From 03025647d6c262980ce0218e2fe96d07f1d3c1ba Mon Sep 17 00:00:00 2001
From: aiongg <aiongtaigi@gmail.com>
Date: Mon, 26 Oct 2026 18:16:28 +0000
Subject: [PATCH] refactor(ui-egui): move show tests to show/tests.rs

---
 crates/ui-egui/src/show.rs       | 1007 +-----------------------------
 crates/ui-egui/src/show/tests.rs |  995 +++++++++++++++++++++++++++++
 2 files changed, 996 insertions(+), 1006 deletions(-)
 create mode 100644 crates/ui-egui/src/show/tests.rs

diff --git a/crates/ui-egui/src/show.rs b/crates/ui-egui/src/show.rs
index a2658391..403b6b59 100644
--- a/crates/ui-egui/src/show.rs
+++ b/crates/ui-egui/src/show.rs
@@ -2380,1009 +2380,4 @@ fn presenter_notes(ui: &mut Ui, notes: &deckcraft_model::text::TextBody, px: f32
 }
 
 #[cfg(test)]
-mod tests {
-    #![allow(clippy::unwrap_used, clippy::expect_used)]
-
-    use super::*;
-
-    /// #1005: shapes stacked above a playing video must be drawn over its frame; the video, what
-    /// is below it and other videos stay out of that overlay.
-    #[test]
-    fn shapes_above_a_playing_video_are_the_overlay() {
-        let mut session = deckcraft_engine::Session::with_new();
-        for _ in 0..3 {
-            session.execute("shape.insert", &json!({"preset": "rect", "rect": [0.0, 0.0, 100.0, 100.0]})).unwrap();
-        }
-        let mut doc = (*session.active().unwrap().doc).clone();
-        // Keep only the three inserted rects (a new slide may start with placeholders).
-        let slide = std::sync::Arc::make_mut(&mut doc.slides[0]);
-        let keep = slide.shapes.len() - 3;
-        slide.shapes.drain(..keep);
-        let ids: Vec<ShapeId> = slide.shapes.iter().map(|s| s.id).collect();
-        slide.shapes[1].kind = deckcraft_model::ShapeKind::Media(deckcraft_model::MediaClip { video: true, ..Default::default() });
-        // Video in the middle: the shape above it is drawn over it.
-        assert_eq!(below_playing_video(&doc, 0, &[ids[1]]), vec![ids[0], ids[1]]);
-        // Video on top: nothing above it, the frame is painted last as before.
-        std::sync::Arc::make_mut(&mut doc.slides[0]).shapes.swap(1, 2);
-        assert!(below_playing_video(&doc, 0, &[ids[1]]).is_empty());
-        // No video playing.
-        assert!(below_playing_video(&doc, 0, &[]).is_empty());
-    }
-
-    /// #968: over a shape a click acts on (a clip with its play trigger, a link) the pointing hand
-    /// never gave way to the idle hide, so a still pointer stayed on the playing video.
-    #[test]
-    fn a_still_cursor_hides_over_a_clickable_shape() {
-        let mut session = deckcraft_engine::Session::with_new();
-        let size = session.active().unwrap().doc.slide_size;
-        let r = session.execute("shape.insert", &json!({"preset": "rect", "rect": [0.0, 0.0, size.width, size.height]})).unwrap();
-        session.execute("insert.hyperlink", &json!({"url": "https://example.org", "ids": [r["id"]]})).unwrap();
-        let app = SlideApp::new(session, crate::Services::default());
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).with_step_dt(0.25).build_ui_state(
-            |ui, app: &mut SlideApp| {
-                app.logic(ui.ctx());
-                app.ui(ui);
-            },
-            app,
-        );
-        harness.run_steps(3);
-        harness.state_mut().start_show(0, false);
-        harness.run_steps(2);
-        harness.hover_at(pos2(500.0, 350.0));
-        harness.run_steps(2);
-        assert_eq!(harness.output().platform_output.cursor_icon, egui::CursorIcon::PointingHand);
-        harness.run_steps(12);
-        assert_eq!(harness.output().platform_output.cursor_icon, egui::CursorIcon::None, "still for 3 s: hidden");
-    }
-
-    /// #1130: the Presenter View's All slides button opens the grid in that window, not on the audience screen.
