Image Processing in Java | Set 4 (Colored image to Negative image conversion)

We strongly recommend to refer below post as a prerequisite of this.

In this set we will be converting a colored image to negative image.
Note: In a negative image the Alpha component of the image will be same as the original image, but the RGB will be changed i.e, all three RGB components will be having a value of 255-original component value.

Algorithm:



  1. Get the RGB value of the pixel.
  2. Calculate new RGB values as follows:
    • R = 255 – R
    • G = 255 – G
    • B = 255 – B
  3. Replace the R, G and B value of the pixel with the values calculated in step 2.
  4. Repeat Step 1 to Step 3 for each pixels of the image.


Implementation of the above algorithm:

// Java program to demonstrate colored to negative conversion
import java.io.File;
import java.io.IOException;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
  
public class Negative
{
    public static void main(String args[])throws IOException
    {
        BufferedImage img = null;
        File f = null;
  
        // read image
        try
        {
            f = new File("G:\\Inp.jpg");
            img = ImageIO.read(f);
        }
        catch(IOException e)
        {
            System.out.println(e);
        }
  
        // Get image width and height
        int width = img.getWidth();
        int height = img.getHeight();
  
        // Convert to negative
        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                int p = img.getRGB(x,y);
                int a = (p>>24)&0xff;
                int r = (p>>16)&0xff;
                int g = (p>>8)&0xff;
                int b = p&0xff;
  
                //subtract RGB from 255
                r = 255 - r;
                g = 255 - g;
                b = 255 - b;
  
                //set new RGB value
                p = (a<<24) | (r<<16) | (g<<8) | b;
                img.setRGB(x, y, p);
            }
        }
  
        // write image
        try
        {
            f = new File("G:\\Out.jpg");
            ImageIO.write(img, "jpg", f);
        }
        catch(IOException e)
        {
            System.out.println(e);
        }
    }
}

Note : This code will not run on online IDE as it needs an image on disk.

Inp.jpg
Inp

Out.jpg
Out

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