big ui moment

libs/flexlove/modules/ZIndex.lua

@@ -0,0 +1,35 @@
+---@class ZIndex
+local ZIndex = {}
+
+-- The effective z-index formula used for sorting is:
+--   rootZ * ROOT_WEIGHT + depth * DEPTH_WEIGHT + ownZ
+-- where rootZ is the z-index of the top-level ancestor, depth is the
+-- nesting level, and ownZ is the element's own z property.
+--
+-- Constraints enforced by these weights:
+--   |ownZ| <= MAX_Z   (must fit within DEPTH_WEIGHT digits)
+--   DEPTH_WEIGHT has enough room for depths well beyond any practical tree
+--   ROOT_WEIGHT has enough room for the rootZ without exceeding double-precision
+---
+---@type integer
+ZIndex.MIN_Z = -999
+---@type integer
+ZIndex.MAX_Z = 999
+---@type integer
+ZIndex.ROOT_WEIGHT = 10000000000
+---@type integer
+ZIndex.DEPTH_WEIGHT = 1000
+
+--- Clamp a z-index value to the valid range
+---@param value number
+---@return integer
+function ZIndex.clamp(value)
+  if value < ZIndex.MIN_Z then
+    return ZIndex.MIN_Z
+  elseif value > ZIndex.MAX_Z then
+    return ZIndex.MAX_Z
+  end
+  return value
+end
+
+return ZIndex