gpui_authoring/elements/
canvas.rs

1use refineable::Refineable as _;
2
3use crate::{
4    App, Bounds, Element, ElementId, GlobalElementId, IntoElement, Pixels, Style, StyleRefinement,
5    Styled, Window,
6};
7
8/// Construct a canvas element with the given paint callback.
9/// Useful for adding short term custom drawing to a view.
10pub fn canvas<T>(
11    prepaint: impl 'static + FnOnce(Bounds<Pixels>, &mut Window, &mut App) -> T,
12    paint: impl 'static + FnOnce(Bounds<Pixels>, T, &mut Window, &mut App),
13) -> Canvas<T> {
14    Canvas {
15        prepaint: Some(Box::new(prepaint)),
16        paint: Some(Box::new(paint)),
17        style: StyleRefinement::default(),
18    }
19}
20
21/// A canvas element, meant for accessing the low level paint API without defining a whole
22/// custom element
23pub struct Canvas<T> {
24    prepaint: Option<Box<dyn FnOnce(Bounds<Pixels>, &mut Window, &mut App) -> T>>,
25    paint: Option<Box<dyn FnOnce(Bounds<Pixels>, T, &mut Window, &mut App)>>,
26    style: StyleRefinement,
27}
28
29impl<T: 'static> IntoElement for Canvas<T> {
30    type Element = Self;
31
32    fn into_element(self) -> Self::Element {
33        self
34    }
35}
36
37impl<T: 'static> Element for Canvas<T> {
38    type RequestLayoutState = Style;
39    type PrepaintState = Option<T>;
40
41    fn id(&self) -> Option<ElementId> {
42        None
43    }
44
45    fn source_location(&self) -> Option<&'static core::panic::Location<'static>> {
46        None
47    }
48
49    fn request_layout(
50        &mut self,
51        _id: Option<&GlobalElementId>,
52        window: &mut Window,
53        cx: &mut App,
54    ) -> (crate::LayoutId, Self::RequestLayoutState) {
55        let mut style = Style::default();
56        style.refine(&self.style);
57        let layout_id = window.request_layout(style.clone(), [], cx);
58        (layout_id, style)
59    }
60
61    fn prepaint(
62        &mut self,
63        _id: Option<&GlobalElementId>,
64        bounds: Bounds<Pixels>,
65        _request_layout: &mut Style,
66        window: &mut Window,
67        cx: &mut App,
68    ) -> Option<T> {
69        Some(self.prepaint.take().unwrap()(bounds, window, cx))
70    }
71
72    fn paint(
73        &mut self,
74        _id: Option<&GlobalElementId>,
75        bounds: Bounds<Pixels>,
76        style: &mut Style,
77        prepaint: &mut Self::PrepaintState,
78        window: &mut Window,
79        cx: &mut App,
80    ) {
81        let prepaint = prepaint.take().unwrap();
82        style.paint(bounds, window, cx, |window, cx| {
83            (self.paint.take().unwrap())(bounds, prepaint, window, cx)
84        });
85    }
86}
87
88impl<T> Styled for Canvas<T> {
89    fn style(&mut self) -> &mut crate::StyleRefinement {
90        &mut self.style
91    }
92}
gpui_authoring/elements/canvas.rs

gpui_authoring/elements/
canvas.rs
