feat: add support for dynamic color with functions in color options (#566)

* feat: allow functions in color options.

* update_evilline

* docs: document color functions

* remove unnecesery stuff

* add dynamic color supoort for themes

* chore: autogen (vimdocs+formating)

* fix dynamic colors not working as color fallback

* fix transitional separators not updating for dynamic colors dynamic colors

* fix failing tests

* apply format

* Allow cases where theme doesn't even define nornal color for some mode

* allow color function to return nil

* some enhancements

* more enhancements

* code cleanup

* if we don't have even normal in theme we should just nvim highlight it with it's ususal stl colors

* not sure how it get here . It should be in different pr

* keep only c of lualine_c in component section name

* use sh to run docgen

* fix filetype component not respecting color option properly

* fix section x,y,z not falling back to correct colors

* auto format

* actually fix xyz not falling back to correct mode

* fix comp sep not correctly removed properly on function hl

* pass only section in color fn

* more enhancements

* update docs

* update create_comp_hl call locations

* enhancements+fixes

* fix broken hls in tabline

* Fix function color options not inheriting right colors

* some enhancements

* fix tests

* tweek docs

Co-authored-by: shadmansaleh <shadmansaleh@users.noreply.github.com>

Makefile

@@ -31,7 +31,7 @@ endif
 	@rm -rf tmp_home
 
 docgen:
-	@bash ./scripts/docgen.sh
+	@sh ./scripts/docgen.sh
 
 precommit_check: docgen format test lint
 

README.md

@@ -374,15 +374,19 @@ sections = {
 
       -- Defines a custom color for the component:
       --
-      -- 'highlight_group_name' | { fg = '#rrggbb'|cterm_value(0-255)|'color_name(red)', bg= '#rrggbb', gui='style' }
+      -- 'highlight_group_name' | { fg = '#rrggbb'|cterm_value(0-255)|'color_name(red)', bg= '#rrggbb', gui='style' } | function
       -- Note:
       --  '|' is synonymous with 'or', meaning a different acceptable format for that placeholder.
+      -- color function has to return one of other color types ('highlight_group_name' | { fg = '#rrggbb'|cterm_value(0-255)|'color_name(red)', bg= '#rrggbb', gui='style' })
+      -- color functions can be used to have different colors based on state as shown below.
       --
       -- Examples:
       --   color = { fg = '#ffaa88', bg = 'grey', gui='italic,bold' },
       --   color = { fg = 204 }   -- When fg/bg are omitted, they default to the your theme's fg/bg.
       --   color = 'WarningMsg'   -- Highlight groups can also be used.
-      --
+      --   color = function(section)
+      --      return { fg = vim.bo.modified and '#aa3355' or '#33aa88' }
+      --   end,
       color = nil, -- The default is your theme's color for that section and mode.
 
       -- Specify what type a component is, if omitted, lualine will guess it for you.

doc/lualine.txt

@@ -387,15 +387,19 @@ General component options              These are options that control behavior
     
           -- Defines a custom color for the component:
           --
-          -- 'highlight_group_name' | { fg = '#rrggbb'|cterm_value(0-255)|'color_name(red)', bg= '#rrggbb', gui='style' }
+          -- 'highlight_group_name' | { fg = '#rrggbb'|cterm_value(0-255)|'color_name(red)', bg= '#rrggbb', gui='style' } | function
           -- Note:
           --  '|' is synonymous with 'or', meaning a different acceptable format for that placeholder.
+          -- color function has to return one of other color types ('highlight_group_name' | { fg = '#rrggbb'|cterm_value(0-255)|'color_name(red)', bg= '#rrggbb', gui='style' })
+          -- color functions can be used to have different colors based on state as shown below.
           --
           -- Examples:
           --   color = { fg = '#ffaa88', bg = 'grey', gui='italic,bold' },
           --   color = { fg = 204 }   -- When fg/bg are omitted, they default to the your theme's fg/bg.
           --   color = 'WarningMsg'   -- Highlight groups can also be used.
-          --
+          --   color = function(section)
+          --      return { fg = vim.bo.modified and '#aa3355' or '#33aa88' }
+          --   end,
           color = nil, -- The default is your theme's color for that section and mode.
     
           -- Specify what type a component is, if omitted, lualine will guess it for you.

examples/evil_lualine.lua

@@ -89,6 +89,9 @@ ins_left {
 ins_left {
   -- mode component
   function()
+    return ''
+  end,
+  color = function()
     -- auto change color according to neovims mode
     local mode_color = {
       n = colors.red,
@@ -112,10 +115,8 @@ ins_left {
       ['!'] = colors.red,
       t = colors.red,
     }
-    vim.api.nvim_command('hi! LualineMode guifg=' .. mode_color[vim.fn.mode()] .. ' guibg=' .. colors.bg)
+    return { fg = mode_color[vim.fn.mode()] }
-    return ''
   end,
-  color = 'LualineMode',
   padding = { right = 1 },
 }
 

lua/lualine.lua

@@ -158,7 +158,7 @@ local statusline = modules.utils.retry_call_wrap(function(sections, is_focused)
       if #section_data > 0 then
         if not applied_midsection_divider and section_name > 'c' then
           applied_midsection_divider = true
-          section_data = modules.highlight.format_highlight('lualine_c') .. '%=' .. section_data
+          section_data = modules.highlight.format_highlight('c', is_focused) .. '%=' .. section_data
         end
         if not applied_trunc and section_name > 'b' then
           applied_trunc = true
@@ -170,7 +170,7 @@ local statusline = modules.utils.retry_call_wrap(function(sections, is_focused)
   end
   if applied_midsection_divider == false and config.options.always_divide_middle ~= false then
     -- When non of section x,y,z is present
-    table.insert(status, modules.highlight.format_highlight('lualine_c') .. '%=')
+    table.insert(status, modules.highlight.format_highlight('c', is_focused) .. '%=')
   end
   return apply_transitional_separators(table.concat(status))
 end)

