Trait LayoutPolicy 

pub trait LayoutPolicy:
    Send
    + Sync
    + Clone
    + PartialEq
    + 'static {
    // Required method
    fn measure(
        &self,
        input: &LayoutInput<'_>,
        output: &mut LayoutOutput<'_>,
    ) -> Result<ComputedData, MeasurementError>;

    // Provided methods
    fn measure_eq(&self, other: &Self) -> bool { ... }
    fn placement_eq(&self, other: &Self) -> bool { ... }
    fn place_children(
        &self,
        _input: &PlacementInput<'_>,
        _output: &mut LayoutOutput<'_>,
    ) -> bool { ... }
}

Pure layout policy for measuring and placing child nodes.

Required Methods

fn measure( &self, input: &LayoutInput<'_>, output: &mut LayoutOutput<'_>, ) -> Result<ComputedData, MeasurementError>

Computes layout for the current node.

Provided Methods

fn measure_eq(&self, other: &Self) -> bool

Compares measurement-relevant state for layout dirty tracking.

fn placement_eq(&self, other: &Self) -> bool

Compares placement-relevant state for layout dirty tracking.

fn place_children( &self, _input: &PlacementInput<'_>, _output: &mut LayoutOutput<'_>, ) -> bool

Recomputes child placements using cached child measurements.

Returns true when the placement pass was handled without remeasurement.

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 LayoutPolicy for DefaultLayoutPolicy