Trait RenderScene 

pub trait RenderScene {
    type HitTarget: HitTestTarget + Clone;

    // Required methods
    fn clear(&mut self);
    fn hit_test(&self, x: f32, y: f32) -> Vec<Self::HitTarget>;
    fn find_target(&self, node_id: NodeId) -> Option<Self::HitTarget>;

    // Provided methods
    fn hit_test_nodes(&self, x: f32, y: f32) -> Vec<NodeId>  { ... }
    fn collect_retained_visual_observation_nodes(
        &self,
        nodes: &mut HashSet<NodeId>,
    ) -> bool { ... }
}

Trait describing the minimal surface area required by the application shell to process pointer events and refresh the frame graph.

Required Associated Types

type HitTarget: HitTestTarget + Clone

Required Methods

fn clear(&mut self)

fn hit_test(&self, x: f32, y: f32) -> Vec<Self::HitTarget>

Performs hit testing at the given coordinates. Returns hit targets ordered by z-index (top-to-bottom).

fn find_target(&self, node_id: NodeId) -> Option<Self::HitTarget>

Finds a hit target by NodeId with fresh geometry from the current scene.

This is the key method for HitPathTracker-style gesture handling:

• On PointerDown, we cache NodeIds (not geometry)
• On Move/Up/Cancel, we call this to get fresh HitTarget with current geometry
• Handler closures are preserved (same Rc), so internal state survives

Returns None if the node no longer exists in the scene (e.g., removed during gesture).

Provided Methods

fn hit_test_nodes(&self, x: f32, y: f32) -> Vec<NodeId>

Returns NodeIds of all hit regions at the given coordinates. This is a convenience method equivalent to hit_test().map(|h| h.node_id()).

fn collect_retained_visual_observation_nodes( &self, nodes: &mut HashSet<NodeId>, ) -> bool

Replaces the set with retained visual observation owners, preserving its capacity. Returns whether the scene provides this information.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl RenderScene for Scene

type HitTarget = HitRegion