CODEWITHSUNDEEP
javabufferedimage
Mathew
Mathew

Reputation: 1430

java croped image all black

I am trying to crop an image using a java, here is my code:

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

public class crop
{
    public static void main(String[] args)
    {

        BufferedImage img = null;
        try
        {
            img = ImageIO.read(new File("/Users/mathewlewis/desktop/pic.jpg"));
            String width = "" + img.getWidth();
            String height = "" + img.getHeight();
            cout("heigth = " + height + " and width = " + width);
            BufferedImage crp = img.getSubimage(0,0,100,200);


            try {
                File outputfile = new File("crop_pic.jpg");
                ImageIO.write(crp, "jpg", outputfile);
            }
            catch (IOException e)
            {
                System.out.println("error");
            }

        }
        catch (IOException e)
        {
            System.out.println("error");
        }
    }
}

Everything runs fine (no errors), but when I open crop_pic.jpg it is all black. Here is pic.jpg.

I would like to know why the image comes out all black, and how I can fix it.

I tried this

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

public class crop
{
    public static void main(String[] args)
    {

        BufferedImage img = null;
        try
        {
            img = ImageIO.read(new File("/Users/mathewlewis/desktop/pic.jpg"));
            BufferedImage rgbImage = new BufferedImage(img.getWidth(), img.getHeight(), BufferedImage.TYPE_3BYTE_BGR);
            ColorConvertOp op = new ColorConvertOp(null);
            op.filter(img, rgbImage);
            BufferedImage crp = rgbImage.getSubimage(300,300,rgbImage.getWidth()-300,rgbImage.getHeight()-300);





            try {
                File outputfile = new File("crop_pic.jpg");
                ImageIO.write(crp, "jpg", outputfile);
            }
            catch (IOException e)
            {
                System.out.println("error");
            }

        }
        catch (IOException e)
        {
            System.out.println("error");
        }
    }
}

and got this error:

crop.java:16: error: cannot find symbol
            ColorConvertOp op = new ColorConvertOp(null);
            ^
  symbol:   class ColorConvertOp
  location: class crop
crop.java:16: error: cannot find symbol
            ColorConvertOp op = new ColorConvertOp(null);
                                    ^
  symbol:   class ColorConvertOp
  location: class crop
2 errors

Thank you Forseth11!! should have noticed that I didn't import java.awt.image.ColorConvertOp! You've been a great help. Thanks a lot!!!

Upvotes: 0

Views: 1045

Answers (1)

Forseth11
Forseth11

Reputation: 1438

I looked around a bit and found that other people have had a similar problem. On my end when testing this I got a strangely colored image, not a black image. This problem is caused because ImageIO is reading the image wrong.

Here is what I have come up with which works, but since I could not replicate your problem and get a black image this may not work for you.

img = ImageIO.read(new File("/Users/mathewlewis/desktop/pic.jpg"));

BufferedImage rgbImage = new BufferedImage(img.getWidth(), img.getHeight(),
BufferedImage.TYPE_3BYTE_BGR);
ColorConvertOp op = new ColorConvertOp(null);
op.filter(img, rgbImage);

String width = "" + rgbImage.getWidth();
String height = "" + rgbImage.getHeight();
System.out.println("heigth = " + height + " and width = " + width);

BufferedImage crp = rgbImage.getSubimage(300,300,rgbImage.getWidth()-300,rgbImage.getHeight()-300);

These are some other posts which have a similar issue:

Edit: I changed where it cropped, so it is easy to see because the upper left part of the image is mostly yellow.

Upvotes: 2

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