cranpose_ui/
focus_order.rs

1use std::cell::RefCell;
2
3use cranpose_core::NodeId;
4use cranpose_ui_graphics::Rect;
5
6use crate::layout::{LayoutBox, LayoutTree};
7
8/// One focus target, with the bounds layout gave it.
9#[derive(Clone, Copy, Debug, PartialEq)]
10pub struct FocusEntry {
11    pub node_id: NodeId,
12    pub rect: Rect,
13}
14
15impl FocusEntry {
16    pub fn center(&self) -> (f32, f32) {
17        (
18            self.rect.x + self.rect.width * 0.5,
19            self.rect.y + self.rect.height * 0.5,
20        )
21    }
22}
23
24thread_local! {
25    static FOCUS_ORDER: RefCell<Vec<FocusEntry>> = const { RefCell::new(Vec::new()) };
26}
27
28/// Replaces the focus order a later [`crate::FocusManager`] move reads. The
29/// app shell publishes it after a layout pass.
30pub fn set_focus_order(entries: Vec<FocusEntry>) {
31    FOCUS_ORDER.with(|cell| *cell.borrow_mut() = entries);
32}
33
34/// Reads the published focus order.
35pub fn with_focus_order<T>(reader: impl FnOnce(&[FocusEntry]) -> T) -> T {
36    FOCUS_ORDER.with(|cell| reader(&cell.borrow()))
37}
38
39/// How many focus targets the last published order holds.
40pub fn focus_order_len() -> usize {
41    FOCUS_ORDER.with(|cell| cell.borrow().len())
42}
43
44/// Walks `tree` in the order the layout pass placed it and keeps the nodes
45/// that registered a focus target and take space on screen.
46pub fn collect_focus_order(tree: &LayoutTree) -> Vec<FocusEntry> {
47    let mut entries = Vec::new();
48    collect_from_box(tree.root(), &mut entries);
49    entries
50}
51
52fn collect_from_box(layout_box: &LayoutBox, entries: &mut Vec<FocusEntry>) {
53    if crate::focus_dispatch::has_focus_target(layout_box.node_id) && takes_space(layout_box.rect) {
54        entries.push(FocusEntry {
55            node_id: layout_box.node_id,
56            rect: layout_box.rect,
57        });
58    }
59    for child in &layout_box.children {
60        collect_from_box(child, entries);
61    }
62}
63
64fn takes_space(rect: Rect) -> bool {
65    rect.width > 0.0
66        && rect.height > 0.0
67        && rect.x.is_finite()
68        && rect.y.is_finite()
69        && rect.width.is_finite()
70        && rect.height.is_finite()
71}
cranpose_ui/focus_order.rs

cranpose_ui/
focus_order.rs