-    #[test]
-    fn presenter_all_slides_does_not_cover_the_audience_screen() {
-        use egui_kittest::kittest::Queryable;
-
-        let mut session = deckcraft_engine::Session::with_new();
-        session.execute("slide.new", &json!({})).unwrap();
-        let doc = session.active().unwrap().doc.clone();
-        let show = Show::new(&doc, 0, false, true);
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(1100.0, 700.0)).build_ui_state(
-            |ui, (doc, show, keep): &mut (std::sync::Arc<Presentation>, Show, bool)| {
-                let now = ui.input(|i| i.time);
-                presenter_window(ui.ctx(), show, doc, now, keep);
-            },
-            (doc, show, true),
-        );
-        harness.run_steps(2);
-        harness.get_by_label("All slides").click();
-        harness.run_steps(2);
-        assert!(harness.state().1.presenter_grid, "the grid opens in the Presenter View");
-        assert!(!harness.state().1.grid, "the audience screen keeps showing the slide");
-        harness.key_press(egui::Key::Escape);
-        harness.run_steps(2);
-        assert!(!harness.state().1.presenter_grid, "Esc closes the Presenter View grid");
-        assert!(harness.state().2, "and does not end the show");
-        harness.key_press(egui::Key::G);
-        harness.run_steps(2);
-        assert!(harness.state().1.presenter_grid, "G in Presenter View opens its own grid");
-        assert!(!harness.state().1.grid, "G in Presenter View leaves the audience screen alone");
-        harness.key_press(egui::Key::G);
-        harness.run_steps(2);
-        assert!(!harness.state().1.presenter_grid, "G again closes it");
-    }
-
-    /// A silent mono 8 kHz WAV, so the clip has a real duration to seek in.
-    fn silent_wav(secs: u32) -> Vec<u8> {
-        let rate = 8_000u32;
-        let data = vec![0u8; (rate * secs * 2) as usize];
-        let mut b = Vec::new();
-        b.extend_from_slice(b"RIFF");
-        b.extend_from_slice(&(36 + data.len() as u32).to_le_bytes());
-        b.extend_from_slice(b"WAVEfmt ");
-        b.extend_from_slice(&16u32.to_le_bytes());
-        b.extend_from_slice(&1u16.to_le_bytes());
-        b.extend_from_slice(&1u16.to_le_bytes());
-        b.extend_from_slice(&rate.to_le_bytes());
-        b.extend_from_slice(&(rate * 2).to_le_bytes());
-        b.extend_from_slice(&2u16.to_le_bytes());
-        b.extend_from_slice(&16u16.to_le_bytes());
-        b.extend_from_slice(b"data");
-        b.extend_from_slice(&(data.len() as u32).to_le_bytes());
-        b.extend_from_slice(&data);
-        b
-    }
-
-    /// A running show on a slide with one 10 s clip. Returns the harness, the clip, a point on the
-    /// bar's seek track, and what `pointer_on_media_bar` said on the last frame.
-    fn show_with_clip() -> (egui_kittest::Harness<'static, SlideApp>, ShapeId, Pos2, std::rc::Rc<std::cell::Cell<bool>>) {
-        let size = vec2(1000.0, 700.0);
-        let mut session = deckcraft_engine::Session::with_new();
-        let id = ShapeId(4000);
-        session
-            .edit(|doc, _| {
-                let media = doc.add_media("clip.wav", "audio/wav", silent_wav(10)).unwrap();
-                let (w, h) = (doc.slide_size.width, doc.slide_size.height);
-                let clip = deckcraft_model::MediaClip { media, video: true, volume: 1.0, duration_ms: 10_000, ..Default::default() };
-                let xfrm = deckcraft_geom::Xfrm::new(w * 0.2, h * 0.2, w * 0.6, h * 0.6);
-                let slide = std::sync::Arc::make_mut(&mut doc.slides[0]);
-                slide.shapes.push(deckcraft_model::Shape {
-                    id,
-                    xfrm: Some(xfrm),
-                    kind: deckcraft_model::ShapeKind::Media(clip),
-                    ..Default::default()
-                });
-                Ok(())
-            })
-            .unwrap();
-        let on_bar = std::rc::Rc::new(std::cell::Cell::new(false));
-        let seen = on_bar.clone();
-        let slide = std::rc::Rc::new(std::cell::Cell::new(Rect::NOTHING));
-        let slide_seen = slide.clone();
-        // Presenter view opens an embedded window over the whole screen here, which takes the clicks.
