xilem: WindowView::with_default_properties for runtime theme swap#1822
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mark-ik wants to merge 2 commits into
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xilem: WindowView::with_default_properties for runtime theme swap#1822mark-ik wants to merge 2 commits into
mark-ik wants to merge 2 commits into
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Surfaces `RenderRoot::set_default_properties` (added in linebender#1821) reactively on `WindowView`, so a Xilem app can swap its theme's default property set mid-session without restarting. `WindowView` gains a reactive `default_properties: Option<Arc<DefaultProperties>>` field plus `with_default_properties(..)`. The new set is pushed to the render root in `rebuild` only when the `Arc` identity changes (`Arc::ptr_eq`), so steady-state frames don't re-apply. `None` (the default) leaves the startup set untouched. Signed-off-by: Markik <54276851+mark-ik@users.noreply.github.com>
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May 31, 2026
Trim verbose field/builder docs and replace the match-style rebuild block with the upstream-idiomatic if-let chain + `is_none_or`, matching linebender#1822. Behavior unchanged; verified live: woodshed theme toggle still recolors default-driven widgets.
mark-ik
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May 31, 2026 21:22
PoignardAzur
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Jul 3, 2026
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| if let Some(props) = &self.default_properties | ||
| && prev | ||
| .default_properties | ||
| .as_ref() | ||
| .is_none_or(|p| !Arc::ptr_eq(p, props)) | ||
| { | ||
| window.render_root().set_default_properties(props.clone()); | ||
| } |
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I think this is fine for now, but I'd add a TODO comment to mention the case where default_properties go from Some to None.
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Scope
One file:
xilem/src/window_view.rs.Background
[
RenderRoot::set_default_properties] (added in #1821) lets a host swap the tree-wide default property set at runtime, but it's only reachable from code that holds aRenderRoot. Xilem apps go throughWindowView, so they can't reach the new method at the moment.Fix
Adds
WindowView::with_default_properties(Arc<DefaultProperties>). The new set gets pushed to the render root inrebuildonly when theArcidentity changes (Arc::ptr_eq), so steady-state frames don't re-apply.None(the default) leaves the startup set untouched.Testing
No tests in this PR. Xilem doesn't have masonry's
TestHarness, and the propagation invariant is already covered by the test that landed with #1821. Anecdotally, when applied to my fork in my app, a theme toggle correctly recolors ContentColor-defaulted widgets without restart. I have screenshots or screen recordings available if desired.Disclosure: AI-assisted; still my responsibility.
Closes #1819.
Relevant issues:
background_color(), system light/dark detection, and the per-widget override API to that issue.