feat: change active color of `buffers`, `tabs` & `windows` component according to mode (#971)

- Added `M.get_mode_suffix()` in `highlight.lua` to simplify retrieving the mode suffix.
- Fixed graphical bug occurring when `buffers` component color was changed.
    - Separators would not change to new color.
    - Fixed by adding the mode suffix to the highlight name
        in `M.component_format_highlight` if the output of
        `highlight.fn()` is a string.
- Added `use_mode_colors` option to `buffers`, `tabs`, and `windows` components.
    - If it's set to true, the component's colors will change with the
      mode, as most other components do.
- Updated readme.

README.md

@@ -504,6 +504,9 @@ sections = {
         alpha = 'Alpha'
       }, -- Shows specific buffer name for that filetype ( { `filetype` = `buffer_name`, ... } )
 
+      -- Automatically updates active buffer color to match color of other components (will be overidden if buffers_color is set)
+      use_mode_colors = false,
+
       buffers_color = {
         -- Same values as the general color option can be used here.
         active = 'lualine_{section}_normal',     -- Color for active buffer.
@@ -667,6 +670,9 @@ sections = {
                 -- 1: Shows tab_name
                 -- 2: Shows tab_nr + tab_name
 
+      -- Automatically updates active tab color to match color of other components (will be overidden if buffers_color is set)
+      use_mode_colors = false,
+
       tabs_color = {
         -- Same values as the general color option can be used here.
         active = 'lualine_{section}_normal',     -- Color for active tab.
@@ -714,6 +720,9 @@ sections = {
 
       disabled_buftypes = { 'quickfix', 'prompt' }, -- Hide a window if its buffer's type is disabled
 
+      -- Automatically updates active window color to match color of other components (will be overidden if buffers_color is set)
+      use_mode_colors = false,
+
       windows_color = {
         -- Same values as the general color option can be used here.
         active = 'lualine_{section}_normal',     -- Color for active window.

lua/lualine/components/buffers/init.lua

@@ -18,6 +18,7 @@ local default_options = {
     fzf = 'FZF',
     alpha = 'Alpha',
   },
+  use_mode_colors = false,
   buffers_color = {
     active = nil,
     inactive = nil,
@@ -35,7 +36,7 @@ local default_options = {
 ---@param is_active boolean
 ---@return string hl name
 local function get_hl(section, is_active)
-  local suffix = is_active and '_normal' or '_inactive'
+  local suffix = is_active and highlight.get_mode_suffix() or '_inactive'
   local section_redirects = {
     lualine_x = 'lualine_c',
     lualine_y = 'lualine_b',
@@ -49,8 +50,12 @@ end
 
 function M:init(options)
   M.super.init(self, options)
+  -- if use_mode_colors is set, use a function so that the colors update
+  local default_active = options.use_mode_colors and
+      function() return get_hl('lualine_' .. options.self.section, true) end
+      or get_hl('lualine_' .. options.self.section, true)
   default_options.buffers_color = {
-    active = get_hl('lualine_' .. options.self.section, true),
+    active = default_active,
     inactive = get_hl('lualine_' .. options.self.section, false),
   }
   self.options = vim.tbl_deep_extend('keep', self.options or {}, default_options)

lua/lualine/components/tabs/init.lua

@@ -8,6 +8,7 @@ local highlight = require('lualine.highlight')
 local default_options = {
   max_length = 0,
   mode = 0,
+  use_mode_colors = false,
   tabs_color = {
     active = nil,
     inactive = nil,
@@ -20,7 +21,7 @@ local default_options = {
 ---@param is_active boolean
 ---@return string hl name
 local function get_hl(section, is_active)
-  local suffix = is_active and '_normal' or '_inactive'
+  local suffix = is_active and highlight.get_mode_suffix() or '_inactive'
   local section_redirects = {
     lualine_x = 'lualine_c',
     lualine_y = 'lualine_b',
@@ -34,15 +35,19 @@ end
 
 function M:init(options)
   M.super.init(self, options)
+  -- if use_mode_colors is set, use a function so that the colors update
+  local default_active = options.use_mode_colors and
+      function() return get_hl('lualine_' .. options.self.section, true) end
+      or get_hl('lualine_' .. options.self.section, true)
   default_options.tabs_color = {
-    active = get_hl('lualine_' .. options.self.section, true),
+    active = default_active,
     inactive = get_hl('lualine_' .. options.self.section, false),
   }
   self.options = vim.tbl_deep_extend('keep', self.options or {}, default_options)
   -- stylua: ignore
   self.highlights = {
-    active = self:create_hl( self.options.tabs_color.active, 'active'),
+    active = self:create_hl(self.options.tabs_color.active, 'active'),
-    inactive = self:create_hl( self.options.tabs_color.inactive, 'inactive'),
+    inactive = self:create_hl(self.options.tabs_color.inactive, 'inactive'),
   }
 end
 

lua/lualine/highlight.lua

@@ -34,6 +34,13 @@ local mode_to_highlight = {
   ['TERMINAL'] = '_terminal',
 }
 
+--- Get highlight suffix for current mode, or inactive if not focused
+---@return string mode_suffix
+function M.get_mode_suffix()
+  local mode = require('lualine.utils.mode').get_mode()
+  return mode_to_highlight[mode] or '_normal'
+end
+
 --- determine if an highlight exist and isn't cleared
 ---@param highlight_name string
 ---@return boolean whether hl_group was defined with highlight_name
@@ -222,8 +229,7 @@ local function append_mode(highlight_group, is_focused)
   if is_focused == false then
     return highlight_group .. '_inactive'
   end
-  local mode = require('lualine.utils.mode').get_mode()
+  return highlight_group .. M.get_mode_suffix()
-  return highlight_group .. (mode_to_highlight[mode] or '_normal')
 end
 
 -- Helper function for create component highlight
@@ -392,13 +398,13 @@ function M.component_format_highlight(highlight, is_focused)
     local color = highlight.fn { section = highlight.section } or {}
     local hl_name = highlight.name
     if type(color) == 'string' then
-      M.highlight(hl_name, nil, nil, nil, color)
+      M.highlight(hl_name .. M.get_mode_suffix(), nil, nil, nil, color)
-      return '%#' .. hl_name .. '#'
+      return '%#' .. hl_name .. M.get_mode_suffix() .. '#'
     elseif type(color) == 'table' then
       if not highlight.no_default and not (color.fg and color.bg) then
         hl_name = append_mode(highlight.name, is_focused)
         color =
-          get_default_component_color(hl_name, append_mode(''):sub(2), highlight.section, color, highlight.options)
+          get_default_component_color(hl_name, M.get_mode_suffix():sub(2), highlight.section, color, highlight.options)
       end
       M.highlight(hl_name, color.fg, color.bg, color.gui, color.link)
       return '%#' .. hl_name .. '#', color