-        let mut app = SlideApp::new(session, crate::Services::default());
-        app.ui.presenter_view = false;
-        let mut harness = egui_kittest::Harness::builder().with_size(size).with_step_dt(0.25).build_ui_state(
-            move |ui, app: &mut SlideApp| {
-                app.logic(ui.ctx());
-                if let (Some(show), Some(d)) = (app.show.as_ref(), app.session.active()) {
-                    let now = ui.input(|i| i.time);
-                    seen.set(pointer_on_media_bar(ui.ctx(), ui, &d.doc, show, now));
-                    slide_seen.set(shown_slide_rect(ui, show, &d.doc));
-                }
-                app.ui(ui);
-            },
-            app,
-        );
-        harness.run_steps(3);
-        harness.state_mut().start_show(0, false);
-        harness.run_steps(2);
-        let doc = harness.state().session.active().unwrap().doc.clone();
-        let bar = slide_media_bars(slide.get(), &doc, 0)[0].3;
-        let track = pos2(bar.min.x + bar.width() * 0.8, bar.center().y);
-        (harness, id, track, on_bar)
-    }
-
-    /// Press and release the primary button at `p`.
-    fn click_at(harness: &mut egui_kittest::Harness<'static, SlideApp>, p: Pos2) {
-        for pressed in [true, false] {
-            harness.event(egui::Event::PointerButton { pos: p, button: egui::PointerButton::Primary, pressed, modifiers: egui::Modifiers::NONE });
-            harness.step();
-        }
-    }
-
-    /// #967: hovering a clip shows its bar and a click on the bar seeks. After 3 s without moving
-    /// the bar is gone, and a click where it was acts on the clip itself (play), not on the bar.
-    #[test]
-    fn media_controls_hide_when_pointer_is_idle() {
-        // Awake: the bar is there and a click on its timeline seeks, leaving the clip paused.
-        let (mut harness, id, track, on_bar) = show_with_clip();
-        harness.hover_at(track);
-        harness.run_steps(2);
-        assert!(harness.state().show.as_ref().unwrap().pointer_awake(harness.ctx.input(|i| i.time)));
-        assert!(on_bar.get(), "the bar is under a pointer that just moved");
-        click_at(&mut harness, track);
-        harness.run_steps(2);
-        let status = harness.state().media.status(id).expect("the click on the bar cued the clip");
-        assert!(!harness.state().media.is_playing(id), "a bar click seeks, it does not play");
-        assert!(status.position > 1.0, "seeked along the timeline, at {}", status.position);
-
-        // Idle: same spot, no movement for 3 s.
-        let (mut harness, id, track, on_bar) = show_with_clip();
-        harness.hover_at(track);
-        harness.run_steps(2);
-        assert!(on_bar.get());
-        harness.run_steps(12);
-        assert!(!harness.state().show.as_ref().unwrap().pointer_awake(harness.ctx.input(|i| i.time)));
-        assert!(!on_bar.get(), "the bar is hidden once the pointer is idle");
-        click_at(&mut harness, track);
-        harness.run_steps(2);
-        assert!(harness.state().media.is_playing(id), "the click reached the clip");
-        let at = harness.state().media.status(id).map_or(0.0, |s| s.position);
-        assert!(at < 5.0, "the click did not seek along the timeline, position {at}");
-    }
-
-    /// Two 1×1 frames (black, then white), 100 ms each.
-    fn two_frame_gif() -> Vec<u8> {
-        let mut b = b"GIF89a\x01\x00\x01\x00\x80\x00\x00\x00\x00\x00\xff\xff\xff".to_vec();
-        for pixel in [b"\x44\x01", b"\x4c\x01"] {
-            b.extend_from_slice(b"\x21\xf9\x04\x00\x0a\x00\x00\x00");
-            b.extend_from_slice(b"\x2c\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02");
-            b.extend_from_slice(pixel);
-            b.push(0);
-        }
-        b.push(0x3b);
-        b
-    }
-
-    /// A running show on the first of two slides; slide 1 holds a large animated GIF. Returns the
-    /// harness, the GIF, and its play/pause button's centre.
