Resizing stage while it is maximized breaks scene size on Linux

[Martin Fox]

Christopher,

Why are you trying to change the size of a maximized stage? I’m not sure what the intended effect is.

Currently this produces all sort of platform-specific behavior and since what you’re seeing on Windows doesn’t match what I’m seeing I think there might be some variation based on OS version. The easiest way out of this thicket is to de-maximize the stage before trying to change its size.

With that said, yes, this Linux bug definitely needs to be fixed. Whatever happens the scene shouldn’t break.

> On Apr 16, 2025, at 3:32 AM, Thiago Milczarek Sayão <thiago.sayao at gmail.com> wrote:
> 
> Hi,
> 
> I’d like to get your thoughts on what the expected behavior should be when setting the size of a window while it's in a maximized state.
> 
> Here are the options I’ve considered:
> 
> a) Ignore the resize while maximized, and when restored, revert to the size before it was maximized
> b) Demaximize the window and apply the new size immediately
> c) Ignore the resize request, but store the values and apply them upon restore

Option A forces the client to de-maximize the window before changing its size. Option B de-maximizes the window automatically. Option C is the only one that brings new functionality to the table but it would be complicated to implement (assuming it can be implemented).

The documentation states that this is how things work when a stage is in fullscreen mode but from I can tell that’s not how any of the platforms actually behave. Trying to resize a fullscreen window produces a variety of immediate platform-specific effects.

> If I understood correctly, Martin mentioned that both macOS and Windows apply the resize immediately while keeping the window maximized.

You understood correctly but I was wrong. On Windows 11 the size changes (I’m seeing only one resize event) and the window stays in the maximized state. This seems to be confusing the OS and it draws the title bar incorrectly. On macOS the size changes and the window leaves the maximized state but due to a bug in the code we don’t update the maximized property correctly.

Martin

> Then, when the window is demaximized, it restores the previous (pre-maximized) size, which suggests behavior leaning toward option a.
> 
> For fullscreen mode, the expected behavior appears to align more with option c, as documented for Stage fullscreen.
> 
> -- Thiago.
> 
> 
> Em sáb., 29 de mar. de 2025 às 09:24, Thiago Milczarek Sayão <thiago.sayao at gmail.com <mailto:thiago.sayao at gmail.com>> escreveu:
>> I did not find a bug report, so I did one and provided a fix:
>> 
>> https://github.com/openjdk/jfx/pull/1748
>> 
>> 
>> 
>> Em sáb., 29 de mar. de 2025 às 08:26, Thiago Milczarek Sayão <thiago.sayao at gmail.com <mailto:thiago.sayao at gmail.com>> escreveu:
>>> @Christopher Schnick <mailto:crschnick at xpipe.io> 
>>> 
>>> Hi, did you open a bug? I have a fix for this.
>>> 
>>> Thanks
>>> 
>>> -- Thiago.
>>> 
>>> Em seg., 17 de mar. de 2025 às 09:49, Christopher Schnick <crschnick at xpipe.io <mailto:crschnick at xpipe.io>> escreveu:
>>>> So on Windows at least, it will change the width temporarily and then revert back to the original width value. So you will receive two width change events if you listen to the stage width property. The maximized property is not changed.
>>>> 
>>>> I guess this also not optimal handling of this. Ideally, no changes would be made in that case.
>>>> 
>>>> On 17/03/2025 10:53, Thiago Milczarek Sayão wrote:
>>>>> Hi Christopher,
>>>>> 
>>>>> It seems like a simple fix.
>>>>> 
>>>>> How does it behave on other platforms? Does it ignore the resize, restore the window to its unmaximized state before resizing, or keep it maximized while adjusting the unmaximized size.
>>>>> 
>>>>> -- Thiago
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> 
>>>>> Em dom., 16 de mar. de 2025 às 05:25, Christopher Schnick <crschnick at xpipe.io <mailto:crschnick at xpipe.io>> escreveu:
>>>>>> Hello,
>>>>>> 
>>>>>> we encountered an issue on Linux where resizing the stage while it is maximized breaks the size of the scene. You can see a video of this at https://github.com/xpipe-io/xpipe/issues/485 . The root cause is that the stage size is modified.
>>>>>> 
>>>>>> When doing this, it temporarily or permanently switches to the size the stage had prior to being maximized, leading to either a flicker or a permanently broken scene that has the wrong size. This happens on Gnome and KDE for me with the latest JavaFX ea version.
>>>>>> 
>>>>>> Here is a simple reproducer:
>>>>>> 
>>>>>> import javafx.application.Application;
>>>>>> import javafx.scene.Scene;
>>>>>> import javafx.scene.control.Button;
>>>>>> import javafx.scene.layout.Region;
>>>>>> import javafx.scene.layout.StackPane;
>>>>>> import javafx.stage.Stage;
>>>>>> 
>>>>>> import java.io.IOException;
>>>>>> import java.util.Base64;
>>>>>> 
>>>>>> public class MaximizeLinuxBug extends Application {
>>>>>> 
>>>>>>     @Override
>>>>>>     public void start(Stage stage) throws IOException {
>>>>>>         Scene scene = new Scene(createContent(), 640, 480);
>>>>>>         var s = "data:text/css;base64," <> + Base64.getEncoder().encodeToString(createCss().getBytes());
>>>>>>         scene.getStylesheets().add(s);
>>>>>>         stage.setTitle("Hello!");
>>>>>>         stage.setScene(scene);
>>>>>>         stage.show();
>>>>>>         stage.centerOnScreen();
>>>>>>         stage.setMaximized(true);
>>>>>>     }
>>>>>> 
>>>>>>     private String createCss() {
>>>>>>         return """
>>>>>>                 * {
>>>>>>                 -fx-border-color: red;
>>>>>>                 -fx-border-width: 1;
>>>>>>                 }
>>>>>>                 """;
>>>>>>     }
>>>>>> 
>>>>>>     private Region createContent() {
>>>>>>         var button = new Button("Click me!");
>>>>>>         button.setOnAction(event -> {
>>>>>>             var w = button.getScene().getWindow();
>>>>>>             w.setWidth(w.getWidth() - 1);
>>>>>>             event.consume();
>>>>>>         });
>>>>>>         var stack = new StackPane(button);
>>>>>>         return stack;
>>>>>>     }
>>>>>> 
>>>>>>     public static void main(String[] args) {
>>>>>>         launch();
>>>>>>     }
>>>>>> }
>>>>>> 
>>>>>> Best
>>>>>> Christopher Schnick
>>>>>> 

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