How to keep the screen position from "zt" after switching buffer

Question

When I use zt to scroll the screen relative to the cursor and then switch buffers with, say, :bn followed by :bN, the screen jumps back to the position before executing zt.

Using for example ctrl-d to scroll in the buffer doesn't have this side effect.

How can I keep the cursor & screen position when using the z-family of commands and toggling between buffers?

Answer 1

TL;DR use autocommands, see the end of this post.

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Here's the result of the investigation I've made:

Calling bn call the ex_bnext function which does two things:

• Go to the desired buffer via the goto_buffer function
• Execute any command line command passed to the bnext command

The goto_buffer function apparently wrap the more generic do_buffer function and calls it with special argument related to the action of going to a buffer (see the first argument is the action which is either DOBUF_SPLIT or DOBUF_GOTO).

The do_buffer function is pretty long, but you can see the interesting part around the end. This function calls the set_curbuf function.

The set_curbuf function set the current buffer to the desired buffer and calls enter_buffer.

The enter_buffer function set/reset some options for the newly displayed buffer and calls scroll_cursor_halfway.

Finnaly, the scroll_cursor_halfway function changes the topline value, meaning the cursor will be displayed halfway the window.

Sooo, I think it's the designed behavior.

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What you can do is, when leaving a buffer, save the current window display with winsaveview and on entering a buffer, reset the view with autocommands:

autocmd! BufWinLeave * let b:winview = winsaveview()
autocmd! BufWinEnter * if exists('b:winview') | call winrestview(b:winview) | unlet b:winview