cranpose_ui/widgets/
box_widget.rs

1//! Box widget implementation
2
3use cranpose_core::NodeId;
4use cranpose_ui_layout::Alignment;
5
6use super::layout::{LayoutEnvironment, compose_layout};
7use crate::{composable, layout::policies::BoxMeasurePolicy, modifier::Modifier};
8
9/// Specification for Box layout behavior.
10#[derive(Clone, Copy, Debug, PartialEq)]
11pub struct BoxSpec {
12    /// Where children sit inside the box. Defaults to top start.
13    pub content_alignment: Alignment,
14    /// Whether the box's minimum constraints pass on to its children. Defaults to `false`.
15    pub propagate_min_constraints: bool,
16}
17
18impl BoxSpec {
19    /// Creates a spec with top start alignment and no minimum constraint propagation.
20    pub fn new() -> Self {
21        Self::default()
22    }
23
24    /// Sets where children sit inside the box.
25    pub fn content_alignment(mut self, alignment: Alignment) -> Self {
26        self.content_alignment = alignment;
27        self
28    }
29
30    /// Sets whether the box's minimum constraints pass on to its children.
31    pub fn propagate_min_constraints(mut self, propagate: bool) -> Self {
32        self.propagate_min_constraints = propagate;
33        self
34    }
35}
36
37impl Default for BoxSpec {
38    fn default() -> Self {
39        Self {
40            content_alignment: Alignment::TOP_START,
41            propagate_min_constraints: false,
42        }
43    }
44}
45
46/// Places children over the same area. `content_alignment` selects each child's
47/// position within the box; later children draw above earlier children.
48///
49/// # Example
50///
51/// ```rust
52/// use cranpose_ui::*;
53///
54/// #[composable]
55/// fn Badge() {
56///     Box(
57///         Modifier::empty()
58///             .size_points(100.0, 100.0)
59///             .background(Color(0.1, 0.3, 0.9, 1.0)),
60///         BoxSpec::default().content_alignment(Alignment::CENTER),
61///         || {
62///             Text("Centered", Modifier::empty(), TextStyle::default());
63///         },
64///     );
65/// }
66/// ```
67#[composable]
68pub fn Box<F>(modifier: Modifier, spec: BoxSpec, content: F) -> NodeId
69where
70    F: FnMut() + 'static,
71{
72    let environment = LayoutEnvironment::current();
73    let mut policy = BoxMeasurePolicy::new(spec.content_alignment, spec.propagate_min_constraints);
74    policy.layout_direction = environment.direction;
75    compose_layout(modifier, policy, environment, content)
76}
cranpose_ui/widgets/box_widget.rs

cranpose_ui/widgets/
box_widget.rs
