Bevy UI theming (docs-first stub)
Not a full port. Docs-first stub. Godot counterpart: godot-ui-theming.
When to use
Load this when many nodes should share colors or a widget style. There is no Godot Theme resource in Bevy.
ECS shape
- Per-node colors opened:
BackgroundColor,BorderColor,BorderRadius,BoxShadow,BackgroundGradient. - Feature:
bevy_feathersis a collection of styled widgets for editors and inspectors. Widget names were not opened. - Window chrome:
WindowThemeis an enum on bevy::window for the window theme variant. That is OS window chrome, not a UI skin. - Systems: you set components. No theme inheritance system was named.
Godot idea to Bevy idiom
| Idea | Bevy idiom (idea only) |
|---|---|
| Theme resource | Your own resource of colors, copied onto BackgroundColor. No Theme type was opened. |
| Style box | BorderRadius and BoxShadow on a Node. |
| Editor widgets | bevy_feathers exists. Do not assume it skins a game HUD. |
Gaps
- No theme, stylebox, or font-theme type was opened under bevy::ui.
- Feathers widget pages were not opened.
Expert Knowledge Delta
Library target in prose: Bevy 0.20.0. Lattice URLs stay unversioned.
Opened canon only: Component, Resource, Query, Commands, Startup, Update, Fixed / FixedMain (bevy::time), .chain(), Plugin, DefaultPlugins, MinimalPlugins. Messages and observers are an ownership slot. This file does not invent their struct APIs. Systems run in parallel unless .chain() orders the ones that conflict.
Who owns state
| Piece | Owner | Who may mutate | Schedule |
|---|---|---|---|
| Data on one entity | Component | One system via Query | Update or FixedMain |
| One value for the whole app | Resource | One system | Startup to insert, then the schedule that reads it |
| Spawn | Commands | The spawning system | Startup for the initial world; later schedules for runtime spawn |
| Order that must not race | .chain() | The chained systems only | Same schedule |
| Plugin boundary | Plugin | build registers systems and resources | Before the app runs |
Borrow rule: two systems that both mutably query the same component must be ordered (.chain()) or split so only one writes. Unrelated systems stay parallel. That is the ECS page rule, not a guess at a system-set API.
Decision
| If you need | Do this | Do not |
|---|---|---|
| Per-entity data | Component + Query | A Godot node script |
| App-wide config or clock | Resource | Copy the value onto every entity |
| Stable simulation step | FixedMain and the Fixed clock | Tie simulation to raw frame Update |
| Startup spawn | Commands in Startup | Spawn from a render system |
| Cross-system notice that is not shared state | Message or observer slot in bevy-events-messaging | A new event type invented in this file |
| An API this skill did not open | A Gaps row | A fabricated crate (solver, navmesh module, net, XR) |
Load references/a-gate-notes.md for the same table plus the gap rule.
NEVER
-
Do not put
/0.20.0/in lattice URLs. WHY: permalinks stay onlatest. The 0.20.0 pin belongs in prose once. -
Do not mutably query the same component from two unordered systems. WHY: the schedule runs systems in parallel unless
.chain()orders them. -
Do not invent a physics, navigation, networking, or XR crate here. WHY: those rows are gaps, blocked, or revisit.
-
No Godot Theme or StyleBox types. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No Godot types in Bevy code. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No invented APIs or unnamed third-party crates as the chosen solver. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No Creation Station content. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
No umbrella skill over Godot and Bevy. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
-
Do not mark this row
ported. It isdocs_mapped. WHY: a Godot port, an unopened API, or a public lie fails the docs-first bar.
Reference
docs.rs links use the unversioned latest permalink. The library pin on bevy-master stays 0.20.0.
Official Documentation
- Migration guides - Unversioned hop index.
- bevy crate - Unversioned API index. Feature list opened for 0.20.0.
- Assets - Official asset catalog. No third-party crate was selected.
- Examples - Example tree on the
latestbranch. - ECS -
Component, systems,Query,Startup,Update, and.chain(). - Plugins -
Plugin,DefaultPlugins,MinimalPlugins, andadd_plugins. - bevy::ui - Color and radius components.
- bevy::feathers - Editor widget collection. Body not opened.
Related Skills
Prerequisites
- bevy-master - Hub and schedules.
- bevy-ecs-composition - Components and systems.
- bevy-ui-layout - Nodes being styled.
Complements
- bevy-ui-text - Font choices stay a text gap.
- godot-ui-theming - Godot counterpart. Source idea only.
Downstream / consumers
- None yet.
Master
- bevy-master - Bevy router.


