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.
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Commit messages:
- Removed unused import
- Merge remote-tracking branch 'upstream/master' into osbackdrop
- OS supplied translucent window backdrops
Changes: https://git.openjdk.org/jfx/pull/2048/files
Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=2048&range=00
Issue: https://bugs.openjdk.org/browse/JDK-8375578
Stats: 727 lines in 29 files changed: 642 ins; 64 del; 21 mod
Patch: https://git.openjdk.org/jfx/pull/2048.diff
Fetch: git fetch https://git.openjdk.org/jfx.git pull/2048/head:pull/2048
PR: https://git.openjdk.org/jfx/pull/2048
