cranpose_render_common/
lib.rs

1//! Common rendering contracts shared between renderer backends.
2
3pub mod style_shared;
4
5use cranpose_foundation::nodes::input::PointerEvent;
6use cranpose_ui::LayoutTree;
7use cranpose_ui_graphics::Size;
8
9pub use cranpose_ui_graphics::Brush;
10
11/// Trait implemented by hit-test targets stored inside a [`RenderScene`].
12pub trait HitTestTarget {
13    /// Dispatches a pointer event to this target's handlers.
14    fn dispatch(&self, event: PointerEvent);
15
16    /// Returns the NodeId associated with this hit target.
17    /// Used by HitPathTracker to cache stable identity instead of geometry.
18    fn node_id(&self) -> cranpose_core::NodeId;
19}
20
21/// Trait describing the minimal surface area required by the application
22/// shell to process pointer events and refresh the frame graph.
23pub trait RenderScene {
24    type HitTarget: HitTestTarget + Clone;
25
26    fn clear(&mut self);
27
28    /// Performs hit testing at the given coordinates.
29    /// Returns hit targets ordered by z-index (top-to-bottom).
30    fn hit_test(&self, x: f32, y: f32) -> Vec<Self::HitTarget>;
31
32    /// Returns NodeIds of all hit regions at the given coordinates.
33    /// This is a convenience method equivalent to `hit_test().map(|h| h.node_id())`.
34    fn hit_test_nodes(&self, x: f32, y: f32) -> Vec<cranpose_core::NodeId> {
35        self.hit_test(x, y)
36            .into_iter()
37            .map(|h| h.node_id())
38            .collect()
39    }
40
41    /// Finds a hit target by NodeId with fresh geometry from the current scene.
42    ///
43    /// This is the key method for HitPathTracker-style gesture handling:
44    /// - On PointerDown, we cache NodeIds (not geometry)
45    /// - On Move/Up/Cancel, we call this to get fresh HitTarget with current geometry
46    /// - Handler closures are preserved (same Rc), so internal state survives
47    ///
48    /// Returns None if the node no longer exists in the scene (e.g., removed during gesture).
49    fn find_target(&self, node_id: cranpose_core::NodeId) -> Option<Self::HitTarget>;
50}
51
52/// Abstraction implemented by concrete renderer backends.
53pub trait Renderer {
54    type Scene: RenderScene;
55    type Error;
56
57    fn scene(&self) -> &Self::Scene;
58    fn scene_mut(&mut self) -> &mut Self::Scene;
59
60    fn rebuild_scene(
61        &mut self,
62        layout_tree: &LayoutTree,
63        viewport: Size,
64    ) -> Result<(), Self::Error>;
65
66    /// Rebuilds the scene by traversing the LayoutNode tree directly via Applier.
67    ///
68    /// This is the new architecture that eliminates per-frame LayoutTree reconstruction.
69    /// Implementors must read layout state from LayoutNode.layout_state() directly.
70    fn rebuild_scene_from_applier(
71        &mut self,
72        applier: &mut cranpose_core::MemoryApplier,
73        root: cranpose_core::NodeId,
74        viewport: Size,
75    ) -> Result<(), Self::Error>;
76
77    /// Draw a development overlay (e.g., FPS counter) on top of the scene.
78    ///
79    /// This is called after rebuild_scene when dev options are enabled.
80    /// The text is drawn directly by the renderer without affecting composition.
81    ///
82    /// Default implementation does nothing.
83    fn draw_dev_overlay(&mut self, _text: &str, _viewport: Size) {
84        // Default: no-op
85    }
86}
cranpose_render_common/lib.rs

cranpose_render_common/
lib.rs
