What is the best way to do smooth scrolling in Vim?

The main scrolling commands in Vim are:

1. Ctrl-B and Ctrl-F, as well as PageUp and PageDown scroll by full page
2. Ctrl-U and Ctrl-D scroll half a page by default
3. Ctrl-Y and Ctrl-E scroll one line

I lose visual context every time for the former two, so I have developed the bad habit of hitting the latter (Ctrl-Y and Ctrl-E) repetitively.

Since there is currently no first party support for smooth scrolling, what are the least objectionable workarounds/plugins?

I use both Vim and GVim depending on the task, and am happy to customize them separately if there is no one really good hack that works for both. The mouse scroll wheel works nicely in GVim, but I'm looking for keyboard based solutions.

Update: I have now pushed this code, refactored somewhat according to the guidelines at :help write-plugin, to a Github repo.

Using the Keyboard

Here is what I have in my .vimrc:

function SmoothScroll(up)
    if a:up
        let scrollaction="^Y"
    else
        let scrollaction="^E"
    endif
    exec "normal " . scrollaction
    redraw
    let counter=1
    while counter<&scroll
        let counter+=1
        sleep 10m
        redraw
        exec "normal " . scrollaction
    endwhile
endfunction

nnoremap <C-U> :call SmoothScroll(1)<Enter>
nnoremap <C-D> :call SmoothScroll(0)<Enter>
inoremap <C-U> <Esc>:call SmoothScroll(1)<Enter>i
inoremap <C-D> <Esc>:call SmoothScroll(0)<Enter>i

Features:

• Scroll on the base of the Vim scroll option.
• Customizable scrolling speed (adjust time argument of the sleep command; I use ten milliseconds). Note: just like slowing down the frame rate on a video, if you slow down the smooth scroll too much it will be jerky scroll, not smooth scroll. But whatever works best for you.
• Works in normal or insert mode.

Note: all you copy-and-pasters, remember that the ^ character indicates a control character; copy-paste will produce invalid results and these must be entered manually!

• ^Y – CTRL-V then CTRL-Y
• ^E – CTRL-V then CTRL-E

However, the <C-U> and <Enter> style syntaxes are literally typed as those characters; the map command intelligently converts them to control characters.

Using the Mouse

The question mentions that scrolling with the mouse works well in GVim, but a keyboard solution is desired. This implies to me that the asker may be interested in a mouse solution if it works in regular terminal Vim.

For me, turning mouse support on allows smooth scrolling through the mouse wheel. Also, for me, smooth scrolling is most important when I am looking around (i.e. in normal mode), not when I am editing (in insert mode), and if I am not actively editing, the need for my hands to stay on the keyboard at all times is removed, so this works well.

On the basis of this question, though, it would seem that some people have to do some more manual setup beyond simply turning the mouse on (I just use set mouse=n):

---

My .vimrc has the following lines

 set mouse=a
 map <ScrollWheelUp> <C-Y>
 map <ScrollWheelDown> <C-E>

---

There is a simple remap hack in vim's tips.txt:

Smooth scrolling					*scroll-smooth*

If you like the scrolling to go a bit smoother, you can use these mappings:

	:map <C-U> <C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y><C-Y>
	:map <C-D> <C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E><C-E>

Shameless plug, but I created a plugin here that you can use to easily adjust the distance, speed, and duration of the scrolling animation: https://github.com/terryma/vim-smooth-scroll

A Recent Plugin

I have posted something similar here, but basically there is a great plugin that we can use now for scrolling, called terryma/vim-smooth-scroll. It provides a very nice and smooth scrolling.

