1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133

use std::{sync::Arc, time::Instant};

use winit::{
    event_loop::EventLoopWindowTarget,
    window::{Window, WindowId},
};

use egui::ViewportId;
#[cfg(feature = "accesskit")]
use egui_winit::accesskit_winit;

use super::epi_integration::EpiIntegration;

/// Create an egui context, restoring it from storage if possible.
pub fn create_egui_context(storage: Option<&dyn crate::Storage>) -> egui::Context {
    crate::profile_function!();

    pub const IS_DESKTOP: bool = cfg!(any(
        target_os = "freebsd",
        target_os = "linux",
        target_os = "macos",
        target_os = "openbsd",
        target_os = "windows",
    ));

    let egui_ctx = egui::Context::default();

    egui_ctx.set_embed_viewports(!IS_DESKTOP);

    let memory = crate::native::epi_integration::load_egui_memory(storage).unwrap_or_default();
    egui_ctx.memory_mut(|mem| *mem = memory);

    egui_ctx
}

/// The custom even `eframe` uses with the [`winit`] event loop.
#[derive(Debug)]
pub enum UserEvent {
    /// A repaint is requested.
    RequestRepaint {
        /// What to repaint.
        viewport_id: ViewportId,

        /// When to repaint.
        when: Instant,

        /// What the frame number was when the repaint was _requested_.
        frame_nr: u64,
    },

    /// A request related to [`accesskit`](https://accesskit.dev/).
    #[cfg(feature = "accesskit")]
    AccessKitActionRequest(accesskit_winit::ActionRequestEvent),
}

#[cfg(feature = "accesskit")]
impl From<accesskit_winit::ActionRequestEvent> for UserEvent {
    fn from(inner: accesskit_winit::ActionRequestEvent) -> Self {
        Self::AccessKitActionRequest(inner)
    }
}

pub trait WinitApp {
    /// The current frame number, as reported by egui.
    fn frame_nr(&self, viewport_id: ViewportId) -> u64;

    fn is_focused(&self, window_id: WindowId) -> bool;

    fn integration(&self) -> Option<&EpiIntegration>;

    fn window(&self, window_id: WindowId) -> Option<Arc<Window>>;

    fn window_id_from_viewport_id(&self, id: ViewportId) -> Option<WindowId>;

    fn save_and_destroy(&mut self);

    fn run_ui_and_paint(
        &mut self,
        event_loop: &EventLoopWindowTarget<UserEvent>,
        window_id: WindowId,
    ) -> EventResult;

    fn on_event(
        &mut self,
        event_loop: &EventLoopWindowTarget<UserEvent>,
        event: &winit::event::Event<UserEvent>,
    ) -> crate::Result<EventResult>;
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum EventResult {
    Wait,

    /// Causes a synchronous repaint inside the event handler. This should only
    /// be used in special situations if the window must be repainted while
    /// handling a specific event. This occurs on Windows when handling resizes.
    ///
    /// `RepaintNow` creates a new frame synchronously, and should therefore
    /// only be used for extremely urgent repaints.
    RepaintNow(WindowId),

    /// Queues a repaint for once the event loop handles its next redraw. Exists
    /// so that multiple input events can be handled in one frame. Does not
    /// cause any delay like `RepaintNow`.
    RepaintNext(WindowId),

    RepaintAt(WindowId, Instant),

    Exit,
}

pub fn system_theme(window: &Window, options: &crate::NativeOptions) -> Option<crate::Theme> {
    if options.follow_system_theme {
        window
            .theme()
            .map(super::epi_integration::theme_from_winit_theme)
    } else {
        None
    }
}

/// Short and fast description of an event.
/// Useful for logging and profiling.
pub fn short_event_description(event: &winit::event::Event<UserEvent>) -> &'static str {
    match event {
        winit::event::Event::UserEvent(user_event) => match user_event {
            UserEvent::RequestRepaint { .. } => "UserEvent::RequestRepaint",
            #[cfg(feature = "accesskit")]
            UserEvent::AccessKitActionRequest(_) => "UserEvent::AccessKitActionRequest",
        },
        _ => egui_winit::short_generic_event_description(event),
    }
}