[Interest] Slow touch event sample rate after 10.3.1 iOS sdk

Patrick Stinson patrickkidd at gmail.com
Sun Apr 23 22:35:22 CEST 2017

Has anyone else noticed that the sample rate for touch events has dropped to 800ms since the last iOS SDK update? I have tested with both Qt-5.8.0 and Qt-dev and it’s happening on my iPhone as well as iPad pro.

I read somewhere that you have to update the view in order to get the sample rate to increase back to the usual 60Hz. Maybe this is intended to save battery life? I’m not even sure if I’m right.

Also not sure how to make a workaround. This problem doesn’t occur for example when dragging a QGraphicsItem around, maybe because that uses mouse events? It does happen when I listen to QEvent::TouchMove, for example doing finger-based painting which now only creates broad, jagged lines with a 1.1Hz sampling frequency.

I hope a whole bunch of released Qt apps didn’t just break!

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