-    fn show_with_gif() -> (egui_kittest::Harness<'static, SlideApp>, ShapeId, Pos2) {
-        let mut session = deckcraft_engine::Session::with_new();
-        // The GIF is on slide 1, the slide the editor has selected, with a slide after it.
-        session.execute("slide.new", &json!({"layout": "blank"})).unwrap();
-        session.execute("slide.new", &json!({"layout": "blank"})).unwrap();
-        session.execute("slide.go", &json!({"index": 1})).unwrap();
-        let id = ShapeId(4100);
-        session
-            .edit(|doc, _| {
-                let media = doc.add_media("a.gif", "image/gif", two_frame_gif()).unwrap();
-                let (w, h) = (doc.slide_size.width, doc.slide_size.height);
-                let slide = std::sync::Arc::make_mut(&mut doc.slides[1]);
-                slide.shapes.push(deckcraft_model::Shape {
-                    id,
-                    xfrm: Some(deckcraft_geom::Xfrm::new(w * 0.2, h * 0.2, w * 0.6, h * 0.6)),
-                    kind: deckcraft_model::ShapeKind::Picture { fill: deckcraft_model::style::PictureFill { media, ..Default::default() } },
-                    ..Default::default()
-                });
-                Ok(())
-            })
-            .unwrap();
-        let slide = std::rc::Rc::new(std::cell::Cell::new(Rect::NOTHING));
-        let slide_seen = slide.clone();
-        let mut app = SlideApp::new(session, crate::Services::default());
-        app.ui.presenter_view = false;
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).with_step_dt(0.25).build_ui_state(
-            move |ui, app: &mut SlideApp| {
-                app.logic(ui.ctx());
-                if let (Some(show), Some(d)) = (app.show.as_ref(), app.session.active()) {
-                    slide_seen.set(shown_slide_rect(ui, show, &d.doc));
-                }
-                app.ui(ui);
-            },
-            app,
-        );
-        harness.run_steps(3);
-        harness.state_mut().start_show(1, false);
-        harness.run_steps(2);
-        let doc = harness.state().session.active().unwrap().doc.clone();
-        let srect = slide.get();
-        let k = srect.width() / doc.slide_size.width.max(1.0) as f32;
-        let rect = doc.slides[1].shapes.last().unwrap().xfrm.unwrap();
-        let button = crate::media::gif_button_rect(on_screen(srect, k, &rect)).center();
-        (harness, id, button)
-    }
-
-    /// The GIF's play/pause button is drawn only while the pointer is awake, so a click on its
-    /// spot after 2.5 s without movement advances the show instead of pausing the GIF.
-    #[test]
-    fn gif_button_click_needs_an_awake_pointer() {
-        let (mut harness, id, button) = show_with_gif();
-        harness.hover_at(button);
-        harness.run_steps(2);
-        click_at(&mut harness, button);
-        harness.run_steps(2);
-        assert!(harness.state().session.gif_paused.contains(&id), "an awake pointer's click pauses the GIF");
-        assert_eq!(harness.state().show.as_ref().unwrap().state.slide, 1);
-
-        let (mut harness, id, button) = show_with_gif();
-        harness.hover_at(button);
-        harness.run_steps(2);
-        harness.run_steps(12);
-        assert!(!harness.state().show.as_ref().unwrap().pointer_awake(harness.ctx.input(|i| i.time)));
-        click_at(&mut harness, button);
-        harness.run_steps(2);
-        assert!(!harness.state().session.gif_paused.contains(&id), "the hidden button is not clickable");
-        assert_eq!(harness.state().show.as_ref().unwrap().state.slide, 2, "the click advanced the show");
-    }
-
-    /// Send real egui key events to the presenter UI, without the audience window's handler.
