On Wed, 19 Aug 2026 17:30:54 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. >> >> --------- >> - [x] I confirm that I make this contribution in accordance with the >> [OpenJDK Interim AI Policy](https://openjdk.org/legal/ai). > > Martin Fox has updated the pull request with a new target base due to a merge > or a rebase. The pull request now contains 24 commits: > > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - Other non-opaque scene fills can now draw over backdrops > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - Remove debug code, fix initial setting of options > - Clients now initialize a stage with a StageBackdrop instead of > StageBackdropStyle > - Using emulated backdrops on Linux > - Windows disables the backdrop with high contrast on > - Windows can now emulate a backdrop color fills > - Merge remote-tracking branch 'upstream/master' into osbackdrop > - Remove duplicate Mac backdrop styles, add HUD on Mac > - ... and 14 more: https://git.openjdk.org/jfx/compare/5e7a4d60...41804987 I'm working on the CSR for this. Any comments on the documentation would be welcome. Still unsure which platform-specific backdrops to include and whether to document them. On Windows 11 there are only three backdrop types. Two are covered by WINDOW and PARTIAL. The third is known as Transient and it's quite translucent (l wouldn't try to draw text on it). I haven't seen any place in the Win11 UI where it's used. The closest equivalent visually on macOS is HUD (Head's Up Display). Both work well when a semi-transparent tint is layered on top which is the only reason to I included them. I would like to expose macOS.ClearGlass after we switch to the macOS 26 SDK. Beyond that I'm thinking of removing three macOS backdrops (Menu, ToolTip, and Popover) since they apply to PopupWindows and developers can't apply backdrops to those stages anyway. The only reason to include macOS.HUD is to match Windows.Transient. ------------- PR Comment: https://git.openjdk.org/jfx/pull/2048#issuecomment-5347351336