lua/lualine/component.lua

@@ -38,7 +38,7 @@ end
 function M:set_separator()
   if self.options.separator == nil then
     if self.options.component_separators then
-      if self.options.self.section < 'lualine_x' then
+      if self.options.self.section < 'x' then
         self.options.separator = self.options.component_separators.left
       else
         self.options.separator = self.options.component_separators.right
@@ -54,7 +54,8 @@ function M:create_option_highlights()
     self.options.color_highlight = highlight.create_component_highlight_group(
       self.options.color,
       self.options.component_name,
-      self.options
+      self.options,
+      false
     )
   end
 end
@@ -89,7 +90,9 @@ end
 ---applies custom highlights for component
 function M:apply_highlights(default_highlight)
   if self.options.color_highlight then
-    self.status = highlight.component_format_highlight(self.options.color_highlight) .. self.status
+    local hl_fmt
+    hl_fmt, M.color_fn_cache = highlight.component_format_highlight(self.options.color_highlight)
+    self.status = hl_fmt .. self.status
   end
   if type(self.options.separator) ~= 'table' and self.status:find('%%#') then
     -- Apply default highlight only when we aren't applying trans sep and
@@ -119,7 +122,7 @@ function M:apply_separator()
   local separator = self.options.separator
   if type(separator) == 'table' then
     if self.options.separator[2] == '' then
-      if self.options.self.section < 'lualine_x' then
+      if self.options.self.section < 'x' then
         separator = self.options.component_separators.left
       else
         separator = self.options.component_separators.right
@@ -159,6 +162,16 @@ function M:strip_separator()
   return self.status
 end
 
+function M:get_default_hl()
+  if self.options.color_highlight then
+    return highlight.component_format_highlight(self.options.color_highlight)
+  elseif self.default_hl then
+    return self.default_hl
+  else
+    return highlight.format_highlight(self.options.self.section)
+  end
+end
+
 -- luacheck: push no unused args
 ---actual function that updates a component. Must be overwritten with component functionality
 function M:update_status(is_focused) end
@@ -172,6 +185,7 @@ function M:draw(default_highlight, is_focused)
   if self.options.cond ~= nil and self.options.cond() ~= true then
     return self.status
   end
+  self.default_hl = default_highlight
   local status = self:update_status(is_focused)
   if self.options.fmt then
     status = self.options.fmt(status or '')

lua/lualine/components/buffers/buffer.lua

@@ -77,11 +77,11 @@ function Buffer:render()
     .. line
 
   -- apply separators
-  if self.options.self.section < 'lualine_x' and not self.first then
+  if self.options.self.section < 'x' and not self.first then
     local sep_before = self:separator_before()
     line = sep_before .. line
     self.len = self.len + vim.fn.strchars(sep_before)
-  elseif self.options.self.section >= 'lualine_x' and not self.last then
+  elseif self.options.self.section >= 'x' and not self.last then
     local sep_after = self:separator_after()
     line = line .. sep_after
     self.len = self.len + vim.fn.strchars(sep_after)

lua/lualine/components/buffers/init.lua

@@ -44,20 +44,22 @@ end
 function M:init(options)
   M.super.init(self, options)
   default_options.buffers_color = {
-    active = get_hl(options.self.section, true),
+    active = get_hl('lualine_' .. options.self.section, true),
-    inactive = get_hl(options.self.section, false),
+    inactive = get_hl('lualine_' .. options.self.section, false),
   }
   self.options = vim.tbl_deep_extend('keep', self.options or {}, default_options)
   self.highlights = {
     active = highlight.create_component_highlight_group(
       self.options.buffers_color.active,
       'buffers_active',
-      self.options
+      self.options,
+      false
     ),
     inactive = highlight.create_component_highlight_group(
       self.options.buffers_color.inactive,
-      'buffers_active',
+      'buffers_inactive',
-      self.options
+      self.options,
+      false
     ),
   }
 end
@@ -112,7 +114,7 @@ function M:update_status()
   if current == -2 then
     local b = Buffer { bufnr = vim.api.nvim_get_current_buf(), options = self.options, highlights = self.highlights }
     b.current = true
-    if self.options.self.section < 'lualine_x' then
+    if self.options.self.section < 'x' then
       b.last = true
       if #buffers > 0 then
         buffers[#buffers].last = nil

lua/lualine/components/diagnostics/init.lua

@@ -33,22 +33,26 @@ function M:init(options)
       error = modules.highlight.create_component_highlight_group(
         self.options.diagnostics_color.error,
         'diagnostics_error',
-        self.options
+        self.options,
+        false
       ),
       warn = modules.highlight.create_component_highlight_group(
         self.options.diagnostics_color.warn,
         'diagnostics_warn',
-        self.options
+        self.options,
+        false
       ),
       info = modules.highlight.create_component_highlight_group(
         self.options.diagnostics_color.info,
         'diagnostics_info',
-        self.options
+        self.options,
+        false
       ),
       hint = modules.highlight.create_component_highlight_group(
         self.options.diagnostics_color.hint,
         'diagnostics_hint',
-        self.options
+        self.options,
+        false
       ),
     }
   end

lua/lualine/components/diff/init.lua

@@ -47,17 +47,20 @@ function M:init(options)
       added = modules.highlight.create_component_highlight_group(
         self.options.diff_color.added,
         'diff_added',
-        self.options
+        self.options,
+        false
       ),
       modified = modules.highlight.create_component_highlight_group(
         self.options.diff_color.modified,
         'diff_modified',
-        self.options
+        self.options,
+        false
       ),
       removed = modules.highlight.create_component_highlight_group(
         self.options.diff_color.removed,
         'diff_removed',
-        self.options
+        self.options,
+        false
       ),
     }
   end

lua/lualine/components/filetype.lua

@@ -22,6 +22,7 @@ function M.update_status()
   return modules.utils.stl_escape(ft)
 end
 
