public Raster getTile(int tileX, int tileY) {
        if (tileX != 0 || tileY != 0) {
            // Error -- bad tile requested
            String msg = PropertyUtil.getString("PNGImageDecoder17");
            throw new IllegalArgumentException(msg);
        }
        return theTile;
    }
Reads in an image of a given size and returns it as a
WritableRaster.
plugins/svg-plugin/batik-codec-fix/src/main/java/org/apache/batik/ext/awt/image/codec/png/PNGImageDecoder.java