What does "scale"even mean in UI context? 10 or 100 controls in app makes difference how exactly? Retained apps redraw when needed, they are idle most of the times. How redrawing every frame helps to scale?
This thread (and post) keeps mistaking immediate mode GUIs with declarative UIs. You can have declarative UIs that aren't immediate: the vast majority of them are, and they are idle most of the time.
Does "immediate mode" mean the UI refreshes at a constant 60fps rate like a video game, redrawing everything all the time?
No.
It means that you build the UI by describing what it should look like now, based on the data / state you own, without referencing any existing "widget" object or trying to manipulate it.
Scale is not about the number of buttons, but the structure of the data.
You have a list of objects, within each objects you have several fields, some of them lists, some of them maps. within some of those sub-items you have other lists and maps, nested arbitrarily.
This would be hell to manage for a retained mode UI. You have to mirror the application data into a widget tree and keep all the elements in sync, all the way down to the arbitrary depths of it.
You'd be writing thousands of lines of code that do nothing but keep your data in sync with widget states. You'd have many one off bugs where one sub field fails to sync in some scenarios. Your only options is to be more defensive: more events, more full-resync. As a result, the codebase is complicated and the application feels slow/heavy, because updating widget states is costly.
In immediate mode, none of that matters. You don't have a parallel widget tree.
> In immediate mode, none of that matters. You don't have a parallel widget tree.
No, instead, you need to have your entire dataset in memory, and potentially rebuild your whole tree on every update. This causes quite a lot of problems for out-of-core datasets - you end up needing to maintain proxies for things like items in scrollable lists that aren't loaded into memory yet.