Annotation Issues with Large PDFs in Calibre-Web

[coderZoe]

Hello Hypothesis team,

I've been utilizing hypothes.is for annotations within Calibre-Web, an e-book library project. While it functions effectively for EPUB format, I'm encountering an issue with larger PDFs.

Here's how the annotation appears for EPUB:

However, for larger PDFs, the experience is different:

Upon selecting text in a PDF and attempting to use the hypothes.is Annotation button, it fails to display the expected text box for annotations, which is seen with EPUB. Interestingly, this problem is prominent with larger PDFs (e.g., several hundred pages). For smaller PDFs, roughly around ten pages, the annotation feature works as anticipated.

For reference, I've been using the Microsoft Edge browser with the hypothes.is plugin sourced from: https://chrome.google.com/webstore/detail/hypothesis-web-pdf-annota/bjfhmglciegochdpefhhlphglcehbmek.

Would appreciate any assistance or insights on this matter. I'm eager to understand whether this is a known issue or if there's a potential solution at hand.

Thank you for your time.

[robertknight]

Hello. Apologies for the late response. I have a few follow-up questions:

• Does it make a difference where in the document the annotation is created (first few pages, page 50, page 100 etc)?
• Do you have an example of a large PDF for which you encountered this issue?
• Are there any errors reported in the browser console?

One possible issue in large PDFs might be to do with computing the position number that is used to sort annotations in the sidebar. This currently involves extracting the text from every page up to the page which you annotated. If this is indeed the issue, then you'd find that annotating pages near the top of the document should work, but annotating pages much later may encounter a delay.