GetQuadrant

This is a user-defined function that you can copy and paste into your addon.

Quick lookup function to find what section of the screen the frame is in. Helpful for anchoring the frame or a tooltip relative to location. Uses the center of the frame, so it will return the quadrant that the majority of the frame lies in if the frame is positioned near the center of the screen. Returns back the quad, horizontal half ("LEFT" or "RIGHT") and the vertical half ("TOP" or "BOTTOM").

local function GetQuadrant(frame)
	local x,y = frame:GetCenter()
	local hhalf = (x > UIParent:GetWidth()/2) and "RIGHT" or "LEFT"
	local vhalf = (y > UIParent:GetHeight()/2) and "TOP" or "BOTTOM"
	return vhalf..hhalf, vhalf, hhalf
end