public int[] getPhysicalDimension() {
        if (!physicalDimensionSet) {
            throw new IllegalStateException(PropertyUtil.getString("PNGEncodeParam16"));
        }
        return (int[])(physicalDimension.clone());
    }
Returns the physical dimension information to be stored
with this image.

<p> If the physical dimension information has not previously
been set, or has been unset, an
<code>IllegalStateException</code> will be thrown.

@throws IllegalStateException if the physical dimension information
       is not set.
plugins/svg-plugin/batik-codec-fix/src/main/java/org/apache/batik/ext/awt/image/codec/png/PNGEncodeParam.java