java - RenderedImage to BufferedImage for multipage-tiff reading

Question

I am using JAI to load in multipage TIFF images

File file = workArea[0];
SeekableStream s = new FileSeekableStream(file);

TIFFDecodeParam param = null;

ImageDecoder dec = ImageCodec.createImageDecoder("tiff", s, param);

//first page
RenderedImage op1 =
    new NullOpImage(dec.decodeAsRenderedImage(0),
                    null,
                    OpImage.OP_IO_BOUND,
                    null);

BufferedImage pg1 = new BufferedImage(op1.getWidth(), op1.getHeight(),
                                      BufferedImage.TYPE_INT_RGB);
pg1.getGraphics().drawImage((Image) op1, 0, 0, null);

However, in the last line I get a runtime error of:

 Exception in thread "main" java.lang.ClassCastException: 
      javax.media.jai.MullOpImage cannot be cast to java.awt.Image

I clear the RenderedImage after attempting to set the BufferedImage so I don't exactly "need" the RenderedImage if there is another method of doing this.

I attempted:

 pg1.setData(op1.getData());

and that gives an ArrayIndexOutOfBoundsException. I'm not sure why exactly as pg1's width and height are set by op1's, but there is probably a very valid reason.

Answer 1

I found a solution at http://www.jguru.com/faq/view.jsp?EID=114602

The first one didn't work, however, the convertRenderedImage function did work.

public BufferedImage convertRenderedImage(RenderedImage img) {
    if (img instanceof BufferedImage) {
        return (BufferedImage)img;  
    }   
    ColorModel cm = img.getColorModel();
    int width = img.getWidth();
    int height = img.getHeight();
    WritableRaster raster = cm.createCompatibleWritableRaster(width, height);
    boolean isAlphaPremultiplied = cm.isAlphaPremultiplied();
    Hashtable properties = new Hashtable();
    String[] keys = img.getPropertyNames();
    if (keys!=null) {
        for (int i = 0; i < keys.length; i++) {
            properties.put(keys[i], img.getProperty(keys[i]));
        }
    }
    BufferedImage result = new BufferedImage(cm, raster, isAlphaPremultiplied, properties);
    img.copyData(raster);
    return result;
}