About the "Deterministic of rendering"

[tiansh]

Current specification describe that "the position and order of each Bullet Chatting is fixed each time it is rendered". When "allowOverlap" is set to false. The position of each bullet chatting is relay on the previous chatting's. User agent have to calculate the position of all chatting's from the very beginning of the list for a certain chatting, which may cause performance issue. And if client try to insert a chatting before current timestamp, should the user agent repaint all chatting's currently shown to fit this change? As I know, There is not any website rendering chatting's like this currently. So, why this characteristics is listed?

[MagicJuly]

@tiansh Allowing the overlap of Bullet Chatting does bring more calculations. The algorithm used by bilibili is O(n^2), But this did not bring much consumption.
The timing of inserting Bullet Chatting is determined by developer, so <bulletchatlist> only cares about the insertion of <bulletchat>, and does not referring outer data list. this characteristics is listed to illustrate the fact that the Bullet Chatting is rendered with fixed rules and is not random.

[tiansh]

I understood that the delay describe the duration from "<bulletchatlist> start playing" to "certain <bulletchat> appearing". But after reading your response, I understood that the delay describe the time from "<bulletchat> element been inserted to dom". This should be clarified in the specification, imo.

[DIYgod]

@tiansh delay is not exact the time from <bulletchat> element been inserted to dom, this time also depends on state, so I think "defines when the Bullet Chatting animation begins" is a better description, just like animation-delay

[minhluuquang]

@MagicJuly Can I ask what is the algorithm bilibli using?