Animations: absolute alpha and setToFinalAlpha, combat feedback text fades on an animation group

Combat feedback text fades in, holds and fades out on an animation group
on the font string instead of an OnUpdate helper frame. Autohide and the
XP/rep bars keep the faded-out alpha with SetToFinalAlpha instead of an
OnFinished that sets it. Pulses, the mail blink, the holiday dusk and the
candle flicker give their alphas with SetFromAlpha / SetToAlpha.

api/unitframes.lua

@@ -781,7 +781,6 @@ function pfUI.uf:UpdateConfig()
   if f.config.hitindicator == "1" then
     f.feedbackText:SetFont(pfUI.media[f.config.hitindicatorfont], f.config.hitindicatorsize, "OUTLINE")
     f.feedbackFontHeight = f.config.hitindicatorsize
-    f.feedbackStartTime = GetTime()
     if f.config.portrait == "bar" or f.config.portrait == "off" then
       f.feedbackText:SetParent(f.texts)
       f.feedbackText:ClearAllPoints()
@@ -793,8 +792,8 @@ function pfUI.uf:UpdateConfig()
     end
     f.combatfeedback = true
   else
+    f.feedback:Stop()
     f.feedbackText:Hide()
-    f.feedback:Hide()
     f.combatfeedback = nil
   end
 
@@ -1177,8 +1176,10 @@ function pfUI.uf.OnEvent()
     elseif event == "UNIT_CONNECTION" then
       pfUI.uf:QueueUpdate(this, "full")
     elseif event == "UNIT_COMBAT" then
+      -- every hit starts the fade over
+      this.feedback:Stop()
       CombatFeedback_OnCombatEvent(arg2, arg3, arg4, arg5)
-      this.feedback:Show()
+      this.feedback:Play()
     elseif event == "INCOMING_RESURRECT_CHANGED" then
       pfUI.uf:QueueUpdate(this, "indicators")
     else
@@ -1317,25 +1318,6 @@ C_Timer.NewTicker(.5, function()
   end
 end)
 
--- Fade the combat feedback text in, hold it, and fade it out -- the timing of
--- CombatFeedback_OnUpdate. Runs on a child frame shown only while the text is.
-local function FeedbackOnUpdate()
-  local frame = this:GetParent()
-  local text = frame.feedbackText
-  local elapsed = GetTime() - frame.feedbackStartTime
-  local fadein, hold = COMBATFEEDBACK_FADEINTIME, COMBATFEEDBACK_HOLDTIME
-  if elapsed < fadein then
-    text:SetAlpha(elapsed / fadein)
-  elseif elapsed < fadein + hold then
-    text:SetAlpha(1)
-  elseif elapsed < fadein + hold + COMBATFEEDBACK_FADEOUTTIME then
-    text:SetAlpha(1 - (elapsed - hold - fadein) / COMBATFEEDBACK_FADEOUTTIME)
-  else
-    text:Hide()
-    this:Hide()
-  end
-end
-
 -- The unit events whose arg1 is the frame's OWN unit -- everything the OnEvent
 -- routes through its "UNIT_XXX Events" branch. These are not registered here:
 -- UpdateVisibility owns them, because it owns the frame's unit (below).
@@ -1592,11 +1574,11 @@ function pfUI.uf:CreateUnitFrame(unit, id, config, tick)
   f.glow = CreateFrame("Frame", nil, f)
   -- Pulse between .8 and .4 for good. The group only advances while the glow
   -- is shown, so a hidden glow costs nothing.
-  f.glow:SetAlpha(.8)
   f.glow.pulse = f.glow:CreateAnimationGroup()
   f.glow.pulse:SetLooping("BOUNCE")
   local fade = f.glow.pulse:CreateAnimation("Alpha")
-  fade:SetChange(-.4)
+  fade:SetFromAlpha(.8)
+  fade:SetToAlpha(.4)
   fade:SetDuration(1.3)
   fade:SetSmoothing("IN_OUT")
   f.glow.pulse:Play()
@@ -1654,9 +1636,21 @@ function pfUI.uf:CreateUnitFrame(unit, id, config, tick)
   f.portrait.model = CreateFrame("PlayerModel", "pfPortraitModel" .. f.label .. f.id, f.portrait)
   f.portrait.model.next = CreateFrame("PlayerModel", nil, nil)
   f.feedbackText = f:CreateFontString("pfHitIndicator" .. f.label .. f.id, "OVERLAY", "NumberFontNormalHuge")
-  f.feedback = CreateFrame("Frame", nil, f)
-  f.feedback:Hide()
-  f.feedback:SetScript("OnUpdate", FeedbackOnUpdate)
+
+  -- Fade the combat feedback text in, hold it, and fade it out -- the timing
+  -- of CombatFeedback_OnUpdate -- then hide it.
+  f.feedback = f.feedbackText:CreateAnimationGroup()
+  local fadein = f.feedback:CreateAnimation("Alpha")
+  fadein:SetOrder(1)
+  fadein:SetDuration(COMBATFEEDBACK_FADEINTIME)
+  fadein:SetToAlpha(1)
+  local fadeout = f.feedback:CreateAnimation("Alpha")
+  fadeout:SetOrder(2)
+  fadeout:SetStartDelay(COMBATFEEDBACK_HOLDTIME)
+  fadeout:SetDuration(COMBATFEEDBACK_FADEOUTTIME)
+  fadeout:SetFromAlpha(1)
+  fadeout:SetToAlpha(0)
+  f.feedback:SetScript("OnFinished", function() f.feedbackText:Hide() end)
 
   if f.label == "raid" and mod(f.id, 5) == 1 then
     local group = math.ceil(f.id/5)