Implement window open animations

niri-visual-tests/src/cases/layout.rs

@@ -0,0 +1,228 @@
+use std::collections::HashMap;
+use std::time::Duration;
+
+use niri::layout::workspace::ColumnWidth;
+use niri::layout::Options;
+use niri::utils::get_monotonic_time;
+use niri_config::Color;
+use smithay::backend::renderer::element::RenderElement;
+use smithay::backend::renderer::gles::GlesRenderer;
+use smithay::desktop::layer_map_for_output;
+use smithay::output::{Mode, Output, PhysicalProperties, Subpixel};
+use smithay::utils::{Logical, Physical, Size};
+
+use super::TestCase;
+use crate::test_window::TestWindow;
+
+type DynStepFn = Box<dyn FnOnce(&mut Layout)>;
+
+pub struct Layout {
+    output: Output,
+    windows: Vec<TestWindow>,
+    layout: niri::layout::Layout<TestWindow>,
+    start_time: Duration,
+    steps: HashMap<Duration, DynStepFn>,
+}
+
+impl Layout {
+    pub fn new(size: Size<i32, Logical>) -> Self {
+        let output = Output::new(
+            String::new(),
+            PhysicalProperties {
+                size: Size::from((size.w, size.h)),
+                subpixel: Subpixel::Unknown,
+                make: String::new(),
+                model: String::new(),
+            },
+        );
+        let mode = Some(Mode {
+            size: size.to_physical(1),
+            refresh: 60000,
+        });
+        output.change_current_state(mode, None, None, None);
+
+        let options = Options {
+            focus_ring: niri_config::FocusRing {
+                off: true,
+                ..Default::default()
+            },
+            border: niri_config::FocusRing {
+                off: false,
+                width: 4,
+                active_color: Color::new(255, 163, 72, 255),
+                inactive_color: Color::new(50, 50, 50, 255),
+            },
+            ..Default::default()
+        };
+        let mut layout = niri::layout::Layout::with_options(options);
+        layout.add_output(output.clone());
+
+        Self {
+            output,
+            windows: Vec::new(),
+            layout,
+            start_time: get_monotonic_time(),
+            steps: HashMap::new(),
+        }
+    }
+
+    pub fn open_in_between(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::new(size);
+
+        rv.add_window(TestWindow::freeform(0), Some(ColumnWidth::Proportion(0.3)));
+        rv.add_window(TestWindow::freeform(1), Some(ColumnWidth::Proportion(0.3)));
+        rv.layout.activate_window(&rv.windows[0]);
+
+        rv.add_step(500, |l| {
+            let win = TestWindow::freeform(2);
+            l.add_window(win.clone(), Some(ColumnWidth::Proportion(0.3)));
+            l.layout.start_open_animation_for_window(&win);
+        });
+
+        rv
+    }
+
+    pub fn open_multiple_quickly(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::new(size);
+
+        for delay in [100, 200, 300] {
+            rv.add_step(delay, move |l| {
+                let win = TestWindow::freeform(delay as usize);
+                l.add_window(win.clone(), Some(ColumnWidth::Proportion(0.3)));
+                l.layout.start_open_animation_for_window(&win);
+            });
+        }
+
+        rv
+    }
+
+    pub fn open_multiple_quickly_big(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::new(size);
+
+        for delay in [100, 200, 300] {
+            rv.add_step(delay, move |l| {
+                let win = TestWindow::freeform(delay as usize);
+                l.add_window(win.clone(), Some(ColumnWidth::Proportion(0.5)));
+                l.layout.start_open_animation_for_window(&win);
+            });
+        }
+
+        rv
+    }
+
+    pub fn open_to_the_left(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::new(size);
+
+        rv.add_window(TestWindow::freeform(0), Some(ColumnWidth::Proportion(0.3)));
+        rv.add_window(TestWindow::freeform(1), Some(ColumnWidth::Proportion(0.3)));
+
+        rv.add_step(500, |l| {
+            let win = TestWindow::freeform(2);
+            let right_of = l.windows[0].clone();
+            l.add_window_right_of(&right_of, win.clone(), Some(ColumnWidth::Proportion(0.3)));
+            l.layout.start_open_animation_for_window(&win);
+        });
+
+        rv
+    }
+
+    pub fn open_to_the_left_big(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::new(size);
+
+        rv.add_window(TestWindow::freeform(0), Some(ColumnWidth::Proportion(0.3)));
+        rv.add_window(TestWindow::freeform(1), Some(ColumnWidth::Proportion(0.8)));
+
+        rv.add_step(500, |l| {
+            let win = TestWindow::freeform(2);
+            let right_of = l.windows[0].clone();
+            l.add_window_right_of(&right_of, win.clone(), Some(ColumnWidth::Proportion(0.5)));
+            l.layout.start_open_animation_for_window(&win);
+        });
+
+        rv
+    }
+
+    fn add_window(&mut self, window: TestWindow, width: Option<ColumnWidth>) {
+        self.layout.add_window(window.clone(), width, false);
+        if window.communicate() {
+            self.layout.update_window(&window);
+        }
+        self.windows.push(window);
+    }
+
+    fn add_window_right_of(
+        &mut self,
+        right_of: &TestWindow,
+        window: TestWindow,
+        width: Option<ColumnWidth>,
+    ) {
+        self.layout
+            .add_window_right_of(right_of, window.clone(), width, false);
+        if window.communicate() {
+            self.layout.update_window(&window);
+        }
+        self.windows.push(window);
+    }
+
+    fn add_step(&mut self, delay_ms: u64, f: impl FnOnce(&mut Self) + 'static) {
+        self.steps
+            .insert(Duration::from_millis(delay_ms), Box::new(f) as _);
+    }
+}
+
+impl TestCase for Layout {
+    fn resize(&mut self, width: i32, height: i32) {
+        let mode = Some(Mode {
+            size: Size::from((width, height)),
+            refresh: 60000,
+        });
+        self.output.change_current_state(mode, None, None, None);
+        layer_map_for_output(&self.output).arrange();
+        self.layout.update_output_size(&self.output);
+        for win in &self.windows {
+            if win.communicate() {
+                self.layout.update_window(win);
+            }
+        }
+    }
+
+    fn are_animations_ongoing(&self) -> bool {
+        self.layout
+            .monitor_for_output(&self.output)
+            .unwrap()
+            .are_animations_ongoing()
+            || !self.steps.is_empty()
+    }
+
+    fn advance_animations(&mut self, mut current_time: Duration) {
+        let run = self
+            .steps
+            .keys()
+            .copied()
+            .filter(|delay| self.start_time + *delay <= current_time)
+            .collect::<Vec<_>>();
+        for key in &run {
+            let f = self.steps.remove(key).unwrap();
+            f(self);
+        }
+        if !run.is_empty() {
+            current_time = get_monotonic_time();
+        }
+
+        self.layout.advance_animations(current_time);
+    }
+
+    fn render(
+        &mut self,
+        renderer: &mut GlesRenderer,
+        _size: Size<i32, Physical>,
+    ) -> Vec<Box<dyn RenderElement<GlesRenderer>>> {
+        self.layout
+            .monitor_for_output(&self.output)
+            .unwrap()
+            .render_elements(renderer)
+            .into_iter()
+            .map(|elem| Box::new(elem) as _)
+            .collect()
+    }
+}

