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