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

Sergey Malenkov malenkov at gmail.com
Thu Sep 29 13:29:46 UTC 2016

The signature of the NSEvent constructor is changed.
It is called from AWTView.m (fixed) and CTrayIcon.m (!not fixed!)

Could you please support not only the phase start, but the phase end too?
It will be useful, when we decide to support precise scrolling in JScrollPane,
because we will be able to align precise wheel rotation to integer part.
So when an user stops scrolling we can align lines in a lists or trees.

>> 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.

Best regards,
Sergey A. Malenkov

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