-    #[test]
-    fn presenter_navigation_uses_its_own_keyboard_events() {
-        use egui_kittest::kittest::Queryable;
-
-        let mut session = deckcraft_engine::Session::with_new();
-        session.execute("slide.new", &json!({})).unwrap();
-        session.execute("slide.new", &json!({})).unwrap();
-        let doc = session.active().unwrap().doc.clone();
-        let show = Show::new(&doc, 0, false, true);
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(1100.0, 700.0)).build_ui_state(
-            |ui, (doc, show, keep): &mut (std::sync::Arc<Presentation>, Show, bool)| {
-                let now = ui.input(|i| i.time);
-                presenter_window(ui.ctx(), show, doc, now, keep);
-            },
-            (doc, show, true),
-        );
-        harness.run_steps(2);
-        for (key, slide) in [
-            (egui::Key::ArrowRight, 1),
-            (egui::Key::ArrowLeft, 0),
-            (egui::Key::Space, 1),
-            (egui::Key::PageDown, 2),
-            (egui::Key::PageUp, 1),
-            (egui::Key::Home, 0),
-            (egui::Key::End, 2),
-        ] {
-            harness.key_press(key);
-            harness.run_steps(2);
-            assert_eq!(harness.state().1.state.slide, slide, "presenter key {key:?}");
-        }
-        harness.key_press(egui::Key::ArrowRight);
-        harness.run_steps(2);
-        assert!(harness.state().1.ended);
-        harness.key_press(egui::Key::ArrowLeft);
-        harness.run_steps(2);
-        assert!(!harness.state().1.ended);
-        assert_eq!(harness.state().1.state.slide, 2, "back from the end screen restores the last slide");
-        harness.key_press(egui::Key::ArrowRight);
-        harness.run_steps(2);
-        assert!(harness.state().1.ended);
-        harness.get_by_label("◀ Previous").click();
-        harness.run_steps(2);
-        assert!(!harness.state().1.ended, "the presenter Previous button also leaves the end screen");
-        harness.key_press(egui::Key::Home);
-        harness.run_steps(2);
-        harness.get_by_label("Next ▶").click();
-        harness.run_steps(2);
-        assert_eq!(harness.state().1.state.slide, 1);
-        harness.key_press(egui::Key::Space);
-        harness.run_steps(2);
-        assert_eq!(harness.state().1.state.slide, 2);
-        assert!(!harness.state().1.ended, "Space must not also activate the focused Next button");
-        harness.key_press(egui::Key::Escape);
-        harness.run_steps(2);
-        assert!(!harness.state().2, "Escape from Presenter View ends the show");
-    }
-
-    #[test]
-    fn slideshow_navigation_advances_once_with_presenter_view() {
-        use egui_kittest::kittest::Queryable;
-
-        let mut session = deckcraft_engine::Session::with_new();
-        session.execute("slide.new", &json!({})).unwrap();
-        session.execute("slide.new", &json!({})).unwrap();
-        let mut app = SlideApp::new(session, crate::Services::default());
-        app.ui.presenter_view = true;
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).build_ui_state(
-            |ui, app: &mut SlideApp| {
-                app.logic(ui.ctx());
-                app.ui(ui);
-            },
-            app,
-        );
-        harness.run_steps(3);
-        harness.state_mut().start_show(0, false);
-        harness.run_steps(2);
-        harness.key_press(egui::Key::ArrowRight);
-        harness.run_steps(2);
-        assert_eq!(harness.state().show.as_ref().unwrap().state.slide, 1, "one key advances one slide");
-        harness.key_press(egui::Key::End);
-        harness.run_steps(2);
-        harness.key_press(egui::Key::ArrowRight);
-        harness.run_steps(2);
-        assert!(harness.state().show.as_ref().unwrap().ended);
-        assert!(harness.query_by_label("End Show").is_some(), "the presenter remains available at the end screen");
-        harness.key_press(egui::Key::Escape);
-        harness.run_steps(2);
-        assert!(harness.state().show.is_none());
-    }
-
-    #[test]
-    fn the_prefetched_frame_is_the_frame_shown_on_entry() {
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({"title": "Second"})).unwrap();
-        let doc = s.active().unwrap().doc.clone();
-        let size = (96, 54);
-        let p = start_prefetch(&doc, 1, size).expect("prefetch starts");
-        assert_eq!(p.key, Key { slide: 1, step: 0, size, doc: std::sync::Arc::as_ptr(&doc) as usize, hidden: vec![], gif: 0, plays: vec![] });
-        let got = p.rx.recv().expect("the frame arrives");
-        let want = render_frame(&doc, 1, ShowState::timeline(&doc, 1), 0, 0.0, size, vec![], &[], 0, &[], &[], None);
-        assert_eq!(got.size, want.size);
-        assert_eq!(got.pixels, want.pixels);
-    }
-
-    /// A glowing full-slide picture in a layout made every animation frame re-render (and re-blur)
-    /// the backdrop: 2–3 frames a second. Frames now draw the slide's shapes over the kept
-    /// backdrop, and must look the same as a whole-slide render.
