Converting an array to image Java

Question

I would like to convert an array of pixels to images so that I can read each pixel of the image, I've converted the image to pixels and now what I'm trying to do is that I have a picture of an RGB circle , After converting the image to pixels I want to draw images again but Not the entire picture again , I want to draw the red circle alone , the green circle alone and the blue circle alone and store the images in a file , how can that be done ?

Here's the code that I used to convert the image to array pixels :

import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.awt.image.ImageObserver;
import java.awt.image.PixelGrabber;
import java.io.File;
import java.io.IOException;

public class BMPtoArray {
public static int[] convertToPixels(Image img) {
    int width = img.getWidth(null);
    int height = img.getHeight(null);
    int[] pixel = new int[width * height];

    PixelGrabber pg = new PixelGrabber(img, 0, 0, width, height, pixel, 0, width);
    try {
        pg.grabPixels();
    } catch (InterruptedException e) {
        throw new IllegalStateException("Error: Interrupted Waiting for Pixels");
    }
    if ((pg.getStatus() & ImageObserver.ABORT) != 0) {
        throw new IllegalStateException("Error: Image Fetch Aborted");
    }
    return pixel;
}
public static void main(String[] args) throws IOException {
    BufferedImage image = ImageIO.read(new File("C:\\Users\\Mhamd\\Desktop\\3rd year 
first semester\\Analysis and Coding\\labs\\2.2Java\\src\\circleRGB.bmp"));
    //System.out.println(convertToPixels(image));
}
}

Here's the image :

so this is basically what I'm trying to achieve

[![This is what I want to Achieve][2]][2]

You might want to look at cropping the image, rather than manipulating pixels. stackoverflow.com/questions/2386064/… — computercarguy
– computercarguy, Commented Nov 24, 2021 at 17:18
Here's a couple more links, some including libraries that might help: stackoverflow.com/questions/7894275/cropping-an-image-in-java and stackoverflow.com/questions/23610007/… and stackoverflow.com/questions/5186597/… — computercarguy
– computercarguy, Commented Nov 24, 2021 at 17:26
@computercarguy thanks but I don't want to crop the image , I want to keep the dimensions of the old image but rather than drawing all the circles , I want to draw each color on its own as in the picture above — Mohammed Hamdoon
– Mohammed Hamdoon, Commented Nov 24, 2021 at 17:28
I was thinking you wanted to keep the color interaction of the overlap, but if that's not the case, then why not simply draw the circles in their own BufferedImage and save them separately? Even if the image is generated dynamically, you should be able to keep track of the individual changes, then recreate them in each of their own image. Or keep an array of BufferedImages for each element that you never display. That'll take up lots of RAM, but it'd be similar to Layers in Photoshop and Gimp. — computercarguy
– computercarguy, Commented Nov 24, 2021 at 17:35
When you’re working with a BufferedImage, you don’t need such complicated approaches, see getRGB and setRGB — Holger
– Holger, Commented Nov 24, 2021 at 17:52

001 · Accepted Answer · 2021-11-24 17:56:48Z

1

Here's a simple example of how to "turn off" the red channel:

final BufferedImage image = ImageIO.read(new File("test.bmp"));
int red = 0x00FF0000;
for (int row = 0; row < image.getHeight(); row++) {
    for (int col = 0; col < image.getWidth(); col++) {
        int color = image.getRGB(col, row);
        color &= ~red;
        image.setRGB(col, row, color);
    }
}

This sets the red in each RGB pixel to 0. You can repeat for other colors and combinations.

This produces this from your source image:

answered Nov 24, 2021 at 17:56

001

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1 Comment

Mohammed Hamdoon Over a year ago

Exactly what is needed , thank you so much

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