It would make sense to have a bound like
`for<'frame> R::Frame<'frame>: AsGlowFrame<'frame>`. But that appears to
not behave properly due to current limitations of the borrow checker:
https://blog.rust-lang.org/2022/10/28/gats-stabilization.html#implied-static-requirement-from-higher-ranked-trait-bounds
Instead, this makes `glow_frame` and `glow_frame_mut` associated
functions of the `AsGlowRenderer` trait. Then it is pretty
straightforward to make the `RenderElement` implementations generic
using that and `FromGlesError`.
It would make sense to make `Self::Error: FromGlessError` a requirement
of the `AsGlowRenderer` trait, but due to the lack of implied bounds
support, that produces a bunch of errors about missing bounds. If Rustc
improves that eventually, some bounds could be cleaned up a bit:
https://github.com/rust-lang/rust/issues/44491
`(w_elements, p_elements)` tuples are used in a bunch of places. A
struct with named fields is generally an improvement just due to the
fact the order is non-obvious.
But we can also add methods. In particular,
`extend_from_workspace_elements` abstracts out some of the more
redundant code in `workspace_elements`.
It would be nice to avoid allocation everywhere, but iterators would
complicate lifetimes, run into issues with needing multiple mutable
borrows to things like the `Renderer`, and be awkward in certain
functions without generator syntax. In any case, cosmic-comp already
relies on allocating vectors here.
If this abstraction is commonly useful in compositors, perhaps it could
be moved to Smithay.
Setting the clipboard is only allowed when the keyboard focus is the
same client as the client trying to set the clipboard. We shouldn't
allow background windows in stacks to set the clipboard.
I don't know if anything else expects `same_client_as` to have this `any`
behavior.
We already direct touch events to Iced, and the Cosmic `HeaderBar`
widget already recognizes drags from touch events. So it seems updating
`last_seat` is all that was needed for windows SSDs.
For stacks, the same works, plus moving using the same logic for
detecting drags that is used for mouse events.
Handling of `PointerTarget::motion` should be unchanged.
`PointerTarget::enter` previously was comparing `loc - geo` rather than
`loc`. The generic version could accommodate that, but I assume this was
incorrect, and the position sent to `enter` wasn't handled correctly.
