aetna_core/
cursor.rs

1//! Pointer-cursor model.
2//!
3//! Widgets opt into a non-default cursor by setting [`crate::tree::El::cursor`].
4//! Per-frame the host runner reads [`crate::state::UiState::cursor`] and forwards
5//! the resolved value to the windowing backend (winit's
6//! `Window::set_cursor_icon`, the browser's `canvas.style.cursor`).
7//!
8//! The variants line up with the CSS `cursor` property — same names
9//! winit's `CursorIcon` already uses — so backend bridges are dumb
10//! `From` impls.
11//!
12//! # Resolution
13//!
14//! [`crate::state::UiState::cursor`] picks the active cursor each frame:
15//!
16//! 1. If a press is captured (button drag, slider thumb, scrollbar
17//!    drag, text selection, …), the cursor follows the *press target*'s
18//!    declared cursor and ignores whatever the pointer is currently
19//!    over. Drag off a button onto a text input and the cursor stays
20//!    [`Cursor::Pointer`] — matches native press-and-hold behaviour.
21//! 2. Else the hovered node and its ancestors are walked root-ward,
22//!    returning the first explicit `.cursor(...)`. So a panel that
23//!    sets `.cursor(Move)` once propagates to children that don't
24//!    override.
25//! 3. Else [`Cursor::Default`].
26//!
27//! Disabled state is *not* auto-mapped to [`Cursor::NotAllowed`] —
28//! widgets that want that affordance branch in their build closure.
29
30/// Pointer cursor. Variant names mirror CSS `cursor` so the
31/// backend mapping is a 1:1 translation.
32#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Hash)]
33#[non_exhaustive]
34pub enum Cursor {
35    /// Platform default arrow.
36    #[default]
37    Default,
38    /// Hand / pointing finger — clickable surfaces (buttons, links,
39    /// checkboxes, switches, radios).
40    Pointer,
41    /// I-beam — text inputs and selectable text regions.
42    Text,
43    /// Slashed circle — disabled / unavailable affordances.
44    NotAllowed,
45    /// Open hand — a draggable target at rest.
46    Grab,
47    /// Closed hand — a draggable target while dragging.
48    Grabbing,
49    /// Generic "drag in any direction" (pan handles, view-port grabs).
50    Move,
51    /// Horizontal resize (←→).
52    EwResize,
53    /// Vertical resize (↑↓).
54    NsResize,
55    /// Diagonal resize (↖↘).
56    NwseResize,
57    /// Anti-diagonal resize (↗↙).
58    NeswResize,
59    /// Column boundary resize (table column dividers).
60    ColResize,
61    /// Row boundary resize (table row dividers).
62    RowResize,
63    /// Crosshair — picker / area-select tools.
64    Crosshair,
65}
66
67#[cfg(test)]
68mod tests {
69    use super::*;
70
71    #[test]
72    fn default_is_default_variant() {
73        assert_eq!(Cursor::default(), Cursor::Default);
74    }
75}
aetna_core/cursor.rs

aetna_core/
cursor.rs
