Most Efficient Way To Render A Viewport

[cmcnicholas]

Hi, I have some PDF's that require a very high level of detail.

We're implementing our own viewer layer and was wondering from those developing/using pdf.js what tricks and/or approaches have worked for you?

Specifically I was going to try and render a tile pyramid of detail (a bit like a slippy map / google map).

I am using getViewport with an appropriate scale factor and offsetX and Y but what I'm unsure of is if pdf.js will only try to render what is "in viewport" and fits on the canvas (essentially cropping and avoiding objects outside the frame).

A picture tells a thousand words, so the following is what I'm trying to answer.

"If a viewport is appropriately set and the canvas is the size of the orange area will pdf.js only attempt to render 'Lovely' or will it off-canvas attempt to render 'Hello World' too at negative coordinates?"

This will help me understand how much "extra" work is being done on a specific tile render.

Any input would be appreciated.