Converting Image to Color array

Question

I load an image in Java and want to convertit to a RGB-Array so I can read the color of each single pixel. I searched on Google, but I only found how to convert Color-Arrays to Images.

Check out the documentation docs.oracle.com/javase/6/docs/api/java/awt/image/…, specifically getRGB(). — Reinstate Monica -- notmaynard
– Reinstate Monica -- notmaynard, Commented Apr 8, 2013 at 14:16
How are you loading your Image? Most likely you can just pass a BufferedImage instead. — Reinstate Monica -- notmaynard
– Reinstate Monica -- notmaynard, Commented Apr 8, 2013 at 14:36
Or you can cast your Image as BufferedImage. If you post your code where you load you image, I can be more specific. — Reinstate Monica -- notmaynard
– Reinstate Monica -- notmaynard, Commented Apr 8, 2013 at 14:44

stacker · Accepted Answer · 2013-04-08 19:59:25Z

3

The following lines illustrate the usage of the API methods:

BufferedImage bi = ImageIO.read( new File( "image.png" ) );
int[] data = ( (DataBufferInt) bi.getRaster().getDataBuffer() ).getData();
for ( int i = 0 ; i < data.length ; i++ ) {
    Color c = new Color(data[i]);
    // RGB is now accessible as
    c.getRed();
    c.getGreen();
    c.getBlue();
}

If you face issues due to the color model, create a copy first

BufferedImage img2 = new BufferedImage( bi.getWidth(), bi.getHeight(), BufferedImage.TYPE_INT_RGB );

img2.getGraphics().drawImage( bi, 0, 0, null );

and use img2 in the above code.

edited Apr 8, 2013 at 19:59

answered Apr 8, 2013 at 14:35

stacker

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4 Comments

jalgames Over a year ago

Does img strand for the Image i want to convert?

stacker Over a year ago

@user2241553 sorry that was a mistake, I fixed that.

Giannis Tzagarakis Over a year ago

why is data.length larger than img.width*img.height ?

stacker Over a year ago

@GiannisTzagarakis thats because width*height is the number of pixels and a pixel can have more than a byte. (RGB values plus alpha deoending on the type e.g. BufferedImage.TYPE_INT_RGB)

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