+local icon_hl_cache = {}
 function M:apply_icon()
   if not self.options.icons_enabled then
     return
@@ -36,14 +37,16 @@ function M:apply_icon()
 
     if icon and self.options.colored then
       local highlight_color = modules.utils.extract_highlight_colors(icon_highlight_group, 'fg')
-      local default_highlight = modules.highlight.format_highlight(self.options.self.section)
+      local default_highlight = self:get_default_hl()
-      local icon_highlight = self.options.self.section .. '_' .. icon_highlight_group
+      local icon_highlight = icon_hl_cache[highlight_color]
-      if not modules.highlight.highlight_exists(icon_highlight .. '_normal') then
+      if not icon_highlight or not modules.highlight.highlight_exists(icon_highlight.name .. '_normal') then
         icon_highlight = modules.highlight.create_component_highlight_group(
           { fg = highlight_color },
           icon_highlight_group,
-          self.options
+          self.options,
+          false
         )
+        icon_hl_cache[highlight_color] = icon_highlight
       end
 
       icon = modules.highlight.component_format_highlight(icon_highlight) .. icon .. default_highlight

lua/lualine/components/tabs/init.lua

@@ -35,8 +35,8 @@ end
 function M:init(options)
   M.super.init(self, options)
   default_options.tabs_color = {
-    active = get_hl(options.self.section, true),
+    active = get_hl('lualine_' .. options.self.section, true),
-    inactive = get_hl(options.self.section, false),
+    inactive = get_hl('lualine_' .. options.self.section, false),
   }
   self.options = vim.tbl_deep_extend('keep', self.options or {}, default_options)
   -- stylua: ignore
@@ -44,12 +44,14 @@ function M:init(options)
     active = highlight.create_component_highlight_group(
       self.options.tabs_color.active,
       'tabs_active',
-      self.options
+      self.options,
+      false
     ),
     inactive = highlight.create_component_highlight_group(
       self.options.tabs_color.inactive,
-      'tabs_active',
+      'tabs_inactive',
-      self.options
+      self.options,
+      false
     ),
   }
 end

lua/lualine/components/tabs/tab.lua

@@ -70,11 +70,11 @@ function Tab:render()
     .. line
 
   -- apply separators
-  if self.options.self.section < 'lualine_x' and not self.first then
+  if self.options.self.section < 'x' and not self.first then
     local sep_before = self:separator_before()
     line = sep_before .. line
     self.len = self.len + vim.fn.strchars(sep_before)
-  elseif self.options.self.section >= 'lualine_x' and not self.last then
+  elseif self.options.self.section >= 'x' and not self.last then
     local sep_after = self:separator_after()
     line = line .. sep_after
     self.len = self.len + vim.fn.strchars(sep_after)

lua/lualine/highlight.lua

@@ -10,6 +10,7 @@ local modules = lualine_require.lazy_require {
 
 local section_highlight_map = { x = 'c', y = 'b', z = 'a' }
 local active_theme = nil
+local theme_hls = {}
 local create_cterm_colors = false
 
 -- table to store the highlight names created by lualine
@@ -44,14 +45,17 @@ end
 local function clear_highlights()
   for highlight_name, _ in pairs(loaded_highlights) do
     vim.cmd('highlight clear ' .. highlight_name)
-    loaded_highlights[highlight_name] = nil
   end
+  loaded_highlights = {}
 end
 
 ---converts cterm, color_name type colors to #rrggbb format
 ---@param color string|number
 ---@return string
 local function sanitize_color(color)
+  if color == nil or color == '' then
+    return 'None'
+  end
   if type(color) == 'string' then
     if color:sub(1, 1) == '#' then
       return color
@@ -65,6 +69,28 @@ local function sanitize_color(color)
   end
 end
 
