虚拟打印的实现。 虚拟打印主要用于将各种文档转换成为各种图形，例如将一个doc文件转换成一个BMP图。我在实现虚拟打印的时候，使用了DDK和DELPHI的一些东西。 -The realization of the virtual printing. Virtual printing is mainly used for a variety of documents to be converted into a variety of graphics, such as a doc file