Taffy maintains a mapping of NodeId <-> Context anyways (and does the
lookup), so it's redundant for us to store it separately. Tl;dr: we get
rid of one map and one map lookup per layout request.
Release Notes:
- N/A
Again. https://github.com/zed-industries/zed/pull/4070
Let's see how it goes this time around. The only thing that might've
been related to that revert on our Slack was about crashing in collab
panel.
Release Notes:
- N/A
I noticed a few places where we were storing `&'static str`s in
`static`s instead of `const`s.
This PR updates them to use `const`.
Release Notes:
- N/A
A minor thing I've spotted and decided to fix on the spot.
It was being cloned twice within the body of that function (one of which
was redundant even without this PR); now in most cases we go down from 2
clones to 0.
Release Notes:
- N/A
This pull request introduces the new
`ElementContext::request_autoscroll(bounds)` and
`ElementContext::take_autoscroll()` methods in GPUI. These new APIs
enable container elements such as `List` to change their scroll position
if one of their children requested an autoscroll. We plan to use this in
the revamped assistant.
As a drive-by, we also:
- Renamed `Element::before_layout` to `Element::request_layout`
- Renamed `Element::after_layout` to `Element::prepaint`
- Introduced a new `List::splice_focusable` method to splice focusable
elements into the list, which enables rendering offscreen elements that
are focused.
Release Notes:
- N/A
---------
Co-authored-by: Nathan <nathan@zed.dev>
See https://zed.dev/channel/gpui-536
Fixes https://github.com/zed-industries/zed/issues/9010
Fixes https://github.com/zed-industries/zed/issues/8883
Fixes https://github.com/zed-industries/zed/issues/8640
Fixes https://github.com/zed-industries/zed/issues/8598
Fixes https://github.com/zed-industries/zed/issues/8579
Fixes https://github.com/zed-industries/zed/issues/8363
Fixes https://github.com/zed-industries/zed/issues/8207
### Problem
After transitioning Zed to GPUI 2, we started noticing that interacting
with the mouse on many UI elements would lead to a pretty annoying
flicker. The main issue with the old approach was that hover state was
calculated based on the previous frame. That is, when computing whether
a given element was hovered in the current frame, we would use
information about the same element in the previous frame.
However, inspecting the previous frame tells us very little about what
should be hovered in the current frame, as elements in the current frame
may have changed significantly.
### Solution
This pull request's main contribution is the introduction of a new
`after_layout` phase when redrawing the window. The key idea is that
we'll give every element a chance to register a hitbox (see
`ElementContext::insert_hitbox`) before painting anything. Then, during
the `paint` phase, elements can determine whether they're the topmost
and draw their hover state accordingly.
We are also removing the ability to give an arbitrary z-index to
elements. Instead, we will follow the much simpler painter's algorithm.
That is, an element that gets painted after will be drawn on top of an
element that got painted earlier. Elements can still escape their
current "stacking context" by using the new `ElementContext::defer_draw`
method (see `Overlay` for an example). Elements drawn using this method
will still be logically considered as being children of their original
parent (for keybinding, focus and cache invalidation purposes) but their
layout and paint passes will be deferred until the currently-drawn
element is done.
With these changes we also reworked geometry batching within the
`Scene`. The new approach uses an AABB tree to determine geometry
occlusion, which allows the GPU to render non-overlapping geometry in
parallel.
### Performance
Performance is slightly better than on `main` even though this new
approach is more correct and we're maintaining an extra data structure
(the AABB tree).

Release Notes:
- Fixed a bug that was causing popovers to flicker.
---------
Co-authored-by: Nathan Sobo <nathan@zed.dev>
Co-authored-by: Thorsten <thorsten@zed.dev>
Upgraded Taffy to v0.4.0 from crates.io (previously using prerelease
version from git).
Code changes required were minor as gpui was already using a recent
version of Taffy.
Release Notes:
- N/A
Reverts zed-industries/zed#7481
This would regress performance because we'd be using the standard
library's hash maps everywhere, so reverting for now.