问题
I'm providing a free sample page that will be downloaded from my website that is in .pdf format. I want to prevent users from selecting and copying the text content of that document. How can I do this for free?
回答1:
With Adobe Acrobat, you can create passwords to protect pdf files. But others can still use some pdf tools to crack passwords. Look at this article. http://www.anypdftools.com/blog/2009/05/12/create-and-crack-pdf-password.html#261
回答2:
Convert the text to image before fetching it as a PDF.
来源：https://stackoverflow.com/questions/4611089/any-free-way-to-disable-copying-text-in-pdf