niri-visual-tests/src/cases/mod.rs

@@ -4,6 +4,7 @@ use smithay::backend::renderer::element::RenderElement;
 use smithay::backend::renderer::gles::GlesRenderer;
 use smithay::utils::{Physical, Size};
 
+pub mod layout;
 pub mod tile;
 pub mod window;
 

niri-visual-tests/src/cases/tile.rs

@@ -41,6 +41,27 @@ impl Tile {
         rv
     }
 
+    pub fn freeform_open(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::freeform(size);
+        rv.window.set_color([0.1, 0.1, 0.1, 1.]);
+        rv.tile.start_open_animation();
+        rv
+    }
+
+    pub fn fixed_size_open(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::fixed_size(size);
+        rv.window.set_color([0.1, 0.1, 0.1, 1.]);
+        rv.tile.start_open_animation();
+        rv
+    }
+
+    pub fn fixed_size_with_csd_shadow_open(size: Size<i32, Logical>) -> Self {
+        let mut rv = Self::fixed_size_with_csd_shadow(size);
+        rv.window.set_color([0.1, 0.1, 0.1, 1.]);
+        rv.tile.start_open_animation();
+        rv
+    }
+
     pub fn with_window(window: TestWindow) -> Self {
         let options = Options {
             focus_ring: niri_config::FocusRing {
@@ -66,6 +87,10 @@ impl TestCase for Tile {
         self.window.communicate();
     }
 
