fix: Use decoration provider on_line callbacks for custom highlights to avoid flickering

Author: kristijanhusak

lua/orgmode/colors/custom_highlighter.lua

@@ -5,12 +5,9 @@ local MarkupHighlighter = nil
 local valid_bufnrs = {}
 
 ---@param bufnr number
----@param first_line number
----@param last_line number
-local function apply_highlights(bufnr, first_line, last_line, tick_changed)
-  local changed_lines = vim.api.nvim_buf_get_lines(bufnr, first_line, last_line, false)
-  HideLeadingStars.apply(namespace, bufnr, changed_lines, first_line, last_line)
-  MarkupHighlighter.apply(namespace, bufnr, changed_lines, first_line, last_line, tick_changed)
+local function apply_highlights(bufnr, line)
+  HideLeadingStars.apply(namespace, bufnr, line)
+  MarkupHighlighter.apply(namespace, bufnr, line)
 end
 
 local function setup()
@@ -25,18 +22,19 @@ local function setup()
   MarkupHighlighter.setup()
 
   vim.api.nvim_set_decoration_provider(namespace, {
-    on_win = function(_, _, bufnr, topline, botline)
-      local changedtick = vim.api.nvim_buf_get_var(bufnr, 'changedtick')
-      local tick_changed = not valid_bufnrs[bufnr] or valid_bufnrs[bufnr] ~= changedtick
-      if valid_bufnrs[bufnr] then
-        valid_bufnrs[bufnr] = changedtick
-        return apply_highlights(bufnr, topline, botline, tick_changed)
-      end
-      local ft = vim.api.nvim_buf_get_option(bufnr, 'filetype')
-      if ft == 'org' then
-        valid_bufnrs[bufnr] = changedtick
-        return apply_highlights(bufnr, topline, botline, tick_changed)
+    on_start = function(_, tick)
+      local bufnr = vim.api.nvim_get_current_buf()
+      if valid_bufnrs[bufnr] == tick or vim.bo[bufnr].filetype ~= 'org' then
+        return false
       end
+      valid_bufnrs[bufnr] = tick
+      return true
+    end,
+    on_win = function(_, _, bufnr)
+      return valid_bufnrs[bufnr] ~= nil and vim.bo[bufnr].filetype == 'org'
+    end,
+    on_line = function(_, _, bufnr, line)
+      return apply_highlights(bufnr, line)
     end,
   })
 end

lua/orgmode/colors/hide_leading_stars.lua

@@ -1,6 +1,10 @@
 local config = require('orgmode.config')
 
-local function update_line_highlight(namespace, bufnr, line_index, line)
+local function apply(namespace, bufnr, line_index)
+  if not config.org_hide_leading_stars then
+    return
+  end
+  local line = vim.api.nvim_buf_get_lines(bufnr, line_index, line_index + 1, false)[1]
   local stars = line:match('^%*+')
   if stars then
     vim.api.nvim_buf_set_extmark(bufnr, namespace, line_index, 0, {
@@ -12,16 +16,6 @@ local function update_line_highlight(namespace, bufnr, line_index, line)
   end
 end
 
-local function apply(namespace, bufnr, changed_lines, first_line, _)
-  if not config.org_hide_leading_stars then
-    return
-  end
-
-  for i, line in ipairs(changed_lines) do
-    update_line_highlight(namespace, bufnr, first_line + i - 1, line)
-  end
-end
-
 return {
   apply = apply,
 }

lua/orgmode/colors/markup_highlighter.lua

@@ -360,38 +360,8 @@ local function get_matches(bufnr, first_line, last_line)
   return result, link_result, latex_result
 end
 
-local function apply(namespace, bufnr, _, first_line, last_line, _)
-  -- Add some offset to make sure everything is covered
-  local line_ranges = { {} }
-  local current_line_range = 1
-  local last_valid_line = -1
-  for i = first_line, last_line do
-    if vim.fn.foldclosed(i + 1) == -1 then
-      -- Generate list of valid ranges
-      if last_valid_line < 0 or (i - 1) == last_valid_line then
-        table.insert(line_ranges[current_line_range], i)
-      else
-        current_line_range = current_line_range + 1
-        line_ranges[current_line_range] = { i }
-      end
-      last_valid_line = i
-    end
-  end
-
-  -- None of the lines are valid
-  if last_valid_line < 0 then
-    return
-  end
-  local ranges = {}
-  local link_ranges = {}
-  local latex_ranges = {}
-
-  for _, range in ipairs(line_ranges) do
-    local r, link_r, latex_r = get_matches(bufnr, math.max(1, range[1] - 5), range[#range] + 5)
-    utils.concat(ranges, r or {})
-    utils.concat(link_ranges, link_r or {})
-    utils.concat(latex_ranges, latex_r or {})
-  end
+local function apply(namespace, bufnr, line_index)
+  local ranges, link_ranges, latex_ranges = get_matches(bufnr, line_index, line_index + 1)
   local hide_markers = config.org_hide_emphasis_markers
 
   for _, range in ipairs(ranges) do