I guess it is preferable to the alternatives. Let's try it this way.