+    fn are_animations_ongoing(&self) -> bool {
+        self.tile.are_animations_ongoing()
+    }
+
     fn advance_animations(&mut self, current_time: Duration) {
         self.tile.advance_animations(current_time, true);
     }

niri-visual-tests/src/main.rs

@@ -16,6 +16,7 @@ use smithay::utils::{Logical, Size};
 use smithay_view::SmithayView;
 use tracing_subscriber::EnvFilter;
 
+use crate::cases::layout::Layout;
 use crate::cases::TestCase;
 
 mod cases;
@@ -85,6 +86,27 @@ fn build_ui(app: &adw::Application) {
         Tile::fixed_size_with_csd_shadow,
         "Fixed Size Tile - CSD Shadow",
     );
+    s.add(Tile::freeform_open, "Freeform Tile - Open");
+    s.add(Tile::fixed_size_open, "Fixed Size Tile - Open");
+    s.add(
+        Tile::fixed_size_with_csd_shadow_open,
+        "Fixed Size Tile - CSD Shadow - Open",
+    );
+
+    s.add(Layout::open_in_between, "Layout - Open In-Between");
+    s.add(
+        Layout::open_multiple_quickly,
+        "Layout - Open Multiple Quickly",
+    );
+    s.add(
+        Layout::open_multiple_quickly_big,
+        "Layout - Open Multiple Quickly - Big",
+    );
+    s.add(Layout::open_to_the_left, "Layout - Open To The Left");
+    s.add(
+        Layout::open_to_the_left_big,
+        "Layout - Open To The Left - Big",
+    );
 
     let content_headerbar = adw::HeaderBar::new();
 

niri-visual-tests/src/test_window.rs

@@ -5,7 +5,7 @@ use std::rc::Rc;
 use niri::layout::{LayoutElement, LayoutElementRenderElement};
 use niri::render_helpers::renderer::NiriRenderer;
 use smithay::backend::renderer::element::solid::{SolidColorBuffer, SolidColorRenderElement};
-use smithay::backend::renderer::element::Kind;
+use smithay::backend::renderer::element::{Id, Kind};
 use smithay::output::Output;
 use smithay::reexports::wayland_server::protocol::wl_surface::WlSurface;
 use smithay::utils::{Logical, Point, Scale, Size, Transform};
@@ -196,6 +196,8 @@ impl LayoutElement for TestWindow {
 
     fn output_leave(&self, _output: &Output) {}
 
+    fn set_offscreen_element_id(&self, _id: Option<Id>) {}
+
     fn is_fullscreen(&self) -> bool {
         false
     }

src/animation.rs

@@ -15,6 +15,13 @@ pub struct Animation {
     duration: Duration,
     start_time: Duration,
     current_time: Duration,
+    curve: Curve,
+}
+
+#[derive(Debug, Clone, Copy)]
+pub enum Curve {
+    EaseOutCubic,
+    EaseOutExpo,
 }
 
 impl Animation {
@@ -29,9 +36,15 @@ impl Animation {
             duration: over.mul_f64(ANIMATION_SLOWDOWN.load(Ordering::Relaxed)),
             start_time: now,
             current_time: now,
+            curve: Curve::EaseOutCubic,
         }
     }
 
+    pub fn with_curve(mut self, curve: Curve) -> Self {
+        self.curve = curve;
+        self
+    }
+
     pub fn set_current_time(&mut self, time: Duration) {
         self.current_time = time;
     }
@@ -44,7 +57,7 @@ impl Animation {
         let passed = (self.current_time - self.start_time).as_secs_f64();
         let total = self.duration.as_secs_f64();
         let x = (passed / total).clamp(0., 1.);
-        EaseOutCubic.y(x) * (self.to - self.from) + self.from
+        self.curve.y(x) * (self.to - self.from) + self.from
     }
 
