Call to Graphics2D.drawImage freezes OS

Question

Whenever I call Graphics2D.drawImage(BufferedImage, BufferedImageOp, int, int), the entire system freezes for about 10 seconds, and then comes back as though nothing had happened. This is playing havoc with my code, because the paint routine is based on the system clock, and a freeze that long is very difficult to overcome. Here is the (abbreviated) code:
public static class Fade extends Transition
     FadeBIO f;
     protected Fade(PointAndClick p)
          super(p);
          f=new FadeBIO();
     public void draw(Graphics g, Registrar r,
          Component c, float p, Node no, Node nn)
          g./* draw back image */;
          Graphics2D gd=(Graphics2D)g;
          BufferedImage i=new BufferedImage(
               parent.W,parent.H,BufferedImage.TYPE_INT_ARGB);
          Graphics2D gi=i.createGraphics();
          ImageWrapper.GamePanel.drawImg(gi,parent,c,r,Color.BLUE,0,0,nn); // this fills the front image
          gd.drawImage(i,f.set(p),0,0); // this is the offending call
     private class FadeBIO implements BufferedImageOp
          int opacity=-1;
          FadeBIO set(float o)
               opacity=((int)(255*o)&0xff<<24)|0xffffff;
               return this;
          public BufferedImage filter(BufferedImage src, BufferedImage dst)
               int width=src.getWidth();
               int height=src.getHeight();
               WritableRaster srcRaster=src.getRaster();
               if (dst==null)
                    dst=createCompatibleDestImage(src,null);
               WritableRaster dstRaster=dst.getRaster();
               int[] inPixels=new int[width];
               for (int y=0;y<height;y++)
                    srcRaster.getDataElements(0,y,width,1,inPixels);
                    for (int x=0; x<width; x++)
                         inPixels[x]&=opacity;
                    dstRaster.setDataElements(0,y,width,1,inPixels);
               return dst;
          public BufferedImage createCompatibleDestImage(BufferedImage src,
               ColorModel dstCM)
               if (dstCM==null) dstCM=src.getColorModel();
               return new BufferedImage(dstCM,dstCM.
                    createCompatibleWritableRaster(src.getWidth(),src
                    .getHeight()),dstCM.isAlphaPremultiplied(),null);
          public Rectangle2D getBounds2D(BufferedImage src)
               return new Rectangle(0,0,src.getWidth(),src.getHeight());
          public Point2D getPoint2D(Point2D s, Point2D d)
               if (d==null) d=new Point2D.Double();
               d.setLocation(s.getX(),s.getY());
               return d;
          public RenderingHints getRenderingHints() {return null;}
}I'm pretty sure the BufferedImageOp checks out, and I am sure the call which freezes the system is the drawImage call. By the way, if anyone knows an alternative way to fade from one image to another, I'm open to suggestions (it's an animation, so it has to be fast).

Answer 1

At the moment, I don't really feel like writing the code verbatim to illustrate for you what I am attempting to explain. I think the confusion stems from a lack of understanding as to how the object references in your code interoperate. I will attempt to explain, and maybe code later if I feel up to it or if someone doesn't beat me to the punch. :) (It's Saturday, and I don't really want to spend it indoors coding....)
Your Graphics2D object _2DSkyImage is a reference to the Graphics2D object that is generated by the BufferedImage biSkyBuffer. Thus, when call any of the drawXXX() methods of your Graphics2D reference, it is drawing that information on to your image. If when you called the PixelGrabber constructor and gave it a reference to your BufferedImage, then, using the Graphics2D object drew something on your BufferedImage, it would (possibly) show up in the PixelGrabber. This is what we call a side-effect (though intended in this case). Once the image has been changed after you drew on it, you may have to tell the PixelGrabber object to reload the image data once it has been altered (via the Graphics2D object) so that it will track the changes.
The worst case scenario is that you'd have to reinstantiate the PixelGrabber object every time you altered the image, and if that was the case, I would consider ditching the implementation. However, you shouldn't have to do this because PixelGrabber does have methods that allow you to reload pixel data without reinstantiating.
Hopefully that clears it up. If not, let us know and we'll give it another shot. ;)
-Dok