RFR: 8358450: Viewport characteristics media features [v16]

[Andy Goryachev]

On Tue, 16 Dec 2025 20:13:49 GMT, Michael Strauß <mstrauss at openjdk.org> wrote:

>> Implementation of [viewport characteristics media features](https://www.w3.org/TR/mediaqueries-5/#mf-viewport-characteristics):
>> * `width`
>> * `height`
>> * `aspect-ratio`: width / height
>> * `orientation`: `portrait`, `landscape`
>> * `display-mode`: `fullscreen`, `standalone` (note: `browser` and `minimal-ui` are not supported in JavaFX)
>> 
>> Here's a small example how the new media features can be used:
>> 
>>     @Override
>>     public void start(Stage stage) {
>>         var button = new Button("Toggle full-screen");
>>         button.setOnAction(_ -> stage.setFullScreen(!stage.isFullScreen()));
>>         var label = new Label();
>>         var root = new BorderPane(button, null, null, label, null);
>>         var scene = new Scene(root, 650, 200);
>>         BorderPane.setAlignment(label, Pos.CENTER);
>>         label.textProperty().bind(scene.widthProperty().map(v -> String.format("Width: %.2f", v.doubleValue())));
>>         scene.getStylesheets().add("data:text/css;base64," + Base64.getEncoder().encodeToString("""
>>             @media (max-width: 500) {
>>                 .button {
>>                     -fx-background-color: red;
>>                 }
>>             }
>> 
>>             @media (600 < width <= 700) {
>>                 .button {
>>                     -fx-background-color: green;
>>                 }
>>             }
>> 
>>             @media (min-width: 800) {
>>                 .button {
>>                     -fx-background-color: yellow;
>>                 }
>>             }
>> 
>>             @media (display-mode: fullscreen) {
>>                 .button {
>>                     -fx-background-color: black !important;
>>                 }
>>             }
>>             """.getBytes(StandardCharsets.UTF_8)));
>> 
>>         stage.initStyle(StageStyle.DECORATED);
>>         stage.setScene(scene);
>>         stage.show();
>>     }
>
> Michael Strauß has updated the pull request incrementally with one additional commit since the last revision:
> 
>   documentation

The feature looks good on macOS 26.1, excellent work!

This needs to be tested on Windows and Linux[es].

Side note: I realized the CSS Playground does not apply the stylesheet to newly created windows, only to already present ones.  Should be ok to test though, with newly added Windows -> Fullscreen etc. menus.

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Marked as reviewed by angorya (Reviewer).

PR Review: https://git.openjdk.org/jfx/pull/1844#pullrequestreview-3584979469