Thanks for your comment! By complicated PDFs, what do you mean exactly? A lot of pages? With forms? I've tried with standard technical books I have bought.

The pdf-diff tool simply captures a sort of "screenshot" of a PDF page and then compares it against to the page from the second PDF file you'd like to compare. Since it works by comparing raw pixels, I guess it'll work with complicated PDFs.

Now "working" does not mean it's a good result for the eye and this is why I asked for help regarding some issues.

ImageMagick's `compare` can do this as well, on a pixel-level.

The issue is that in some cases, for example when the change is that a long sentence has been inserted in the middle of the document, the following headline and some of the first paragraph of the following section move to the next page. Then everything that follows is just marked red and the diff becomes useless.

> ImageMagick's `compare` can do this as well, on a pixel-level.

Yes, thanks for the comment. I wanted to build something with golang :)

Aha. If one paragraph is added on page 1, it might show a diff on every following page in the same chapter after that, if it causes things to shift?

It's not easy to decide when such a change needs review and when it doesn't

Yes, if it causes things to shift, the tool shows every page red. This tool is meant to be ran in the final phase of typesetting, the moment when you want to focus attention on details (e.g. spacing).