* all those resources to the used resources on document level.
* @param gen the PSGenerator to write the DSC comments with
* @exception IOException In case of an I/O problem
*/
public void writePageResources(PSGenerator gen) throws IOException {
new DSCCommentPageResources(pageResources).generate(gen);
if (usedResources == null) {
usedResources = new java.util.HashSet();
}
usedResources.addAll(pageResources);
}