JScrollPane jitter during trackpad scrolling on MacOS/Aqua

[Sergey Bylokhov]

Hi, Eirik.
Did you create a bug at bugreport.java.com?

On 20/01/16 00:51, Eirik Bakke wrote:
>
> The "left-to-right is scroll up" feature is not how native apps work on
> MacOS, so my guess would be it could simply be disabled on MacOS.

I will take a look what we can do here. The problem only occurs if the 
second(horisontal) scrollbar is invisible.

>
> Note also that when scrolling with the trackpad in native MacOS apps,
> the OS makes a decision as to whether the scroll is vertical or
> horizontal, and then scrolls in that direction only. The cut-off is 45
> degrees, giving the user plenty of wiggle room. You can never scroll
> truly diagonally except by zig-zaging.

Not sure but personally I like the possibility to scroll diagonally w/o 
zig-zaging when two scrolls are visible.

>
> -- Eirik
>
> On 1/19/16, 11:50 AM, "Sergey Bylokhov" <Sergey.Bylokhov at oracle.com
> <mailto:Sergey.Bylokhov at oracle.com>> wrote:
>
>     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.
>


-- 
Best regards, Sergey.