Question

16. What do the following two code fragments do given integers a and b? a-a + b b-a b just print the code you wrote with comments RGBA color format. Some of Java's classes (Bufferedlmage, PixelGrabber) use a special encoding called RGBA to store the color of each pixel. The format consists of tour integers, representing the red, green, and blue intensities from 0 (not present) to 255 (fully used), and also the alpha transparency value from O (transparent) to 255 (opaque). The four 8-bit integers are compacted into a single 32-bit integer. Write a code fragment to extract the four components from the RGBA integer, and to go the other way.

Answer 1

import java.util.Scanner;

public class RGBA {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        System.out.print("Enter a 32-bit integer: ");
        int num = in.nextInt();
        int r = (num >> 24) & 0xFF;
        int g = (num >> 16) & 0xFF;
        int b = (num >> 8) & 0xFF;
        int a = num & 0xFF;
        System.out.println("Red = " + r);
        System.out.println("Green = " + g);
        System.out.println("Blue = " + b);
        System.out.println("Alpha = " + a);
    }

}

Enter a 32-bit integer: Red 127 Green = 2 5 5 Blue = 255 Alpha = 248 Process finished with e xit code 0