feat: add compositor overview scene

compositor/src/overview.rs

@@ -0,0 +1,408 @@
+use std::{collections::HashMap, time::Duration};
+
+use ferese_animation::{AnimatedRect, SpringConfig};
+use ferese_layout::{Direction, Rect, WindowId};
+
+use crate::Ferese;
+
+const OVERVIEW_MARGIN: f64 = 48.0;
+const OVERVIEW_GAP: f64 = 24.0;
+const MAX_PREVIEW_SCALE: f64 = 0.82;
+
+#[derive(Debug, Default)]
+pub(crate) struct OverviewState {
+    active: bool,
+    selected: Option<WindowId>,
+    presentations: HashMap<WindowId, AnimatedRect>,
+}
+
+impl OverviewState {
+    pub(crate) fn is_active(&self) -> bool {
+        self.active
+    }
+
+    pub(crate) fn is_presenting(&self) -> bool {
+        self.active || !self.presentations.is_empty()
+    }
+
+    pub(crate) fn selected(&self) -> Option<WindowId> {
+        self.selected
+    }
+
+    pub(crate) fn select_direction(&mut self, direction: Direction) -> bool {
+        let Some(current) = self
+            .selected
+            .and_then(|id| self.presentations.get(&id))
+            .map(|presentation| presentation.current)
+        else {
+            return false;
+        };
+        let current_center = rect_center(current);
+        let next = self
+            .presentations
+            .iter()
+            .filter(|(id, _)| Some(**id) != self.selected)
+            .filter_map(|(id, presentation)| {
+                let center = rect_center(presentation.current);
+                directional_distance(direction, current_center, center)
+                    .map(|distance| (*id, distance))
+            })
+            .min_by(|(left_id, left), (right_id, right)| {
+                left.total_cmp(right)
+                    .then_with(|| left_id.0.cmp(&right_id.0))
+            })
+            .map(|(id, _)| id);
+        let Some(next) = next else {
+            return false;
+        };
+
+        self.selected = Some(next);
+        true
+    }
+
+    pub(crate) fn presented_rect(&self, id: WindowId, normal: Rect) -> Rect {
+        self.presentations
+            .get(&id)
+            .map_or(normal, |presentation| presentation.current)
+    }
+
+    fn enter(
+        &mut self,
+        targets: HashMap<WindowId, (Rect, Rect)>,
+        selected: Option<WindowId>,
+        animations_enabled: bool,
+    ) {
+        self.active = true;
+        self.selected = selected
+            .filter(|id| targets.contains_key(id))
+            .or_else(|| targets.keys().copied().min_by_key(|id| id.0));
+        self.retarget(targets, animations_enabled);
+    }
+
+    fn retarget(&mut self, targets: HashMap<WindowId, (Rect, Rect)>, animations_enabled: bool) {
+        self.presentations.retain(|id, _| targets.contains_key(id));
+
+        for (id, (normal, target)) in targets {
+            let presentation = self
+                .presentations
+                .entry(id)
+                .or_insert_with(|| AnimatedRect::new(normal));
+
+            presentation.set_target(target);
+            if !animations_enabled {
+                presentation.snap();
+            }
+        }
+    }
+
+    fn exit(&mut self, normal: HashMap<WindowId, Rect>, animations_enabled: bool) {
+        self.active = false;
+        self.selected = None;
+        self.presentations.retain(|id, presentation| {
+            let Some(target) = normal.get(id).copied() else {
+                return false;
+            };
+
+            presentation.set_target(target);
+            if !animations_enabled {
+                presentation.snap();
+            }
+            true
+        });
+
+        if !animations_enabled {
+            self.presentations.clear();
+        }
+    }
+
+    pub(crate) fn advance(
+        &mut self,
+        delta: Duration,
+        spring: SpringConfig,
+        animations_enabled: bool,
+    ) -> bool {
+        let mut active_animation = false;
+
+        for presentation in self.presentations.values_mut() {
+            if animations_enabled {
+                active_animation |= presentation.advance(delta, spring);
+            } else {
+                presentation.snap();
+            }
+        }
+
+        if !self.active && !active_animation {
+            self.presentations.clear();
+        }
+
+        active_animation
+    }
+}
+
+impl Ferese {
+    pub(crate) fn set_overview_active(&mut self, active: bool) {
+        if self.overview.is_active() == active {
+            return;
+        }
+
+        if active {
+            let targets = self.overview_targets();
