Description
1 Problem Description
In this homework you are going to use JavaFX to create a paint tool similar to Microsoft Paint. This assignment will
test your understanding and ability to use lambda expressions and event-driven programming.
You will be provided one file, Tool.java. Tool is an interface that represents a general tool used for drawing
on the canvas, such as a Pencil tool or Rectangle tool. Tool has three abstract methods: onPress, onDrag, and
onRelease. These methods represent actions that should occur when the mouse button is pressed down, dragged
while still pressed down, and then released. You will implement this interface to create different tools for your paint
program.
2 Requirements
This assignment is meant to be open-ended. The implementation and design is up to you to decide. The quality of
your design will be graded in accordance with the concepts you have learned in this class.
At the very minimum, your submission should include the following:
1. A file named PaintFX.java which starts up your JavaFX application.
2. A canvas that you can draw on using various tools, and a way to clear everything on the canvas.
3. A way to change the current color.
4. You will also need to implement the following tools:
(a) A Pencil tool to draw simple lines on the canvas.
(b) A Rectangle tool to draw solid rectangles.
(c) One (or more) tools of your choosing. This can be another kind of shape, an eraser, a paintbrush, or
anything else that could be considered useful. Try to have fun with this one, but please don’t submit
something trivial or something that you wouldn’t normally see in a paint program. Feel free to add as
much functionality as you want as long as the base requirements are fufilled.
3 Solution and Tips
To help you with this assignment, here are some suggested readings and links to useful classes in the JavaFX API.
1. JavaFX Layouts
2. Helpful JavaFX Classes: Canvas, GraphicsContext, ColorPicker, Color
3. Re-read the lecture slides on action events in JavaFX. You will need them to complete this assignment.
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4 Example
5 Javadocs
We are going to have you do Javadocs for this assignment (and for all assignments here on out). Javadocs are a clean
and useful way to document your code’s functionality. For more information on what Javadocs are and why they are
awesome, the online documentation for them is very detailed and helpful. The relevant tags that you need to have are
@author, @version, @param, and @return. Here is an example of a properly Javadoc’d class:
import java.util.Scanner;
/**
* This class represents a Dog object.
* @author George P. Burdell
* @version 13.31
*/
public class Dog {
/**
* Creates an awesome dog (NOT a dawg!)
*/
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public Dog(){
…
}
/**
* This method takes in two ints and returns their sum
* @param a first number
* @param b second number
* @return sum of a and b
*/
public int add(int a, int b){
…
}
}
6 Checkstyle
You must run checkstyle on your submission. The checkstyle cap for this assignment is 100 points.
Review the Style Guide and download the Checkstyle jar and associated XML file. Run Checkstyle on your code like
so:
$ java -jar checkstyle-6.0-all.jar -c cs1331-checkstyle.xml *.java
Starting audit…
Audit done.
The message above means there were no Checkstyle errors. You can easily count Checkstyle errors by piping the
output of Checkstyle through wc -l and subtracting 2 for the two non-error lines printed above (which is how we
will deduct points). For example:
$ java -jar checkstyle-6.0-all.jar -c cs1331-checkstyle.xml *.java | wc -l
2
Alternatively, if you are on Windows, you can use the following instead:
C:\> java -jar checkstyle-6.0-all.jar -c cs1331-checkstyle.xml *.java | findstr /v “Starting audit…” |
findstr /v “Audit done” | find /c /v “hashcode()”
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Food for thought: is there a one-liner like above that shows you only the number of errors? Hint: man
grep.
The Java source files we provide contain no Checkstyle errors. For this assignment, there will be a maximum of 100
points lost due to Checkstyle errors (1 point per error). In future homeworks we will be increasing this cap, so get into
the habit of fixing these style errors early!
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7 Turn-in Procedure
Submit all of the Java source files you modified and resources your program requires to run to T-Square. Do not submit
any compiled bytecode (.class files), the Checkstyle jar file, or the
cs1331-checkstyle.xml file. When you’re ready, double-check that you have submitted and not just saved a
draft.
Please remember to run your code with Checkstyle!
Verify the Success of Your Submission to T-Square
Practice safe submission! Verify that your HW files were truly submitted correctly, the upload was successful, and that
the files compile and run. It is solely your responsibility to turn in your homework and practice this safe submission
safeguard.
1. After uploading the files to T-Square you should receive an email from T-Square listing the names of the files
that were uploaded and received. If you do not get the confirmation email almost immediately, something is
wrong with your HW submission and/or your email. Even receiving the email does not guarantee that you
turned in exactly what you intended.
2. After submitting the files to T-Square, return to the Assignment menu option and this homework. It should show
the submitted files.
3. Download copies of your submitted files from the T-Square Assignment page placing them in a new folder.
4. Recompile and test those exact files.
5. This helps guard against a few things.
(a) It helps insure that you turn in the correct files.
(b) It helps you realize if you omit a file or files. 1
(If you do discover that you omitted a file, submit all of
your files again, not just the missing one.)
(c) Helps find last minute causes of files not compiling and/or running.
1Missing files will not be given any credit, and non-compiling homework solutions will receive few to zero points. Also recall that late homework
will not be accepted regardless of excuse. Treat the due date with respect. The real due date is midnight. Do not wait until the last minute!
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