feat(hl): add 'TreesitterContextLineNumberBottom'

README.md

@@ -231,12 +231,21 @@ context line numbers if `line_numbers` is set. Per default it links to `LineNr`.
 Use the highlight group `TreesitterContextSeparator` to change the colors of the
 separator if `separator` is set. By default it links to `FloatBorder`.
 
-Use the highlight group `TreesitterContextBottom` to change the highlight of the
-last line of the context window. By default it links to `NONE`.
-However, you can use this to create a border by applying an underline highlight, e.g:
+Use the highlight groups `TreesitterContextBottom` and/or
+`TreesitterContextLineNumberBottom` to change the highlight of the last line of
+the context window. By default it links to `NONE`.
+However, you can use this to create a border by applying an underline highlight, e.g,
+for an underline across the screen:
 
 ```vim
 hi TreesitterContextBottom gui=underline guisp=Grey
+hi TreesitterContextLineNumberBottom gui=underline guisp=Grey
+```
+
+Or an underline below the line numbers only:
+
+```vim
+hi TreesitterContextLineNumberBottom gui=underline guisp=Grey
 ```
 
 ## Jumping to context (upwards)

lua/treesitter-context.lua

@@ -188,6 +188,7 @@ local function init()
 
   api.nvim_set_hl(0, 'TreesitterContext', { link = 'NormalFloat', default = true })
   api.nvim_set_hl(0, 'TreesitterContextLineNumber', { link = 'LineNr', default = true })
+  api.nvim_set_hl(0, 'TreesitterContextLineNumberBottom', { link = 'NONE', default = true })
   api.nvim_set_hl(0, 'TreesitterContextBottom', { link = 'NONE', default = true })
   api.nvim_set_hl(0, 'TreesitterContextSeparator', { link = 'FloatBorder', default = true })
 end

lua/treesitter-context/render.lua

@@ -232,6 +232,16 @@ local function highlight_bottom(bufnr, row)
   })
 end
 
+---@param bufnr integer
+---@param row integer
+local function highlight_lno_bottom(bufnr, row)
+  add_extmark(bufnr, row, 0, {
+    end_line = row + 1,
+    hl_group = 'TreesitterContextLineNumberBottom',
+    hl_eol = true,
+  })
+end
+
 --- @param buf integer
 --- @param text string[]
 --- @param highlights StatusLineHighlight[][]
@@ -293,7 +303,7 @@ local function render_lno(win, bufnr, contexts, gutter_width)
 
   set_lines(bufnr, lno_text)
   highlight_lno_str(bufnr, lno_text, lno_highlights)
-  highlight_bottom(bufnr, #lno_text - 1)
+  highlight_lno_bottom(bufnr, #lno_text - 1)
 end
 
 ---@param winid? integer