在某些场景下，我们经常需要给PDF页面添加页码。 Foxit PDF SDK的页眉页脚功能可以实现。 （C++）示例代码如下：
HeaderFooter headerfooter = doc.GetEditableHeaderFooter();
HeaderFooterContentGenerator contentgenerator;
//set the type of content
contentgenerator.AddPageNumber(HeaderFooterContentGenerator::e_PageNumberFormatNumberSlashCount);
HeaderFooterContent content;
content.footer_center_content = contentgenerator.GenerateContent();
headerfooter.content = content;
//set the font and color
headerfooter.font = Font(L"Simsun", Font::e_StylesSmallCap, Font::e_CharsetGB2312, 0);
headerfooter.text_color = 0x000000;
//set the page range
headerfooter.page_range = PageNumberRange(1, doc.GetPageCount(), foxit::common::Range::e_All);
headerfooter.has_fixedsize_for_print = false;
headerfooter.has_text_shrinked = false;
headerfooter.start_page_number = 1;
headerfooter.page_margin = RectF(36, 30, 36, 30);
headerfooter.text_size = 12;
//add it to document and save
doc.AddHeaderFooter(headerfooter);
WString output_file = output_directory + L"HeaderFooter_AddHeaderFooter.pdf";
doc.SaveAs(output_file, PDFDoc::e_SaveFlagNoOriginal);
关于HeaderFooter对象的详细使用，请查看API手册和simple sample目录下的demo。
