feat(scrollbar): implement scrollbar in lua

autoload/SpaceVim/plugins/scrollbar.vim

@@ -6,6 +6,21 @@
 " License: GPLv3
 "=============================================================================
 
+if has('nvim-0.9.0')
+  function! SpaceVim#plugins#scrollbar#usable() abort
+    return luaeval('require("spacevim.plugin.scrollbar").usable()')
+  endfunction
+  function! SpaceVim#plugins#scrollbar#show() abort
+    lua require('spacevim.plugin.scrollbar').show()
+  endfunction
+  function! SpaceVim#plugins#scrollbar#clear(...) abort
+    lua require('spacevim.plugin.scrollbar').clear()
+  endfunction
+  finish
+endif
+
+
+
 let s:VIM = SpaceVim#api#import('vim')
 let s:BUF = SpaceVim#api#import('vim#buffer')
 let s:WIN = SpaceVim#api#import('vim#window')

lua/spacevim/plugin/scrollbar.lua

@@ -0,0 +1,161 @@
+--=============================================================================
+-- scrollbar.lua --- scrollbar for SpaceVim
+-- Copyright (c) 2016-2022 Wang Shidong & Contributors
+-- Author: Wang Shidong < wsdjeg@outlook.com >
+-- URL: https://spacevim.org
+-- License: GPLv3
+--=============================================================================
+
+local M = {}
+
+local win = require('spacevim.api.vim.window')
+
+local default_conf = {
+  max_size = 10,
+  min_size = 3,
+  width = 1,
+  right_offset = 1,
+  excluded_filetypes = {
+    'startify',
+    'git-commit',
+    'leaderf',
+    'NvimTree',
+    'tagbar',
+    'defx',
+    'neo-tree',
+    'qf',
+  },
+  shape = {
+    head = '▲',
+    body = '█',
+    tail = '▼',
+  },
+  highlight = {
+    head = 'Normal',
+    body = 'Normal',
+    tail = 'Normal',
+  },
+}
+local function get(opt)
+
+  return default_conf[opt]
+
+end
+
+local scrollbar_bufnr = -1
+local scrollbar_winid = -1
+local scrollbar_size = -1
+local ns_id = vim.api.nvim_create_namespace('scrollbar')
+
+local function add_highlight(bufnr, size)
+  local highlight = get('highlight')
+  vim.api.nvim_buf_add_highlight(bufnr, ns_id, highlight.head, 0, 0, -1)
+  for i = 1, size - 2 do
+    vim.api.nvim_buf_add_highlight(bufnr, ns_id, highlight.body, i, 0, -1)
+  end
+  vim.api.nvim_buf_add_highlight(bufnr, ns_id, highlight.tail, size - 1, 0, -1)
+end
+
+local function fix_size(size)
+  return math.max(get('min_size'), math.min(get('max_size'), math.floor(size + 0.5)))
+end
+
+local function gen_bar_lines(size)
+  local shape = get('shape')
+  local lines = { shape.head }
+  for _ = 2, size - 1 do
+    table.insert(lines, shape.body)
+  end
+  table.insert(lines, shape.tail)
+  return lines
+end
+
+local function create_scrollbar_buffer(size, lines)
+  if not vim.api.nvim_buf_is_valid(scrollbar_bufnr) then
+    scrollbar_bufnr = vim.api.nvim_create_buf(false, true)
+  end
+  vim.api.nvim_buf_set_lines(scrollbar_bufnr, 0, -1, false, lines)
+  add_highlight(scrollbar_bufnr, size)
+  return scrollbar_bufnr
+end
+
+function M.show()
+  local saved_ei = vim.o.eventignore
+  vim.o.eventignore = 'all'
+  local winnr = vim.fn.winnr()
+  local bufnr = vim.fn.bufnr()
+  local winid = vim.fn.win_getid()
+  if win.is_float(winid) then
+    M.clear()
+    vim.o.eventignore = saved_ei
+    return
+  end
+
+  local total = vim.api.nvim_buf_line_count(bufnr)
+  local height = vim.fn.winheight(winnr)
+
+  if total <= height then
+    M.clear()
+    vim.o.eventignore = saved_ei
+    return
+  end
+
+  local curr_line = vim.fn.line('w0')
+  local bar_size = fix_size(height * height / total)
+  local width = vim.fn.winwidth(winnr)
+  local col = width - get('width') - get('right_offset')
+  local precision = height - bar_size
+  local each_line = (total - height) * 1.0 / precision
+  local visble_line = vim.fn.min({ curr_line, total - height + 1 })
+  local row
+  if each_line >= 1 then
+    row = vim.fn.float2nr(visble_line / each_line)
+  else
+    row = vim.fn.float2nr(visble_line / each_line - 1 / each_line)
+  end
+
+  local opts = {
+    style = 'minimal',
+    relative = 'win',
+    win = winid,
+    width = get('width'),
+    height = bar_size,
+    row = row,
+    col = vim.fn.float2nr(col),
+    focusable = false,
+    zindex = 10,
+  }
+
+  if win.is_float(scrollbar_winid) then
+    if bar_size ~= scrollbar_size then
+      scrollbar_size = bar_size
+      local bar_lines = gen_bar_lines(bar_size)
+      vim.api.nvim_buf_set_lines(scrollbar_bufnr, 0, -1, false, bar_lines)
+      add_highlight(scrollbar_bufnr, bar_size)
+    end
+    vim.api.nvim_win_set_config(scrollbar_winid, opts)
+  else
+    scrollbar_size = bar_size
+    local bar_lines = gen_bar_lines(bar_size)
+    scrollbar_bufnr = create_scrollbar_buffer(bar_size, bar_lines)
+    scrollbar_winid = vim.api.nvim_open_win(scrollbar_bufnr, false, opts)
+    vim.fn.setwinvar(
+      vim.fn.win_id2win(scrollbar_winid),
+      '&winhighlight',
+      'Normal:ScrollbarWinHighlight'
+    )
+  end
+  vim.o.eventignore = saved_ei
+end
+
+function M.clear()
+  if vim.api.nvim_win_is_valid(scrollbar_winid) then
+    vim.api.nvim_win_close(scrollbar_winid, true)
+  end
+end
+
+function M.usable()
+  return true
+end
+
+return M