Dave, > I have a few questions about rendering PDFs and wondered if > anyone here could help.
In my open source iOS PDF viewer (https://github.com/vfr/Reader) I employ two techniques: 1) Show a low resolution image of the page below the CATiledLayer-based zoom-able page view. These low resolution page images are generated on a background thread and are also cached as PNGs for future use. This gives the user something to see while CATiledLayer draws in the details on top of it. 2) Reduce the number (and increase the size) of tiles that CATiledLayer asks to be drawn. I set the CATiledLayer's tile size to either 512 or 1024 pixels depending on the device's screen size and scale (CATiledLayer limits the tile size to 1024 pixels). If the screen scale is greater than 1.0, I set the levelsOfDetailBias to 1 (any higher and CATiledLayer asks for many, smaller tiles). I also return a small value for +fadeDuration (as returning 0.0 exposes a bug in CATiledLayer - sometimes a tile won't draw or flickers in and out until you touch the screen). All of this is done in a CATiledLayer subclass (https://github.com/vfr/Reader/blob/master/Sources/ReaderContentTile.m) which is used to back the PDF page content UIView. You should also be aware that there is a bug in iOS 5.1.x where CATiledLayer will ask for the same tile to be drawn 2 or 3 times. If there is anything else, let me know...jo _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
