首先，这是一个纯友情的推广贴。作者没有开源，但是放了可执行文件。github页面里也放了不同水印的处理方法，有需要的佬友也可以享用 
GitHub - Charltsing/oPDF: oPDF is a powerful PDF contents analysis and processing tool, featuring universal watermark removal functionality., used to remove PDF Watermarks, including but not limited to annotation watermarks, text watermarks, curve watermarks, path watermarks, trace watermarks, form watermarks, image watermarks, and...