     pub fn to(&self) -> f64 {
@@ -56,3 +69,12 @@ impl Animation {
         self.from
     }
 }
+
+impl Curve {
+    pub fn y(self, x: f64) -> f64 {
+        match self {
+            Curve::EaseOutCubic => EaseOutCubic.y(x),
+            Curve::EaseOutExpo => 1. - 2f64.powf(-10. * x),
+        }
+    }
+}

src/handlers/compositor.rs

@@ -120,6 +120,7 @@ impl CompositorHandler for State {
                     };
 
                     if let Some(output) = output.cloned() {
+                        self.niri.layout.start_open_animation_for_window(&window);
                         self.niri.queue_redraw(output);
                     }
                     return;

src/layout/mod.rs

@@ -37,7 +37,7 @@ use std::time::Duration;
 use niri_config::{self, CenterFocusedColumn, Config, SizeChange, Struts};
 use smithay::backend::renderer::element::solid::SolidColorRenderElement;
 use smithay::backend::renderer::element::surface::WaylandSurfaceRenderElement;
-use smithay::backend::renderer::element::AsRenderElements;
+use smithay::backend::renderer::element::{AsRenderElements, Id};
 use smithay::desktop::space::SpaceElement;
 use smithay::desktop::Window;
 use smithay::output::Output;
@@ -52,6 +52,7 @@ pub use self::monitor::MonitorRenderElement;
 use self::monitor::{Monitor, WorkspaceSwitch, WorkspaceSwitchGesture};
 use self::workspace::{compute_working_area, Column, ColumnWidth, OutputId, Workspace};
 use crate::animation::Animation;
+use crate::niri::WindowOffscreenId;
 use crate::niri_render_elements;
 use crate::render_helpers::renderer::NiriRenderer;
 use crate::utils::output_size;
@@ -105,6 +106,7 @@ pub trait LayoutElement: PartialEq {
     fn set_preferred_scale_transform(&self, scale: i32, transform: Transform);
     fn output_enter(&self, output: &Output);
     fn output_leave(&self, output: &Output);
+    fn set_offscreen_element_id(&self, id: Option<Id>);
 
     /// Whether the element is currently fullscreen.
     ///
@@ -292,6 +294,11 @@ impl LayoutElement for Window {
         SpaceElement::output_leave(self, output)
     }
 
+    fn set_offscreen_element_id(&self, id: Option<Id>) {
+        let data = self.user_data().get_or_insert(WindowOffscreenId::default);
+        data.0.replace(id);
+    }
+
     fn is_fullscreen(&self) -> bool {
         self.toplevel()
             .current_state()
@@ -1593,6 +1600,39 @@ impl<W: LayoutElement> Layout<W> {
         };
         monitor.move_workspace_up();
     }
+
+    pub fn start_open_animation_for_window(&mut self, window: &W) {
+        match &mut self.monitor_set {
+            MonitorSet::Normal { monitors, .. } => {
+                for mon in monitors {
+                    for ws in &mut mon.workspaces {
+                        for col in &mut ws.columns {
+                            for tile in &mut col.tiles {
+                                if tile.window() == window {
+                                    tile.start_open_animation();
+                                    return;
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+            MonitorSet::NoOutputs { workspaces, .. } => {
+                for ws in workspaces {
+                    if ws.has_window(window) {
+                        for col in &mut ws.columns {
+                            for tile in &mut col.tiles {
+                                if tile.window() == window {
+                                    tile.start_open_animation();
+                                    return;
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
 }
 
 impl Layout<Window> {
@@ -1757,6 +1797,8 @@ mod tests {
 
         fn output_leave(&self, _output: &Output) {}
 
+        fn set_offscreen_element_id(&self, _id: Option<Id>) {}
+
         fn is_fullscreen(&self) -> bool {
             false
         }

src/layout/tile.rs

@@ -3,13 +3,17 @@ use std::rc::Rc;
 use std::time::Duration;
 
 use smithay::backend::renderer::element::solid::{SolidColorBuffer, SolidColorRenderElement};
-use smithay::backend::renderer::element::utils::{Relocate, RelocateRenderElement};
-use smithay::backend::renderer::element::Kind;
+use smithay::backend::renderer::element::utils::{
+    Relocate, RelocateRenderElement, RescaleRenderElement,
+};
+use smithay::backend::renderer::element::{Element, Kind};
 use smithay::utils::{Logical, Point, Rectangle, Scale, Size};
 
 use super::focus_ring::FocusRing;
 use super::{LayoutElement, LayoutElementRenderElement, Options};
+use crate::animation::{Animation, Curve};
 use crate::niri_render_elements;
+use crate::render_helpers::offscreen::OffscreenRenderElement;
 use crate::render_helpers::renderer::NiriRenderer;
 
