RFR: 8351867: No UI changes while iconified

[Martin Fox]

On Thu, 13 Mar 2025 10:36:40 GMT, John Hendrikx <jhendrikx at openjdk.org> wrote:

> Adds code to trigger a scene update when a Window is restored
> 
> This seems to solve https://bugs.openjdk.org/browse/JDK-8351867 and https://bugs.openjdk.org/browse/JDK-8146479

At least on the Mac there seems to be a timing issue. If the MIMIMIZE notification is sent before a scheduled draw occurs the drawing code will clear the scene dirty bit but then skip the actual drawing since the window is minimized. But I've also seen cases where drawing completes before MINIMIZE is sent.

When the window is restored notifyRepaint will be called on Windows and Linux which looks like it will call entireSceneNeedsRepaint to set the scene dirty bit (based on my reading of the code). Windows calls notifyRepaint whenever it gets a WM_PAINT event and I've verified that that happens after a window is restored. Looking at the sources it seems that Linux calls notifyRepaint _only_ when a window is restored (!)

Mac never calls notifyRepaint. There's code to call it but given where it's located I don't think it will ever be executed.

It would be nice to get some clarification on when notifyRepaint should be called and get the platforms to behave more consistently.

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PR Comment: https://git.openjdk.org/jfx/pull/1733#issuecomment-2734611810