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 retained_visual_observation_nodes(&self) -> Option<HashSet<NodeId>> { ... }
}

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 retained_visual_observation_nodes(&self) -> Option<HashSet<NodeId>>

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