ImageProcessing.java

import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
public class ImageProcessing {
	
	public static int [][][] loadBMP(String filename) {					//converts an image to a string array
		BufferedImage img = null;
		try {
			img = ImageIO.read(new File(filename));
		} catch (IOException e) {
			System.out.println(e); 
		}
		int height = img.getHeight();
		int width = img.getWidth();
		int image[][][] = new int[height][width][3];
		int rgb;
		for (int h=0; h<height; h++)
		{
			for (int w = 0; w<width; w++)
			{ 
				rgb = img.getRGB(w, h);
				image[h][w][0] = (rgb >> 16 ) & 0x000000FF;
				image[h][w][1] = (rgb >> 8 ) & 0x000000FF;
				image[h][w][2] = (rgb) & 0x000000FF;
			}
		}
		return image;
	}
	
	public static void saveBMP(int image[][][], String filename) {		//saves an array with depth 3 as a picture with color bmp type
		int height = image.length;
		int width = image[0].length;
		BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		int p, r, g, b;
		for (int h=0; h<height; h++)
		{
			for (int w = 0; w<width; w++)
			{ 
				r = image[h][w][0]; 
				g = image[h][w][1]; 
				b = image[h][w][2]; 
				// set the pixel value 
				p = (r << 16) | (g << 8) | b; 
				img.setRGB(w, h, p); 
			}
		}
		// write image 
		try { 
			File f = new File(filename); 
			ImageIO.write(img, "bmp", f); 
		} 
		catch (IOException e) { 
			System.out.println(e); 
		}
	}
	
	public static void saveGrayscaleBMP(int image[][], String filename) {	//saves an array with depth 2 as a gray scale picture bmp type
		int height = image.length;
		int width = image[0].length;
		BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
		for (int h=0; h<height; h++)
		{
			for (int w = 0; w<width; w++)
			{ 
				int p = (image[h][w] << 16) | (image[h][w] << 8) | image[h][w]; 
				img.setRGB(w, h, p); 
			}
		}
		// write image 
		try { 
			File f = new File(filename); 
			ImageIO.write(img, "bmp", f); 
		} 
		catch (IOException e) { 
			System.out.println(e); 
		}
	}
	
	public static int numOfNumbers(String a) {							//finds how many numbers there are in a string
		int nums=0;
		for(int i=0;i<a.length();i++) {
			for(int c='0';c<='9';c++) {
				if(a.charAt(i)==c)
					nums++;
			}
		}
		return nums;
	}
	
	public static void main(String[] args) {
		String photo_edit=args[0];		//what type of photo edit function the user chooses
		switch (photo_edit) {			//6 different functions with certain names
		case "-display":
			if(numOfNumbers(args[args.length-2])!=args[args.length-2].length())						//Case error 4: checks if the string is not a number
				System.out.println("Missing arguments about pixel position. Program is terminated");
			else {
			int x=Integer.parseInt(args[args.length-2]), y=Integer.parseInt(args[args.length-1]);
			for(int i=1;i<args.length-2;i++)
				display(args[i],x,y);
			}
			break;
		case "-hflip":
			for(int i=1;i<args.length;i++)
				hflip(args[i]);
			break;
		case "-vflip":
			for(int i=1;i<args.length;i++)
				vflip(args[i]);
			break;
		case "-right90":
			for(int i=1;i<args.length;i++)
				right90(args[i]);
			break;
		case "-left90":
			for(int i=1;i<args.length;i++)
				left90(args[i]);
			break;
		case "-grey":
			for(int i=1;i<args.length;i++)
				grey(args[i]);
			break;
		default:			//In case the photo edit function given is not available within this program or it is written incorrectly 
			System.out.println("Wrong option given. Program is terminated");
		}
		
	}
	
	public static void display(String pic_name, int x, int y) {		//Gives the values or Red, Green and Blue in integer numbers (color pick RGB values)
		int[][][] arr=loadBMP(pic_name);
		int width=arr[0].length-1, height=arr.length-1;
		if(x>height)												//Case error 1: Out of bounds height
			System.out.println("Height out of bounds!");
		else if(y>width)											//Case error 2: Out of bounds width
			System.out.println("Width out of bounds!");
		else if(!pic_name.endsWith(".bmp"))							//Case error 3: Not a BMP picture
			System.out.println("Image is not bmp. Program is terminated");
		else
			System.out.println("RGB["+x+','+y+"] = ("+arr[x][y][0]+','+arr[x][y][1]+','+arr[x][y][2]+')');
	}
	