-    #[test]
-    fn an_animation_frame_over_the_kept_backdrop_matches_a_full_render() {
-        let mut s = deckcraft_engine::Session::with_new();
-        let r = s.execute("shape.insert", &json!({"preset": "star5", "rect": [100.0, 100.0, 300.0, 200.0]})).unwrap();
-        s.execute("animation.set", &json!({"effect": "fade", "ids": [r["id"]]})).unwrap();
-        let mut doc = (*s.active().unwrap().doc).clone();
-        // A glowing master graphic under the animated star.
-        let mut deco = doc.slides[0].shapes.last().unwrap().clone();
-        deco.id = ShapeId(9000);
-        deco.xfrm = deco.xfrm.map(|x| deckcraft_geom::Xfrm { x: x.x - 60.0, y: x.y + 40.0, ..x });
-        deco.effects = Some(deckcraft_model::Effects {
-            glow: Some(deckcraft_model::style::Glow {
-                color: deckcraft_model::style::ColorRef::rgb(deckcraft_color::Rgba::rgb(0, 120, 255)),
-                radius: 12.0,
-            }),
-            ..Default::default()
-        });
-        std::sync::Arc::make_mut(&mut doc.masters[0]).shapes.push(deco);
-        let doc = std::sync::Arc::new(doc);
-        let size = (480, 270);
-        let key = BackKey { slide: 0, size, doc: std::sync::Arc::as_ptr(&doc) as usize };
-        let mut show = Show::new(&doc, 0, false, false);
-        show.prefetch_backdrop(&doc, key);
-        let back = show.backdrop(&doc, key);
-        let tl = ShowState::timeline(&doc, 0);
-        assert!(!tl.is_empty());
-        // Half-way through the fade, the star half see-through over the glow.
-        let fast = render_frame(&doc, 0, tl.clone(), 0, 0.25, size, vec![], &[], 0, &[], &[], Some(&back));
-        let full = render_frame(&doc, 0, tl, 0, 0.25, size, vec![], &[], 0, &[], &[], None);
-        assert_eq!(fast.size, full.size);
-        let worst = fast
-            .pixels
-            .iter()
-            .zip(&full.pixels)
-            .map(|(a, b)| a.to_array().iter().zip(b.to_array()).map(|(x, y)| x.abs_diff(y)).max().unwrap_or(0))
-            .max();
-        assert!(worst.is_some_and(|d| d <= 2), "frames differ by up to {worst:?}");
-        // The backdrop is kept, not rendered again.
-        assert!(std::sync::Arc::ptr_eq(&back, &show.backdrop(&doc, key)));
-        // Another document under the same key (an edit whose copy reused the old address) gets
-        // its own backdrop.
-        let edited = std::sync::Arc::new((*doc).clone());
-        assert!(!std::sync::Arc::ptr_eq(&back, &show.backdrop(&edited, key)));
-    }
-
-    #[test]
-    fn a_transition_keeps_the_old_slide_in_its_own_texture() {
-        // #33: the old slide's handle was cloned, so the new slide was rendered into the same
-        // texture and every transition blended the new slide with itself.
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({})).unwrap();
-        s.execute("transition.set", &json!({"kind": "fade", "index": 1})).unwrap();
-        let doc = s.active().unwrap().doc.clone();
-        let ctx = egui::Context::default();
-        let red = crate::textures::upload(&ctx, "show", egui::ColorImage::filled([1, 1], Color32::RED));
-        let mut show = Show::new(&doc, 0, false, false);
-        show.tex = Some((Key { slide: 0, step: 0, size: (1, 1), doc: 0, hidden: vec![], gif: 0, plays: vec![] }, red.clone()));
-        assert!(show.apply(ShowAction::Slide(1), &doc, 0.0));
-        let tr = show.trans.as_ref().expect("the fade plays");
-        assert_eq!(tr.old.as_ref().map(TextureHandle::id), Some(red.id()));
-        assert_eq!(tr.from, Some(0));
-        assert!(show.tex.is_none(), "the new slide gets a texture of its own instead of overwriting the old one");
-    }
-
-    #[test]
-    fn media_in_the_click_sequence_plays_with_its_step() {
-        // #116: media set to play in the click sequence never started; only a click on it did.
