ipad / objective c - create a low resolution image prior to pdf page rendering

Obviously during the rendering of a high quality PDF, there can be a开发者_Go百科 decent amount of time taken to completely draw the page, I'm trying to find a way to efficiently display a low quality image of that PDF page (ala iBooks) in order to make this wait time sting a little bit less from a user perspective.

Any ideas on the best way to accomplish this?