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https://github.com/arjun1237/canvas-drawing-tool---assignment

Java Assignment
https://github.com/arjun1237/canvas-drawing-tool---assignment

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Java Assignment

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# Canvas-Drawing-Tool---Assignment

Java Assignment



CO882 Assignment 1 (Version 2016.11.15.01)



Copyright 2016 David J. Barnes



Posting of this document outside kent.ac.uk is not permitted



Introduction



This assignment is designed to assess your understanding of code quality issues, such as

refactoring, coupling and cohesion, as well as providing further practical experience

working with a substantial piece of program code.



Date set: 15th November 2016



Date due: 23:55 7th December 2016



Weighting: 35% of the coursework mark.



The task has been broken down into two stages to guide you in its development.



The Task



The task is to adapt the scribble project from chapter 6 with the addition of a text-based

user interface to create drawings:



https://www.cs.kent.ac.uk/~djb/co882/LOCAL-ONLY/assign1.zip



You are provided with the source code of three classes – Pen, Canvas and InputReader –

but the BlueJ editor for these classes is currently showing the Documentation view of them

rather than the Source Code view. The Documentation view is simply the javadoc

documentation for the classes that has been generated from the comments and method

headers that are in the source code. The idea is that it should be easy to use these

classes without needing to see details of the source code. You can flip the views by using

the drop-down menu in the top-right corner of the editor window. There should be no need

to change the source code of any of these classes. However, if you feel that you need to

make changes to them then ask me whether this is acceptable or appropriate before doing

so.



Your task is to complete the code currently in the DrawingTool class so that users can

interactively create and manipulate shapes to create pictures. You may add any further

classes that you feel are necessary to fulfil the requirements and you may modify the

existing code of the DrawingTool class in any way that you wish.



Assessment criteria



The following sections give details of the tasks that are required. In completing these,

please bear in mind that your work will be assessed primarily against the following criteria:



• Accurate implementation of the drawing commands.



• Adherence to appropriate principles of cohesion and coupling.



• Appropriate use of Java and its library classes.



• Appropriate detection and reporting of errors when a user uses the command

language incorrectly or inappropriately.



• Good coding style: well laid out with the fields, methods and constructors properly

documented. In particular, use of javadoc-style notation is a requirement and

adherence to these will be included in the marking scheme.



If in doubt about good style, a style guide is available: http://www.bluej.org/objectsfirst/

styleguide.html.



Background



The idea is that users should be able to interactively create drawings manipulating a Pen

object on a Canvas via typing commands into the terminal window. If you create a

DrawingTool object and then call its draw method, the following will appear in the terminal

window:



Welcome to the drawing tool.



Pen position: 0,0



The pen is up.



Type bye to exit.



>



If you type bye then the draw method will terminate. That is pretty-much all of the

functionality that is currently available in the DrawingTool class. Your task will be to add

more as described below.



How it currently works



A DrawingTool object uses an InputReader object to prompt for and read input from the

user in the Terminal Window. Whatever the user types at the command prompt is read by

the InputReader and separated into individual words – just as is done in the tech-support

project in chapter 6. However, in this project the words are not stored in a HashSet but

returned from the InputReader’s getInput method as a LinkedList of individual String

objects. For instance, if the user typed:



moveto 20 30



these would be returned as an ordered list containing three String objects: “moveto”, “20”

and “30”.



What to add



Your task is to enhance the current functionality so that users can create drawings on the

canvas using a Pen object. Commands typed by the user will need to be turned into calls

to methods defined in the Pen class, such as move, penUp, etc. The task has been broken

down into two stages but these are only for guidance.



In Stage One of the assignment you will implement a command language that will work

with just a single Pen. In later stages the language will be extended to allow the creation

and manipulation of multiple pens as well as user-defined command sequences.



The drawing language – Stage One [60%]



Implement the following commands to control the Pen:



• up



Raise the pen off the canvas so that movements do not cause drawing.



• down



Lower the pen onto the canvas so that movements cause drawing.



• move distance



Move the pen the specified distance in its direction of movement. distance must be

an integer value.



• moveto x y



Move to co-ordinate position x,y on the canvas. Both x and y must be integers.



