perf: mitigate the cursor flickering issue (#298)

Instead of letting the `:hl` to redraw all things globally, use the
`nvim__redraw` api to limit the redraw on the notification windows only.
The api also handles the case of redrawing during blocking events by
flushing the screen changes.

lua/notify/config/init.lua

@@ -71,8 +71,8 @@ local function validate_highlight(colour_or_group, needs_opacity)
     end
   end
   return function()
-    local group = vim.api.nvim_get_hl_by_name(colour_or_group, true)
-    if not group or not group.background then
+    local group = vim.api.nvim_get_hl(0, { name = colour_or_group, create = false, link = false })
+    if not group or not group.bg then
       if needs_opacity and not opacity_warned then
         opacity_warned = true
         vim.schedule(function()
@@ -88,14 +88,14 @@ Defaulting to #000000]], "warn", {
             title = "nvim-notify",
             on_open = function(win)
               local buf = vim.api.nvim_win_get_buf(win)
-              vim.api.nvim_buf_set_option(buf, "filetype", "markdown")
+              vim.api.nvim_set_option_value("filetype", "markdown", { buf = buf })
             end,
           })
         end)
       end
       return "#000000"
     end
-    return string.format("#%x", group.background)
+    return string.format("#%x", group.bg)
   end
 end
 

lua/notify/service/buffer/highlights.lua

@@ -11,24 +11,6 @@ local util = require("notify.util")
 ---@field _config table
 local NotifyBufHighlights = {}
 
-local function manual_get_hl(name)
-  local synID = vim.fn.synIDtrans(vim.fn.hlID(name))
-  local result = {
-    foreground = tonumber(vim.fn.synIDattr(synID, "fg"):gsub("#", ""), 16),
-    background = tonumber(vim.fn.synIDattr(synID, "bg"):gsub("#", ""), 16),
-  }
-  return result
-end
-
-local function get_hl(name)
-  local definition = vim.api.nvim_get_hl_by_name(name, true)
-  if definition[true] then
-    -- https://github.com/neovim/neovim/issues/18024
-    return manual_get_hl(name)
-  end
-  return definition
-end
-
 function NotifyBufHighlights:new(level, buffer, config)
   local function linked_group(section)
     local orig = "Notify" .. level .. section
@@ -38,8 +20,11 @@ function NotifyBufHighlights:new(level, buffer, config)
     local new = orig .. buffer
 
     vim.api.nvim_set_hl(0, new, { link = orig })
+    local hl = vim.api.nvim_get_hl(0, { name = orig, create = false, link = false })
+    -- Removes the unwanted 'default' key, as we will copy the table for updating the highlight later.
+    hl.default = nil
 
-    return new, get_hl(new)
+    return new, hl
   end
 
   local title, title_def = linked_group("Title")
@@ -83,7 +68,7 @@ function NotifyBufHighlights:_redefine_treesitter()
       return new
     end
     vim.api.nvim_set_hl(0, new, { link = orig })
-    self.groups[new] = get_hl(new)
+    self.groups[new] = vim.api.nvim_get_hl(0, { name = new, link = false })
     return new
   end
 
@@ -150,31 +135,30 @@ end
 function NotifyBufHighlights:set_opacity(alpha)
   if
     not self._treesitter_redefined
-    and vim.api.nvim_buf_get_option(self.buffer, "filetype") ~= "notify"
+    and vim.api.nvim_get_option_value("filetype", { buf = self.buffer }) ~= "notify"
   then
     self:_redefine_treesitter()
   end
   self.opacity = alpha
   local background = self._config.background_colour()
+  local updated = false
   for group, fields in pairs(self.groups) do
-    local updated_fields = {}
-    vim.api.nvim_set_hl(0, group, updated_fields)
-    local hl_string = ""
-    if fields.foreground then
-      hl_string = "guifg=#"
-        .. string.format("%06x", util.blend(fields.foreground, background, alpha / 100))
+    local fg = fields.fg
+    if fg then
+      fg = util.blend(fg, background, alpha / 100)
     end
-    if fields.background then
-      hl_string = hl_string
-        .. " guibg=#"
-        .. string.format("%06x", util.blend(fields.background, background, alpha / 100))
+    local bg = fields.bg
+    if bg then
+      bg = util.blend(bg, background, alpha / 100)
     end
 
-    if hl_string ~= "" then
-      -- Can't use nvim_set_hl https://github.com/neovim/neovim/issues/18160
-      vim.cmd("hi " .. group .. " " .. hl_string)
+    if fg ~= fields.fg or bg ~= fields.bg then
+      local hl = vim.tbl_extend('force', fields, { fg = fg, bg = bg })
+      vim.api.nvim_set_hl(0, group, hl)
+      updated = true
     end
   end
+  return updated
 end
 
 function NotifyBufHighlights:get_opacity()

lua/notify/service/init.lua

@@ -55,12 +55,7 @@ function NotificationService:push(notif)
   self._pending:push(notif_buf)
   if not self._running then
     self:_run()
-  else
-    -- Forces a render during blocking events
-    -- https://github.com/rcarriga/nvim-notify/issues/5
-    pcall(self._animator.render, self._animator, self._pending, 1 / self._fps)
   end
-  vim.cmd("redraw")
   return buf
 end
 

lua/notify/windows/init.lua

@@ -273,12 +273,11 @@ function WindowAnimator:_get_dimensions(notif_buf)
 end
 
 function WindowAnimator:_apply_win_state(win, win_state)
-  local win_updated = false
+  local hl_updated = false
   if win_state.opacity then
-    win_updated = true
     local notif_buf = self.notif_bufs[win]
     if notif_buf:is_valid() then
-      notif_buf.highlights:set_opacity(win_state.opacity.position)
+      hl_updated = notif_buf.highlights:set_opacity(win_state.opacity.position)
       vim.fn.setwinvar(
         win,
         "&winhl",
@@ -288,6 +287,7 @@ function WindowAnimator:_apply_win_state(win, win_state)
   end
   local exists, conf = util.get_win_config(win)
   local new_conf = {}
+  local win_updated = false
   if not exists then
     self:_remove_win(win)
   else
@@ -317,7 +317,9 @@ function WindowAnimator:_apply_win_state(win, win_state)
       api.nvim_win_set_config(win, new_conf)
     end
   end
-  return win_updated
+  -- The 'flush' key is set to enforce redrawing during blocking event.
+  vim.api.nvim__redraw({ win = win, valid = false, flush = true })
+  return hl_updated or win_updated
 end
 
 ---@return WindowAnimator