egui_winit/
window_settings.rs

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
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
use egui::ViewportBuilder;

/// Can be used to store native window settings (position and size).
#[derive(Clone, Copy, Debug, Default)]
#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
#[cfg_attr(feature = "serde", serde(default))]
pub struct WindowSettings {
    /// Position of window content in physical pixels.
    inner_position_pixels: Option<egui::Pos2>,

    /// Position of window frame/titlebar in physical pixels.
    outer_position_pixels: Option<egui::Pos2>,

    fullscreen: bool,

    /// Inner size of window in logical pixels
    inner_size_points: Option<egui::Vec2>,
}

impl WindowSettings {
    pub fn from_window(egui_zoom_factor: f32, window: &winit::window::Window) -> Self {
        let inner_size_points = window
            .inner_size()
            .to_logical::<f32>(egui_zoom_factor as f64 * window.scale_factor());

        let inner_position_pixels = window
            .inner_position()
            .ok()
            .map(|p| egui::pos2(p.x as f32, p.y as f32));

        let outer_position_pixels = window
            .outer_position()
            .ok()
            .map(|p| egui::pos2(p.x as f32, p.y as f32));

        Self {
            inner_position_pixels,
            outer_position_pixels,

            fullscreen: window.fullscreen().is_some(),

            inner_size_points: Some(egui::vec2(
                inner_size_points.width,
                inner_size_points.height,
            )),
        }
    }

    pub fn inner_size_points(&self) -> Option<egui::Vec2> {
        self.inner_size_points
    }

    pub fn initialize_viewport_builder(
        &self,
        egui_zoom_factor: f32,
        event_loop: &winit::event_loop::ActiveEventLoop,
        mut viewport_builder: ViewportBuilder,
    ) -> ViewportBuilder {
        crate::profile_function!();

        // `WindowBuilder::with_position` expects inner position in Macos, and outer position elsewhere
        // See [`winit::window::WindowBuilder::with_position`] for details.
        let pos_px = if cfg!(target_os = "macos") {
            self.inner_position_pixels
        } else {
            self.outer_position_pixels
        };
        if let Some(pos) = pos_px {
            let monitor_scale_factor = if let Some(inner_size_points) = self.inner_size_points {
                find_active_monitor(egui_zoom_factor, event_loop, inner_size_points, &pos)
                    .map_or(1.0, |monitor| monitor.scale_factor() as f32)
            } else {
                1.0
            };

            let scaled_pos = pos / (egui_zoom_factor * monitor_scale_factor);
            viewport_builder = viewport_builder.with_position(scaled_pos);
        }

        if let Some(inner_size_points) = self.inner_size_points {
            viewport_builder = viewport_builder
                .with_inner_size(inner_size_points)
                .with_fullscreen(self.fullscreen);
        }

        viewport_builder
    }

    pub fn initialize_window(&self, window: &winit::window::Window) {
        if cfg!(target_os = "macos") {
            // Mac sometimes has problems restoring the window to secondary monitors
            // using only `WindowBuilder::with_position`, so we need this extra step:
            if let Some(pos) = self.outer_position_pixels {
                window.set_outer_position(winit::dpi::PhysicalPosition { x: pos.x, y: pos.y });
            }
        }
    }

    pub fn clamp_size_to_sane_values(&mut self, largest_monitor_size_points: egui::Vec2) {
        use egui::NumExt as _;

        if let Some(size) = &mut self.inner_size_points {
            // Prevent ridiculously small windows:
            let min_size = egui::Vec2::splat(64.0);
            *size = size.at_least(min_size);

            // Make sure we don't try to create a window larger than the largest monitor
            // because on Linux that can lead to a crash.
            *size = size.at_most(largest_monitor_size_points);
        }
    }

    pub fn clamp_position_to_monitors(
        &mut self,
        egui_zoom_factor: f32,
        event_loop: &winit::event_loop::ActiveEventLoop,
    ) {
        // If the app last ran on two monitors and only one is now connected, then
        // the given position is invalid.
        // If this happens on Mac, the window is clamped into valid area.
        // If this happens on Windows, the window becomes invisible to the user 🤦‍♂️
        // So on Windows we clamp the position to the monitor it is on.
        if !cfg!(target_os = "windows") {
            return;
        }

        let Some(inner_size_points) = self.inner_size_points else {
            return;
        };

        if let Some(pos_px) = &mut self.inner_position_pixels {
            clamp_pos_to_monitors(egui_zoom_factor, event_loop, inner_size_points, pos_px);
        }
        if let Some(pos_px) = &mut self.outer_position_pixels {
            clamp_pos_to_monitors(egui_zoom_factor, event_loop, inner_size_points, pos_px);
        }
    }
}

fn find_active_monitor(
    egui_zoom_factor: f32,
    event_loop: &winit::event_loop::ActiveEventLoop,
    window_size_pts: egui::Vec2,
    position_px: &egui::Pos2,
) -> Option<winit::monitor::MonitorHandle> {
    crate::profile_function!();

    let monitors = event_loop.available_monitors();

    // default to primary monitor, in case the correct monitor was disconnected.
    let Some(mut active_monitor) = event_loop
        .primary_monitor()
        .or_else(|| event_loop.available_monitors().next())
    else {
        return None; // no monitors 🤷
    };

    for monitor in monitors {
        let window_size_px = window_size_pts * (egui_zoom_factor * monitor.scale_factor() as f32);
        let monitor_x_range = (monitor.position().x - window_size_px.x as i32)
            ..(monitor.position().x + monitor.size().width as i32);
        let monitor_y_range = (monitor.position().y - window_size_px.y as i32)
            ..(monitor.position().y + monitor.size().height as i32);

        if monitor_x_range.contains(&(position_px.x as i32))
            && monitor_y_range.contains(&(position_px.y as i32))
        {
            active_monitor = monitor;
        }
    }

    Some(active_monitor)
}

fn clamp_pos_to_monitors(
    egui_zoom_factor: f32,
    event_loop: &winit::event_loop::ActiveEventLoop,
    window_size_pts: egui::Vec2,
    position_px: &mut egui::Pos2,
) {
    crate::profile_function!();

    let Some(active_monitor) =
        find_active_monitor(egui_zoom_factor, event_loop, window_size_pts, position_px)
    else {
        return; // no monitors 🤷
    };

    let mut window_size_px =
        window_size_pts * (egui_zoom_factor * active_monitor.scale_factor() as f32);
    // Add size of title bar. This is 32 px by default in Win 10/11.
    if cfg!(target_os = "windows") {
        window_size_px += egui::Vec2::new(
            0.0,
            32.0 * egui_zoom_factor * active_monitor.scale_factor() as f32,
        );
    }
    let monitor_position = egui::Pos2::new(
        active_monitor.position().x as f32,
        active_monitor.position().y as f32,
    );
    let monitor_size_px = egui::Vec2::new(
        active_monitor.size().width as f32,
        active_monitor.size().height as f32,
    );

    // Window size cannot be negative or the subsequent `clamp` will panic.
    let window_size = (monitor_size_px - window_size_px).max(egui::Vec2::ZERO);
    // To get the maximum position, we get the rightmost corner of the display, then
    // subtract the size of the window to get the bottom right most value window.position
    // can have.
    *position_px = position_px.clamp(monitor_position, monitor_position + window_size);
}