	public static void hflip(String pic_name) {						//Flips an image horizontally
		int[][][] arr=loadBMP(pic_name);
		int width=arr[0].length, height=arr.length, color=arr[0][0].length;
		int temp;
		if(!pic_name.endsWith(".bmp"))								//Case error 3
			System.out.println("Image is not bmp. Program is terminated");
		else {
			for(int h=0;h<height;h++) {
				for(int w=0;w<=width/2;w++) {
					for(int c=0;c<color;c++) {
						temp=arr[h][w][c];
						arr[h][w][c]=arr[h][width-1-w][c];
						arr[h][width-1-w][c]=temp;
					}
				}
			}
			saveBMP(arr, "hflip-"+pic_name);
		}
	}
	
	public static void vflip(String pic_name) {					//Flips an image vertically
		int[][][] arr=loadBMP(pic_name);
		int width=arr[0].length, height=arr.length, color=3;
		int temp;
		if(!pic_name.endsWith(".bmp"))							//Case error 3
			System.out.println("Image is not bmp. Program is terminated");
		else {
			for(int w=0;w<width;w++) {
				for(int h=0;h<height/2;h++) {
					for(int c=0;c<color;c++) {
						temp=arr[h][w][c];
						arr[h][w][c]=arr[height-1-h][w][c];
						arr[height-1-h][w][c]=temp;
					}
				}
			}
			saveBMP(arr, "vflip-"+pic_name);
		}
	}
	
	public static void right90(String pic_name) {			//Rotates an image right by 90 degrees
		int[][][] arr=loadBMP(pic_name);
		int width=arr[0].length, height=arr.length, color=arr[0][0].length;
		int[][][] arr_r90=new int[width][height][color];
		if(!pic_name.endsWith(".bmp"))						//Case error 3
			System.out.println("Image is not bmp. Program is terminated");
		else {
			for(int w=0;w<width;w++) {
				for(int h=0;h<height;h++) {
					for(int c=0;c<color;c++) {
						arr_r90[w][height-1-h][c]=arr[h][w][c];
					}
				}
			}
			saveBMP(arr_r90, "right90-"+pic_name);
		}
	}
	
	public static void left90(String pic_name) {		//Rotates an image left by 90 degrees
		int[][][] arr=loadBMP(pic_name);
		int width=arr[0].length, height=arr.length, color=arr[0][0].length;
		int[][][] arr_l90=new int[width][height][color];
		if(!pic_name.endsWith(".bmp"))					//Case error 3
			System.out.println("Image is not bmp. Program is terminated");
		else {
			for(int h=0;h<height;h++) {
				for(int w=0;w<width;w++) {
					for(int c=0;c<color;c++) {
						arr_l90[width-1-w][h][c]=arr[h][w][c];
					}
				}
			}
			saveBMP(arr_l90, "left90-"+pic_name);
		}
	}
	
	public static void grey(String pic_name) {		//Turns a colorful image to a black and white image (grey scale filter)
		int[][][] arr=loadBMP(pic_name);
		int width=arr[0].length, height=arr.length;
		int[][] arr_grey=new int[height][width];
		if(!pic_name.endsWith(".bmp"))				//Case error 3
			System.out.println("Image is not bmp. Program is terminated");
		else {
			for(int h=0;h<height;h++) {
				for(int w=0;w<width;w++) {
					arr_grey[h][w]=(int)(arr[h][w][0]*0.299+arr[h][w][1]*0.587+arr[h][w][2]*0.114);
				}
			}
			saveGrayscaleBMP(arr_grey,"grey-"+pic_name);
		}
	}
}
/**
* Author: Theonitsa Chrysanthou
* Written: 09/11/2024
* Last updated: 09/11/2024
*
* Compilation: javac ImageProcessing.java
* Execution: java ImageProcessing -grey image1.bmp
* 			 java ImageProcessing -vflip image1.bmp image2.bmp
* 			 java ImageProcessing hflip image2.bmp
* 			 java ImageProcessing -grey image1.jpg
* 			 java ImageProcessing -left90 image3.bmp
* 			 java ImageProcessing -right90 image1.bmp
* 			 java ImageProcessing -display image1.bmp 1 1
* 			 java ImageProcessing -display 3x4 3 0
* 			 java ImageProcessing -display 3x4.bmp 0
* 			 java ImageProcessing -display 3x4.bmp 0 4
* 			 java ImageProcessing -hflip image1.bmp
* 			 java ImageProcessing -display 3x4
* 
* The program above is a simple photo editor with basic functions (horizontal flip, vertical flip, left rotation by 90 degrees, right rotation by 90 degrees,
* gray scale filter, color pick RGB values) and it can only process pictures of the bmp type. The logic of the program lays within multi-dementional tables' logic,
* since the pictures being processed are first turned into 3D tables of integer values that represent the values of red, green and blue that are used in a certain
* pixel to create its color.
*/