RFR: 8273355: Lanai: Flickering on tooltip appearance IntelliJ IDEA 2021.2.1

[Alexey Ushakov]

On Sun, 12 Sep 2021 21:50:54 GMT, Sergey Bylokhov <serb at openjdk.org> wrote:

> > The scenario from RenderPerf differs from this issue. In RenderPerf we create a window and then perform rendering of multiple primitives. Whereas in this bug we create a new window each time and see the flickering.
> 
> But the code path is the same, we create a window and try to clear/fill it by the background as fast as possible. And the flickering occurs because the time between g.fillRect()->actual image on the screen is too big.

I suppose that the problem is not because the lag is too big - in a normal state (when the window is created) we don't need to flush the layer content faster than DisplayLink provides. The problem happens in the transition state during creating the window. So, long term solution would be an immediate rendering to the window surface for the first time (as you previously suggested). In the short term, we can just provide the correct background.

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PR: https://git.openjdk.java.net/jdk/pull/5373