+function M.get_lualine_hl(name)
+  local hl = loaded_highlights[name]
+  if hl and not hl.empty then
+    if hl.link then
+      return modules.utils.extract_highlight_colors(hl.link)
+    end
+    local hl_def = {
+      fg = hl.fg ~= 'None' and vim.deepcopy(hl.fg),
+      bg = hl.bg ~= 'None' and vim.deepcopy(hl.bg),
+    }
+    if hl.gui then
+      for _, flag in ipairs(vim.split(hl.gui, ',')) do
+        if flag ~= 'None' then
+          hl_def[flag] = true
+        end
+      end
+    end
+
+    return hl_def
+  end
+end
+
 --- Define a hl_group
 ---@param name string
 ---@param foreground string|number: color
@@ -74,46 +100,113 @@ end
 function M.highlight(name, foreground, background, gui, link)
   local command = { 'highlight!' }
   if link and #link > 0 then
+    if loaded_highlights[name] and loaded_highlights[name].link == link then
+      return
+    end
     vim.list_extend(command, { 'link', name, link })
   else
     foreground = sanitize_color(foreground)
     background = sanitize_color(background)
+    gui = (gui ~= nil and gui ~= '') and gui or 'None'
+    if
+      loaded_highlights[name]
+      and loaded_highlights[name].fg == foreground
+      and loaded_highlights[name].bg == background
+      and loaded_highlights[name].gui == gui
+    then
+      return -- color is already defined why are we doing this anyway ?
+    end
     table.insert(command, name)
-    if foreground and foreground ~= 'None' then
     table.insert(command, 'guifg=' .. foreground)
+    table.insert(command, 'guibg=' .. background)
+    table.insert(command, 'gui=' .. gui)
     if create_cterm_colors then
       table.insert(command, 'ctermfg=' .. modules.color_utils.rgb2cterm(foreground))
-      end
-    end
-    if background and background ~= 'None' then
-      table.insert(command, 'guibg=' .. background)
-      if create_cterm_colors then
       table.insert(command, 'ctermbg=' .. modules.color_utils.rgb2cterm(background))
-      end
-    end
-    if gui then
       table.insert(command, 'cterm=' .. gui)
-      table.insert(command, 'gui=' .. gui)
     end
   end
   vim.cmd(table.concat(command, ' '))
-  loaded_highlights[name] = true
+
+  -- update attached hl groups
+  local old_hl_def = loaded_highlights[name]
+  if old_hl_def and next(old_hl_def.attached) then
+    -- Update attached hl groups as they announced to depend on hl_group 'name'
+    -- 'hl' being in 'name'a attached table means 'hl'
+    -- depends of 'name'.
+    -- 'hl' key in attached table will contain a table that
+    -- defines the reletaion between 'hl' & 'name'.
+    -- name.attached.hl = { bg = 'fg' } means
+    -- hl's fg is same as 'names' bg . So 'hl's fg should
+    -- be updated when ever 'name' changes it's 'bg'
+    local bg_changed = old_hl_def.bg ~= background
+    local fg_changed = old_hl_def.bg ~= foreground
+    local gui_changed = old_hl_def.gui ~= gui
+    for attach_name, attach_desc in pairs(old_hl_def.attached) do
+      if bg_changed and attach_desc.bg and loaded_highlights[attach_name] then
+        M.highlight(
+          attach_name,
+          attach_desc.bg == 'fg' and background or loaded_highlights[attach_name].fg,
+          attach_desc.bg == 'bg' and background or loaded_highlights[attach_name].bg,
+          loaded_highlights[attach_name].gui,
+          loaded_highlights[attach_name].link
+        )
+      end
+      if fg_changed and attach_desc.fg and loaded_highlights[attach_name] then
+        M.highlight(
+          attach_name,
+          attach_desc.fg == 'fg' and foreground or loaded_highlights[attach_name].fg,
+          attach_desc.fg == 'bg' and foreground or loaded_highlights[attach_name].bg,
+          loaded_highlights[attach_name].gui,
+          loaded_highlights[attach_name].link
+        )
+      end
+      if gui_changed and attach_desc.gui and loaded_highlights[attach_name] then
+        M.highlight(
+          attach_name,
+          loaded_highlights[attach_name].fg,
+          loaded_highlights[attach_name].bg,
+          gui,
+          loaded_highlights[attach_name].link
+        )
+      end
+    end
+  end
+  -- store current hl state
+  loaded_highlights[name] = {
+    fg = foreground,
+    bg = background,
+    gui = gui,
+    link = link,
+    attached = old_hl_def and old_hl_def.attached or {},
+  }
 end
 
+---Attach an hl to another so attachee auto updated on change to hl it's attached too.
+---@param provider string the hl receiver is getting attached to
+---@param receiver string the hl that will be auto updated upon change to provider
+---@param provider_el_type string (fg/bg) what element receiver relates to of provider
+---@param receiver_el_type string (fg/bg) what element provider relates to of receiver
+local function attach_hl(provider, receiver, provider_el_type, receiver_el_type)
+  if loaded_highlights[provider] == nil then
+    loaded_highlights[provider] = { empty = true, attached = {} }
+  end
+  loaded_highlights[provider].attached[receiver] = { [provider_el_type] = receiver_el_type }
+end
 ---define hl_groups for a theme
 ---@param theme table
 function M.create_highlight_groups(theme)
   clear_highlights()
   active_theme = theme
+  theme_hls = {}
+  local psudo_options = { self = { section = 'a' } }
   create_cterm_colors = not vim.go.termguicolors
   for mode, sections in pairs(theme) do
+    theme_hls[mode] = {}
     for section, color in pairs(sections) do
-      local highlight_group_name = { 'lualine', section, mode }
+      local hl_tag = mode
-      if type(color) == 'string' then -- link to a highlight group
+      psudo_options.self.section = section
-        M.highlight(table.concat(highlight_group_name, '_'), nil, nil, nil, color)
+      theme_hls[mode][section] = M.create_component_highlight_group(color, hl_tag, psudo_options, true)
-      else -- Define a new highlight
-        M.highlight(table.concat(highlight_group_name, '_'), color.fg, color.bg, color.gui, nil)
-      end
     end
   end
 end
@@ -121,7 +214,7 @@ end
 ---@description: adds '_mode' at end of highlight_group
 ---@param highlight_group string name of highlight group
 ---@return string highlight group name with mode
-function M.append_mode(highlight_group, is_focused)
+local function append_mode(highlight_group, is_focused)
   if is_focused == nil then
     is_focused = modules.utils.is_focused()
   end
@@ -134,27 +227,67 @@ end
 
