bevy/examples/window/screenshot.rs
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

93 lines
2.4 KiB
Rust

//! An example showing how to save screenshots to disk
use bevy::{
prelude::*,
render::view::screenshot::{save_to_disk, Capturing, Screenshot},
window::SystemCursorIcon,
winit::cursor::CursorIcon,
};
fn main() {
App::new()
.add_plugins(DefaultPlugins)
.add_systems(Startup, setup)
.add_systems(Update, (screenshot_on_spacebar, screenshot_saving))
.run();
}
fn screenshot_on_spacebar(
mut commands: Commands,
input: Res<ButtonInput<KeyCode>>,
mut counter: Local<u32>,
) {
if input.just_pressed(KeyCode::Space) {
let path = format!("./screenshot-{}.png", *counter);
*counter += 1;
commands
.spawn(Screenshot::primary_window())
.observe(save_to_disk(path));
}
}
fn screenshot_saving(
mut commands: Commands,
screenshot_saving: Query<Entity, With<Capturing>>,
windows: Query<Entity, With<Window>>,
) {
let Ok(window) = windows.get_single() else {
return;
};
match screenshot_saving.iter().count() {
0 => {
commands.entity(window).remove::<CursorIcon>();
}
x if x > 0 => {
commands
.entity(window)
.insert(CursorIcon::from(SystemCursorIcon::Progress));
}
_ => {}
}
}
/// set up a simple 3D scene
fn setup(
mut commands: Commands,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
// plane
commands.spawn((
Mesh3d(meshes.add(Plane3d::default().mesh().size(5.0, 5.0))),
MeshMaterial3d(materials.add(Color::srgb(0.3, 0.5, 0.3))),
));
// cube
commands.spawn((
Mesh3d(meshes.add(Cuboid::default())),
MeshMaterial3d(materials.add(Color::srgb(0.8, 0.7, 0.6))),
Transform::from_xyz(0.0, 0.5, 0.0),
));
// light
commands.spawn((
PointLight {
shadows_enabled: true,
..default()
},
Transform::from_xyz(4.0, 8.0, 4.0),
));
// camera
commands.spawn((
Camera3d::default(),
Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
));
commands.spawn((
Text::new("Press <spacebar> to save a screenshot to disk"),
Node {
position_type: PositionType::Absolute,
top: Val::Px(12.0),
left: Val::Px(12.0),
..default()
},
));
}