(UI 0.9.9)
UI\Draw\Stroke::__construct — 构造一个新的 Stroke
$cap = UI\Draw\Line\Cap::Flat,$join = UI\Draw\Line\Join::Miter,$thickness = 1,$miterLimit = 10将构造一个新的 Stroke
capUI\Draw\Line\Cap::Flat、UI\Draw\Line\Cap::Round 或 UI\Draw\Line\Cap::Square
joinUI\Draw\Line\Join::Miter、UI\Draw\Line\Join::Round 或 UI\Draw\Line\Join::Bevel
thickness笔划的粗细
miterLimit斜接限制(默认值对所有支持的平台都适用)