JScrollPane jitter during trackpad scrolling on MacOS/Aqua

[Sergey Bylokhov]

I am not sure that this is regression or a bug. In your case you scroll 
from left-down to right-up.
But left-to-right is a scroll to up, and down-to-up is a scroll to down. 
So you scroll in both direction at the same time.

On 19/01/16 19:18, Eirik Bakke wrote:
> Hi, macos-port-dev.
>
> Here's another bug report for Swing on Aqua/MacOS. In recent Java versions (6-12 months, not sure), trackpad scrolling in any JScrollPane has become extremely jittery, as demonstrated in the following video:
>
> https://vimeo.com/151843642
>
> The source code for the example app used can be found here: https://gist.github.com/eirikbakke/09a090ab8052d38c8c87
> Note that the "implements Scrollable" business is not necessary to trigger the bug, I just did it to set the getScrollableBlockIncrement to something higher than 1 so that you'd see the jitter clearly on a video.
>
> This happens in any app that uses a JScrollPane, including the NetBeans IDE's code editor and other scrollable panels, as well as in trivial apps like the linked example. The bug occurs consistently, with or without external monitors attached, at any resolution, and with or without simulated retina mode enabled. I'm on a 13-inch mid-2012 MacBook Air.
>
> If no one knows about an existing bug report about this, I'll submit it on http://bugreport.java.com<http://bugreport.java.com/> (I searched bugs.openjdk.java.net ).
>
> -- Eirik
>


-- 
Best regards, Sergey.