1use refineable::Refineable as _;
 2
 3use crate::{Bounds, Element, IntoElement, Pixels, Style, StyleRefinement, Styled, WindowContext};
 4
 5pub fn canvas(callback: impl 'static + FnOnce(&Bounds<Pixels>, &mut WindowContext)) -> Canvas {
 6    Canvas {
 7        paint_callback: Some(Box::new(callback)),
 8        style: StyleRefinement::default(),
 9    }
10}
11
12pub struct Canvas {
13    paint_callback: Option<Box<dyn FnOnce(&Bounds<Pixels>, &mut WindowContext)>>,
14    style: StyleRefinement,
15}
16
17impl IntoElement for Canvas {
18    type Element = Self;
19
20    fn element_id(&self) -> Option<crate::ElementId> {
21        None
22    }
23
24    fn into_element(self) -> Self::Element {
25        self
26    }
27}
28
29impl Element for Canvas {
30    type State = Style;
31
32    fn request_layout(
33        &mut self,
34        _: Option<Self::State>,
35        cx: &mut WindowContext,
36    ) -> (crate::LayoutId, Self::State) {
37        let mut style = Style::default();
38        style.refine(&self.style);
39        let layout_id = cx.request_layout(&style, []);
40        (layout_id, style)
41    }
42
43    fn paint(&mut self, bounds: Bounds<Pixels>, style: &mut Style, cx: &mut WindowContext) {
44        style.paint(bounds, cx, |cx| {
45            (self.paint_callback.take().unwrap())(&bounds, cx)
46        });
47    }
48}
49
50impl Styled for Canvas {
51    fn style(&mut self) -> &mut crate::StyleRefinement {
52        &mut self.style
53    }
54}