Requirements to get full credits in Documentation 1.A description of each method is also needed. 2.Some additional comments inside of methods to explain code that are hard to follow should be written. You can look at the Java programs in the text book to see how comments are added to programs. Minimal Submitted Files You are required, but not limited, to turn in the following source files: Assignment7.java (No need to be changed) DrawingPane.java -- to be completed. You may add more classes or more methods than the specified ones. (You might need them.) Skills to be Applied: JavaFX Classes may be needed: Button, ComboBox, Color, Graphics, Line, ActionHandler, MouseHandler. You may use other classes. Here is Assignment7.java: import javafx.application.Application; import javafx.stage.Stage; import javafx.scene.Scene; import javafx.scene.layout.StackPane; public class Assignment7 extends Application { public void start(Stage primaryStage) { //create a DrawPane object. See DrawPane.java for details. DrawingPane gui = new DrawingPane(); //put gui on top of the rootPane StackPane rootPane = new StackPane(); rootPane.getChildren().add(gui); // Create a scene and place rootPane in the stage Scene scene = new Scene(rootPane, 600, 400); primaryStage.setTitle("Line Drawing"); primaryStage.setScene(scene); // Place the scene in the stage primaryStage.show(); // Display the stage } public static void main(String[] args) { Application.launch(args); } } Here is DrawingPane.java (This is a semi-finished product, you need to add): //import any classes necessary here //---- import javafx.scene.control.Button; import javafx.scene.control.ComboBox; import javafx.scene.layout.Pane; import javafx.scene.layout.BorderPane; import javafx.scene.layout.HBox; import javafx.scene.shape.Line; import javafx.scene.paint.Color; import javafx.geometry.Insets; import javafx.geometry.Pos; import javafx.geometry.Orientation; import javafx.event.ActionEvent; import javafx.event.EventHandler; import javafx.scene.input.MouseEvent; import java.util.ArrayList; public class DrawingPane extends BorderPane { private Button undoButton, eraseButton; private ComboBox colorCombo, widthCombo; private ArrayList lineList; private Pane canvas; //declare any other necessary instance variables here //---- //Constructor public DrawingPane() { //Step #1: initialize instance variable and set up layout undoButton = new Button("Undo"); eraseButton = new Button("Erase"); undoButton.setMinWidth(80.0); eraseButton.setMinWidth(80.0); //Create the color comboBox and width comboBox, //---- //initialize lineList, it is a data structure we used //to track the lines we created //---- //topPane should contain two combo boxes and ...