iOS Problem when viewing PDF from Code

Question

I need to show a PDF in my view and zoom and scroll it. I tried using the example from Apple. It works, but when I zoom in/out the image appears to be very pixelated and the result is very bad... can you help me avoiding the bad quality when I zoom ( when I finish to zoom, the pdf is shown right...)

Thanks in advance.

Answer 1

The zoom is implemented this way to reduce resource usage while zooming, because rendering a PDF page can be very resource intensive. During zooming a bitmap version of the page is used for display and when the zoom ends, the PDF page is rendered again. You could implement continuous page rendering during zooming but I'm afraid the result would be unusable.

Answer 2

Note that this does not really answer your question, but I don't think that the pixelation is a problem. The few milliseconds where the PDF is pixelated are not a big deal and will barely be noticed. The Apple apps do it like this too, I think - or at least they are not constantly updating the image/PDF.