CustomLayouts.lua

local AceGUI = LibStub("AceGUI-3.0")
local math_max = math.max
local function safelayoutcall(object, func, ...)
	layoutrecursionblock = true
	object[func](object, ...)
	layoutrecursionblock = nil
end
local xpcall = xpcall

local function errorhandler(err)
	return geterrorhandler()(err)
end

local function safecall(func, ...)
	if func then
		return xpcall(func, errorhandler, ...)
	end
end
AceGUI:RegisterLayout("CenteredFlow", function(content, children)
	if layoutrecursionblock then
		return
	end
	--used height so far
	local height = 0
	--width used in the current row
	local usedwidth = 0
	--height of the current row
	local rowheight = 0
	local rowoffset = 0

	local width = content.width or content:GetWidth() or 0

	--control at the start of the row
	local rowstart
	local rowstartoffset
	local isfullheight

	local frameoffset
	local lastframeoffset
	local oversize
	for i = 1, #children do
		local child = children[i]
		oversize = nil
		local frame = child.frame
		local frameheight = frame.height or frame:GetHeight() or 0
		local framewidth = frame.width or frame:GetWidth() or 0
		lastframeoffset = frameoffset
		-- HACK: Why did we set a frameoffset of (frameheight / 2) ?
		-- That was moving all widgets half the widgets size down, is that intended?
		-- Actually, it seems to be neccessary for many cases, we'll leave it in for now.
		-- If widgets seem to anchor weirdly with this, provide a valid alignoffset for them.
		-- TODO: Investigate moar!
		frameoffset = child.alignoffset or (frameheight / 2)

		if child.width == "relative" then
			framewidth = width * child.relWidth
		end

		frame:Show()
		frame:ClearAllPoints()
		if i == 1 then
			-- anchor the first control to the top left
			frame:SetPoint("TOPLEFT", content)
			rowheight = frameheight
			rowoffset = frameoffset
			rowstart = frame
			rowstartoffset = frameoffset
			usedwidth = framewidth
			if usedwidth > width then
				oversize = true
			end
		else
			-- if there isn't available width for the control start a new row
			-- if a control is "fill" it will be on a row of its own full width
			if usedwidth == 0 or (framewidth + usedwidth > width) or child.width == "fill" then
				if isfullheight then
					-- a previous row has already filled the entire height, there's nothing we can usefully do anymore
					-- (maybe error/warn about this?)
					break
				end
				--anchor the previous row, we will now know its height and offset
				rowstart:SetPoint("TOPLEFT", content, "TOPLEFT", 0, -(height + (rowoffset - rowstartoffset) + 3))
				height = height + rowheight + 3
				--save this as the rowstart so we can anchor it after the row is complete and we have the max height and offset of controls in it
				rowstart = frame
				rowstartoffset = frameoffset
				rowheight = frameheight
				rowoffset = frameoffset
				usedwidth = framewidth
				if usedwidth > width then
					oversize = true
				end
				-- put the control on the current row, adding it to the width and checking if the height needs to be increased
			else
				--handles cases where the new height is higher than either control because of the offsets
				--math.max(rowheight-rowoffset+frameoffset, frameheight-frameoffset+rowoffset)

				--offset is always the larger of the two offsets
				rowoffset = math_max(rowoffset, frameoffset)
				rowheight = math_max(rowheight, rowoffset + (frameheight / 2))

				frame:SetPoint("TOPLEFT", children[i - 1].frame, "TOPRIGHT", 0, frameoffset - lastframeoffset)
				usedwidth = framewidth + usedwidth
			end
		end

		if child.width == "fill" then
			safelayoutcall(child, "SetWidth", width)
			frame:SetPoint("RIGHT", content)

			usedwidth = 0
			rowstart = frame
			rowstartoffset = frameoffset

			if child.DoLayout then
				child:DoLayout()
			end
			rowheight = frame.height or frame:GetHeight() or 0
			rowoffset = child.alignoffset or (rowheight / 2)
			rowstartoffset = rowoffset
		elseif child.width == "relative" then
			safelayoutcall(child, "SetWidth", width * child.relWidth)

			if child.DoLayout then
				child:DoLayout()
			end
		elseif oversize then
			if width > 1 then
				frame:SetPoint("RIGHT", content)
			end
		end

		if child.height == "fill" then
			frame:SetPoint("BOTTOM", content)
			isfullheight = true
		end
	end

	--anchor the last row, if its full height needs a special case since  its height has just been changed by the anchor
	if isfullheight then
		rowstart:SetPoint("TOPLEFT", content, "TOPLEFT", 0, -height)
	elseif rowstart then
		local centered_offset = 180 - 180 / 9 * math.min(#children, 9)
		if #children == 1 then
			centered_offset = 0
		end
		rowstart:SetPoint("TOPLEFT", content, "TOPLEFT", centered_offset, -(height + (rowoffset - rowstartoffset) + 3))
	end

	height = height + rowheight + 3
	safecall(content.obj.LayoutFinished, content.obj, nil, height)
end)

AceGUI:RegisterLayout("ListTight", function(content, children)
	local height = 0
	local width = content.width or content:GetWidth() or 0
	for i = 1, #children do
		local child = children[i]

		local frame = child.frame
		frame:ClearAllPoints()
		frame:Show()
		if i == 1 then
			frame:SetPoint("TOPLEFT", content, 0, 20)
		else
			frame:SetPoint("TOPLEFT", children[i - 1].frame, "BOTTOMLEFT", 0, 23)
		end

		if child.width == "fill" then
			child:SetWidth(width)
			frame:SetPoint("RIGHT", content)

			if child.DoLayout then
				child:DoLayout()
			end
		elseif child.width == "relative" then
			child:SetWidth(width * child.relWidth)

			if child.DoLayout then
				child:DoLayout()
			end
		end

		height = height + (frame.height or frame:GetHeight() or 0)
	end
	safecall(content.obj.LayoutFinished, content.obj, nil, height)
end)