feat(layout): overlay scrolling tab indicators and hover titles

compositor/src/state/tab_indicator.rs

@@ -0,0 +1,558 @@
+use super::*;
+use crate::config::TabIndicatorSettings;
+use smithay::reexports::calloop::{
+    RegistrationToken,
+    timer::{TimeoutAction, Timer},
+};
+
+#[derive(Debug)]
+pub(crate) struct Overlay {
+    pub anchor: WindowId,
+    pub opacity: AnimatedValue,
+}
+
+#[derive(Debug, Default)]
+pub(crate) struct TabIndicatorState {
+    pub hover: Option<Overlay>,
+    pub flash: Option<Overlay>,
+    pub first_row: usize,
+    timer: Option<RegistrationToken>,
+}
+
+impl TabIndicatorState {
+    pub fn is_animating(&self) -> bool {
+        [&self.hover, &self.flash]
+            .into_iter()
+            .flatten()
+            .any(|o| o.opacity.is_animating())
+    }
+
+    pub fn advance(&mut self, delta: Duration, spring: SpringConfig, enabled: bool) -> bool {
+        let mut moving = false;
+        for overlay in [&mut self.hover, &mut self.flash] {
+            if let Some(value) = overlay {
+                if enabled {
+                    moving |= value
+                        .opacity
+                        .advance(delta, crate::presentation::emphasis_spring(spring));
+                } else {
+                    value.opacity.snap();
+                }
+                if !value.opacity.is_animating() && value.opacity.current == 0.0 {
+                    *overlay = None;
+                }
+            }
+        }
+        moving
+    }
+}
+
+#[derive(Clone, Copy, Debug)]
+pub(crate) struct IndicatorGeometry {
+    pub rail: Rect,
+    pub hit: Rect,
+    pub list: Rect,
+    pub segment_height: f64,
+    pub pitch: f64,
+    pub row_height: f64,
+    pub padding: f64,
+    pub rows: usize,
+}
+
+pub(crate) fn contains(rect: Rect, p: Point<f64, Logical>) -> bool {
+    p.x >= rect.x && p.x < rect.x + rect.width && p.y >= rect.y && p.y < rect.y + rect.height
+}
+
+impl IndicatorGeometry {
+    pub fn new(content: Rect, output: Rect, left_boundary: f64, count: usize, c: TabIndicatorSettings) -> Option<Self> {
+        if count < 2 || content.width <= 0.0 || content.height <= 0.0 || output.width <= 0.0 || output.height <= 0.0 {
+            return None;
+        }
+        let left = content.x.max(output.x);
+        let right = (content.x + content.width).min(output.x + output.width);
+        let top = content.y.max(output.y);
+        let bottom = (content.y + content.height).min(output.y + output.height);
+        if right - left < c.width || bottom <= top {
+            return None;
+        }
+        let gap = (content.x - left_boundary).max(0.0);
+        let x = if content.x >= output.x && gap >= c.gap_threshold {
+            content.x - (c.gap_threshold + c.width) * 0.5
+        } else {
+            left
+        }
+        .clamp(output.x, (right - c.width).max(output.x));
+        let natural = count as f64 * c.segment_height + count.saturating_sub(1) as f64 * c.segment_gap;
+        let fit = ((bottom - top) / natural).min(1.0);
+        let height = (natural * fit).min(bottom - top);
+        let rail = Rect::new(x, top + (bottom - top - height) * 0.5, c.width, height);
+        let hit_width = c.hit_width.min(output.width);
+        let hit = Rect::new(
+            (x + c.width * 0.5 - hit_width * 0.5).clamp(output.x, output.x + output.width - hit_width),
+            rail.y,
+            hit_width,
+            rail.height,
+        );
+        let padding = c.padding.min(output.height * 0.1).min(output.width * 0.1);
+        let row_height = c.row_height.min((output.height - 2.0 * padding).max(f64::EPSILON));
+        let rows = (((output.height - 2.0 * padding) / row_height).floor() as usize)
+            .max(1)
+            .min(count);
+        let list_width = c.list_width.min(output.width);
+        let list_height = (rows as f64 * row_height + 2.0 * padding).min(output.height);
+        let x = if hit.x + hit.width + padding + list_width <= output.x + output.width {
+            hit.x + hit.width + padding
+        } else if hit.x - padding - list_width >= output.x {
+            hit.x - padding - list_width
+        } else {