+            self.overview
+                .enter(targets, self.focused_window, self.animations_enabled());
+        } else {
+            let normal = self.normal_window_rects();
+            self.overview.exit(normal, self.animations_enabled());
+        }
+
+        self.notify_overview_state();
+        crate::backends::direct::render_all(self);
+    }
+
+    pub(crate) fn toggle_overview(&mut self) {
+        self.set_overview_active(!self.overview.is_active());
+    }
+
+    pub(crate) fn focus_overview_direction(&mut self, direction: Direction) -> bool {
+        if !self.overview.is_active() {
+            return false;
+        }
+
+        if self.overview.select_direction(direction) {
+            crate::backends::direct::render_all(self);
+        }
+
+        true
+    }
+
+    pub(crate) fn select_overview_window(&mut self, id: WindowId) -> bool {
+        if !self.overview.is_active() || !self.overview.presentations.contains_key(&id) {
+            return false;
+        }
+
+        if !self.activate_managed_window(id) {
+            return false;
+        }
+
+        self.set_overview_active(false);
+        true
+    }
+
+    pub(crate) fn retarget_overview(&mut self) {
+        if !self.overview.is_active() {
+            return;
+        }
+
+        let targets = self.overview_targets();
+        self.overview.retarget(targets, self.animations_enabled());
+    }
+
+    pub(crate) fn presented_window_rect(&self, id: WindowId) -> Option<Rect> {
+        let normal = self.window_geometry.get(&id)?.visual.current;
+
+        Some(self.overview.presented_rect(id, normal))
+    }
+
+    pub(crate) fn inverse_presented_window_point(
+        &self,
+        id: WindowId,
+        x: f64,
+        y: f64,
+    ) -> Option<(f64, f64)> {
+        let geometry = self.window_geometry.get(&id)?;
+        let source = geometry.client.committed_size?;
+        let presented = self.overview.presented_rect(id, geometry.visual.current);
+
+        if source.width <= 0
+            || source.height <= 0
+            || presented.width <= 0.0
+            || presented.height <= 0.0
+        {
+            return None;
+        }
+
+        let scale_x = presented.width / f64::from(source.width);
+        let scale_y = presented.height / f64::from(source.height);
+
+        Some(((x - presented.x) / scale_x, (y - presented.y) / scale_y))
+    }
+
+    pub(crate) fn overview_selected(&self, id: WindowId) -> bool {
+        self.overview.is_active() && self.overview.selected() == Some(id)
+    }
+
+    fn overview_targets(&self) -> HashMap<WindowId, (Rect, Rect)> {
+        let mut targets = HashMap::new();
+
+        for output in self.space.outputs() {
+            let Some(output_id) = self.output_id(output) else {
+                continue;
+            };
+            let Some(workspace) = self.output_workspaces.active_workspace(output_id) else {
+                continue;
+            };
+            let Some(bounds) = self.output_bounds_for(output) else {
+                continue;
+            };
+            let mut windows = self
+                .window_ids
+                .values()
+                .filter(|id| self.workspaces.workspace_for_window(**id) == Some(workspace))
+                .filter_map(|id| {
+                    let normal = self.window_geometry.get(id)?.visual.current;
+                    Some((*id, normal))
+                })
+                .collect::<Vec<_>>();
+
+            windows.sort_by_key(|(id, _)| id.0);
+            for (id, target) in overview_layout(bounds, &windows) {
+                let normal = self.window_geometry[&id].visual.current;
+                targets.insert(id, (normal, target));
+            }
+        }
+
+        targets
+    }
+
+    fn normal_window_rects(&self) -> HashMap<WindowId, Rect> {
+        self.window_geometry
+            .iter()
+            .map(|(id, geometry)| (*id, geometry.visual.current))
+            .collect()
+    }
+}
+
+fn overview_layout(bounds: Rect, windows: &[(WindowId, Rect)]) -> HashMap<WindowId, Rect> {
+    if windows.is_empty() {
+        return HashMap::new();
+    }
+
+    let content_width = (bounds.width - OVERVIEW_MARGIN * 2.0).max(1.0);
+    let content_height = (bounds.height - OVERVIEW_MARGIN * 2.0).max(1.0);
+    let aspect = (content_width / content_height).max(0.1);
+    let columns = ((windows.len() as f64 * aspect).sqrt().ceil() as usize).clamp(1, windows.len());
+    let rows = windows.len().div_ceil(columns);
