【界面UI】装备对比浮窗：属性差值的红绿提示

---属性差值的计算与呈现
local ATTR_NAMES = {
    atk = "攻击", magic = "魔法", defense = "防御",
    hp = "生命",敏捷 = "敏捷",
}

function Compare.build(newItem, equipped)
    local diff = {}
    for _, key in ipairs(Compare.order) do
        local nv = newItem[key] or 0
        local ov = equipped[key] or 0
        if nv ~= ov then
            diff[#diff + 1] = {
                name = ATTR_NAMES[key] or key,
                delta = nv - ov,
            }
        end
    end
    table.sort(diff, function(a, b)
        return math.abs(a.delta) > math.abs(b.delta)
    end)
    return diff
end

---浮窗的挂载：悬停新装备时展示
function Compare.attach(slotNode, newItem)
    GUI:addOnClickEvent(slotNode, function()
        local equipped = BagUI.equippedOf(newItem.slot)
        if not equipped then
            SL:ShowSystemTips("当前无同部位装备")
            return
        end
        local diff = Compare.build(newItem, equipped)
        Compare.render(slotNode, equipped, diff)
    end)
end

---浮窗的渲染：双方名字与差值列表
function Compare.render(anchor, equipped, diff)
    local win = GUI:Win_Create(Compare.layer, "cmp", 0, 0, 220, 60 + #diff * 18)
    GUI:Text_Create(win, "old", 10, 8, 12, "#CCCCCC",
        "当前：" .. equipped.name)
    GUI:Text_Create(win, "new", 10, 28, 12, "#FFFFFF",
        "新获：" .. anchor.item.name)
    for i, d in ipairs(diff) do
        local color = d.delta > 0 and "#66CC66" or "#FF6666"
        local sign = d.delta > 0 and "+" or ""
        GUI:Text_Create(win, "d" .. i, 10, 48 + (i - 1) * 18,
            12, color, d.name .. " " .. sign .. d.delta)
    end
end