【界面UI】安全区边界警示：越界提示的可视化设计细节

local function refreshBoundary(px, py, zone)
    local dist = math.min(px - zone.x1, zone.x2 - px, py - zone.y1, zone.y2 - py)
    if dist >= 0 and dist <= 2 then
        GUI:setVisible(boundaryLine, true)
        GUI:setOpacity(boundaryLine, 200 - dist * 80)
    else
        GUI:setVisible(boundaryLine, false)
    end
end

local warned = false
local function onLeaveZone()
    if warned then return end
    warned = true
    SL:ShowSystemTips("已离开安全区，野外可能遭遇攻击！")
    SL:Schedule(function() warned = false end, 300)
end