Quick notes

This section will mention notes that did not come up in the tutorial but may still be helpful for you.

Misc Cob Syntax

Splat

splat is a shorthand way for multiple fields to be set the same value, you may have already encountered this in bevy with Vec2::splat or Vec3::splat.

To use splat the data type should implement splattable.

For example Splat<Border>(15px)

This should not be defined in a FlexNode or AbsoluteNode but as a seperate line.

Loading Cob files

When you have a cob file that defines scenes, you must register with the app by using this syntax (or add it to a manifest section of another file): .load("main.cob")

Waiting for LoadState::Done

If your UI is to appear at the start of the game then you should wait to ensure cobweb has had a chance to read its scene data. .add_systems(OnEnter(LoadState::Done), build_ui)

If your UI comes up in response to player actions on other UI, then calling it using observers or events should be fine as cob files would have been already read by cobweb.

Other features not covered (at least for now!)

Cobweb has reactive features.

Some examples can be found here.

You can use broadcasts to refresh your ui, update_on(broadcast::<MyArbitaryStruct>(),|/*bevy query*/|{}); Call it using commands.react().broadcast(MyArbitaryStruct).

There are others as well.

Other features

Radio button widget: we hope to have an example later. It can also be useful for tabbing.
Here's a good starting point for animations, states, interactions.
Localization: there is an example here, with documentation here.
Commands: cob files include a #commands section. TODO

Cob documentation.

You can find more details about cob files here.

For creating nodes from scratch we used commands.ui_builder(UiRoot) (or commands.ui_root()). If we want to modify an existing UI node, substitue UiRoot with the entity you want to edit. If you use commands.get you can end up with this error:

WARN bevy_ui::layout: Node (233769v8) is in a non-UI entity hierarchy. You are using an entity with UI components as a child of an entity without UI components, your UI layout may be broken. at /home/lyndonm/.cargo/registry/src/index.crates.io-6f17d22bba15001f/bevy_ui-0.15.0-rc.3/src/layout/mod.rs:267

cobweb book