feat(renderer): add NvimTreeOpenedFolderIcon NvimTreeClosedFolderIcon (#1768)

* feat: Add highlight group for opened folder

closes #1674

* docs: Add NvimTreeOpenedFolderIcon default

* feat: Add NvimTreeClosedFolderIcon highlight group

Defaults to NvimTreeFolderIcon

Author: baahrens

doc/nvim-tree-lua.txt

@@ -1414,6 +1414,8 @@ NvimTreeSymlink
 NvimTreeFolderName          (Directory)
 NvimTreeRootFolder
 NvimTreeFolderIcon
+NvimTreeOpenedFolderIcon    (NvimTreeFolderIcon)
+NvimTreeClosedFolderIcon    (NvimTreeFolderIcon)
 NvimTreeFileIcon
 NvimTreeEmptyFolderName     (Directory)
 NvimTreeOpenedFolderName    (Directory)

lua/nvim-tree/colors.lua

@@ -61,6 +61,8 @@ local function get_links()
     FolderName = "Directory",
     EmptyFolderName = "Directory",
     OpenedFolderName = "Directory",
+    OpenedFolderIcon = "NvimTreeFolderIcon",
+    ClosedFolderIcon = "NvimTreeFolderIcon",
     Normal = "Normal",
     NormalNC = "NvimTreeNormal",
     EndOfBuffer = "EndOfBuffer",

lua/nvim-tree/renderer/builder.lua

@@ -127,7 +127,11 @@ function Builder:_build_folder(node, padding, git_hl, git_icons_tbl)
   self:_insert_line(line)
 
   if #icon > 0 then
-    self:_insert_highlight("NvimTreeFolderIcon", offset, offset + #icon)
+    if node.open then
+      self:_insert_highlight("NvimTreeOpenedFolderIcon", offset, offset + #icon)
+    else
+      self:_insert_highlight("NvimTreeClosedFolderIcon", offset, offset + #icon)
+    end
   end
 
   local foldername_hl = "NvimTreeFolderName"