+            (hit.x + hit.width + padding).clamp(output.x, output.x + output.width - list_width)
+        };
+        let list = Rect::new(
+            x,
+            (rail.y + rail.height * 0.5 - list_height * 0.5).clamp(output.y, output.y + output.height - list_height),
+            list_width,
+            list_height,
+        );
+        Some(Self {
+            rail,
+            hit,
+            list,
+            segment_height: c.segment_height * fit,
+            pitch: (c.segment_height + c.segment_gap) * fit,
+            row_height,
+            padding,
+            rows,
+        })
+    }
+
+    pub fn row(&self, visible_index: usize) -> Rect {
+        Rect::new(
+            self.list.x + self.padding,
+            self.list.y + self.padding + visible_index as f64 * self.row_height,
+            (self.list.width - 2.0 * self.padding).max(0.0),
+            self.row_height,
+        )
+    }
+
+    pub fn hover_contains(&self, p: Point<f64, Logical>) -> bool {
+        let left = self.hit.x.min(self.list.x);
+        let top = self.hit.y.min(self.list.y);
+        contains(
+            Rect::new(
+                left,
+                top,
+                (self.hit.x + self.hit.width).max(self.list.x + self.list.width) - left,
+                (self.hit.y + self.hit.height).max(self.list.y + self.list.height) - top,
+            ),
+            p,
+        )
+    }
+}
+
+impl Ferese {
+    pub(crate) fn scrolling_tab_bar(&self, anchor: WindowId) -> Option<&ferese_layout::TabBar> {
+        let workspace = self.workspaces.workspace_for_window(anchor)?;
+        if !matches!(
+            self.workspaces.workspace(workspace)?.layout,
+            WorkspaceLayout::Scrolling(_)
+        ) {
+            return None;
+        }
+        self.visible_tab_bars(workspace)
+            .find(|bar| bar.group.windows.first() == Some(&anchor))
+    }
+
+    pub(crate) fn tab_indicator_geometry(
+        &self,
+        bar: &ferese_layout::TabBar,
+        content: Rect,
+    ) -> Option<IndicatorGeometry> {
+        let workspace = self.workspaces.workspace_for_window(bar.group.active)?;
+        let output_id = self.output_workspaces.output_for_workspace(workspace)?;
+        if self.output_workspaces.active_workspace(output_id) != Some(workspace) {
+            return None;
+        }
+        let output = self.outputs_by_id.get(&output_id)?;
+        let g = self.space.output_geometry(output)?;
+        let bounds = Rect::new(g.loc.x as f64, g.loc.y as f64, g.size.w as f64, g.size.h as f64);
+        let mut boundary = bounds.x;
+        // Measure the current visible gap, including animated column positions.
+        for window in self.space.elements() {
+            let Some(id) = self.windows.ids().get(window).copied() else {
+                continue;
+            };
+            if id == bar.group.active
+                || self.workspaces.workspace_for_window(id) != Some(workspace)
+                || !self.workspaces.workspace(workspace)?.layout.contains(id)
+            {
+                continue;
+            }
+            let Some(rect) = self.presented_window_rect(id) else {
+                continue;
+            };
+            if rect.x + rect.width <= content.x
+                && rect.y < content.y + content.height
+                && rect.y + rect.height > content.y
+            {
+                boundary = boundary.max(rect.x + rect.width);
+            }
+        }
+        IndicatorGeometry::new(
+            content,
+            bounds,
+            boundary,
+            bar.group.windows.len(),
+            self.tab_indicator_settings,
+        )
+    }
+
+    fn tab_indicator_can_hit(&self, active: WindowId, p: Point<f64, Logical>) -> bool {
+        if self.session_lock.active()
+            || self.input_capture.active()
+            || self.overview.is_presenting()
+            || self.seat.get_pointer().is_some_and(|p| p.is_grabbed())
+            || self.layer_surface_under(p, &[Layer::Overlay, Layer::Top]).is_some()
+        {
+            return false;
+        }
+        // Match the renderer's per-window stacking. An overlay can cover its
+        // own client and lower windows, never floating windows/popups above it.
