feat(render): add per-depth context highlight groups

README.md

@@ -130,6 +130,7 @@ Note: support for specific languages is strictly community maintained and can br
   - [ ] `blueprint`
   - [ ] `bp`
   - [ ] `brightscript`
+  - [ ] `c3`
   - [ ] `caddy`
   - [ ] `cairo`
   - [ ] `chatito`
@@ -190,6 +191,7 @@ Note: support for specific languages is strictly community maintained and can br
   - [ ] `gowork`
   - [ ] `gpg`
   - [ ] `gren`
+  - [ ] `groq`
   - [ ] `gstlaunch`
   - [ ] `hack`
   - [ ] `hare`
@@ -222,6 +224,7 @@ Note: support for specific languages is strictly community maintained and can br
   - [ ] `just`
   - [ ] `kcl`
   - [ ] `kconfig`
+  - [ ] `kitty`
   - [ ] `koto`
   - [ ] `kusto`
   - [ ] `lalrpop`
@@ -254,6 +257,7 @@ Note: support for specific languages is strictly community maintained and can br
   - [ ] `perl`
   - [ ] `phpdoc`
   - [ ] `pioasm`
+  - [ ] `pkl`
   - [ ] `po`
   - [ ] `pod`
   - [ ] `poe_filter`
@@ -285,6 +289,7 @@ Note: support for specific languages is strictly community maintained and can br
   - [ ] `rego`
   - [ ] `requirements`
   - [ ] `rescript`
+  - [ ] `rifleconf`
   - [ ] `rnoweb`
   - [ ] `robot`
   - [ ] `robots`
@@ -300,10 +305,12 @@ Note: support for specific languages is strictly community maintained and can br
   - [ ] `slint`
   - [ ] `smithy`
   - [ ] `snakemake`
+  - [ ] `snl`
   - [ ] `soql`
   - [ ] `sosl`
   - [ ] `sourcepawn`
   - [ ] `sparql`
+  - [ ] `sproto`
   - [ ] `sql`
   - [ ] `squirrel`
   - [ ] `ssh_config`
@@ -342,12 +349,14 @@ Note: support for specific languages is strictly community maintained and can br
   - [ ] `wgsl_bevy`
   - [ ] `wing`
   - [ ] `wit`
+  - [ ] `wxml`
   - [ ] `xcompose`
   - [ ] `xresources`
   - [ ] `yuck`
   - [ ] `zathurarc`
   - [ ] `ziggy`
   - [ ] `ziggy_schema`
+  - [ ] `zsh`
 
 </details>
 
@@ -384,6 +393,11 @@ require'treesitter-context'.setup{
 Use the highlight group `TreesitterContext` to change the colors of the
 context. Per default it links to `NormalFloat`.
 
+Use `TreesitterContextLevel1` ... `TreesitterContextLevel8` to apply
+depth-specific highlights for nested context rows. By default each level links
+to `TreesitterContext`. Nesting depths greater than 8 fall back to
+`TreesitterContext`.
+
 Use the highlight group `TreesitterContextLineNumber` to change the colors of the
 context line numbers if `line_numbers` is set. Per default it links to `LineNr`.
 

doc/nvim-treesitter-context.txt

@@ -75,6 +75,19 @@ HIGHLIGHTS                                  *nvim-treesitter-context-highlights*
 
     Colors of the context.
 
+`TreesitterContextLevel1`                               *hl-TreesitterContextLevel1*
+`TreesitterContextLevel2`                               *hl-TreesitterContextLevel2*
+`TreesitterContextLevel3`                               *hl-TreesitterContextLevel3*
+`TreesitterContextLevel4`                               *hl-TreesitterContextLevel4*
+`TreesitterContextLevel5`                               *hl-TreesitterContextLevel5*
+`TreesitterContextLevel6`                               *hl-TreesitterContextLevel6*
+`TreesitterContextLevel7`                               *hl-TreesitterContextLevel7*
+`TreesitterContextLevel8`                               *hl-TreesitterContextLevel8*
+    (default: links to `TreesitterContext`)
+
+    Depth-specific colors for nested context rows.
+    Depths greater than 8 fall back to `TreesitterContext`.
+
 `TreesitterContextLineNumber`                     *hl-TreesitterContextLineNumber*
     (default: links to `LineNr`)
 

