rotating an image 90 degrees in java

Question

I have managed to rotate an image 180 degrees but wish to rotate it 90 degrees clockwise can someone edit my code so that it does this with explanation. Thanks.

 private void rotateClockwise()
    {
        if(currentImage != null){
            int width = currentImage.getWidth();
            int height = currentImage.getHeight();
            OFImage newImage = new OFImage(width, height);
            for(int y = 0; y < height; y++) {
                for(int x = 0; x < width; x++) {
                    newImage.setPixel( x, height-y-1, currentImage.getPixel(x, y));
                }
        }
            currentImage = newImage;
            imagePanel.setImage(currentImage);
            frame.pack();
    }
    }

Answer 1

Use this method.

/**
 * Rotates an image. Actually rotates a new copy of the image.
 * 
 * @param img The image to be rotated
 * @param angle The angle in degrees
 * @return The rotated image
 */
public static Image rotate(Image img, double angle)
{
    double sin = Math.abs(Math.sin(Math.toRadians(angle))),
           cos = Math.abs(Math.cos(Math.toRadians(angle)));

    int w = img.getWidth(null), h = img.getHeight(null);

    int neww = (int) Math.floor(w*cos + h*sin),
        newh = (int) Math.floor(h*cos + w*sin);

    BufferedImage bimg = toBufferedImage(getEmptyImage(neww, newh));
    Graphics2D g = bimg.createGraphics();

    g.translate((neww-w)/2, (newh-h)/2);
    g.rotate(Math.toRadians(angle), w/2, h/2);
    g.drawRenderedImage(toBufferedImage(img), null);
    g.dispose();

    return toImage(bimg);
}

taken from my ImageTool class.

Hope it helps.