1use crate::{
 2    geometry::{rect::RectF, vector::Vector2F},
 3    AfterLayoutContext, Element, ElementBox, Event, EventContext, LayoutContext, PaintContext,
 4    SizeConstraint,
 5};
 6
 7pub struct Stack {
 8    children: Vec<ElementBox>,
 9}
10
11impl Stack {
12    pub fn new() -> Self {
13        Stack {
14            children: Vec::new(),
15        }
16    }
17}
18
19impl Element for Stack {
20    type LayoutState = ();
21    type PaintState = ();
22
23    fn layout(
24        &mut self,
25        constraint: SizeConstraint,
26        ctx: &mut LayoutContext,
27    ) -> (Vector2F, Self::LayoutState) {
28        let mut size = constraint.min;
29        for child in &mut self.children {
30            size = size.max(child.layout(constraint, ctx));
31        }
32        (size, ())
33    }
34
35    fn after_layout(
36        &mut self,
37        _: Vector2F,
38        _: &mut Self::LayoutState,
39        ctx: &mut AfterLayoutContext,
40    ) {
41        for child in &mut self.children {
42            child.after_layout(ctx);
43        }
44    }
45
46    fn paint(
47        &mut self,
48        bounds: RectF,
49        _: &mut Self::LayoutState,
50        ctx: &mut PaintContext,
51    ) -> Self::PaintState {
52        for child in &mut self.children {
53            ctx.scene.push_layer(None);
54            child.paint(bounds.origin(), ctx);
55            ctx.scene.pop_layer();
56        }
57    }
58
59    fn dispatch_event(
60        &mut self,
61        event: &Event,
62        _: RectF,
63        _: &mut Self::LayoutState,
64        _: &mut Self::PaintState,
65        ctx: &mut EventContext,
66    ) -> bool {
67        for child in self.children.iter_mut().rev() {
68            if child.dispatch_event(event, ctx) {
69                return true;
70            }
71        }
72        false
73    }
74}
75
76impl Extend<ElementBox> for Stack {
77    fn extend<T: IntoIterator<Item = ElementBox>>(&mut self, children: T) {
78        self.children.extend(children)
79    }
80}