Lab 2: Mean Image Median Displayed

Overview

In this assignment, you will incorporate lab 1 feedback from your instructor (if available), and load and display images in a graphical user interface.

Video introduction for the lab

Pre-Lab (DUE BEFORE LAB - see due date in Canvas)

As part of the pre-lab activity you must ensure that you have JavaFX installed on your laptop.

Installing JavaFX [14:25]
Written instructions

If you are continuing to use the same repository as you used for the first assignment, you’ll need to add the VM options to the run configuration for this project since the run configuration for new projects that you configured following the installation instructions only apply to new projects.

Assignment

In addition to incorporating feedback from your instructor, you must replace the code in the mocked package with appropriate JavaFX code (change the imports to use the javafx.scene.image classes). You must:

Declare readPPMImage() and writePPMImage() as private methods
Ensure that alpha value is set to 255 in readPPMImage()
Implement readImage() and writeImage() methods with the same parameters as readPPMImage() and writePPMImage() and return type that will call readPPMImage() and writePPMImage() when the file extention on the Path ends with .ppm.
Ensure calculateMedianImage() and calculateMeanImage() calculate alpha value for each pixel.
Create a Lab2 class that extends the JavaFX Application class and overrides the start() method. (Delete the Lab1 class or comment out calls to readPPMImage() and writePPMImage() since they are now private methods)
Update readImage() and writeImage() methods to use JavaFX classes to add support for reading and writing JPG and PNG file formats.
If a path with an unsupported file extension is passed to either readImage() or writeImage(), the method should throw an IllegalArgumentException.
Ensure that the Lab2 class catches any exceptions thrown and displays a useful error message before exiting gracefully.
The program should display the calculated image in a window.

Writing an image in PNG or JPG format can be done with the javax.imageio.ImageIO.write() method, and you can use the javafx.embed.swing.SwingFXUtils.fromFXImage() method to get a BufferedImage (that is a RenderedImage). If writing PNG files works but it doesn't work for JPG files, don't worry about it.

Your program must run as a .jar file from the command line and accept the following arguments:

Operation preference — either median or mean (all lowercase)
Output filename — e.g., images/output.png
At least two input image filenames — e.g., images/input1.jpg and images/input2.jpg

Potentially useful tutorials:

Once the .jar file is created, move it from the out/artifacts/... folder into the project folder (same folder as the README.md file) and rename it lab2.jar.

The program will process the input images to produce the desired output and then save and display the resulting image. For example,

java -jar lab2.jar median images/codeMedian.ppm images/code1.png images/code2.png images/code3.png

will produce codeMedian.ppm in the images folder that is the median of the first three codeX.png images.

You can display an Image in the Scene by placing the Image in a ImageView that is placed in an HBox that then gets added to the Scene.

Exception Handling

If any problems are encountered with reading the input files or writing the output file, the program should display a useful error message to the console and terminate gracefully. The program should not crash or display any exceptions.

Just For Fun

Ambitious students may wish to:

Display all of the input images as well as the output image.

Acknowledgement

This laboratory assignment, developed by Dr. Chris Taylor.

See your professor's instructions for details on submission guidelines and due dates.