Re: [9] Review request for 8166591 [macos 10.12] Trackpad scrolling of text on OS X 10.12 Sierra is very fast (Trackpad, Retina only)

[Semyon Sadetsky]

Looks good.

--Semyon


On 9/28/2016 8:16 PM, Alexander Scherbatiy wrote:

Hello,

Could you review the fix:
  bug: https://bugs.openjdk.java.net/browse/JDK-8166591
  webrev: http://cr.openjdk.java.net/~alexsch/8166591/webrev.02

This issue has been risen and investigated by JetBrains team in the email:

http://mail.openjdk.java.net/pipermail/awt-dev/2016-September/011991.html

MacOS Sierra 10.12 sends many scroll events with values close to zero when the trackpad is used. The small scroll values are rounded to +1 or -1 so one line scroll would be possible. It leads that many small scroll events causes fast scrolling.

The proposed fix accumulates scroll values from the trackpad until they exceed some threshold values. Only after that MouseWheelEvent.wheelRotation value is set. Mouse wheel scroll events are handled as before, small values are just rounded to + or -1.

  Thanks,
  Alexandr.