 /// Toplevel window with decorations.
@@ -39,6 +43,9 @@ pub struct Tile<W: LayoutElement> {
     /// The size we were requested to fullscreen into.
     fullscreen_size: Size<i32, Logical>,
 
+    /// The animation upon opening a window.
+    open_animation: Option<Animation>,
+
     /// Configurable properties of the layout.
     options: Rc<Options>,
 }
@@ -47,6 +54,7 @@ niri_render_elements! {
     TileRenderElement => {
         LayoutElement = LayoutElementRenderElement<R>,
         SolidColor = RelocateRenderElement<SolidColorRenderElement>,
+        Offscreen = RescaleRenderElement<OffscreenRenderElement>,
     }
 }
 
@@ -59,6 +67,7 @@ impl<W: LayoutElement> Tile<W> {
             is_fullscreen: false, // FIXME: up-to-date fullscreen right away, but we need size.
             fullscreen_backdrop: SolidColorBuffer::new((0, 0), [0., 0., 0., 1.]),
             fullscreen_size: Default::default(),
+            open_animation: None,
             options,
         }
     }
@@ -76,7 +85,7 @@ impl<W: LayoutElement> Tile<W> {
         }
     }
 
-    pub fn advance_animations(&mut self, _current_time: Duration, is_active: bool) {
+    pub fn advance_animations(&mut self, current_time: Duration, is_active: bool) {
         let width = self.border.width();
         self.border.update(
             (width, width).into(),
@@ -88,6 +97,25 @@ impl<W: LayoutElement> Tile<W> {
         self.focus_ring
             .update((0, 0).into(), self.tile_size(), self.has_ssd());
         self.focus_ring.set_active(is_active);
+
+        match &mut self.open_animation {
+            Some(anim) => {
+                anim.set_current_time(current_time);
+                if anim.is_done() {
+                    self.open_animation = None;
+                }
+            }
+            None => (),
+        }
+    }
+
+    pub fn are_animations_ongoing(&self) -> bool {
+        self.open_animation.is_some()
+    }
+
+    pub fn start_open_animation(&mut self) {
+        self.open_animation =
+            Some(Animation::new(0., 1., Duration::from_millis(150)).with_curve(Curve::EaseOutExpo));
     }
 
     pub fn window(&self) -> &W {
@@ -160,6 +188,22 @@ impl<W: LayoutElement> Tile<W> {
         self.window.size()
     }
 
+    /// Returns an animated size of the tile for rendering and input.
+    ///
+    /// During the window opening animation, windows to the right should gradually slide further to
+    /// the right. This is what this visual size is used for. Other things like window resizes or
+    /// transactions or new view position calculation always use the real size, instead of this
+    /// visual size.
+    pub fn visual_tile_size(&self) -> Size<i32, Logical> {
+        let size = self.tile_size();
+        let v = self
+            .open_animation
+            .as_ref()
+            .map(|anim| anim.value())
+            .unwrap_or(1.);
+        Size::from(((f64::from(size.w) * v).round() as i32, size.h))
+    }
+
     pub fn buf_loc(&self) -> Point<i32, Logical> {
         let mut loc = Point::from((0, 0));
         loc += self.window_loc();
@@ -251,7 +295,7 @@ impl<W: LayoutElement> Tile<W> {
         self.effective_border_width().is_some() || self.window.has_ssd()
     }
 
