On Wed, 8 Apr 2026 17:58:25 GMT, Martin Fox <[email protected]> wrote:
>> This PR enables translucent window backdrops for JavaFX stages on macOS and >> Windows 11. Since we’re reliant on the operating system for these effects >> (they typically require real-time blurring of the desktop) I needed to flesh >> out a fairly complete prototype to sort out the API. I will start a >> discussion about the API on the mailing list. >> >> There’s a crude manual test for trying out the different backdrop materials. >> >> java @build/run.args -Djavafx.enablePreview=true >> tests/manual/stage/BackdropTest.java >> >> You’ll want to drag the windows around to avoid having them overlap each >> other since they’re all created in the center of the screen. For windows >> without title bars you can click anywhere on the background to drag the >> window except for TRANSPARENT stages on Windows which are a bit tricker to >> get a hold of; try to click on a text label. >> >> If you create an UNDECORATED stage on Windows the backdrop won’t be >> translucent initially. This can be corrected by changing the stage’s color >> scheme. This is an OS bug that I haven’t found a workaround for. >> >> The changes on Windows 11 are minimal since we’re just invoking an OS >> feature by calling DwmSetWindowAttribute. I did need to make two small >> changes to the D3D9 Prism code to ensure that the swap chain and back buffer >> support an alpha channel so JavaFX can composite its content on top of the >> backdrop. This is the same way the old UNIFIED stage style worked before it >> became unreliable (see >> [JDK-8154847](https://bugs.openjdk.org/browse/JDK-8154847)). >> >> On macOS I moved the GlassHostView so it’s now a permanent part of the >> NSWindow. For some time the host view has been a remnant left over from an >> older approach to implementing fullscreen. Now it serves as a common parent >> for the NSVisualEffectView that provides the backdrop and the GlassView3D >> that contains the JavaFX content. Making it the permanent contentView of the >> NSWindow simplifies some code. >> >> To validate the API I did prototype this for Windows 10 (thanks @mstr2!). >> Well, I prototyped this using DirectComposition so it should work on Win10 >> but I can't test Win10 myself. Using DirectComposition is much more involved >> so I shelved that implementation for now but it does inform the API. It’s >> the reason the backdrop needs to be specified before the Java window is >> shown and the platform window created. > > Martin Fox has updated the pull request with a new target base due to a merge > or a rebase. The pull request now contains eight commits: > > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - Backdrops are now objects created by specifying a material. The > list of materials is now open-ended. > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - Removed unused import > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - OS supplied translucent window backdrops Could that approach potentially support customization? For example liquid glass allows a tint color, etc. Also, would stuff like the window border radius be considered a part of the backdrop? Because that is also available to be changed via native APIs ------------- PR Comment: https://git.openjdk.org/jfx/pull/2048#issuecomment-4448068575
