On Wednesday, February 25, 2015 at 2:40:12 AM UTC-5, Paul Rouget wrote: > When is onscroll called if apzc is enabled?
The scroll event is fired every time APZC sends a repaint request to the main thread (which is what changes the scroll position). > How often? Generally this is controlled by the apz.pan_repaint_interval during panning (while the finger is down) and the apz.fling_repaint_interval during flinging (residual movement after the finger has been lifted). However we can also request repaints at other times for various reasons, and there is some code that prevents multiple repaint requests from being inflight simultaneously. Note that since the scroll event is dispatched on the main thread, any blocking main-thread operations will also impact this. So there isn't a definite answer to this but if you reduce apz.pan_repaint_interval and apz.fling_repaint_interval to around 16 that's about as fast as it's going to get. > When is the first scroll event fired? Should be apz.pan_repaint_interval milliseconds after the scroll starts. > Will using onscroll prevent apzc to work properly? Using onscroll doesn't slow down the APZ like touch listeners do, but if you're doing a lot of stuff in that handler it may cause the main thread to be more busy which can increase the risk of checkerboarding. Short-running listeners should have negligible impact. Cheers, kats _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
