Advanced Software Paradigms - Assignment 3 (Concurrency)

Description of the task

The main objective in this assignment is to convert grayscale to color using multi-threaded and single-threaded programming.

The output application is supposed to take three arguments from the command line:

• filename (directory of the file)
• square size
• the processing mode

Example command: program inputfile.jpg 15 M

• file name: the name of the grayscale image file in jpg format (no size constraints)
• square size: the side of the square
• processing mode: 'S' - single threaded and 'M' - multi threaded

During the execution of the program, the grayscale image is first shown, and the following procedures starts:

• The program converts the grayscale pixels into color from left to right, top to bottom for each of the (square size) x (square size) boxes. While converting grayscale to color creativity is considered more important than reproduction of the original from the grayscale.
• The result of the program is shown by progress, not at once. The result picture is saved to the same directory as result.jpg file
• In the multi-processing mode ('M'), the procedure is performed in parallel threads. The number of threads are selected according to the computer's CPU cores. In this assignment Runtime.getRuntime().availableProcessors() is used to use number of processors available to the JVM during the runtime.

Description to run program

Firstly, a program needs to be compiled with the following command:

javac Main.java

Secondly, for a successfull execution of a program, all three parameters (file name, square size and processing mode) needs to be passed as command line arguments as mentioned in the task description. The parameters should be seperated by a single space. In the examples given below some of the commands to execute the program are given.

• For the command with parameters(file name: SampleInput1.jpg, square size: 15, and processing mode: S) run:

java Main.java SampleInput1.jpg 15 S

• For the command with parameters(file name: SampleInput2.jpg, square size: 10, and processing mode: M) run:

java Main.java SampleInput2.jpg 10 M

Description of program

There are 3 parts of the program:

• Main.java
• Coordinates.java
• Processing.java

Description of Main Class

Main class takes the arguments from the command line and uses the following methods:

• convert_image() Description: This method the picture in the given command line argument is imported and based on the given processing mode either singleMode()or multiMode() method is called

• singleMode() Description: This method calls processing.convert() method with single thread where the processing of the picture from grayscale to color is happened

• multiMode() Description: This method first creates extra threads with Runtime.getRuntime().availableProcessors() and equallly distribute the picture among the threads. This method calls Coordinates class where the coordinates for the threads are assigned and processing.convert() method where the processing of the picture with multithreads is happened. Seperately processed pieces of picture via multithreads are joined in this method

• The processing of the picture from grayscale to color in Processing class is done with the following code:

  {Color col = new Color(20, color.getGreen(), 20);
  input_image.setRGB(j + l, i + k, col.getRGB());}
  
  
  else if (color.getRed()<150 && color.getGreen()<150 && color.getBlue()<150 )
  {Color col = new Color(color.getRed(), color.getGreen(), 20);
  input_image.setRGB(j + l, i + k, col.getRGB());}
  
  
  else if (color.getRed()<170 && color.getGreen()<170 && color.getBlue()<170 )
  {Color col = new Color(color.getRed(), color.getGreen(), 5);
  input_image.setRGB(j + l, i + k, col.getRGB());}
  
  else if (color.getRed()<200 && color.getGreen()<200 && color.getBlue()<200 )
  {Color col = new Color(150, 150, color.getBlue());
  input_image.setRGB(j + l, i + k, col.getRGB());}
  
  else 
  {Color col = new Color(color.getRed(), color.getGreen(),150);
  input_image.setRGB(j + l, i + k, col.getRGB());}```