TOPIC:

//flatten pdf
        
            // create and load the document.
            PDFDoc *pdfDocument = [[PDFDoc alloc] init];
            PDF_ERR err = [pdfDocument open:[destinationPath stringByAppendingPathComponent:fileName] :nil];
            
            // create the cache.
            NSString *cacheName = [[NSTemporaryDirectory() stringByAppendingString:@""] stringByAppendingString:@"cache.dat"];
            [pdfDocument setCache:cacheName];
            
            // get the page count.
            int pageCount = [pdfDocument pageCount];
            
            // loop through the pages.
            for (int pageIndex = 0; pageIndex < pageCount; pageIndex++)
            {
                // get the page and prepare it.
                PDFPage *page = [pdfDocument page:pageIndex];
                [page flatAnnots];
            }
            
            [pdfDocument save];