public int getNumPages() throws IOException {
        return 1;
    }
Returns the number of pages present in the current stream.
By default, the return value is 1.  Subclasses that deal with
multi-page formats should override this method.
plugins/svg-plugin/batik-codec-fix/src/main/java/org/apache/batik/ext/awt/image/codec/util/ImageDecoderImpl.java