COMP 14 Fall 2000 Assignment 9 Turtle Graphics Last One Assigned Tue Nov 21 2000 Part 1 Submission Date Fri Dec 1 5pm There will be extra lab hours on Thu night Nov 30 7 11pm Part 2 Submission Date Thu Dec 7 before class starts Objectives Create and manipulate graphical shapes Use the MVC Model View Controller architecture Use the switch statement and inheritance Use a Java toolkit AWT or Swing In this assignment you will create a turtle editor In part 1 you will use ObjectEditor to display and manipulate the turtle and in part 2 you will use standard Java libraries and the MVC architecture to do so In your implementation you should use switch statements and inheritance wherever you can A sample applet implementation of part 2 with extra credit is linked from the assignments page Its URL is http www cs unc edu dewan comp14 f00 assignments turtle ATurtleAppletComposer htm Try it before you begin the assignment It will work only if your autoexec file has put shapes jar in the CLASSPATH Access the applet from the computer on which you did the first assignment Part 1 Create a turtle editor that allows a user to move a turtle on the screen This part includes a regular component and an extra credit component The figure on the next page shows features of both components Regular Credit As shown in the figure the turtle is represented by two adjacent solid circles one for the body and another for the head The head always points in the direction in which the turtle is pointing The turtle can point in the north south east or west direction and can move both forward and backward in the direction it is pointing Initially the turtle is pointing eastwards as shown in the left window of the figure The turtle should have one instance integer property MoveDistance In addition it should provide the following instance public parameter less procedures 1 rotate Rotate the turtle 90 degrees in the anti clockwise direction 2 move Move the turtle the number of pixel units given by the MoveDistance property Movement is in forward backward direction if the value of the property is positive negative As you saw in the first assignment ObjectEditor creates a menu to invoke all public methods of an object except the getter and setter methods which are called implicitly when you edit the properties they define The name of the menu is the class of the object Use this menu to test these procedures You are free to choose the sizes and colors of the body and head and the initial position of the turtle One of the potentially messy tasks you have to worry about is rotating the turtle It will be best to store the direction of the turtle as a positive number between 0 and 3 1 Extra Credit 1 Allow users to draw lines by moving the turtle on the screen telling the turtle to pick up or put down a pen as it moves right window of the figure A boolean property PenDown determines if the pen is up or down as shown in the figure Since the number of lines is variable look at the section in chapter 13 on exposing dynamic indexed elements 2 Add two new integer properties StepSize and StepTime and the following instance public parameter less procedure animationMove Like move this method moves the turtle the number of pixel units given by the MoveDistance property While move essentially makes the turtle take one big step to its new position this makes it take several small steps to its destination animating the turtle as it moves The size of the step in pixels is given by the property StepSize and the time to take a step is given by the property StepTime To implement animation you will need to look at the sections on animation given in Chapter 12 which will probably not be covered in class or the exam So do this part only if you have plenty of time to spare These two extra credit features are independent in that you will get separate credit for each of them 2 Part 2 For this part you will no longer rely on ObjectEditor to display and manipulate the turtle directly using Java libraries You can use the AWT or Swing library The figure below shows both the regular and extra credit features for this part Regular Credit Make a turtle model object out of the turtle object of part 1 You will make full points only if the class and interface of the former are subtypes of the class and interface of the latter Next implement a view and controller for the turtle model that provide a a text field that allows the user to change the MoveDistance property of the turtle and b buttons to invoke the move and rotate methods of the turtle Also provide a quit button to terminate the program Implement a composer that creates two turtle editors for a turtle model simultaneously on the screen as shown in the figure below The controller and views of the editors should ensure that after each command that changes the turtle model all of the views of the model are updated immediately Creating two editors that are in sync should be trivial if you have followed the MVC architecture Make sure the two editor windows are not located at the same position otherwise you will see only one of them You will need to read both chapters 14 and 15 to implement these features The code for point history view and controller should serve as a template for the turtle model and view Extra Credit 1 Provide a way to create the two editors in an applet as shown in the sample turtle implementation This can be done even if you did not do any extra credit for part 1 For this feature you need to create your composer class as a subclass of Applet In the Applet version be sure to comment out all console I O code println readString and so on in your programs otherwise the browser will give you an exception Also you will need to put all the class files both for part 1 and 2 in the directory in which your HTML file is located Applets will probably not be covered in class or the exam How to create them is described in chapter 15 2 If you implemented line drawing in part 1 provide a check box to change the PenDown property Look the discussion on checkboxes in Problem 8 chapter 15 3 If you implemented animation in part 1 do the same for this part Provide a button to invoke animationMove If you wish you can also allow the user to edit the step size and step time properties When the animation move command is executed each animation step should be displayed in all views Read the sections on animation in chapter 15 Again this will probably not be covered in class or the exam 3