Temporarily hide the cursor when scrolling with the mouse wheel off-screen in Neovim v0.8

hide_scroll.lua

-- This script temporarily hides the 'cursorline' (and cursor if 'tgc' is set) if the cursor
-- would be scrolled outside of the window viewport when using the mouse wheel.
--
-- Written for @deagle.50:matrix.org for use with Neovide's smooth scrolling feature. :)
-- Tested using Neovim v0.8.
--
-- TODO: if the window is split before restoring, the hidden 'cul' state will leak into the new
-- window. Can probably be fixed with some autocmd hackery.

local api, fn, keymap = vim.api, vim.fn, vim.keymap
local o, wo = vim.o, vim.wo

api.nvim_set_hl(0, 'noCursor', { reverse = true, blend = 100 })

local restore_timer, restore_cb = vim.loop.new_timer(), nil

local function scroll(key)
  local wins = api.nvim_tabpage_list_wins(0)
  local save_toplines = vim.tbl_map(function(win)
    return fn.getwininfo(win)[1].topline
  end, wins)

  api.nvim_feedkeys(api.nvim_replace_termcodes(key, true, false, true), 'nx', false)

  for i, win in ipairs(wins) do
    local wininfo = fn.getwininfo(win)[1]
    -- Trigger for the scrolled window. We cannot use WinScrolled here as it doesn't fire for
    -- non-current windows yet (they can be scrolled with the mouse).
    if wininfo.topline ~= save_toplines[i] then
      local row = api.nvim_win_get_cursor(win)[1]
      local so = wo[win].scrolloff
      -- Check if the cursor (probably) would have scrolled outside of view.
      if row <= wininfo.topline + so or row >= wininfo.botline - so then
        if restore_cb then
          restore_cb()
        end

        local save_gcr, save_cul = o.guicursor, o.cursorline
        o.guicursor = 'a:noCursor'
        wo[win].cursorline = false

        restore_cb = function()
          if o.guicursor == 'a:noCursor' then
            o.guicursor = save_gcr
          end
          if api.nvim_win_is_valid(win) and not wo[win].cursorline then
            wo[win].cursorline = save_cul
          end
        end

        restore_timer:start(500, 0, function()
          vim.schedule(restore_cb)
          restore_cb = nil
        end)
        return
      end
    end
  end
end

keymap.set('n', '<ScrollWheelUp>', function()
  scroll('<ScrollWheelUp>')
end)
keymap.set('n', '<ScrollWheelDown>', function()
  scroll('<ScrollWheelDown>')
end)