Java BufferedImage alternatives

Question

I am trying to implement a simple class that will allow a user to crop an image to be used for their profile picture. This is a java web application.

I have done some searching and found that java.awt has a BufferedImage class, and this appears (at first glance) to be perfect for what I need. However, it seems that there is a bug in this (or perhaps java, as I have seen suggested) that means that the cropping does not always work correctly.

Here is the code I am using to try to crop my image:

    BufferedImage profileImage = getProfileImage(form, modelMap);
    if (profileImage != null) {
        BufferedImage croppedImage = profileImage
                .getSubimage(form.getStartX(), form.getStartY(), form.getWidth(), form.getHeight());
        System.err.println(form.getStartX());
        System.err.println(form.getStartY()); 
        File finalProfileImage = new File(form.getProfileImage());
        try {
            String imageType = getImageType(form.getProfileImage());
            ImageIO.write(croppedImage, imageType, finalProfileImage);
        }
        catch (Exception e) {
            logger.error("Unable to write cropped image", e);
        }
    }
    return modelAndView;
}

protected BufferedImage getProfileImage(CropImageForm form, Map<String, Object> modelMap) {
    String profileImageFileName = form.getProfileImage();
    if (validImage(profileImageFileName) && imageExists(profileImageFileName)) {
        BufferedImage image = null;
        try {
            image = getCroppableImage(form, ImageIO.read(new File(profileImageFileName)), modelMap);
        }
        catch (IOException e) {
            logger.error("Unable to crop image, could not read profile image: [" + profileImageFileName + "]");
            modelMap.put("errorMessage", "Unable to crop image.  Please try again");
            return null;
        }
        return image;
    }

    modelMap.put("errorMessage", "Unable to crop image.  Please try again.");
    return null;
}

private boolean imageExists(String profileImageFileName) {
    return new File(profileImageFileName).exists();
}

private BufferedImage getCroppableImage(CropImageForm form, BufferedImage image, Map<String, Object> modelMap) {
    int cropHeight = form.getHeight();
    int cropWidth = form.getWidth();
    if (cropHeight <= image.getHeight() && cropWidth <= image.getWidth()) {
        return image;
    }
    modelMap.put("errorMessage", "Unable to crop image. Crop size larger than image.");
    return null;
}

private boolean validImage(String profileImageFileName) {
    String extension = getImageType(profileImageFileName);
    return (extension.equals("jpg") || extension.equals("gif") || extension.equals("png"));
}

private String getImageType(String profileImageFileName) {
    int indexOfSeparator = profileImageFileName.lastIndexOf(".");
    return profileImageFileName.substring(indexOfSeparator + 1);
}

The form referred to in this code snippet is a simple POJO which contains integer values of the upper left corner to start cropping (startX and startY) and the width and height to make the new image.

What I end up with, however, is a cropped image that always starts at 0,0 rather than the startX and startY position. I have inspected the code to make sure the proper values are being passed in to the getSubimage method, and they appear to be.

Are there simple alternatives to using BufferedImage for cropping an image. I have taken a brief look at JAI. I would rather add a jar to my application than update the jdk installed on all of the production boxes, as well as any development/testing servers and local workstations.

My criteria for selecting an alternative are: 1) simple to use to crop an image as this is all I will be using it for 2) if not built into java or spring, the jar should be small and easily deployable in a web-app

Any suggestions?

Note: The comment above that there is an issue with bufferedImage or Java was something I saw in this posting: Guidance on the BufferedImage.getSubimage(int x, int y, int w, int h) method?

Answer 1

Thanks for all who replied. It turns out that the problem was not in the cropping code at all.

When I displayed the image to be cropped, I resized it to fit into my layout nicely, then used a javascript cropping tool to figure out the coordinates to crop.

Since I had resized my image, but didn't take the resizing into account when I was determining the cropping coordinates, I ended up with coordinates that appeared to coincide with the top left corner.

I have changed the display to no longer resize the image, and now cropping is working beautifully.

Answer 2

I have used getSubimage() numerous times before without any problems. Have you added a System.out.println(form.getStartX() + " " + form.getStartY()) before that call to make sure they're not both 0?

Also, are you at least getting an image that is form.getWidth() x form.getHeight()?

Do make sure you are not modifying/disposing profileImage in any way since the returned BufferedImage shares the same data array as the parent.

The best way is to just simply draw it across if you want a completely new and independent BufferedImage:

BufferedImage croppedImage = new BufferedImage(form.getWidth(),form.getHeight(),BufferedImage.TYPE_INT_ARGB);

Graphics g = croppedImage.getGraphics();
g.drawImage(profileImage,0,0,form.getWidth(),form.getHeight(),form.getStartX(),form.getStartY(),form.getWidth(),form.getHeight(),null);
g.dispose();

Answer 3

You can do it in this manner as well (code is not 100% tested as I adopted for example from an existing app i did):

import javax.imageio.*;
import java.awt.image.*;
import java.awt.geom.*;

...

BufferedImage img = ImageIO.read(imageStream);

...

/*
 *  w = image width, h = image height, l = crop left, t = crop top
 */

ColorModel dstCM = img.getColorModel();
BufferedImage dst = new BufferedImage(dstCM, dstCM.createCompatibleWritableRaster(w, h), dstCM.isAlphaPremultiplied(), null);

Graphics2D g = dst.createGraphics();
g.drawRenderedImage(img, AffineTransform.getTranslateInstance(-l,-t));
g.dispose();

java.io.File outputfile = new java.io.File(sessionScope.get('absolutePath') + java.io.File.separator + sessionScope.get('lastUpload'));
ImageIO.write(dst, 'png', outputfile);