Add blinking effect

[PavelTurk]

In JavaFX 23 CSS transition was added. At the same time CSS animation issue was closed since animated transitions in CSS were added (see comments). So, I think we can state than CSS animation won't be implemented in the next 99 years.

This is an example of blinking affect in TextFlow using transitions:

public class JavaFxTest10 extends Application {

    public static final String CSS = "data:text/css," +
        """
        .myText{
           -fx-font-size:20px;
           -fx-opacity: 1;
        }

        .myText:blink{
            -fx-opacity: 0;
        }
        """;

    private static final String TEXT = "Some text.";

    @Override
    public void start(Stage primaryStage) {
        var blink = PseudoClass.getPseudoClass("blink");
        var text = new Text(TEXT);
        text.setStyle("transition-property: -fx-opacity;transition-duration: 0.5s;");
        text.getStyleClass().add("myText");
        text.addEventHandler(TransitionEvent.END,
                event -> text.pseudoClassStateChanged(blink, !text.getPseudoClassStates().contains(blink)));

        var textFlow = new TextFlow(text);
        VBox root = new VBox(textFlow);
        Scene scene = new Scene(root, 400, 200);
        scene.getStylesheets().add(CSS);

        primaryStage.setScene(scene);
        primaryStage.setOnShown(e -> text.pseudoClassStateChanged(blink, true));
        primaryStage.show();

    }

    public static void main(String[] args) {
        launch(args);
    }
}

And result:

And I suggest to add blinking affect to RichTextFX. As I understand RichTextFX internally creates distinct nodes for text of different style classes (StyleClassedTextArea) and different styles (InlineCssTextArea). If so, we can add CSS declaration like -rtfx-blink-rate: <duration>ms; and If RichTextFX detects this declaration in style or style class then it will add TransitionEvent.END event handler to this node as in the example with TextFlow.