JScrollPane jitter during trackpad scrolling on MacOS/Aqua

[Eirik Bakke]

Hi again, Sergey.

I just filed a bug report and got review ID JI-9028846. Thanks for your
help!

-- Eirik

On 1/20/16, 9:13 PM, "Sergey Bylokhov" <Sergey.Bylokhov at oracle.com> wrote:

>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.