move fader code to helpers

core/frame.lua

@@ -377,37 +377,8 @@ function Frame:IsDockedFocus()
 	return false
 end
 
-
 --[[ Fading ]]--
 
-local function fader_Create(parent)
-	local fadeGroup = parent:CreateAnimationGroup()
-	fadeGroup:SetLooping('NONE')
-	fadeGroup:SetScript('OnFinished', function(self) parent:SetAlpha(self.targetAlpha) end)
-
-	local fade = fadeGroup:CreateAnimation('Alpha')
-	fade:SetSmoothing('IN_OUT')
-
-	return function(targetAlpha, duration)
-		if fadeGroup:IsPlaying() then
-			fadeGroup:Pause()
-		end
-
-		fadeGroup.targetAlpha = targetAlpha
-		fade:SetFromAlpha(parent:GetAlpha())
-		fade:SetToAlpha(targetAlpha)
-		fade:SetDuration(duration)
-		fadeGroup:Play()
-	end
-end
-
-local Fade = setmetatable({}, {__index = function(t, parent)
-	local fade = fader_Create(parent)
-	t[parent] = fade
-	return fade
-end})
-
-
 --fades the frame from the current opacity setting
 --to the expected setting
 function Frame:Fade()
@@ -419,14 +390,13 @@ function Frame:Fade()
 		return
 	end
 
-	Fade[self](self:GetExpectedAlpha(), 0.1)
+	Addon:Fade(self, self:GetExpectedAlpha(), 0.1)
 
 	if Addon:IsLinkedOpacityEnabled() then
 		self:ForDocked('Fade')
 	end
 end
 
-
 --[[ Visibility ]]--
 
 function Frame:ShowFrame()
@@ -874,4 +844,4 @@ end
 
 --[[ exports ]]--
 
-Addon.Frame = Frame
+Addon.Frame = Frame

core/helpers.lua

@@ -1,4 +1,4 @@
--- functions I call at least three times
+-- functions I call at least three(ish) times
 
 local AddonName = ...
 local Addon = _G[AddonName]
@@ -38,4 +38,46 @@ function Addon:CreateNameGenerator(prefix)
 		id = id + 1
 		return ('%s_%s_%d'):format(AddonName, prefix, id)
 	end
-end
+end
+
+-- A functional way to fade a frame from one opacity to another without constantly
+-- creating new animation groups for the frame
+do
+    local faders = {}
+
+    local function fader_OnFinished(self)
+        self:GetParent():SetAlpha(self.toAlpha)
+    end
+
+    local function fader_Create(parent)
+        local animation = parent:CreateAnimationGroup()
+        animation:SetLooping('NONE')
+        animation:SetScript('OnFinished', fader_OnFinished)
+
+        local fade = animation:CreateAnimation('Alpha')
+        fade:SetSmoothing('IN_OUT')
+
+        return function(toAlpha, duration)
+            if animation:IsPlaying() then
+                animation:Pause()
+            end
+
+            fade:SetFromAlpha(parent:GetAlpha())
+            fade:SetToAlpha(toAlpha)
+            fade:SetDuration(duration)
+
+            animation.toAlpha = toAlpha
+            animation:Play()
+        end
+    end
+
+    function Addon:Fade(frame, toAlpha, duration)
+        local fade = faders[frame]
+
+        if not fade then
+            fade = fader_Create(frame)
+        end
+
+        fade(toAlpha, duration)
+    end
+end