lua/treesitter-context/render.lua

@@ -5,6 +5,7 @@ local util = require('treesitter-context.util')
 local config = require('treesitter-context.config')
 
 local ns = api.nvim_create_namespace('nvim-treesitter-context')
+local MAX_DEPTH_HIGHLIGHT_GROUPS = 8
 
 --- List of free buffers that can be reused.
 --- @type integer[]
@@ -211,6 +212,36 @@ local function highlight_contexts(bufnr, ctx_bufnr, contexts)
   end)
 end
 
+--- @param depth integer
+--- @return string
+local function get_depth_highlight_group(depth)
+  if depth <= MAX_DEPTH_HIGHLIGHT_GROUPS then
+    local level_hl = string.format('TreesitterContextLevel%d', depth)
+    if fn.hlexists(level_hl) == 1 then
+      return level_hl
+    end
+  end
+  return 'TreesitterContext'
+end
+
+--- @param bufnr integer
+--- @param contexts Range4[]
+local function highlight_depth_backgrounds(bufnr, contexts)
+  local offset = 0
+  for depth, context in ipairs(contexts) do
+    local hl_group = get_depth_highlight_group(depth)
+    local height = util.get_range_height(context)
+    for row = 0, height - 1 do
+      add_extmark(bufnr, offset + row, 0, {
+        end_row = offset + row + 1,
+        hl_group = hl_group,
+        hl_eol = true,
+      })
+    end
+    offset = offset + height
+  end
+end
+
 --- @class StatusLineHighlight
 --- @field group string
 --- @field groups? string[]
@@ -526,6 +557,7 @@ function M.open(winid, ctx_ranges, ctx_lines, force_hl_update)
     highlight_contexts(bufnr, ctx_bufnr, ctx_ranges)
     copy_extmarks(bufnr, ctx_bufnr, ctx_ranges)
     highlight_bottom(ctx_bufnr, win_height - 1, 'TreesitterContextBottom')
+    highlight_depth_backgrounds(ctx_bufnr, ctx_ranges)
     horizontal_scroll_contexts(winid, window_context.context_winid)
   end
 end

plugin/treesitter-context.lua

@@ -11,6 +11,12 @@ end, {
 })
 
 vim.api.nvim_set_hl(0, 'TreesitterContext', { link = 'NormalFloat', default = true })
+for i = 1, 8 do
+  vim.api.nvim_set_hl(0, string.format('TreesitterContextLevel%d', i), {
+    link = 'TreesitterContext',
+    default = true,
+  })
+end
 vim.api.nvim_set_hl(0, 'TreesitterContextLineNumber', { link = 'LineNr', default = true })
 vim.api.nvim_set_hl(0, 'TreesitterContextBottom', { link = 'NONE', default = true })
 vim.api.nvim_set_hl(

test/ts_context_spec.lua

@@ -8,6 +8,7 @@ local clear = helpers.clear
 local exec_lua = helpers.exec_lua
 local cmd = helpers.api.nvim_command
 local feed = helpers.feed
+local eq = helpers.eq
 
 describe('ts_context', function()
   local screen --- @type test.screen
@@ -105,6 +106,19 @@ describe('ts_context', function()
     })
   end)
 
+  it('defines per-depth context highlight groups', function()
+    local level_hls_exist = exec_lua([[
+      for i = 1, 8 do
+        if vim.fn.hlexists('TreesitterContextLevel' .. i) ~= 1 then
+          return false
+        end
+      end
+      return true
+    ]])
+
+    eq(true, level_hls_exist)
+  end)
+
   it('#627', function()
     exec_lua(install_langs, { 'vimdoc' })
     exec_lua(tc_helpers.setup, { multiwindow = true })