Hi Michael,
Thank you very much for your reply. Yes, I am testing a JavaFX
application on Ubuntu 20, and when I noticed that there was no window
border, I assumed this was an intended feature of extended stages. If,
as you say, extended stages are supposed to have window borders on all
operating systems, then yes, that would solve the problem. I only raised
the question about corner radius because of that border.
I simply assumed that on Linux only the rounded corners were not yet
implemented, while everything else (including the window border) was
already in place. That's where the misunderstanding came from.
Best regards, Pavel
On 6/19/26 19:00, Michael Strauß wrote:
Hi Pavel,
you're probably talking about the Linux implementation, because both
on macOS and Windows, extended stages already have a window border.
In general, an extended stage is like a decorated stage where the OS
is responsible for drawing window borders. It is neither intended nor
supported that applications draw their own window borders.
So instead of adding new API, would your use case be covered if
extended stages on Linux just looked like platform-native decorated
windows?
On Fri, Jun 19, 2026 at 4:23 PM PavelTurk <[email protected]> wrote:
In addition to JDK-8386317, I proposed adding an API that would allow
JavaFX applications to obtain the window corner radius from the
operating system. However, Michael Strauß pointed out that this is most
likely not feasible because operating systems generally do not expose
such information.
Let's look at the problem from a practical perspective. Virtually every
application running in a non-maximized window requires a border
(typically 1 px). This is a standard UI convention. If JavaFX supports
EXTENDED windows with rounded corners, the corners of that border must
also be rendered correctly. Otherwise, the result will look visually
inconsistent.
If obtaining the corner radius from the OS is not possible, I would
suggest one of the following solutions:
1. Add an API that allows the operating system to render the window
border itself, while the JavaFX developer only specifies its
appearance (color, thickness, dash pattern, etc.).
2. Allow the JavaFX developer to specify the corner radius explicitly,
while the operating system uses that information solely for
rendering the native window shadow.
Best regards, Pavel