-    pub fn render<R: NiriRenderer>(
+    fn render_inner<R: NiriRenderer>(
         &self,
         renderer: &mut R,
         location: Point<i32, Logical>,
@@ -300,4 +344,46 @@ impl<W: LayoutElement> Tile<W> {
         });
         rv.chain(elem)
     }
+
+    pub fn render<R: NiriRenderer>(
+        &self,
+        renderer: &mut R,
+        location: Point<i32, Logical>,
+        scale: Scale<f64>,
+        focus_ring: bool,
+    ) -> impl Iterator<Item = TileRenderElement<R>> {
+        if let Some(anim) = &self.open_animation {
+            let renderer = renderer.as_gles_renderer();
+            let elements = self.render_inner(renderer, location, scale, focus_ring);
+            let elements = elements.collect::<Vec<TileRenderElement<_>>>();
+
+            let elem = OffscreenRenderElement::new(
+                renderer,
+                scale.x as i32,
+                &elements,
+                anim.value() as f32,
+            );
+            self.window()
+                .set_offscreen_element_id(Some(elem.id().clone()));
+
+            let mut center = location;
+            center.x += self.tile_size().w / 2;
+            center.y += self.tile_size().h / 2;
+
+            Some(TileRenderElement::Offscreen(
+                RescaleRenderElement::from_element(
+                    elem,
+                    center.to_physical_precise_round(scale),
+                    (anim.value() / 2. + 0.5).min(1.),
+                ),
+            ))
+            .into_iter()
+            .chain(None.into_iter().flatten())
+        } else {
+            self.window().set_offscreen_element_id(None);
+
+            let elements = self.render_inner(renderer, location, scale, focus_ring);
+            None.into_iter().chain(Some(elements).into_iter().flatten())
+        }
+    }
 }

src/layout/workspace.rs

@@ -230,7 +230,7 @@ impl<W: LayoutElement> Workspace<W> {
     }
 
     pub fn are_animations_ongoing(&self) -> bool {
-        self.view_offset_anim.is_some()
+        self.view_offset_anim.is_some() || self.columns.iter().any(Column::are_animations_ongoing)
     }
 
     pub fn update_config(&mut self, options: Rc<Options>) {
@@ -507,6 +507,16 @@ impl<W: LayoutElement> Workspace<W> {
         x
     }
 
+    fn visual_column_x(&self, column_idx: usize) -> i32 {
+        let mut x = 0;
+
+        for column in self.columns.iter().take(column_idx) {
+            x += column.visual_width() + self.options.gaps;
+        }
+
+        x
+    }
+
     pub fn add_window(
         &mut self,
         window: W,
@@ -978,13 +988,13 @@ impl<W: LayoutElement> Workspace<W> {
     }
 
     fn tiles_in_render_order(&self) -> impl Iterator<Item = (&'_ Tile<W>, Point<i32, Logical>)> {
-        let view_pos = self.view_pos();
+        let view_pos = self.visual_column_x(self.active_column_idx) + self.view_offset;
 
         // Start with the active window since it's drawn on top.
         let col = &self.columns[self.active_column_idx];
         let tile = &col.tiles[col.active_tile_idx];
         let tile_pos = Point::from((
-            self.column_x(self.active_column_idx) - view_pos,
+            self.visual_column_x(self.active_column_idx) - view_pos,
             col.tile_y(col.active_tile_idx),
         ));
         let first = iter::once((tile, tile_pos));
@@ -997,7 +1007,7 @@ impl<W: LayoutElement> Workspace<W> {
             // Keep track of column X position.
             .map(move |(col_idx, col)| {
                 let rv = (col_idx, col, x);
-                x += col.width() + self.options.gaps;
+                x += col.visual_width() + self.options.gaps;
                 rv
             })
             .flat_map(move |(col_idx, col, x)| {
@@ -1279,6 +1289,10 @@ impl<W: LayoutElement> Column<W> {
         }
     }
 
+    pub fn are_animations_ongoing(&self) -> bool {
+        self.tiles.iter().any(Tile::are_animations_ongoing)
+    }
+
     pub fn contains(&self, window: &W) -> bool {
         self.tiles.iter().map(Tile::window).any(|win| win == window)
     }
@@ -1477,6 +1491,14 @@ impl<W: LayoutElement> Column<W> {
             .unwrap()
     }
 
+    fn visual_width(&self) -> i32 {
+        self.tiles
+            .iter()
+            .map(|tile| tile.visual_tile_size().w)
+            .max()
+            .unwrap()
+    }
+
     fn focus_up(&mut self) {
         self.active_tile_idx = self.active_tile_idx.saturating_sub(1);
     }