cranpose_render_common/
lib.rs

1//! Common rendering contracts shared between renderer backends.
2
3pub mod bounded_lru_cache;
4pub mod debug_toggles;
5pub mod dev_overlay;
6
7/// The frame background every renderer clears to (linear values; sRGB
8/// surfaces display this as rgb(75, 75, 86)). One definition so backends
9/// cannot drift.
10pub const FRAME_CLEAR_COLOR: [f32; 4] = [18.0 / 255.0, 18.0 / 255.0, 24.0 / 255.0, 1.0];
11pub mod brush_sampling;
12pub mod font_layout;
13pub mod font_source;
14mod font_tracking;
15pub mod geometry;
16pub mod gpos_kerning;
17pub mod graph;
18mod graph_hash;
19pub mod graph_scene;
20pub mod hit_graph;
21pub mod image_compare;
22pub mod layer_composition;
23pub mod layer_shadow;
24pub mod layer_transform;
25pub mod primitive_emit;
26pub mod raster_cache;
27pub mod render_contract;
28pub mod scene_builder;
29pub mod shape_sdf;
30pub mod software_text_raster;
31pub mod style_shared;
32pub mod text_hyphenation;
33pub mod text_measure;
34
35use cranpose_core::{MemoryApplier, collections::map::HashSet};
36use cranpose_foundation::nodes::input::PointerEvent;
37use cranpose_ui::LayoutTree;
38pub use cranpose_ui_graphics::Brush;
39use cranpose_ui_graphics::Size;
40
41/// Trait implemented by hit-test targets stored inside a [`RenderScene`].
42pub trait HitTestTarget {
43    /// Dispatches a pointer event to this target's handlers.
44    fn dispatch(&self, event: PointerEvent);
45
46    /// Dispatches a pointer event using the current live node state when available.
47    ///
48    /// Render-scene hit targets may cache closures from an older scene build. Pointer
49    /// dispatch goes through this hook so implementations can resolve fresh handlers
50    /// from the current applier while still using the target's geometry snapshot.
51    fn dispatch_with_applier(&self, _applier: &mut MemoryApplier, event: PointerEvent) {
52        self.dispatch(event);
53    }
54
55    /// Returns the NodeId associated with this hit target.
56    /// Used by HitPathTracker to cache stable identity instead of geometry.
57    fn node_id(&self) -> cranpose_core::NodeId;
58
59    /// The pointer's appearance while it hovers this target, when the target
60    /// names one.
61    ///
62    /// The shell asks the hit list top-down and applies the first answer, so
63    /// the innermost region under the pointer decides the cursor.
64    fn pointer_icon(&self) -> Option<cranpose_ui_graphics::PointerIcon> {
65        None
66    }
67
68    /// Returns the node capture path that should stay attached to this target's gesture.
69    ///
70    /// The default is just this target's own node. Renderers can override this to
71    /// include stable ancestor pointer-input nodes that must continue receiving
72    /// Move/Up/Cancel even if the original descendant target is recycled.
73    fn capture_path(&self) -> Vec<cranpose_core::NodeId> {
74        vec![self.node_id()]
75    }
76}
77
78/// Trait describing the minimal surface area required by the application
79/// shell to process pointer events and refresh the frame graph.
80pub trait RenderScene {
81    type HitTarget: HitTestTarget + Clone;
82
83    fn clear(&mut self);
84
85    /// Performs hit testing at the given coordinates.
86    /// Returns hit targets ordered by z-index (top-to-bottom).
87    fn hit_test(&self, x: f32, y: f32) -> Vec<Self::HitTarget>;
88
89    /// Returns NodeIds of all hit regions at the given coordinates.
90    /// This is a convenience method equivalent to `hit_test().map(|h| h.node_id())`.
91    fn hit_test_nodes(&self, x: f32, y: f32) -> Vec<cranpose_core::NodeId> {
92        self.hit_test(x, y)
93            .into_iter()
94            .map(|h| h.node_id())
95            .collect()
96    }
97
98    /// Finds a hit target by NodeId with fresh geometry from the current scene.
99    ///
100    /// This is the key method for HitPathTracker-style gesture handling:
101    /// - On PointerDown, we cache NodeIds (not geometry)
102    /// - On Move/Up/Cancel, we call this to get fresh HitTarget with current geometry
103    /// - Handler closures are preserved (same Rc), so internal state survives
104    ///
105    /// Returns None if the node no longer exists in the scene (e.g., removed during gesture).
106    fn find_target(&self, node_id: cranpose_core::NodeId) -> Option<Self::HitTarget>;
107
108    /// Replaces the set with retained visual observation owners, preserving its capacity.
109    /// Returns whether the scene provides this information.
110    fn collect_retained_visual_observation_nodes(
111        &self,
112        nodes: &mut HashSet<cranpose_core::NodeId>,
113    ) -> bool {
114        nodes.clear();
115        false
116    }
117}
118
119/// Abstraction implemented by concrete renderer backends.
120pub trait Renderer {
121    type Scene: RenderScene;
122    type Error;
123
124    /// Installs renderer-provided app services into the target AppContext.
125    ///
126    /// AppShell calls this before the first composition pass.
127    /// Renderers that provide text measurement or other per-app services should install
128    /// them here rather than as constructor side effects.
129    fn attach_app_context_services(&mut self, _app_context: &cranpose_ui::AppContext) {}
130
131    fn scene(&self) -> &Self::Scene;
132    fn scene_mut(&mut self) -> &mut Self::Scene;
133
134    fn rebuild_scene(
135        &mut self,
136        layout_tree: &LayoutTree,
137        viewport: Size,
138    ) -> Result<(), Self::Error>;
139
140    /// Rebuilds the scene by traversing the LayoutNode tree directly via Applier.
141    ///
142    /// This is the new architecture that eliminates per-frame LayoutTree reconstruction.
143    /// Implementors must read layout state from LayoutNode.layout_state() directly.
144    fn rebuild_scene_from_applier(
145        &mut self,
146        applier: &mut cranpose_core::MemoryApplier,
147        root: cranpose_core::NodeId,
148        viewport: Size,
149    ) -> Result<(), Self::Error>;
150
151    fn update_scene_from_applier(
152        &mut self,
153        applier: &mut cranpose_core::MemoryApplier,
154        root: cranpose_core::NodeId,
155        viewport: Size,
156        dirty_nodes: &[cranpose_core::NodeId],
157    ) -> Result<(), Self::Error> {
158        let _ = dirty_nodes;
159        self.rebuild_scene_from_applier(applier, root, viewport)
160    }
161
162    fn update_visual_scene_from_applier(
163        &mut self,
164        applier: &mut cranpose_core::MemoryApplier,
165        root: cranpose_core::NodeId,
166        viewport: Size,
167        dirty_nodes: &[cranpose_core::NodeId],
168    ) -> Result<(), Self::Error> {
169        self.update_scene_from_applier(applier, root, viewport, dirty_nodes)
170    }
171
172    /// Draw a development overlay (e.g., FPS counter) on top of the scene.
173    ///
174    /// This is called after rebuild_scene when dev options are enabled.
175    /// The text is drawn directly by the renderer without affecting composition.
176    ///
177    /// Default implementation does nothing.
178    fn draw_dev_overlay(&mut self, _text: &str, _viewport: Size) {}
179
180    /// Returns whether renderer-side cache materialization needs a visible follow-up frame.
181    fn needs_frame_warmup(&self) -> bool {
182        false
183    }
184}
cranpose_render_common/lib.rs

cranpose_render_common/
lib.rs
