perf: reduce renders, mutate state

Misc performance improvements (some inspired by
http://wiki.luajit.org/Numerical-Computing-Performance-Guide)

Major one is diffing the window configs before updating to avoid
unnecessary rendering.

Also switched to mutating existing state in spring rather than creating
a new table which reduces number of allocations (one per field window per
draw).

Should help #63 and potentially #72

lua/notify/animate/spring.lua

@@ -7,24 +7,17 @@ local cos = math.cos
 local sqrt = math.sqrt
 
 ---@class SpringState
----@field position number | string
----@field goal number | string
+---@field position number
 ---@field velocity number | nil
----@field damping number
----@field frequency number
 
 ---@param dt number @Step in time
 ---@param state SpringState
----@return SpringState
-return function(dt, state, settings)
-  local damping = settings.damping
-  local angular_freq = settings.frequency * 2 * pi
+return function(dt, goal, state, frequency, damping)
+  local angular_freq = frequency * 2 * pi
 
-  local cur_os = state.position
   local cur_vel = state.velocity or 0
-  local goal = state.goal
 
-  local offset = cur_os - goal
+  local offset = state.position - goal
   local decay = exp(-dt * damping * angular_freq)
 
   local new_pos
@@ -43,7 +36,7 @@ return function(dt, state, settings)
         * decay
       + goal
     new_vel = (i * c * cur_vel - j * (cur_vel * damping + angular_freq * offset)) * decay / c
-  elseif damping > 1 then -- overdamped
+  else -- overdamped
     local c = sqrt(damping * damping - 1)
 
     local r1 = -angular_freq * (damping - c)
@@ -58,11 +51,6 @@ return function(dt, state, settings)
     new_pos = e1 + e2 + goal
     new_pos = r1 * e1 + r2 * e2
   end
-  return {
-    position = new_pos,
-    velocity = new_vel,
-    goal = goal,
-    damping = state.damping,
-    frequency = state.frequency,
-  }
+  state.position = new_pos
+  state.velocity = new_vel
 end

lua/notify/util/init.lua

@@ -77,19 +77,13 @@ function M.get_win_config(win)
   if not success or not conf.row then
     return false, conf
   end
-  for _, field in pairs({ "row", "col" }) do
-    if type(conf[field]) == "table" then
-      conf[field] = conf[field][false]
-    end
+  if type(conf.row) == "table" then
+    conf.row = conf.row[false]
   end
-  return success, conf
-end
-
-function M.set_win_config(win, conf)
-  for _, field in pairs({ "height", "width" }) do
-    conf[field] = math.max(M.round(conf[field]), 1)
+  if type(conf.col) == "table" then
+    conf.col = conf.col[false]
   end
-  return (pcall(vim.api.nvim_win_set_config, win, conf))
+  return success, conf
 end
 
 function M.open_win(notif_buf, enter, opts)
@@ -103,11 +97,7 @@ function M.open_win(notif_buf, enter, opts)
     "&winhl",
     "Normal:" .. notif_buf.highlights.body .. ",FloatBorder:" .. notif_buf.highlights.border
   )
-  vim.fn.setwinvar(
-    win,
-    "&wrap",
-    0
-  )
+  vim.fn.setwinvar(win, "&wrap", 0)
   return win
 end
 
@@ -129,52 +119,6 @@ function M.numbers_to_rgb(colours)
   return colour
 end
 
-function M.deep_equal(t1, t2, ignore_mt)
-  local ty1 = type(t1)
-  local ty2 = type(t2)
-
-  if ty1 ~= ty2 then
-    return false
-  end
-  if ty1 ~= "table" then
-    return t1 == t2
-  end
-
-  local mt = getmetatable(t1)
-  if not ignore_mt and mt and mt.__eq then
-    return t1 == t2
-  end
-
-  local checked
-
-  for k1, v1 in pairs(t1) do
-    local v2 = t2[k1]
-    checked[k1] = true
-    if v2 == nil or not M.deep_equal(v1, v2, ignore_mt) then
-      return false
-    end
-  end
-
-  for k2, _ in pairs(t2) do
-    if not checked[k2] then
-      return false
-    end
-  end
-  return true
-end
-
-function M.update_configs(updates)
-  for win, win_updates in pairs(updates) do
-    local exists, conf = M.get_win_config(win)
-    if exists then
-      for _, field in pairs({ "row", "col", "height", "width" }) do
-        conf[field] = win_updates[field] or conf[field]
-      end
-      M.set_win_config(win, conf)
-    end
-  end
-end
-
 function M.highlight(name, fields)
   local fields_string = ""
   for field, value in pairs(fields) do

lua/notify/windows/init.lua

@@ -2,6 +2,8 @@ local config = require("notify.config")
 local api = vim.api
 local animate = require("notify.animate")
 local util = require("notify.util")
+local round = util.round
+local max = math.max
 
