What is the difference of Wayland and the Android display server?
Why were Wayland developed instead of re-use the Android display server on the Linux desktop?
Android's solutions are ad-hock good enough hacks for smartphones. By analogy, Android's solutions are like Chinese crap - it's cheap, good enough, anyone uses it and as time passes it gets mild upgrades to be competitive quality/price wise. But there's better stuff if you have the money and knowledge - e.g. the USA military uses a different type of chips etc. which are more robust and cost a lot more.
Wayland is trying to be not just a cheap mildly good solution for the masses but a really good one, flexible with a well thought design. Android doesn't plan to use Wayland because there's little value for end customers just like you don't need a chip (CPU) which can withstand solar flares. But since the desktop is much more sophisticated and powerful than a smartphone, going after Wayland makes sense for us, desktop users.
It is not just used on smartphones, it is used on tablets too. Also on Android devices that people plug into their TV to turn it into some media center.
The Android backend is Surfaceflinger, which doesn't support windowing, cascading, or a bunch of other critical display server features. They have tacked on windowing support to it, but it is finnicky at best. It also has no networking support, and a while back it was redrawing the entire screen every update.
It's unfortunate that Android isn't a community project, because this is something that would help:
- Make a better Android
- Improve Linux Desktop <---> Android app mobility. (Blur the lines)
- Reduce Duplication of work in this very tricky area. (Faster improvements, more use)