I’m looking for any advice on ways to have a rather large scrollview (let’s say 8192×8192) which is essentially a grid and it has subviews of about 5-100 buttons placed in it.
The brute force approach runs out of memory as CALayer seems to be allocating a bitmap for the size of the scrollview’s content (the memory issue is especially prominent when zooming is used)
I next added CATiledLayer to it, that’s fixed the memory issue but there is a blurry effect on the grid as tiles are generated asynchronously and is still not ideal in that it’s using a lot of memory for what is essentially a trivial ‘draw some lines’ task.
It seems like if I could somehow get control to draw my own grid via OpenGL each frame and tell UIKit not to create a bitmap buffer for the scrollview it would be perfect but not sure if this is feasible or even the right approach?
On Android I just took control of the entire drawing/zooming/panning but this seems vastly overkill on iOS which seems to offer most of this already?
You should check out the WWDC 2009 video session 102: “Mastering iPhone Scroll Views” along with the ScrollViewSuite sample project from Apple. They explain how to do a tiled scroll view with different zoom levels, which sounds like it is what you need.