 ---@class WindowAnimator
 ---@field win_states table<number, table<string, SpringState>>
@@ -57,27 +59,28 @@ function WindowAnimator:push_pending(queue)
     win_opts.noautocmd = true
     local win = util.open_win(notif_buf, false, win_opts)
     self.win_stages[win] = 2
+    self.win_states[win] = {}
     self.notif_bufs[win] = notif_buf
     notif_buf:open(win)
     queue:pop()
   end
 end
 
 function WindowAnimator:advance_stages(goals)
-  local default_complete = function(goal, position)
-    return goal == util.round(position, 2)
-  end
   for win, _ in pairs(self.win_stages) do
     local win_goals = goals[win]
     local complete = true
-    for field, state in pairs(self.win_states[win] or {}) do
-      if win_goals[field].complete then
-        complete = win_goals[field].complete(state.position)
-      else
-        complete = default_complete(state.goal, state.position)
-      end
-      if not complete then
-        break
+    local win_state = self.win_states[win]
+    for field, goal in pairs(win_goals) do
+      if field ~= "time" then
+        if goal.complete then
+          complete = goal.complete(win_state[field].position)
+        else
+          complete = goal[1] == round(win_state[field].position, 2)
+        end
+        if not complete then
+          break
+        end
       end
     end
     if complete and not win_goals.time then
@@ -121,8 +124,6 @@ function WindowAnimator:remove_win(win)
 end
 
 function WindowAnimator:update_states(time, goals)
-  local updated_states = {}
-
   for win, win_goals in pairs(goals) do
     if win_goals.time and not self.timed[win] then
       local buf_time = self.notif_bufs[win]:timeout()
@@ -143,48 +144,53 @@ function WindowAnimator:update_states(time, goals)
       end
     end
 
-    updated_states[win] = self:stage_state(win, win_goals, time)
+    self:update_win_state(win, win_goals, time)
   end
-
-  self.win_states = updated_states
 end
 
-function WindowAnimator:stage_state(win, goals, time)
-  local cur_state = self.win_states[win] or {}
+function WindowAnimator:update_win_state(win, goals, time)
+  local cur_state = self.win_states[win]
 
-  local exists, win_conf = util.get_win_config(win)
-  if not exists then
-    self:remove_win(win)
-    return
+  local win_configs = {}
+
+  local function win_conf(win_)
+    if win_configs[win_] then
+      return win_configs[win_]
+    end
+    local exists, conf = util.get_win_config(win_)
+    if not exists then
+      self:remove_win(win_)
+      return
+    end
+    win_configs[win_] = conf
+    return conf
   end
 
-  local new_state = {}
   for field, goal in pairs(goals) do
     if field ~= "time" then
       local goal_type = type(goal)
       -- Handle spring goal
       if goal_type == "table" and goal[1] then
-        local init_state = (
-            field == "opacity" and self.notif_bufs[win].highlights:get_opacity() or win_conf[field]
-          )
-        local cur_field_state = cur_state[field] or {}
-        new_state[field] = animate.spring(time, {
-          position = cur_field_state.position or init_state,
-          velocity = cur_field_state.velocity,
-          goal = goal[1],
-        }, {
-          frequency = goal.frequency or 1,
-          damping = goal.damping or 1,
-        })
+        if not cur_state[field] then
+          if field == "opacity" then
+            cur_state[field] = { position = self.notif_bufs[win].highlights:get_opacity() }
+          else
+            local conf = win_conf(win)
+            if not conf then
+              return
+            end
+            cur_state[field] = { position = conf[field] }
+          end
+        end
+        animate.spring(time, goal[1], cur_state[field], goal.frequency or 1, goal.damping or 1)
         --- Directly move goal
       elseif goal_type ~= "table" then
-        new_state[field] = { position = goal }
+        cur_state[field] = { position = goal }
       else
         print("nvim-notify: Invalid stage goal: " .. vim.inspect(goal))
       end
     end
   end
-  return new_state
 end
 
 function WindowAnimator:get_goals()
@@ -213,22 +219,40 @@ function WindowAnimator._get_dimensions(notif_buf)
 end
 
 function WindowAnimator:apply_updates()
-  local updates = {}
+  local updated = false
   for win, states in pairs(self.win_states) do
-    updates[win] = {}
-    for field, state in pairs(states) do
-      if field == "opacity" then
-        self.notif_bufs[win].highlights:set_opacity(state.position)
-      else
-        updates[win][field] = state.position
+    updated = true
+    if states.opacity then
+      self.notif_bufs[win].highlights:set_opacity(states.opacity.position)
+    end
+    local exists, conf = util.get_win_config(win)
+    if not exists then
+      self:remove_win(win)
+    else
+      local win_updated = false
+      local function set_field(field, round_field)
+        if not states[field] then
+          return
+        end
+        local new_value = round_field and max(round(states[field].position), 1)
+          or states[field].position
+        if new_value == conf[field] then
+          return
+        end
+        win_updated = true
+        conf[field] = new_value
+      end
+      set_field("row", false)
+      set_field("col", false)
+      set_field("width", true)
+      set_field("height", true)
+
+      if win_updated then
+        api.nvim_win_set_config(win, conf)
       end
     end
   end
-  if vim.tbl_isempty(updates) then
-    return false
-  end
-  util.update_configs(updates)
-  return true
+  return updated
 end
 
 ---@return WindowAnimator