On Wed, 3 Dec 2025 00:48:52 GMT, Michael Strauß <[email protected]> wrote:

>> On Windows, the `Stage.width` and `Stage.height` correspond to the window 
>> size as returned by `GetWindowRect`.
>> 
>> Up until Windows 10, the size of a window was identical to its visual 
>> borders. However, since Windows 10 has introduced thin visual window 
>> borders, the window manager adds an invisible border of a few pixels around 
>> the window to make it easier to resize the window. Since `GetWindowRect` 
>> returns the window size _including_ these invisible borders, the location 
>> and size of a `Stage` isn't exactly what we'd expect.
>> 
>> For example, if we place a `Stage` at `setX(0)` and `setY(0)`, the window 
>> appears with a small distance from the screen edge, and the window size 
>> extends a few pixels beyond its visual borders (in the following images, the 
>> screenshot size corresponds to the window size; note the invisible padding 
>> around the edges):
>> <img width="300" alt="window-size-1" 
>> src="https://github.com/user-attachments/assets/76ea6861-885f-4bea-aeb7-e8e6464b7199";
>>  />
>> 
>> What we actually want is to have the visual borders line up with the edges 
>> of the screen, and have the window size correspond to the visual borders:
>> <img width="295" alt="window-size-2" 
>> src="https://github.com/user-attachments/assets/ca6bed73-e4e7-4df6-9491-d82792bb0866";
>>  />
>> 
>> The implementation is quite simple: instead of `GetWindowRect`, we use 
>> `DwmGetWindowAttribute(DWMA_EXTENDED_FRAME_BOUNDS)`. This gives us the 
>> bounds of the visual window borders. If this function fails, we fall back to 
>> `GetWindowRect` (now, I don't know why 
>> `DwmGetWindowAttribute(DWMA_EXTENDED_FRAME_BOUNDS)` would ever fail... maybe 
>> an old Windows version in a remote desktop scenario?).
>
> Michael Strauß has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   add comments

With this fix applied, the problem described in 
[JDK-8285983](https://bugs.openjdk.org/browse/JDK-8285983) disappears and the 
reported position and size of a full-screen window is as a sane person would 
expect it to be (position = 0,0 and size = visual bounds of the screen).

I suggest we re-open the bug (which was closed as "not an issue") and add it to 
this PR.

-------------

PR Comment: https://git.openjdk.org/jfx/pull/1982#issuecomment-3648909539

Reply via email to