---

The install is quite easy:

1 I use Vundle so I simply appended this in .vimrc.bundles :

Bundle terryma/vim-smooth-scroll

In the latest version of Vundle available today, 29th April of 2016, you can put this in your .vimrc:

Plugin 'terryma/vim-smooth-scroll'

2 As stated in the doc, you can set up 3 arguments: distance, duration and speed.

I am using this in my .vimrc file:

noremap <silent> <c-b> :call smooth_scroll#up(&scroll*2, 10, 4)<CR>
noremap <silent> <c-f> :call smooth_scroll#down(&scroll*2, 10, 4)<CR>

What I do is I set the keyboard repeat to very fast, about 120 chars / second, and the delay small. Then I map to 4j and to 4k I navigate up and down source code using j and k which moves the cursor up and down nice and quick, pretty smooth. But here's the good part, and this works on Linux, not Windows. For a number of years now, X11's keyboard input works in such a way that when you press and hold j it obviously starts putting out j characters. But when you then keep holding down j and then also press the ctrl key, X11 starts putting out c-j characters without you having to re-press the j key. Then when you let go of the ctrl key and still keep on pressing j, X11 continues to put j's again. So j makes the cursor start moving nice and smooth downwards, and you can periodically hit ctrl without letting go of j to give it a boost, a jolt.

Also, I do what Devin does, and I set scrolloffset to 5.

Lastly, I swap ctrl and cap lock. The default position of the ctrl key is completely retarded (no offense intended). It makes you have to rotate your left hand. I almost never use caps lock, so I swap them. Then my left pink finger can reach the ctrl key without any yoga moves.

These things have worked for me for years. I only use vim, never gvim.

This isn't exactly smooth scrolling, but it's how I handle not losing context when jumping pages.

set so=7

'scrolloff' 'so' number (default 0) global
{not in Vi}
Minimal number of screen lines to keep above and below the cursor. This will make some context visible around where you are working. If you set it to a very large value (999) the cursor line will always be in the middle of the window (except at the start or end of the file or when long lines wrap). For scrolling horizontally see 'sidescrolloff'. NOTE: This option is set to 0 when 'compatible' is set.

The Plugin cskeeters/vim-smooth-scroll supports smooth scrolling and requires no configuration. It supports to support smooth scrolling with zt, zz, and zb. It's a fork of terryma's plugin. Some of the open pull requests have been applied.

This combines many of these answers, and this is what I use.

noremap <expr> <C-u> repeat("\<C-y> :sleep 10m<CR>", winheight('%')/2)
noremap <expr> <C-d> repeat("\<C-e> :sleep 10m<CR>", winheight('%')/2)

N <CR-E>
N <CR-Y>

...where 'N' is the number of single lines you want to scroll.

Not smooth in literal sense, but you keep the keyboard.

This may be controversial for hardcore users, but... the best way to smooth scroll in Vim is... mouse wheel.

I just found this plugin called "accelerated-smooth-scroll" ("Vim plugin for accelerated smooth scroll (mapping to <C-D>/<C-U>, <C-F>/<C-B>)") which can be for example used through Vundle by putting this line in your .vimrc:

Plugin 'yonchu/accelerated-smooth-scroll'

Then by restarting Vim and running the :PluginInstall command, then again restart Vim and use the <C-D> (Ctrl+D) and <C-O> (Ctrl+O) commands normally.

Sadly, this plugin also moves the cursor instead of what I wanted: to just scroll the screen like the <C-E> and <C-Y> commands.

I slightly modified @Keith Pinson's code so that ctrl-f and ctrl-b can be mapped too:

function SmoothScroll(scroll_direction, n_scroll)
    let n_scroll = a:n_scroll
    if a:scroll_direction == 1
        let scrollaction=""
    else 
        let scrollaction=""
    endif
    exec "normal " . scrollaction
    redraw
    let counter=1
    while counter<&scroll*n_scroll
        let counter+=1
        sleep 10m " ms per line
        redraw
        exec "normal " . scrollaction
    endwhile
endfunction

" smoothly scroll the screen for some scrolling operations
nnoremap <C-U> :call SmoothScroll(1,1)<cr>
nnoremap <C-D> :call SmoothScroll(2,1)<cr>
nnoremap <C-B> :call SmoothScroll(1,2)<cr>
nnoremap <C-F> :call SmoothScroll(2,2)<cr>