Feature request: option to bypass UIImage decoding/drawing in ASImageNode about asyncdisplaykit HOT 2 CLOSED

We are working on changing the semantics of clearing rendered content to address this. The current behavior is derived from how nodes are used in Paper, which isn't really comparable to how other apps may want to adopt them.

In Paper, two exceptional conditions are true:

1. Essentially everything has a "working range", similar to what is implemented for ASTableView.
2. The content, in general, is so memory intensive that in order to avoid constantly triggering memory warnings (which /cannot/ be relied upon for stable operation, as they aren't guaranteed to be sent before the app is killed), any content outside of the working range should be purged of rendered backing stores.

The easiest way to achieve this was having nodes clear their contents when removed from the hierarchy, which should work quite well in ASTableView with reasonably-set working ranges. It also works well in apps that have organic transitions between different states, rather than UIViewController pushes and pops. Of course, neither of those things are true for many other apps, so it would make more sense to require an explicit call to clear contents.

Lastly, using a system that pre-decodes images is an anti-pattern with ASDK. Such systems are typically wasteful of memory because they don't adjust according to what content is coming onscreen soon, or what content is now offscreen and no longer needed. We found that driving these decisions at the UI layer, in close reaction to what the user is currently doing, allowed us to make more careful use of memory—while also minimizing the chance that the user reaches un-rendered content.

I believe task 37 describes essentially the same thing as this, but we'll leave this one open until it is resolved.

from asyncdisplaykit.

Play around with the framework after the fix for issue 37 and let me know your thoughts. I believe it now implements the proper tradeoff of controlling memory usage (it should be easily possible to discard the decoded version to save memory, knowing that if the node has to be shown again, a decode cost will be paid again).

There are probably several things that could be done to better explore the right way to use AsyncDisplayKit with image download helpers, but most of them should support downloading images without doing the decoding. If you're using AsyncDisplayKit in the scenarios where it will really help your app, it seems best to me that it controls when images are decoded and you also use its -recursivelyReclaimMemory method to keep memory usage under control.

from asyncdisplaykit.