+    let cell_width = ((content_width - OVERVIEW_GAP * columns.saturating_sub(1) as f64)
+        / columns as f64)
+        .max(1.0);
+    let cell_height =
+        ((content_height - OVERVIEW_GAP * rows.saturating_sub(1) as f64) / rows as f64).max(1.0);
+    let origin_x = bounds.x + OVERVIEW_MARGIN;
+    let origin_y = bounds.y + OVERVIEW_MARGIN;
+
+    windows
+        .iter()
+        .enumerate()
+        .map(|(index, (id, source))| {
+            let column = index % columns;
+            let row = index / columns;
+            let scale = (cell_width / source.width.max(1.0))
+                .min(cell_height / source.height.max(1.0))
+                .min(MAX_PREVIEW_SCALE);
+            let width = (source.width * scale).max(1.0);
+            let height = (source.height * scale).max(1.0);
+            let cell_x = origin_x + column as f64 * (cell_width + OVERVIEW_GAP);
+            let cell_y = origin_y + row as f64 * (cell_height + OVERVIEW_GAP);
+            let target = Rect::new(
+                cell_x + (cell_width - width) / 2.0,
+                cell_y + (cell_height - height) / 2.0,
+                width,
+                height,
+            );
+
+            (*id, target)
+        })
+        .collect()
+}
+
+fn rect_center(rect: Rect) -> (f64, f64) {
+    (rect.x + rect.width / 2.0, rect.y + rect.height / 2.0)
+}
+
+fn directional_distance(
+    direction: Direction,
+    current: (f64, f64),
+    candidate: (f64, f64),
+) -> Option<f64> {
+    let delta_x = candidate.0 - current.0;
+    let delta_y = candidate.1 - current.1;
+    let (primary, secondary) = match direction {
+        Direction::Left if delta_x < 0.0 => (-delta_x, delta_y.abs()),
+        Direction::Right if delta_x > 0.0 => (delta_x, delta_y.abs()),
+        Direction::Up if delta_y < 0.0 => (-delta_y, delta_x.abs()),
+        Direction::Down if delta_y > 0.0 => (delta_y, delta_x.abs()),
+        _ => return None,
+    };
+
+    Some(primary + secondary * 0.35)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn overview_grid_fits_windows_inside_the_output() {
+        let bounds = Rect::new(0.0, 0.0, 1920.0, 1080.0);
+        let windows = (1..=5)
+            .map(|id| (WindowId(id), Rect::new(0.0, 0.0, 960.0, 1000.0)))
+            .collect::<Vec<_>>();
+        let layout = overview_layout(bounds, &windows);
+
+        assert_eq!(layout.len(), windows.len());
+        assert!(layout.values().all(|rect| {
+            rect.x >= bounds.x
+                && rect.y >= bounds.y
+                && rect.x + rect.width <= bounds.x + bounds.width
+                && rect.y + rect.height <= bounds.y + bounds.height
+        }));
+    }
+
+    #[test]
+    fn overview_grid_preserves_preview_aspect_ratio() {
+        let source = Rect::new(0.0, 0.0, 1200.0, 800.0);
+        let layout = overview_layout(
+            Rect::new(0.0, 0.0, 1920.0, 1080.0),
+            &[(WindowId(1), source)],
+        );
+        let preview = layout[&WindowId(1)];
+
+        assert!((preview.width / preview.height - source.width / source.height).abs() < 0.001);
+    }
+
+    #[test]
+    fn leaving_overview_keeps_presentations_until_they_settle() {
+        let id = WindowId(1);
+        let normal = Rect::new(0.0, 0.0, 1000.0, 800.0);
+        let target = Rect::new(200.0, 150.0, 500.0, 400.0);
+        let mut overview = OverviewState::default();
+
+        overview.enter(HashMap::from([(id, (normal, target))]), Some(id), false);
+        overview.exit(HashMap::from([(id, normal)]), true);
+
+        assert_eq!(overview.presented_rect(id, normal), target);
+        assert!(!overview.is_active());
+        assert!(overview.advance(Duration::from_millis(16), SpringConfig::default(), true));
+    }
+
+    #[test]
+    fn directional_selection_uses_presented_geometry() {
+        let left = WindowId(1);
+        let right = WindowId(2);
+        let left_rect = Rect::new(0.0, 0.0, 400.0, 400.0);
+        let right_rect = Rect::new(500.0, 0.0, 400.0, 400.0);
+        let mut overview = OverviewState::default();
+
+        overview.enter(
+            HashMap::from([
+                (left, (left_rect, left_rect)),
+                (right, (right_rect, right_rect)),
+            ]),
+            Some(left),
+            false,
+        );
+
+        assert!(overview.select_direction(Direction::Right));
+        assert_eq!(overview.selected(), Some(right));
+        assert!(!overview.select_direction(Direction::Right));
+    }
+}