CODEWITHSUNDEEP
javaimage-processing
Kailash
Kailash

Reputation: 642

pixel value representation for the image in java

I am trying to read the pixel values of the image using the below code

 int[] pixel;
 BufferedImage imageA = ImageIO.read(new File("xyz.bmp"));
 for (int y = 0; y < imageA.getHeight(); ++y) {
 for (int x = 0; x < imageA.getWidth(); ++x) {
    pixel = imageA.getRaster().getPixel(x, y, new int[3]);  
}}

values of RGB are stored in pixel[0],pixel[1] and pixel[2] respectively and when i saw the output i saw the values ranging between 0 to 255. I saw some use the below code to get pixel values

int pixel;
BufferedImage imageA = ImageIO.read(new File("xyz.bmp"));
for (int y = 0; y < imageA.getHeight(); ++y) {
for (int x = 0; x < imageA.getWidth(); ++x) {
       pixel = imageA.getRGB(x, y);
}}

When i saw the output for a particular pixel it was -14935264 . What does this value represent and whats the difference between the above two methods.

Upvotes: 1

Views: 501

Answers (1)

Jesper
Jesper

Reputation: 206996

In the second case, you get an int that contains the RGB-values in the lower 24 bits. The red component is bits 23-16, the green component is bits 15-8 and the blue component is bits 7-0.

If you want to get the components out of the int:

int red = (pixel >> 16) & 0xFF;
int green = (pixel >> 8) & 0xFF;
int blue = pixel & 0xFF;

The other way around:

int pixel = (red << 16) | (green << 8) | blue;

Upvotes: 0

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