Trait UiRoot

pub trait UiRoot: Component {
    type Param: SystemParam;
    type Item: QueryData;

    // Required method
    fn compute_root_transform(
        &mut self,
        param: &mut SystemParamItem<'_, '_, Self::Param>,
        item: QueryItem<'_, Self::Item>,
    ) -> (Transform, Vec2);
}

UI root component.

These provide root transforms and available space for UI nodes. For example, Camera2dRoot provides a bottom-left transform and physical viewport size as available space.

Note

Do not add Ui nodes to the same entity as UI roots. Instead, spawn them as children entities.

Required Associated Types

type Param: SystemParam

The parameter required for computing the transform and available space.

type Item: QueryData

Necessary neighbor components. Failing to fetch these will make the measure output as zero.

Required Methods

fn compute_root_transform( &mut self, param: &mut SystemParamItem<'_, '_, Self::Param>, item: QueryItem<'_, Self::Item>, ) -> (Transform, Vec2)

Computes the root transform. The returned Transform should be located at the bottom-left vertex of the available space box.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl UiRoot for Camera2dRoot

type Param = ()

type Item = (&'static Camera, &'static OrthographicProjection, Has<UiUnrounded>)