bevy/crates/bevy_ecs/src
Carter Anderson 015f2c69ca
Merge Style properties into Node. Use ComputedNode for computed properties. (#15975)
# Objective

Continue improving the user experience of our UI Node API in the
direction specified by [Bevy's Next Generation Scene / UI
System](https://github.com/bevyengine/bevy/discussions/14437)

## Solution

As specified in the document above, merge `Style` fields into `Node`,
and move "computed Node fields" into `ComputedNode` (I chose this name
over something like `ComputedNodeLayout` because it currently contains
more than just layout info. If we want to break this up / rename these
concepts, lets do that in a separate PR). `Style` has been removed.

This accomplishes a number of goals:

## Ergonomics wins

Specifying both `Node` and `Style` is now no longer required for
non-default styles

Before:
```rust
commands.spawn((
    Node::default(),
    Style {
        width:  Val::Px(100.),
        ..default()
    },
));
```

After:

```rust
commands.spawn(Node {
    width:  Val::Px(100.),
    ..default()
});
```

## Conceptual clarity

`Style` was never a comprehensive "style sheet". It only defined "core"
style properties that all `Nodes` shared. Any "styled property" that
couldn't fit that mold had to be in a separate component. A "real" style
system would style properties _across_ components (`Node`, `Button`,
etc). We have plans to build a true style system (see the doc linked
above).

By moving the `Style` fields to `Node`, we fully embrace `Node` as the
driving concept and remove the "style system" confusion.

## Next Steps

* Consider identifying and splitting out "style properties that aren't
core to Node". This should not happen for Bevy 0.15.

---

## Migration Guide

Move any fields set on `Style` into `Node` and replace all `Style`
component usage with `Node`.

Before:
```rust
commands.spawn((
    Node::default(),
    Style {
        width:  Val::Px(100.),
        ..default()
    },
));
```

After:

```rust
commands.spawn(Node {
    width:  Val::Px(100.),
    ..default()
});
```

For any usage of the "computed node properties" that used to live on
`Node`, use `ComputedNode` instead:

Before:
```rust
fn system(nodes: Query<&Node>) {
    for node in &nodes {
        let computed_size = node.size();
    }
}
```

After:
```rust
fn system(computed_nodes: Query<&ComputedNode>) {
    for computed_node in &computed_nodes {
        let computed_size = computed_node.size();
    }
}
```
2024-10-18 22:25:33 +00:00
..
entity bevy_ecs: Special-case Entity::PLACEHOLDER formatting (#15839) 2024-10-11 03:12:01 +00:00
event Add World::get_resource_or_init as an alternative to World::get_resource_or_insert_with (#15758) 2024-10-09 20:56:26 +00:00
identifier Add core and alloc over std Lints (#15281) 2024-09-27 00:59:59 +00:00
observer Add Trigger::components, which lists the component targets that were triggered (#15811) 2024-10-15 02:17:03 +00:00
query Merge Style properties into Node. Use ComputedNode for computed properties. (#15975) 2024-10-18 22:25:33 +00:00
reflect Allow World::entity family of functions to take multiple entities and get multiple references back (#15614) 2024-10-07 15:21:40 +00:00
schedule Add World::get_resource_or_init as an alternative to World::get_resource_or_insert_with (#15758) 2024-10-09 20:56:26 +00:00
storage Add Trigger::components, which lists the component targets that were triggered (#15811) 2024-10-15 02:17:03 +00:00
system Fix *most* clippy lints (#15906) 2024-10-14 20:52:35 +00:00
world Add Trigger::components, which lists the component targets that were triggered (#15811) 2024-10-15 02:17:03 +00:00
archetype.rs Add Trigger::components, which lists the component targets that were triggered (#15811) 2024-10-15 02:17:03 +00:00
batching.rs Fix *most* clippy lints (#15906) 2024-10-14 20:52:35 +00:00
bundle.rs Add Trigger::components, which lists the component targets that were triggered (#15811) 2024-10-15 02:17:03 +00:00
change_detection.rs Migrate from Query::single and friends to Single (#15872) 2024-10-13 20:32:06 +00:00
component.rs Remove thiserror from bevy_ecs (#15774) 2024-10-09 14:20:58 +00:00
intern.rs Add core and alloc over std Lints (#15281) 2024-09-27 00:59:59 +00:00
label.rs Add core and alloc over std Lints (#15281) 2024-09-27 00:59:59 +00:00
lib.rs Add insert_batch and variations (#15702) 2024-10-13 18:14:16 +00:00
removal_detection.rs Remove thiserror from bevy_ecs (#15774) 2024-10-09 14:20:58 +00:00
traversal.rs Bubbling observers traversal should use query data (#15385) 2024-09-23 18:08:36 +00:00