Resize text font size to fit a text-box in Javafx8

Question

I have a javafx gui which contains a text-box. I want to know how I can find the best font-size for the text to be set to.

The text-box cannot be resized to fit the text and the text cannot be truncated/overflow.

During the program, the text-box can change its dimensions and the text can change font (eg. from Arial to Comic Sans), or change the text itself (from single words to paragraphs), and I need to make sure that the text gets resized to fit the text-box.

The text-box can be any node that holds text like label,textFlow,textArea...

I wrote 3 different attempts to try and develop such algorithm but none of them worked.

Main Code:

public class Main extends Application{

    String text = new String("Lorem ipsum dolor sit amet, consectetur adipiscing elit. In scelerisque elit ante, eu lacinia dui molestie quis. Donec consectetur elementum.");



    TextFlow textBox;
    AnchorPane anchorPane;

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

    @Override
    public void start(Stage primaryStage) throws Exception{
        textBox = new TextFlow(new Text(text));
        textBox.setTextAlignment(TextAlignment.CENTER);

        anchorPane = new AnchorPane(textBox);

        AnchorPane.setTopAnchor(textBox,0d);
        AnchorPane.setBottomAnchor(textBox,0d);
        AnchorPane.setRightAnchor(textBox,0d);
        AnchorPane.setLeftAnchor(textBox,0d);


        Scene scene = new Scene(anchorPane);
        primaryStage.setScene(scene);
        primaryStage.show();

        textBox.widthProperty().addListener(new ChangeListener<Number>(){
            @Override
            public void changed(ObservableValue<? extends Number> observable, Number oldValue, Number newValue){
                autoSizeTextBoxText();
            }
        });

        textBox.heightProperty().addListener(new ChangeListener<Number>(){
            @Override
            public void changed(ObservableValue<? extends Number> observable, Number oldValue, Number newValue){
                autoSizeTextBoxText();
            }
        });
    }

    public void setTextBoxFont(Font font){
        ((Text)textBox.getChildren().get(0)).setFont(font);
        autoSizeTextBoxText();
    }

    public void setTextBoxText(String text){
        ((Text)textBox.getChildren().get(0)).setText(text);
        autoSizeTextBoxText();
    }


    public void autoSizeTextBoxText(){
        Font font = TextAndFontHelper.getOptimalFont(((Text)textBox.getChildren().get(0)).getText(),textBox,((Text)textBox.getChildren().get(0)).getFont());
        System.out.println(font.getSize());
        ((Text)textBox.getChildren().get(0)).setFont(font);
        anchorPane.layout();
        textBox.layout();
    }

}

public class TextAndFontHelper{
    public static double getTextWidth(Text text){
        double width = text.getBoundsInLocal().getWidth();
        return width;
    }

    public static double getTextHeight(Text text){
        double height = text.getBoundsInLocal().getHeight();
        return height;
    }

    public static double getTextArea(Text text){
        double area = getTextHeight(text)*getTextWidth(text);
        return area;
    }

    public static Font getOptimalFont(String textString, Region textBox,Font font){

        //... This is the method that I want to write

    }
}

These are my attempts:

Attempt #1:This attempt is very glitchy, the text size is continuously changing from a good size(although not perfect as it can be increased a bit) to a big size that doesn't fit the screen every time that the algorithm triggers. https://i.stack.imgur.com/4mGxJ.jpg

        Text text = new Text(textString);
        if (font != null)
            text.setFont(font);

        double textBoxArea = textBox.getHeight()*textBox.getWidth();
        double textArea = getTextArea(text);

        double ratio = textBoxArea/textArea;

        return new Font(text.getFont().getFamily(),text.getFont().getSize()*ratio);

Attempt #2:This attempt is very glitchy, the text size is continuously changing from too small to too big the screen every time that the algorithm triggers. https://i.stack.imgur.com/yOCq2.jpg

        Text text = new Text(textString);
        if (font != null)
            text.setFont(font);

        double heightRatio = textBox.getHeight()/getTextHeight(text);
        double widthRatio = textBox.getWidth()/getTextWidth(text);

        double ratio = heightRatio*widthRatio;
        return new Font(text.getFont().getFamily(),text.getFont().getSize()*ratio);

Attempt #3: This attempt was made based on this question: Resize a SKLabelNode font size to fit?. While this algorithm isn't glitchy, the size of the text is resized to fit just 1 line (sometimes overflowing into the 2nd) and thus being too small. https://i.stack.imgur.com/XkcPq.jpg

        Text text = new Text(textString);
        if (font != null)
            text.setFont(font);

        double heightRatio = textBox.getHeight()/getTextHeight(text);
        double widthRatio = textBox.getWidth()/getTextWidth(text);

        double ratio = Math.min(heightRatio,widthRatio);
        return new Font(text.getFont().getFamily(),text.getFont().getSize()*ratio);