 -- Helper function for create component highlight
 ---Handles fall back of colors when creating highlight group
+---@param hl_name string name of highlight that we are setting default values for
+---@param mode string mode which default component color should be given.
+---@param section string the lualine section component is in.
 ---@param color table color passed for creating component highlight
----@param options_color table color set by color option for component
+---@param options table Options table of component this is first fall back
----       this is first fall back
+local function get_default_component_color(hl_name, mode, section, color, options)
----@param default_color table colors et in theme this is 2nd fall back
+  local default_theme_color
----@param kind string fg/bg
+  if active_theme[mode] and active_theme[mode][section] then
-local function get_default_component_color(color, options_color, default_color, kind)
+    default_theme_color = active_theme[mode][section]
-  if color[kind] then
+  elseif section >= 'c' and active_theme[mode] and active_theme[mode][section_highlight_map[section]] then
-    return color[kind]
+    default_theme_color = active_theme[mode][section_highlight_map[section]]
+  elseif section >= 'c' and active_theme.normal[section_highlight_map[section]] then
+    default_theme_color = active_theme.normal[section_highlight_map[section]]
+  else
+    default_theme_color = active_theme.normal[section]
   end
-  if options_color then
+
-    if type(options_color) == 'table' and options_color[kind] then
+  local ret = { fg = color.fg, bg = color.bg, gui = color.gui }
-      return options_color[kind]
+  if ret.fg and ret.bg then
-    elseif type(options_color) == 'string' then
+    return ret
-      return modules.utils.extract_highlight_colors(options_color, kind)
+  end
+
+  local function apply_default(def_color, def_name)
+    if type(def_color) == 'function' and loaded_highlights[def_name] and not loaded_highlights[def_name].empty then
+      if loaded_highlights[def_name].link then
+        def_color = loaded_highlights[def_name].link
+      else
+        def_color = loaded_highlights[def_name]
       end
     end
-  if type(default_color) == 'table' then
+    if type(def_color) == 'function' then
-    return default_color[kind]
+      def_color = def_color { section = section }
-  elseif type(default_color) == 'string' then
-    return modules.utils.extract_highlight_colors(default_color, kind)
     end
+    if type(def_color) == 'string' then
+      def_color = modules.utils.extract_highlight_colors(def_color)
+    end
+    if type(def_color) == 'table' then
+      if not ret.fg then
+        ret.fg = def_color.fg
+        attach_hl(def_name, hl_name, 'fg', 'fg')
+      end
+      if not ret.bg then
+        ret.bg = def_color.bg
+        attach_hl(def_name, hl_name, 'bg', 'bg')
+      end
+    end
+  end
+
+  if
+    options.color
+    and options.color_highlight
+    and options.color_highlight.name
+    and options.color_highlight.name .. '_' .. mode ~= hl_name
+  then
+    apply_default(options.color, options.color_highlight.name .. '_' .. mode)
+  else
+    apply_default(default_theme_color, string.format('lualine_%s_%s', section, mode))
+  end
+  ret.fg = sanitize_color(ret.fg)
+  ret.bg = sanitize_color(ret.bg)
+  return ret
 end
 
 ---Create highlight group with fg bg and gui from theme
@@ -164,31 +297,50 @@ end
 ---@param highlight_tag string is unique tag for highlight group
 ---returns the name of highlight group
 ---@param options table is parameter of component.init() function
----@return string unique name that can be used by component_format_highlight
+---@return table that can be used by component_format_highlight
 ---  to retrieve highlight group
-function M.create_component_highlight_group(color, highlight_tag, options)
+function M.create_component_highlight_group(color, highlight_tag, options, apply_no_default)
+  local section = options.self.section
+  if section > 'c' and not active_theme.normal[section] then
+    section = section_highlight_map[section]
+  end
+
   local tag_id = 0
   while
-    M.highlight_exists(table.concat({ 'lualine', highlight_tag, 'no_mode' }, '_'))
+    M.highlight_exists(table.concat({ 'lualine', section, highlight_tag }, '_'))
-    or (
+    or (section and M.highlight_exists(table.concat({ 'lualine', section, highlight_tag, 'normal' }, '_')))
-      options.self.section
-      and M.highlight_exists(table.concat({ options.self.section, highlight_tag, 'normal' }, '_'))
-    )
   do
     highlight_tag = highlight_tag .. '_' .. tostring(tag_id)
     tag_id = tag_id + 1
   end
+
   if type(color) == 'string' then
-    local highlight_group_name = table.concat({ 'lualine', highlight_tag, 'no_mode' }, '_')
+    local highlight_group_name = table.concat({ 'lualine', section, highlight_tag }, '_')
     M.highlight(highlight_group_name, nil, nil, nil, color) -- l8nk to group
-    return highlight_group_name
+    return {
+      name = highlight_group_name,
+      fn = nil,
+      no_mode = true,
+      link = true,
+      section = section,
+      options = options,
+      no_default = apply_no_default,
+    }
   end
-  if color.bg and color.fg then
+
+  if type(color) ~= 'function' and (apply_no_default or (color.bg and color.fg)) then
     -- When bg and fg are both present we donn't need to set highlighs for
     -- each mode as they will surely look the same. So we can work without options
-    local highlight_group_name = table.concat({ 'lualine', highlight_tag, 'no_mode' }, '_')
+    local highlight_group_name = table.concat({ 'lualine', section, highlight_tag }, '_')
     M.highlight(highlight_group_name, color.fg, color.bg, color.gui, nil)
-    return highlight_group_name
+    return {
+      name = highlight_group_name,
+      fn = nil,
+      no_mode = true,
+      section = section,
+      options = options,
+      no_default = apply_no_default,
+    }
   end
 
