config.lua

local w, h = display.pixelWidth, display.pixelHeight

local modes = {1, 1.5, 2, 3, 4, 6, 8} -- Scaling factors to try
local contentW, contentH = 320, 480 -- Minimal size your content can fit in

-- Try each mode and find the best one
local _w, _h, _m = w, h, 1

for i = 1, #modes do
	local m = modes[i]
	local lw, lh = w / m, h / m
	
	if (lw < contentW or lh < contentH) then
		break
	else
		_w, _h, _m = lw, lh, m
	end
end
-- If scaling is not pixel perfect (between 1 and 2) - use letterbox
if (_m < 2) then
	local scale = math.max(contentW / w, contentH / h)
	_w, _h = w * scale, h * scale
end

application = {
	content = {
		width = _w,
		height = _h,
		scale = "letterbox",
		fps = 60,
		imageSuffix = {
			["@2x"] = 1.1,
			["@4x"] = 2.1
		}}}