SC 1.4.10 Reflow and PDFs

I don't have much knowledge of PDF accessibility but I'm a little bit confused about how SC 1.4.10 Reflow can be supported. I'd be grateful if anyone can correct any wrong assumptions in the following and provide further clarity.


As I understand it, SC 1.4.10  states that content should be viewable at a screen width equivalent to 320px without loss of information or functionality and should also be readable without the need for horizontal scrolling. And that the reason for this is to support zooming to 400% on a screen size of 1280px, giving you 320 virtual pixels.


A PDF doesn’t reflow in a web browser so if you zoom you have to scroll horizontally to read the text. But PDF reader applications like Adobe Reader have reflow functions that reflow the text both when you zoom and when you narrow the window. However, the Reflow function in Adobe Reader removes all the images in PDFs I've tested. Which means there is loss of information, which fails 1.4.10 reflow.


So it seems like there may not be a way for users to reflow PDFs at all without losing info. Is that right, or is it maybe to do with how the images in the PDFs I've looked at are encoded? Is it possible to include images in a way that they don’t disappear when you use Adobe Reflow? Or are there other PDF reading tools that reflow text without removing images?


Or am I thinking in completely the wrong direction here?


Thanks,

Mark