   local modes = {
@@ -200,64 +352,87 @@ function M.create_component_highlight_group(color, highlight_tag, options)
     'terminal',
     'inactive',
   }
-  local normal_hl
-  -- convert lualine_a -> a before setting section
-  local section = options.self.section:match('lualine_(.*)')
-  if section > 'c' and not active_theme.normal[section] then
-    section = section_highlight_map[section]
-  end
   for _, mode in ipairs(modes) do
-    local highlight_group_name = { options.self.section, highlight_tag, mode }
+    local hl_name = table.concat({ 'lualine', section, highlight_tag, mode }, '_')
-    local default_color_table = active_theme[mode] and active_theme[mode][section] or active_theme.normal[section]
+    local cl = color
-    local bg = get_default_component_color(color, options.color, default_color_table, 'bg')
+    if type(color) == 'function' then
-    local fg = get_default_component_color(color, options.color, default_color_table, 'fg')
+      cl = color { section = section } or {}
-    -- Check if it's same as normal mode if it is no need to create aditional highlight
-    if mode ~= 'normal' then
-      if bg ~= normal_hl.bg or fg ~= normal_hl.fg then
-        M.highlight(table.concat(highlight_group_name, '_'), fg, bg, color.gui, nil)
     end
+    if type(cl) == 'string' then
+      cl = { link = cl }
     else
-      normal_hl = { bg = bg, fg = fg }
+      cl = get_default_component_color(hl_name, mode, section, cl, options)
-      M.highlight(table.concat(highlight_group_name, '_'), fg, bg, color.gui, nil)
     end
+    M.highlight(hl_name, cl.fg, cl.bg, cl.gui, cl.link)
   end
-  return options.self.section .. '_' .. highlight_tag
+  return {
+    name = table.concat({ 'lualine', section, highlight_tag }, '_'),
+    fn = type(color) == 'function' and color,
+    no_mode = false,
+    link = false,
+    section = section,
+    options = options,
+    no_default = apply_no_default,
+  }
 end
 
 ---@description: retrieve highlight_groups for components
----@param highlight_name string highlight group name without mode
+---@param highlight table return value of create_component_highlight_group
 ---  return value of create_component_highlight_group is to be passed in
 ---  this parameter to receive highlight that was created
 ---@return string formatted highlight group name
-function M.component_format_highlight(highlight_name)
+function M.component_format_highlight(highlight, is_focused)
-  local highlight_group = highlight_name
+  if not highlight.fn then
-  if highlight_name:find('no_mode') == #highlight_name - #'no_mode' + 1 then
+    local highlight_group = highlight.name
+    if highlight.no_mode then
       return '%#' .. highlight_group .. '#'
     end
-  highlight_group = M.append_mode(highlight_group)
+    highlight_group = append_mode(highlight_group, is_focused)
-  if M.highlight_exists(highlight_group) then
     return '%#' .. highlight_group .. '#'
   else
-    return '%#' .. highlight_name .. '_normal#'
+    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)
+      return '%#' .. hl_name .. '#'
+    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
+        )
+      end
+      M.highlight(hl_name, color.fg, color.bg, color.gui, color.link)
+      return '%#' .. hl_name .. '#', color
+    end
   end
 end
 
 ---@description: retrieve highlight_groups for section
----@param highlight_group string highlight group name without mode
+---@param section string highlight group name without mode
 ---  return value of create_component_highlight_group is to be passed in
 ---  this parameter to receive highlight that was created
 ---@param is_focused boolean
 ---@return string formatted highlight group name
-function M.format_highlight(highlight_group, is_focused)
+function M.format_highlight(section, is_focused)
-  local highlight_name = M.append_mode(highlight_group, is_focused)
+  local mode = append_mode('', is_focused):sub(2)
-  if highlight_group > 'lualine_c' and not M.highlight_exists(highlight_name) then
+  local ret = ''
-    highlight_group = 'lualine_' .. section_highlight_map[highlight_group:match('lualine_(.)')]
+
-    highlight_name = M.append_mode(highlight_group, is_focused)
+  if theme_hls[mode] and theme_hls[mode][section] then
+    ret = M.component_format_highlight(theme_hls[mode][section], is_focused)
+  elseif theme_hls[mode] and section > 'c' and theme_hls[mode][section_highlight_map[section]] then
+    ret = M.component_format_highlight(theme_hls[mode][section_highlight_map[section]], is_focused)
+  elseif theme_hls['normal'] and theme_hls['normal'][section] then
+    ret = M.component_format_highlight(theme_hls['normal'][section], is_focused)
+  elseif theme_hls['normal'] and section > 'c' and theme_hls['normal'][section_highlight_map[section]] then
+    ret = M.component_format_highlight(theme_hls['normal'][section_highlight_map[section]], is_focused)
   end
-  if M.highlight_exists(highlight_name) then
+
-    return '%#' .. highlight_name .. '#'
+  return ret
-  end
-  return '%#' .. highlight_group .. '_normal#'
 end
 
 ---@description : Provides transitional highlights for section separators.
@@ -286,6 +461,8 @@ function M.get_transitional_highlights(left_hl, right_hl)
       return nil -- Separator won't be visible anyway
     end
     M.highlight(highlight_name, fg, bg, nil)
+    attach_hl(left_hl, highlight_name, 'bg', 'fg')
+    attach_hl(right_hl, highlight_name, 'bg', 'bg')
   end
   return '%#' .. highlight_name .. '#'
 end

lua/lualine/utils/loader.lua

@@ -91,7 +91,7 @@ component type '%s' isn't recognised. Check if spelling is correct.]],
 end
 
