StageStyle.EXTENDED with transparent background

Thu Nov 13 17:22:19 UTC 2025

I think I stumbled upon this UNIFIED issue a while ago but the 
workaround by setting -Dprism.forceUploadingPainter=true fixes it. And 
these applications have been tested by many users no one ever mentioned 
issues, so I'm reasonably sure that everything works fine here.

On macOS, it adds a NSGlassEffectView subview behind the default JavaFX 
NSView, yes. Any transparency is handled correctly with this approach 
when the stage style is UNIFIED. It would be great if EXTENDED could 
support this as well.

In general, it would be desirable for EXTENDED to have all the 
properties of UNIFIED, otherwise I don't see much use for it.

Furthermore, an API to apply these window background themes without any 
custom native calls would be cool as well, but here the challenge is 
whether it would be accepted to have a platform-specific list of 
available materials/themes in the API, plus a few customization options. 
Because I don't see the possibility of a generic API that works well on 
all platforms as they all work so differently.

On 13/11/2025 18:09, Martin Fox wrote:
> Christopher,
>
> It will only work with UNIFIED. With the exception of UNIFIED and 
> TRANSPARENT the core Java code will draw an opaque background fill 
> behind the scene.
>
> On macOS the glass platform code will remove the layer’s alpha channel 
> unless the stage style is UNIFIED. I think that’s a workaround for a 
> bug that has long since been fixed (don’t have the bug number handy). 
> That logic wasn’t carried over to the Metal branch and I would like to 
> remove it for OpenGL as well.
>
> UNIFIED doesn’t work reliably on Windows since the rendering pipeline 
> isn’t guaranteed to add an alpha channel (see 
> https://bugs.openjdk.org/browse/JDK-8154847). Are you doing something 
> to kick the HWND so you always get an alpha channel?
>
> On macOS you must be adding a visual effect view to what is known as 
> the host view. It’s vestigial these days but I always figured it would 
> come in handy as a container for a visual effect view. Looks like 
> you’ve discovered that also.
>
> Martin
>
>> On Nov 13, 2025, at 8:22 AM, Christopher Schnick <crschnick at xpipe.io> 
>> wrote:
>>
>> Haha yeah I thought the MonkeyTester would make a good demo content 
>> page for a sample application. And it does!
>>
>> On 13/11/2025 17:20, Andy Goryachev wrote:
>>> What Kickstart FX?  :-)
>>>
>>> Joking, joking, I am glad you found it helping.
>>>
>>> -andy
>>>
>>> *
>>>
>>> Confidential- Oracle Internal
>>>
>>> From: *openjfx-dev <openjfx-dev-retn at openjdk.org> on behalf of 
>>> Christopher Schnick <crschnick at xpipe.io>
>>> *Date: *Thursday, November 13, 2025 at 06:27
>>> *To: *Michael Strauß <michaelstrau2 at gmail.com>
>>> *Cc: *OpenJFX <openjfx-dev at openjdk.org>
>>> *Subject: *Re: StageStyle.EXTENDED with transparent background
>>>
>>> We run our applications with native materials for some time now 
>>> without any issues.
>>>
>>> On Windows 11, it uses the Mica material for the Stage. It 
>>> automatically adjusts based on the system theme, so you will always 
>>> have a good look and contrast for all theme configurations. The mica 
>>> material can also be swtiched to the acrylic one, however the 
>>> acrylic theme was primarily intended for Windows 10 and is being 
>>> replaced by Mica for Windows 11.
>>>
>>> On macOS, it uses the new Liquid Glass material in macOS 26 and the 
>>> Vibrant material for older versions. With Liquid Glass you can also 
>>> configure the tint if needed.
>>>
>>> This can all be achieved via a few native calls with the existing 
>>> Stages, at least with the older stage styles like Unified.
>>>
>>> Isn't the original issue just about the extended stage style using a 
>>> white background? I'm no expert on the implementation, but the other 
>>> types of Stages like Unified show their background if you set the 
>>> Scene and root node background to be transparent. Normally that 
>>> window fill was always white anyway as JavaFX did not support window 
