Consistent window view when exiting Bufstop window

[bruhtus]

I have noticed that sometimes the current line position got changed when exit Bufstop window. Sometimes the current line position at the top (like doing normal mode command zt) and sometime the current line position in the middle (like using normal mode command zz). That's kind of annoying, so I tried to use winsaveview() to make window view (current line position, etc) more consistent when exit Bufstop window.

I haven't tested it in split window, but I think it should be the same.

My remove trailling whitespace autocommand kicks in and that makes it looks like I changed a bunch of line, so please ignore that 😅

[mihaifm]

This is very promising if it works. I didn't know about winsaveview, guess there is something to learn every day. This issue bothers me too, but kind of learned to live with it. Let me test this, it would be a very useful fix.

[bruhtus]

I didn't know about winsaveview, guess there is something to learn every day.

I didn't realize at first that I could initialize winsaveview() at the command until I saw fzf.vim source code and I thought "maybe it can solve Bufstop current line position issue?" and then here we are.

Let me test this, it would be a very useful fix.

Alright, let me know if there's some problem. I only apply winsaveview() in Bufstop, BufstopPreview, and BufstopFast because I thought it has something to do with Bufstop window, but if you think we should apply winsaveview() in every Bufstop command then I'll change the script again.

EDIT:
I forgot to remove extra g:BufstopData variable 😅

[mihaifm]

You need to return to the previous window here (wincmd p), othewise your code won't work when two or more windows are present (split windows).

[bruhtus]

Ah I see, between endif and endfunction right? for single window (not using split window), there's no problem?

EDIT:
Wait, I think it's more appropriate to put wincmd p between q and if, it will look like this:

q
wincmd p
if exists('b:bufstop_winview')
  call winrestview(b:bufstop_winview)
  unlet b:bufstop_winview
endif
endfunction

go back to previous window first, and then apply winsaveview()

[mihaifm]

yes, this should work

[bruhtus]

I think I found another issue, when deleting the first buffer (6612881), the window view changed back to how it was before (the current line position at the top like doing zt normal mode command).
I'm not sure where I should initialize the winsaveview() when delete the buffer, do you have any idea where should I initialize the winsaveview()?

Inside

if delkey
   call s:BufstopWipeBuffer(s:bufnr)

or inside

function! s:BufstopWipeBuffer(bufnr)

or maybe somewhere else?

EDIT:
I think the dummy buffer causing the window view not restored when exiting Bufstop window.

Here's a step to reproduce that:

• open a file with vim
• put the cursor at the bottom of the window by doing L normal mode command
• open another file (using a buffer, not split window)
• delete the recent opened file with Bufstop window
• and then close Bufstop window using BufstopDismissKey

EDIT 2:
When I delete the first buffer and it back to the second buffer, the second buffer doesn't have b:bufstop_winview variable even tho it is in opened.

I think I figure out where I should initialize winsaveview(), It's in s:BufstopWipeBuffer(bufnr) function, like this:

exe window . "wincmd w"
exe "silent b" candidate
if !exists('b:bufstop_winview')
  let b:bufstop_winview = winsaveview()
endif

CMIIW

[mihaifm]

I think I figure out where should I initialize winsaveview(), It's in s:BufstopWipeBuffer(bufnr) function, like this:

exe window . "wincmd w"
exe "silent b" candidate
if !exists('b:bufstop_winview')
  let b:bufstop_winview = winsaveview()
endif

This looks good

[mihaifm]

Good stuff, thanks for the contribution, it's an awesome fix. I will do some minor refactoring on top of these changes.

[bruhtus]

Glad I could help!