import javafx.animation.KeyFrame;
import javafx.animation.KeyValue;
import javafx.animation.Timeline;
import javafx.application.Application;
import javafx.beans.property.SimpleDoubleProperty;
import javafx.scene.Scene;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.control.TextArea;
import javafx.scene.layout.Pane;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;
import javafx.util.Duration;

public class TestShrink extends Application
{
    private class ShrinkableTextArea extends TextArea
    {
        final SimpleDoubleProperty scale = new SimpleDoubleProperty(1.0);
        public ShrinkableTextArea(String content)
        {
            super(content);
            setMinHeight(0.0);
            scale.addListener((observable, oldVal, newVal) -> 
              setPrefHeight(newVal.doubleValue() * computePrefHeight(9999)));
        }
    }
    
    @Override
    public void start(Stage primaryStage) throws Exception
    {
        ShrinkableTextArea area = new ShrinkableTextArea("Some amount\nof text\nin this box\netc");
        area.setMaxWidth(300.0);
        // Wrap text makes no difference here:
        //area.setWrapText(true);
        
        Button shrink = new Button("Shrink");
        // Scales text area to nothing
        shrink.setOnAction(e -> {
            new Timeline(new KeyFrame(Duration.millis(2000), new KeyValue(area.scale, 0.0))).play();
        });
        shrink.setLayoutX(300);
        shrink.setLayoutY(50);
        
        VBox outer = new VBox();
        outer.getChildren().addAll(new Label("Start"), area, new Label("End"));
        
        Pane p = new Pane(outer, shrink);
        p.setMinWidth(400);
        p.setMinHeight(600);
        primaryStage.setScene(new Scene(p));
        primaryStage.show();
        
    }
}