>>> theming before, but if the window theme is set to something 
>>> different, then that sticks out. Is there something fundamentally 
>>> limiting so that the Extended stage is forced to draw a white 
>>> background?
>>>
>>> Unified:
>>>
>>> <aBRzaHD5w0KvUgrJ.png>
>>>
>>> Extended, even with DWMWA_USE_IMMERSIVE_DARK_MODE set to true:
>>>
>>> <HRrOi0IB1NCsFlHW.png>
>>>
>>> On 13/11/2025 00:33, Michael Strauß wrote:
>>>
>>>         I finally got around to looking into this. I see two
>>>         requests here, one to add per-pixel window transparency to
>>>         EXTENDED stages and another to support backdrop materials
>>>         like Windows’ Mica and Acrylic. On the Mac adding per-pixel
>>>         transparency to all stage styles is easy. On Windows it
>>>         would take a lot more work and as far as I know can’t be
>>>         done with the existing DX9 back end (the necessary
>>>         DirectComposition API’s are tied to DX11). We would also
>>>         need to reconcile platform differences related to hit
>>>         testing and drop shadows. So it’s a big ask.
>>>
>>>     I think we can probably get there by using a WS_EX_LAYERED
>>>     window like we do for StageStyle.TRANSPARENT, if we accept the
>>>     significant performance impact. With DirectComposition, we can
>>>     directly interface with the DWM composition engine and skip the
>>>     GDI window surface completely. This requires a fair bit of
>>>     integration with JavaFX that goes beyond changes in the Glass
>>>     toolkit. However, it doesn't require a D3D11 rendering pipeline.
>>>     It works with the existing D3D9 pipeline by having D3D9 render
>>>     into a shared off-screen surface, which is then accessed by
>>>     DirectComposition with ID3D11Device::OpenSharedResource.
>>>
>>>         (I know there’s a DX12 version of JavaFX in the works but
>>>         it’s hard for me to get enthused. I run Windows in a VM and
>>>         it’s likely to be stuck on DX11 for a long time.) Supporting
>>>         translucent backdrop materials is simpler since we can ask
>>>         the OS to draw the effect and then composite the JavaFX
>>>         content over it all within an opaque window. This is how the
>>>         UNIFIED stage style works so we can leverage that logic. On
>>>         Mac this is easy to set up. On Windows 11 22H2 and beyond we
>>>         can easily access a couple of materials. For earlier Windows
>>>         versions or for a more extensive list of materials we would
>>>         need to roll our own using DirectComposition.
>>>
>>>     That's correct, it's reasonably simple to support
>>>     platform-provided backdrop materials. Anything custom is a lot
>>>     more difficult. I have a prototype of JavaFX with
>>>     DirectComposition, along with a custom acrylic implementation.
>>>     It's very old, and looks like this (running on Windows 10):
>>>     https://github.com/user-attachments/assets/cd702a74-603a-4d7e-9078-52f915a4448a
>>>     In the end, there doesn't seem to be much common ground between
>>>     the various OS platforms for any reasonably powerful
>>>     cross-platform API. Maybe we could have the supporting
>>>     infrastructure in JavaFX, but only exposing API in a
>>>     platform-specific module (either as part of OpenJFX or 3rd
>>>     party)? This certainly requires quite a bit of work.
>>>
>>>         I know nothing about DirectComposition but I’m pretty sure
>>>         someone on this list has used it to prototype an Acrylic
>>>         effect for JavaFX. I’ll see if I can find that e-mail. I’m
>>>         particularly interested in whether this can easily be turned
>>>         on and off on-the-fly and how dark mode would be handled
>>>         (the platform-provided materials respond to dark mode).
>>>
>>>     I've never heard of any previous effort, and it couldn't have
>>>     been me beacuse I haven't talked about this up util now. I'd be
>>>     interested to learn about other attempts at solving this.
>>>
>
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