Chapter 16 Exercise 14, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

16.14 (Select a font)
Write a program that can dynamically change the font of a
text in a lbl displayed on a stack pane. The text can be
displayed in bold and italic at the same time. You can select
the font name or font size from combo boxes, as shown in Figure
16.42a. The available font names can be obtained using Font.getFamilies().
The combo box for the font size is initialized with numbers from 1 to 100.

import javafx.application.Application;
import javafx.geometry.Insets;
import javafx.geometry.Pos;
import javafx.scene.Scene;
import javafx.scene.control.CheckBox;
import javafx.scene.control.ComboBox;
import javafx.scene.control.ContentDisplay;
import javafx.scene.control.Label;
import javafx.scene.layout.BorderPane;
import javafx.scene.layout.HBox;
import javafx.scene.layout.StackPane;
import javafx.scene.text.Font;
import javafx.scene.text.FontPosture;
import javafx.scene.text.FontWeight;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class Exercise_14 extends Application {

    Text text = new Text("Programming is fun");
    ComboBox<String> cbFontFamilies = new ComboBox<>();

    CheckBox chkBold = new CheckBox("Bold");
    ComboBox<Integer> cbFontSize = new ComboBox<>();

    CheckBox chkItalic = new CheckBox("Italic");
    @Override
    public void start(Stage primaryStage) throws Exception {

        // Center Text

        Integer[] sizes = new Integer[100];

        for (int i = 0; i < 100; i++)
            sizes[i] = i + 1;
        // Top pane nodes
        cbFontFamilies.getItems().addAll(Font.getFamilies());
        cbFontFamilies.setValue(text.getFont().getFamily());
        cbFontFamilies.setOnAction(e-> update());
        Label lblFontFamilies = new Label("Font Name", cbFontFamilies);
        lblFontFamilies.setContentDisplay(ContentDisplay.RIGHT);

        cbFontSize.getItems().addAll(getSizes());
        cbFontSize.setValue((int)text.getFont().getSize());
        cbFontSize.setOnAction(e -> {
            update();
            primaryStage.sizeToScene();
        });
        Label lblFontSizes = new Label("Font Size",cbFontSize);
        lblFontSizes.setContentDisplay(ContentDisplay.RIGHT);

        // Top pane
        HBox topPane = new HBox(lblFontFamilies, lblFontSizes);
        topPane.setSpacing(5);
        topPane.setPadding(new Insets(5));


        // Bottom pane nodes
        chkBold.setOnAction(e-> update());
        chkItalic.setOnAction(e-> update());

        // Bottom pane
        HBox bottomPane = new HBox(chkBold, chkItalic);
        bottomPane.setAlignment(Pos.CENTER);

        StackPane centerPane = new StackPane(text);
        BorderPane borderPane = new BorderPane(centerPane);
        borderPane.setTop(topPane);
        borderPane.setBottom(bottomPane);
        primaryStage.setTitle("Text Changer");
        primaryStage.setScene(new Scene(borderPane));
        primaryStage.show();

    }
    private void update(){
        FontWeight fontWeight = (chkBold.isSelected()) ? FontWeight.BOLD : FontWeight.NORMAL;
        FontPosture fontPosture = (chkItalic.isSelected()) ? FontPosture.ITALIC : FontPosture.REGULAR;
        String fontFamily = cbFontFamilies.getValue();
        double size = cbFontSize.getValue();
        text.setFont(Font.font(fontFamily, fontWeight, fontPosture, size));
    }

    private Integer[] getSizes() {
        Integer[] sizes = new Integer[100];

        for (int i = 0; i < 100; i++)
            sizes[i] = i + 1;

        return sizes;
    }

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