-        let s = deckcraft_engine::Session::with_new();
-        let mut doc = s.active().unwrap().doc.clone();
-        let id = doc.slides[0].shapes[0].id;
-        let play = |delay_ms| deckcraft_model::Animation {
-            shape: id,
-            class: deckcraft_model::AnimClass::Media,
-            effect: "play".into(),
-            duration_ms: 5000,
-            delay_ms,
-            ..Default::default()
-        };
-        std::sync::Arc::make_mut(&mut std::sync::Arc::make_mut(&mut doc).slides[0]).animations = vec![play(0), play(2000)];
-        let mut show = Show::new(&doc, 0, false, false);
-        assert!(show.apply(ShowAction::Slide(0), &doc, 0.0));
-        // Next: the first step plays and sets off its Play once.
-        let a = show.state.next(&doc);
-        assert_eq!(a, ShowAction::PlayStep(0));
-        assert!(show.apply(a, &doc, 1.0));
-        show.cue_media(&doc, 0, 0.0);
-        show.cue_media(&doc, 0, 0.5);
-        assert_eq!(std::mem::take(&mut show.media_cues), [(id, "play".to_string())]);
-        // The step doesn't wait for the video: the step clock ends it at once.
-        assert_eq!(show.timeline(&doc).step_duration(0), 0.0);
-        let a = show.state.step_done(&doc);
-        assert!(show.apply(a, &doc, 1.0));
-        assert!(show.media_cues.is_empty(), "set off once");
-        // Next again, before the second Play's delay: cutting the step short still sets it off.
-        let a = show.state.next(&doc);
-        assert_eq!(a, ShowAction::PlayStep(1));
-        assert!(show.apply(a, &doc, 2.0));
-        show.cue_media(&doc, 1, 0.5);
-        assert!(show.media_cues.is_empty());
-        let a = show.state.step_done(&doc);
-        assert!(show.apply(a, &doc, 2.6));
-        assert_eq!(std::mem::take(&mut show.media_cues), [(id, "play".to_string())]);
-        // Going back doesn't set anything off.
-        let a = show.state.prev(&doc);
-        assert!(show.apply(a, &doc, 3.0));
-        show.cue_media(&doc, 1, 9.0);
-        assert!(show.media_cues.is_empty());
-    }
-
-    #[test]
-    fn the_laser_and_the_pen_are_not_on_together() {
-        let doc = deckcraft_model::Presentation::default();
-        let mut show = Show::new(&doc, 0, false, false);
-        show.set_laser(true);
-        assert!(show.laser && !show.pen);
-        show.set_pen(true);
-        assert!(show.pen && !show.laser);
-        show.set_laser(true);
-        show.arrow();
-        assert!(!show.laser && !show.pen);
-        show.set_laser(false);
-        assert!(!show.laser);
-    }
-
-    fn deck_with_first_animation(start: deckcraft_model::anim::AnimStart) -> Presentation {
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({})).unwrap();
-        let mut doc = Presentation::clone(&s.active().unwrap().doc);
-        let slide = std::sync::Arc::make_mut(&mut doc.slides[1]);
-        let shape = slide.shapes[0].id;
-        slide.animations = vec![deckcraft_model::anim::Animation { shape, start, duration_ms: 3000, ..Default::default() }];
-        doc
-    }
-
-    #[test]
-    fn a_first_animation_after_or_with_previous_plays_when_the_slide_appears() {
-        // #631: it was started twice and the second start finished it, so the slide appeared
-        // fully built.
-        use deckcraft_model::anim::AnimStart;
-        for start in [AnimStart::AfterPrevious, AnimStart::WithPrevious] {
-            let doc = deck_with_first_animation(start);
-            // Starting the show on the slide.
