I need to have in the same page both onecolumn and twocolumn. As default, a page in ACM SIGPLAN latex is twocolumn. But I have a picture that need to be located in onecolumn. When I use : \onecolumn here picture \twocolumn ... My image will be put in a seprate page (alone). But I don't put it in a seprate page. I wonder if I have in the same page both onecolumn and twocolumn, i.e have that image at the top of the page in onecolumn, and the rest of that page contains ordinary text in two columnn.
Is it possible? SIGPLAN latex: http://drupal.sigplan.org/sites/default/files/sigplanconf-guide.pdf