 --- Shows notice about invalid types passed as component
---- @param index number the index of component jn section table
+--- @param index number the index of component in section table
 --- @param component table containing component elements
 --- return bool whether check passed or not
 local function is_valid_component_type(index, component)
@@ -141,7 +141,7 @@ local function load_sections(sections, options)
       end
       if is_valid_component_type(index, component) then
         component.self = {}
-        component.self.section = section_name
+        component.self.section = section_name:match('lualine_(.*)')
         -- apply default args
         component = vim.tbl_extend('keep', component, options)
         section[index] = component_loader(component)

lua/lualine/utils/section.lua

@@ -15,7 +15,7 @@ local highlight = require('lualine.highlight')
 ---@return string formated string for a section
 --TODO Clean this up this does lots of messy stuff.
 function M.draw_section(section, section_name, is_focused)
-  local highlight_name = highlight.format_highlight('lualine_' .. section_name, is_focused)
+  local highlight_name = highlight.format_highlight(section_name, is_focused)
 
   local status = {}
   for _, component in pairs(section) do
@@ -26,6 +26,8 @@ function M.draw_section(section, section_name, is_focused)
     table.insert(status, component:draw(highlight_name, is_focused))
   end
 
+  local section_color = utils.extract_highlight_colors(string.match(highlight_name, '%%#(.*)#'))
+
   -- Flags required for knowing when to remove component separator
   local strip_next_component = false
   local last_component_found = false
@@ -60,8 +62,18 @@ function M.draw_section(section, section_name, is_focused)
     end
     -- Remove component separator when color option is used to color background
     if
-      (type(section[component_no].options.color) == 'table' and section[component_no].options.color.bg)
+      (
+        type(section[component_no].options.color) == 'table'
+        and section[component_no].options.color.bg
+        and section[component_no].options.color.bg ~= section_color.bg
+      )
       or type(section[component_no].options.color) == 'string'
+      or (
+        type(section[component_no].options.color) == 'function'
+        and section[component_no].color_fn_cache
+        and section[component_no].color_fn_cache.bg
+        and section[component_no].color_fn_cache.bg ~= section_color.bg
+      )
     then
       strip_next_component = true
       status[component_no] = section[component_no]:strip_separator()

lua/lualine/utils/utils.lua

@@ -9,10 +9,12 @@ local M = {}
 ---@return table|string returns #rrggbb formated color when scope is specified
 ----                       or comolete color table when scope isn't specified
 function M.extract_highlight_colors(color_group, scope)
+  local color = require('lualine.highlight').get_lualine_hl(color_group)
+  if not color then
     if vim.fn.hlexists(color_group) == 0 then
       return nil
     end
-  local color = vim.api.nvim_get_hl_by_name(color_group, true)
+    color = vim.api.nvim_get_hl_by_name(color_group, true)
     if color.background ~= nil then
       color.bg = string.format('#%06x', color.background)
       color.background = nil
@@ -21,6 +23,7 @@ function M.extract_highlight_colors(color_group, scope)
       color.fg = string.format('#%06x', color.foreground)
       color.foreground = nil
     end
+  end
   if scope then
     return color[scope]
   end

lua/tests/helpers.lua

@@ -29,10 +29,10 @@ function M.init_component(component, opts)
 end
 
 -- Checks ouput of a component
-M.assert_component = function(component, opts, result)
+M.assert_component = function(component, opts, result, is_active)
   local comp = M.init_component(component, opts)
   -- for testing global options
-  eq(result, comp:draw(opts.hl))
+  eq(result, comp:draw(opts.hl, is_active or true))
 end
 
 function M.assert_component_instence(comp, result)
@@ -49,7 +49,7 @@ M.build_component_opts = function(opts)
     end
   end
   if not opts.self then
-    opts.self = { section = 'lualine_c' }
+    opts.self = { section = 'c' }
   end
   if not opts.theme then
     opts.theme = 'gruvbox'

lua/tests/spec/component_spec.lua

@@ -15,7 +15,7 @@ describe('Component:', function()
     local comp = require('lualine.components.special.function_component')(opts)
     -- correct for lualine_c
     eq('', comp.options.separator)
-    local opts2 = build_component_opts { self = { section = 'lualine_y' } }
+    local opts2 = build_component_opts { self = { section = 'y' } }
     local comp2 = require('lualine.components.special.function_component')(opts2)
     -- correct for lualine_u
     eq('', comp2.options.separator)
@@ -40,7 +40,12 @@ describe('Component:', function()
     -- color highlight wan't in options when create_comp_hl was
     -- called so remove it before assert
     comp1.options.color_highlight = nil
-    assert.stub(hl.create_component_highlight_group).was_called_with(color, comp1.options.component_name, comp1.options)
+    assert.stub(hl.create_component_highlight_group).was_called_with(
+      color,
+      comp1.options.component_name,
+      comp1.options,
+      false
+    )
     hl.create_component_highlight_group:revert()
     color = 'MyHl'
     local opts2 = build_component_opts { color = color }
@@ -51,7 +56,12 @@ describe('Component:', function()
     -- color highlight wan't in options when create_comp_hl was
     -- called so remove it before assert
     comp2.options.color_highlight = nil
-    assert.stub(hl.create_component_highlight_group).was_called_with(color, comp2.options.component_name, comp2.options)
+    assert.stub(hl.create_component_highlight_group).was_called_with(
+      color,
+      comp2.options.component_name,
+      comp2.options,
+      false
+    )
     hl.create_component_highlight_group:revert()
   end)
 
