My question:

Is there any way to either suppress unloading of specific pages (say, by intercepting an event) or changing how aggressively PDF.js de-renders pages?

my usecase:

I use PDF.js to render textbooks.

observed behavior:

Some pages take a while to render. Scrolling away from those pages and scrolling back results in a spinner while the page loads.

why this is a problem:

For my specific usecase: students are most likely to need to refer back to the most slow-rendering pages while reading another part of the textbook. (e.g. flow charts and diagrams).

In general: I often want to leave multiple points in a document loaded (e.g., all the pages containing a search result). The re-rendering is problematic and I'm OK throwing a little more CPU and memory at the problem.

bonus points

is there a way to do this on the Firefox pdf renderer? even as a plugin or bookmarklet?