[RequestAnimationFrame] What about paint-callbacks finishing too late for display-refresh

• From: Jan Linnebank <jan@linnebank.nl>
• Date: Sat, 16 Jul 2011 04:51:02 +0200
• To: public-web-perf@w3.org
• Message-ID: <4E20FC96.6010709@linnebank.nl>

Regarding "Timing control for script-based animations, W3C Editor’s 
Draft 27 June 2011"

WHAT WITH PAINT-CALLBACKS FINISHING TOO LATE FOR SCHEDULED DISPLAY-REFRESH

To the editors,


What would happen when a user's frame-callback doesn't return in time 
for the frame to be actually displayed on it's scheduled display-refresh?

Will it just be displayed on a later display-refresh?

Will the user have access to the timestamp of that actual later 
display-refresh (perhaps as extra param in the next callback, e.g. 
'lastRefreshTime')?
Or will that timestamp simply be determinable by subtracting the 
refresh-interval from the timestamp of the next requestAnimationFrame 
callback?
(The latter two questions motivated again with regard to psychological 
reaction-time related experiments.)

Regards,

Jan Linnebank

at UvA NeuroTest B.V.

Received on Saturday, 16 July 2011 02:51:27 UTC