@@ -186,7 +196,7 @@ describe('Component:', function()
         color = 'MyHl',
       }
       local comp = require('lualine.components.special.function_component')(opts)
-      local custom_link_hl_name = 'lualine_' .. comp.options.component_name .. '_no_mode'
+      local custom_link_hl_name = 'lualine_c_' .. comp.options.component_name
       eq('%#' .. custom_link_hl_name .. '#test', comp:draw(opts.hl))
       local opts2 = build_component_opts {
         component_separators = { left = '', right = '' },
@@ -280,26 +290,36 @@ describe('Filetype component', function()
         return '*', 'test_highlight_group'
       end,
     }
-
+    vim.g.actual_curwin = tostring(vim.api.nvim_get_current_win())
     local hl = require('lualine.highlight')
     local utils = require('lualine.utils.utils')
     stub(hl, 'create_component_highlight_group')
+    stub(hl, 'format_highlight')
     stub(utils, 'extract_highlight_colors')
-    hl.create_component_highlight_group.returns('MyCompHl')
+    hl.create_component_highlight_group.returns { name = 'MyCompHl', no_mode = false, section = 'a' }
+    hl.format_highlight.returns('%#lualine_c_normal#')
     utils.extract_highlight_colors.returns('#000')
 
     local opts = build_component_opts {
       component_separators = { left = '', right = '' },
+      hl = '%#lualine_c_normal#',
       padding = 0,
       colored = true,
       icon_only = false,
     }
-    assert_component('filetype', opts, '%#MyCompHl_normal#*%#lualine_c_normal# lua')
+    assert_component('filetype', opts, '%#MyCompHl_normal#*%#lualine_c_normal# lua%#lualine_c_normal#')
     assert.stub(utils.extract_highlight_colors).was_called_with('test_highlight_group', 'fg')
-    assert.stub(hl.create_component_highlight_group).was_called_with({ fg = '#000' }, 'test_highlight_group', opts)
+    assert.stub(hl.create_component_highlight_group).was_called_with(
+      { fg = '#000' },
+      'test_highlight_group',
+      opts,
+      false
+    )
     hl.create_component_highlight_group:revert()
+    hl.format_highlight:revert()
     utils.extract_highlight_colors:revert()
     package.loaded['nvim-web-devicons'] = nil
+    vim.g.actual_curwin = nil
   end)
 
   it("Doesn't color when colored is false", function()

lua/tests/spec/utils_spec.lua

@@ -5,6 +5,7 @@ local helpers = require('tests.helpers')
 
 local eq = assert.are.same
 local build_component_opts = helpers.build_component_opts
+local stub = require('luassert.stub')
 
 describe('Utils', function()
   local utils = require('lualine.utils.utils')
@@ -55,6 +56,10 @@ describe('Cterm genarator', function()
 end)
 
 describe('Section genarator', function()
+  local hl = require('lualine.highlight')
+  stub(hl, 'format_highlight')
+  hl.format_highlight.returns('%#lualine_c_normal#')
+
   local sec = require('lualine.utils.section')
   it('can draw', function()
     local opts = build_component_opts { section_separators = { left = '', right = '' } }
@@ -62,10 +67,18 @@ describe('Section genarator', function()
       require('lualine.components.special.function_component')(opts),
       require('lualine.components.special.function_component')(opts),
     }
-    eq('%#lualine_MySection_normal# test %#lualine_MySection_normal# test ', sec.draw_section(section, 'MySection'))
+    eq('%#lualine_c_normal# test %#lualine_c_normal# test ', sec.draw_section(section, 'c', true))
+
+    hl.format_highlight:revert()
   end)
 
   it('can remove separators from component with custom colors', function()
+    stub(hl, 'format_highlight')
+    stub(hl, 'get_lualine_hl')
+    hl.format_highlight.returns('%#lualine_MySection_normal#')
+    hl.get_lualine_hl.returns { fg = '#000000', bg = '#ffffff' }
+
+    vim.g.actual_curwin = tostring(vim.api.nvim_get_current_win())
     local opts = build_component_opts { section_separators = { left = '', right = '' } }
     local opts_colored = build_component_opts { color = 'MyColor' }
     local opts_colored2 = build_component_opts {
@@ -82,20 +95,20 @@ describe('Section genarator', function()
       require('lualine.components.special.function_component')(opts_colored),
       require('lualine.components.special.function_component')(opts),
     }
-    local highlight_name2 = 'lualine_' .. section[2].options.component_name .. '_no_mode'
+    local highlight_name2 = 'lualine_c_' .. section[2].options.component_name
     -- Removes separator on string color
     eq(
       '%#lualine_MySection_normal# test %#' .. highlight_name2 .. '#' .. ' test %#lualine_MySection_normal# test ',
       sec.draw_section(section, 'MySection')
     )
-    section[2] = require('lua.lualine.components.special.function_component')(opts_colored2)
+    section[2] = require('lualine.components.special.function_component')(opts_colored2)
     local highlight_name = '%#lualine_c_' .. section[2].options.component_name .. '_normal#'
     -- Removes separator on color with bg
     eq(
       '%#lualine_MySection_normal# test ' .. highlight_name .. ' test %#lualine_MySection_normal# test ',
       sec.draw_section(section, 'MySection')
     )
-    section[2] = require('lua.lualine.components.special.function_component')(opts_colored3)
+    section[2] = require('lualine.components.special.function_component')(opts_colored3)
     highlight_name2 = '%#lualine_c_' .. section[2].options.component_name .. '_normal#'
     -- Doesn't remove separator on color without bg
     eq(
@@ -104,5 +117,9 @@ describe('Section genarator', function()
         .. ' test %#lualine_MySection_normal#%#lualine_MySection_normal# test ',
       sec.draw_section(section, 'MySection')
     )
+    vim.g.actual_curwin = nil
+
+    hl.format_highlight:revert()
+    hl.get_lualine_hl:revert()
   end)
 end)