• turn angle



Change the direction of movement by angle degrees. angle must be an integer.



• turnto angle



Change the direction of movement to angle degrees. angle must be an integer.



• colour colour-name



Change the drawing colour to be colour-name. colour-name must be one of the

following: “red”, “blue”, “yellow”, “magenta”, “green” or “black”.



• help



Print an explanatory help message.



Valid commands must have exactly the correct number of elements. For instance:



move 30



is valid, but



move 30 40



is not valid. Commands that are not valid should produce an error message and there

should be no change to the state of the pen or the canvas.



Example for Stage 1



The following example sequence of commands would draw a green square with side

length 20 pixels, starting at position 10,10:



up



colour green



moveto 10 10



down



turnto 0



move 20



turn 90



move 20



turn 90



move 20



turn 90



move 20



Note that the InputReader class includes methods that will help you to check for and

convert strings that contain integer values.



The drawing language – Stage Two [40%]



Extend the command language so that multiple pens may be created and controlled. The

following additional commands must be added:



• pen name



Create a new Pen that will be referred to with the given name. It is an error to

attempt to create a pen with a name that is currently in use.



• select name



Select the pen with the given name as the one to which future commands will apply.



It is an error to attempt to select a pen with a name that is not currently in use.



• delete name



Delete the pen with the given name. The name will no longer be in use. It is an error

to attempt to select a pen with a name that is not currently in use. It is possible to

create a new pen with a name that has previously been used but deleted.



In this version, no Pen object should be created when the DrawingTool object is created.

All Pen objects must be created as the result of a pen command.



Immediately following the successful execution of a pen or select command, all

commands of the Stage 1 language apply to that pen. Other pens remain inactive until

selected again.



Example for Stage 2



The following example will draw two parallel lines using two separate pens; the upper line

is drawn in green and the lower line in magenta:



pen first



up



colour green



moveto 10 10



down



moveto 20 10



pen second



up



colour magenta



moveto 20 20



down



moveto 10 20



What to submit



You will submit a Java ZIP file of your project via a Moodle hand-in area to be provided

shortly. In addition, a transcript of a typical user session and a screenshot of what it draws

must be provided to illustrate a representative sample of your program working. Use the

“Save to file” option of the BlueJ terminal to save the transcript as a text file.



Plagiarism and Duplication of Material



The work you submit must be your own. We will run checks on all submitted work in an

effort to identify possible plagiarism, and take disciplinary action against anyone found to

have committed plagiarism.



Some guidelines on avoiding plagiarism:



• One of the most common reasons for programming plagiarism is leaving work until

the last minute. Avoid this by making sure that you know what you have to do (that

is not necessarily the same as how to do it) as soon as an assessment is set. Then

decide what you will need to do in order to complete the assignment. This will

typically involve doing some background reading and programming practice. If in

doubt about what is required, ask a member of the course team.



• Another common reason is working too closely with one or more other students on

the course. Do not program together with someone else, by which I mean do not

work together at a single PC, or side by side, typing in more or less the same code.

By all means discuss parts of an assignment, but do not thereby end up submitting

the same code.



• It is not acceptable to submit code that differs only in the comments and variable

names, for instance. It is very easy for us to detect when this has been done and

we will check for it.



• Never let someone else have a copy of your code, no matter how desperate they

are. Always advise someone in this position to seek help from their class supervisor

or lecturer. Otherwise they will never properly learn for themselves.



• It is not acceptable to post assignments on sites such as Freelancer and we treat

such actions as evidence of attempted plagiarism, regardless of whether or not

work is payed for. In addition, posting anywhere other than kent.ac.uk would be an

infringement of the author’s copyright.



Further advice on plagiarism and collaboration is also available at:



http://www.cs.kent.ac.uk/teaching/student/assessment/plagiarism.local



You are reminded of the rules about plagiarism that can be found in the course Handbook.

These rules apply to programming assignments. We reserve the right to apply checks to

programs submitted for assignment in order to guard against plagiarism and to use

programs submitted to test and refine our plagiarism detection methods both during the

course and in the future.



David Barnes