+        for window in self.space.elements().rev() {
+            let Some(id) = self.windows.ids().get(window).copied() else {
+                continue;
+            };
+            if id == active {
+                break;
+            }
+            if self.presented_window_rect(id).is_some_and(|r| contains(r, p)) {
+                return false;
+            }
+        }
+        if self
+            .window_under_visual(p)
+            .is_some_and(|w| self.windows.ids().get(&w) == Some(&active))
+            && let Some((mut surface, _)) = self.window_surface_under(p)
+        {
+            while let Some(parent) = smithay::wayland::compositor::get_parent(&surface) {
+                surface = parent;
+            }
+            if self
+                .windows
+                .window(active)
+                .and_then(|w| w.toplevel())
+                .is_none_or(|t| t.wl_surface() != &surface)
+            {
+                return false;
+            }
+        }
+        true
+    }
+
+    pub(crate) fn indicator_tab_at(&self, p: Point<f64, Logical>) -> Option<WindowId> {
+        let workspace = self.workspace_under_pointer(p)?;
+        if !matches!(
+            self.workspaces.workspace(workspace)?.layout,
+            WorkspaceLayout::Scrolling(_)
+        ) {
+            return None;
+        }
+        for bar in self.visible_tab_bars(workspace) {
+            let Some(content) = self.presented_window_rect(bar.group.active) else {
+                continue;
+            };
+            let Some(g) = self.tab_indicator_geometry(bar, content) else {
+                continue;
+            };
+            if !self.tab_indicator_can_hit(bar.group.active, p) {
+                continue;
+            }
+            let anchor = bar.group.windows[0];
+            let expanded = self
+                .tab_indicator
+                .hover
+                .as_ref()
+                .is_some_and(|h| h.anchor == anchor && h.opacity.target > 0.0);
+            if expanded && contains(g.list, p) {
+                let first = self
+                    .tab_indicator
+                    .first_row
+                    .min(bar.group.windows.len().saturating_sub(g.rows));
+                let index = ((p.y - g.list.y - g.padding).max(0.0) / g.row_height).floor() as usize;
+                return bar.group.windows.get(first + index.min(g.rows - 1)).copied();
+            }
+            if contains(g.hit, p) {
+                let index = ((p.y - g.rail.y) / g.pitch).floor() as usize;
+                return bar.group.windows.get(index.min(bar.group.windows.len() - 1)).copied();
+            }
+            if expanded && g.hover_contains(p) {
+                return Some(bar.group.active);
+            }
+        }
+        None
+    }
+
+    pub(crate) fn update_tab_indicator_hover(&mut self, p: Point<f64, Logical>) {
+        let anchor = self.indicator_tab_at(p).and_then(|id| {
+            self.workspaces
+                .workspace_for_window(id)
+                .and_then(|ws| self.workspaces.workspace(ws))
+                .and_then(|ws| ws.layout.tab_group(id))
+                .and_then(|group| group.windows.first().copied())
+        });
+        let unchanged = match (anchor, &self.tab_indicator.hover) {
+            (Some(anchor), Some(hover)) => hover.anchor == anchor && hover.opacity.target == 1.0,
+            (None, Some(hover)) => hover.opacity.target == 0.0,
+            (None, None) => true,
+            _ => false,
+        };
+        if unchanged {
+            return;
+        }
+        self.advance_animations(Instant::now());
+        if let Some(anchor) = anchor {
+            let same = self.tab_indicator.hover.as_ref().is_some_and(|h| h.anchor == anchor);
+            if !same {
+                let selected = self
+                    .scrolling_tab_bar(anchor)
+                    .and_then(|bar| {
+                        let g = self.tab_indicator_geometry(bar, self.presented_window_rect(bar.group.active)?)?;
+                        let selected = bar.group.windows.iter().position(|id| *id == bar.group.active)?;
+                        Some(
+                            selected
+                                .saturating_sub(g.rows / 2)
+                                .min(bar.group.windows.len().saturating_sub(g.rows)),
+                        )
+                    })
+                    .unwrap_or(0);
