How to animate big images in iOS

Question

I'm looking for solution of animation about 50 images on retina iPad each has 2048*1536 size. I want to animate them on finger move(change images on uiimageview sync with touches moved event). Images loads slowly and animation freezes. I want to find any solution to solve that problem. Thanks.

Answer 1

There are a couple of issues that make this situation very hard to deal with. First, the memory usage of 50 full screen images is very large. For some background on how much memory that actually requires, see this blog post Video and Memory usage on iOS devices. The second issue you have run into is CPU usage. A retina iPad has multiple CPUs, but decoding huge PNG images still takes a lot of CPU cycles and that will prevent the animations from running smoothly. So, the only way you will get this to work well is to avoid decoding the image data at runtime and also avoid holding all the decoded data in memory because that would crash the device. The best solution is to simply mmap() all the decoded data and decode it ahead of time, that makes it possible to blit image data into CoreGraphics without actually having to copy the data. If you would like to use my library that does all that, it is linked at the bottom of the blog post.