目 录 前言 ----------------------------------------------------------------------------------------------------------------------- 1 PDF 简介 ----------------------------------------------------------------------------------------------------------- 1 项目简介 ---------------------------------------------------------------------------------------------------------- 2 PDF 文件格式 ----------------------------------------------------------------------------------------------------------- 3 PDF 区域内容呈现方式 --------------------------------------------------------------------------------------- 3 PDF 文件头(header) ---------------------------------------------------------------------------------------- 3 文件主干部分(body) --------------------------------------------------------------------------------------- 3 参照表(Cros