+                self.tab_indicator.first_row = selected;
+                self.tab_indicator.hover = Some(Overlay {
+                    anchor,
+                    opacity: AnimatedValue::new(0.0),
+                });
+            }
+            if let Some(hover) = &mut self.tab_indicator.hover {
+                if hover.opacity.target == 1.0 {
+                    return;
+                }
+                hover.opacity.retarget_preserving_motion(1.0);
+                if !self.animations_enabled {
+                    hover.opacity.snap();
+                }
+            }
+        } else if let Some(hover) = &mut self.tab_indicator.hover {
+            if hover.opacity.target == 0.0 {
+                return;
+            }
+            hover.opacity.retarget_preserving_motion(0.0);
+            if !self.animations_enabled {
+                hover.opacity.snap();
+            }
+        } else {
+            return;
+        }
+        crate::backends::direct::render_all(self);
+    }
+
+    pub(crate) fn scroll_tab_indicator(&mut self, p: Point<f64, Logical>, amount: f64) -> bool {
+        let Some(hover) = &self.tab_indicator.hover else {
+            return false;
+        };
+        if hover.opacity.target == 0.0 || self.indicator_tab_at(p).is_none() {
+            return false;
+        }
+        let Some(bar) = self.scrolling_tab_bar(hover.anchor) else {
+            return false;
+        };
+        let Some(content) = self.presented_window_rect(bar.group.active) else {
+            return false;
+        };
+        let Some(g) = self.tab_indicator_geometry(bar, content) else {
+            return false;
+        };
+        let max = bar.group.windows.len().saturating_sub(g.rows);
+        if amount != 0.0 {
+            self.tab_indicator.first_row = if amount > 0.0 {
+                self.tab_indicator.first_row.saturating_add(1).min(max)
+            } else {
+                self.tab_indicator.first_row.saturating_sub(1).min(max)
+            };
+            crate::backends::direct::render_all(self);
+        }
+        true
+    }
+
+    pub(crate) fn flash_tab_switch(&mut self, previous: WindowId, current: WindowId) {
+        if previous == current {
+            return;
+        }
+        let Some(workspace) = self
+            .workspaces
+            .workspace_for_window(current)
+            .and_then(|ws| self.workspaces.workspace(ws))
+        else {
+            return;
+        };
+        let WorkspaceLayout::Scrolling(layout) = &workspace.layout else {
+            return;
+        };
+        let Some(group) = layout.tab_group(current).filter(|g| g.windows.contains(&previous)) else {
+            return;
+        };
+        if self.tab_indicator_settings.flash_duration.is_zero() {
+            return;
+        }
+        let anchor = group.windows[0];
+        if let Some(token) = self.tab_indicator.timer.take() {
+            self.loop_handle.remove(token);
+        }
+        if let Some(flash) = self.tab_indicator.flash.as_mut().filter(|f| f.anchor == anchor) {
+            flash.opacity.retarget_preserving_motion(1.0);
+        } else {
+            let mut opacity = AnimatedValue::new(0.0);
+            opacity.set_target(1.0);
+            self.tab_indicator.flash = Some(Overlay { anchor, opacity });
+        }
+        if !self.animations_enabled
+            && let Some(flash) = &mut self.tab_indicator.flash
+        {
+            flash.opacity.snap();
+        }
+        match self.loop_handle.insert_source(
+            Timer::from_duration(self.tab_indicator_settings.flash_duration),
+            |_, _, state| {
+                state.tab_indicator.timer = None;
+                if let Some(flash) = &mut state.tab_indicator.flash {
+                    flash.opacity.set_target(0.0);
+                    if !state.animations_enabled {
+                        flash.opacity.snap();
+                    }
+                }
+                crate::backends::direct::render_all(state);
+                TimeoutAction::Drop
+            },
+        ) {
+            Ok(token) => self.tab_indicator.timer = Some(token),
+            Err(error) => {
+                self.tab_indicator.flash = None;
+                tracing::warn!(%error, "could not schedule tab feedback");
+            }
+        }
+        crate::backends::direct::render_all(self);
+    }
+
+    pub(crate) fn reconcile_tab_indicator(&mut self) {
