1use anyhow::{anyhow, Result};
 2use derive_more::{Deref, DerefMut};
 3use gpui::{scene::EventHandler, EngineLayout, EventContext, LayoutId, RenderContext, ViewContext};
 4pub use gpui::{LayoutContext, PaintContext as LegacyPaintContext};
 5use std::{any::TypeId, rc::Rc};
 6pub use taffy::tree::NodeId;
 7
 8#[derive(Deref, DerefMut)]
 9pub struct PaintContext<'a, 'b, 'c, 'd, V> {
10    #[deref]
11    #[deref_mut]
12    pub(crate) legacy_cx: &'d mut LegacyPaintContext<'a, 'b, 'c, V>,
13    pub(crate) scene: &'d mut gpui::SceneBuilder,
14}
15
16impl<'a, 'b, V> RenderContext<'a, 'b, V> for PaintContext<'a, 'b, '_, '_, V> {
17    fn text_style(&self) -> gpui::fonts::TextStyle {
18        self.legacy_cx.text_style()
19    }
20
21    fn push_text_style(&mut self, style: gpui::fonts::TextStyle) {
22        self.legacy_cx.push_text_style(style)
23    }
24
25    fn pop_text_style(&mut self) {
26        self.legacy_cx.pop_text_style()
27    }
28
29    fn as_view_context(&mut self) -> &mut ViewContext<'a, 'b, V> {
30        &mut self.view_context
31    }
32}
33
34impl<'a, 'b, 'c, 'd, V: 'static> PaintContext<'a, 'b, 'c, 'd, V> {
35    pub fn new(
36        legacy_cx: &'d mut LegacyPaintContext<'a, 'b, 'c, V>,
37        scene: &'d mut gpui::SceneBuilder,
38    ) -> Self {
39        Self { legacy_cx, scene }
40    }
41
42    pub fn on_event<E: 'static>(
43        &mut self,
44        order: u32,
45        handler: impl Fn(&mut V, &E, &mut ViewContext<V>) + 'static,
46    ) {
47        let view = self.weak_handle();
48
49        self.scene.event_handlers.push(EventHandler {
50            order,
51            handler: Rc::new(move |event, window_cx| {
52                if let Some(view) = view.upgrade(window_cx) {
53                    view.update(window_cx, |view, view_cx| {
54                        let mut event_cx = EventContext::new(view_cx);
55                        handler(view, event.downcast_ref().unwrap(), &mut event_cx);
56                        event_cx.bubble
57                    })
58                } else {
59                    true
60                }
61            }),
62            event_type: TypeId::of::<E>(),
63        })
64    }
65
66    pub(crate) fn computed_layout(&mut self, layout_id: LayoutId) -> Result<EngineLayout> {
67        self.layout_engine()
68            .ok_or_else(|| anyhow!("no layout engine present"))?
69            .computed_layout(layout_id)
70    }
71}