+        if self.session_lock.active() || self.input_capture.active() || self.overview.is_presenting() {
+            self.clear_tab_indicator();
+            return;
+        }
+        if self
+            .tab_indicator
+            .hover
+            .as_ref()
+            .is_some_and(|h| self.scrolling_tab_bar(h.anchor).is_none())
+        {
+            self.tab_indicator.hover = None;
+        }
+        if self
+            .tab_indicator
+            .flash
+            .as_ref()
+            .is_some_and(|h| self.scrolling_tab_bar(h.anchor).is_none())
+        {
+            self.tab_indicator.flash = None;
+            if let Some(token) = self.tab_indicator.timer.take() {
+                self.loop_handle.remove(token);
+            }
+        }
+    }
+
+    pub(crate) fn clear_tab_indicator(&mut self) {
+        if let Some(token) = self.tab_indicator.timer.take() {
+            self.loop_handle.remove(token);
+        }
+        self.tab_indicator = TabIndicatorState::default();
+    }
+
+    pub(crate) fn tab_indicator_output_animating(&self, output: &Output) -> bool {
+        [&self.tab_indicator.hover, &self.tab_indicator.flash]
+            .into_iter()
+            .flatten()
+            .any(|o| o.opacity.is_animating() && self.window_belongs_to_output(o.anchor, output))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn settings() -> TabIndicatorSettings {
+        crate::config::Config::parse_source("")
+            .unwrap()
+            .tab_indicator_settings()
+            .unwrap()
+    }
+
+    #[test]
+    fn rail_uses_gap_or_inner_edge_without_changing_content_geometry() {
+        let content = Rect::new(100.25, 20.5, 400., 300.);
+        let output = Rect::new(0., 0., 800., 600.);
+        let c = settings();
+        for gap in [0., 7.99, 8., 24.] {
+            let g = IndicatorGeometry::new(content, output, content.x - gap, 3, c).unwrap();
+            assert_eq!(
+                (g.rail.width, g.rail.height, g.segment_height, g.pitch),
+                (4., 62., 18., 22.)
+            );
+            assert_eq!(g.rail.y, content.y + (content.height - 62.) * 0.5);
+            assert_eq!(g.hit.width, 12.);
+            if gap >= 8. {
+                assert!(g.rail.x >= content.x - gap && g.rail.x + g.rail.width <= content.x);
+            } else {
+                assert!(g.rail.x >= content.x && g.rail.x + g.rail.width <= content.x + 12.);
+            }
+            assert!(g.hover_contains((g.hit.x + g.hit.width, g.rail.y + 2.).into()));
+        }
+        assert!(IndicatorGeometry::new(content, output, 0., 1, c).is_none());
+    }
+
+    #[test]
+    fn overflow_and_fractional_output_edges_keep_list_and_rail_reachable() {
+        for output in [
+            Rect::new(-800.25, 10.5, 800., 600.),
+            Rect::new(0., 0., 100., 40.),
+            Rect::new(0., 0., 8., 0.5),
+        ] {
+            let content = Rect::new(output.x - 20., output.y, output.width + 40., output.height);
+            let g = IndicatorGeometry::new(content, output, output.x, 100, settings()).unwrap();
+            for rect in [g.rail, g.hit, g.list] {
+                assert!(rect.x >= output.x && rect.y >= output.y);
+                assert!(rect.x + rect.width <= output.x + output.width + 1e-8);
+                assert!(rect.y + rect.height <= output.y + output.height + 1e-8);
+            }
+            assert!(g.rows < 100 && g.rows > 0);
+            assert!(g.segment_height > 0.);
+        }
+    }
+
+    #[test]
+    fn interrupted_hover_spring_keeps_motion_and_settles_without_background_ticks() {
+        let mut state = TabIndicatorState {
+            hover: Some(Overlay {
+                anchor: WindowId(1),
+                opacity: AnimatedValue::new(0.),
+            }),
+            ..Default::default()
+        };
+        state.hover.as_mut().unwrap().opacity.set_target(1.);
+        state.advance(Duration::from_millis(30), SpringConfig::default(), true);
+        let before = state.hover.as_ref().unwrap().opacity;
+        state.hover.as_mut().unwrap().opacity.retarget_preserving_motion(0.);
+        let after = state.hover.as_ref().unwrap().opacity;
+        assert_eq!((before.current, before.velocity), (after.current, after.velocity));
+        for _ in 0..300 {
+            state.advance(Duration::from_millis(16), SpringConfig::default(), true);
+        }
+        assert!(state.hover.is_none());
+        assert!(!state.is_animating());
+    }
+}