-            let mut show = Show::new(&doc, 1, false, false);
-            show.after_enter(&doc, 5.0);
-            assert_eq!((show.state.step, show.state.playing), (0, true), "{start:?} from the start");
-            assert_eq!(show.step_start, 5.0);
-            // Arriving from the slide before.
-            let mut show = Show::new(&doc, 0, false, false);
-            let a = show.state.next(&doc);
-            assert!(matches!(a, ShowAction::Slide(1)));
-            assert!(show.apply(a, &doc, 7.0));
-            assert_eq!((show.state.step, show.state.playing), (0, true), "{start:?} on arrival");
-        }
-        // On Click still waits for the click.
-        let doc = deck_with_first_animation(AnimStart::OnClick);
-        let mut show = Show::new(&doc, 1, false, false);
-        show.after_enter(&doc, 5.0);
-        assert_eq!((show.state.step, show.state.playing), (0, false));
-        assert!(matches!(show.state.next(&doc), ShowAction::PlayStep(0)));
-    }
-
-    #[test]
-    fn zoom_stays_on_the_slide_and_the_grid_hits_a_thumbnail() {
-        let uv = zoom_uv(0.5, 0.5, 2.0);
-        assert!((uv.min.x - 0.25).abs() < 1e-4 && (uv.min.y - 0.25).abs() < 1e-4);
-        assert!((uv.width() - 0.5).abs() < 1e-4);
-        let corner = zoom_uv(0.0, 0.0, 2.0);
-        assert_eq!(corner.min, pos2(0.0, 0.0));
-        assert!(corner.max.x <= 1.0 && corner.max.y <= 1.0);
-        let full = Rect::from_min_size(Pos2::ZERO, vec2(1728.0, 1084.0));
-        let cells = see_all_cells(full, 7, 16.0 / 9.0);
-        assert_eq!(cells.len(), 7);
-        for (i, a) in cells.iter().enumerate() {
-            assert!(full.contains_rect(*a), "cell {i} leaves the window");
-            for b in cells.iter().skip(i + 1) {
-                let overlap = a.intersect(*b);
-                assert!(overlap.width() < 1.0 || overlap.height() < 1.0, "thumbnails overlap {a:?} {b:?}");
-            }
-        }
-        let hit = see_all_hit(full, 7, 16.0 / 9.0, cells[3].center());
-        assert_eq!(hit, Some(3));
-        assert_eq!(see_all_hit(full, 7, 16.0 / 9.0, pos2(2.0, 2.0)), None);
-        let srect = Rect::from_min_size(pos2(10.0, 20.0), vec2(200.0, 100.0));
-        assert_eq!(norm_on_slide(srect, unit_uv(), pos2(110.0, 70.0)), Some((0.5, 0.5)));
-        let zoomed = zoom_uv(0.5, 0.5, 2.0);
-        let back = norm_on_slide(srect, zoomed, pos2(110.0, 70.0)).expect("on the slide");
-        assert!((back.0 - 0.5).abs() < 1e-3 && (back.1 - 0.5).abs() < 1e-3);
-    }
-
-    fn near(a: f32, b: f32) -> bool {
-        (a - b).abs() < 1e-3
-    }
-
-    /// #1286: Ctrl+wheel zooms around the pointer, four notches per doubling, up to 4× (the most
-    /// PowerPoint's magnifier goes); zooming back to the whole slide leaves the zoom.
-    #[test]
-    fn wheel_zoom_keeps_the_point_under_the_pointer_and_stops_at_4x() {
-        let doc = deckcraft_model::Presentation::default();
-        let mut show = Show::new(&doc, 0, false, false);
-        // A 16:9 slide, not at the origin, and a pointer off its centre.
-        let srect = Rect::from_min_size(pos2(40.0, 30.0), vec2(320.0, 180.0));
-        let p = pos2(40.0 + 320.0 * 0.2, 30.0 + 180.0 * 0.3);
-        show.wheel_zoom(srect, p, 4.0);
-        let (_, _, scale) = show.zoom_view().expect("zoomed in");
-        assert!(near(scale, 2.0), "four notches double, got {scale}");
-        // The window keeps the slide's shape: half the width and half the height of the slide.
-        let uv = show.zoom_uv();
-        assert!(near(uv.width(), 0.5) && near(uv.height(), 0.5), "{uv:?}");
-        assert!(near(uv.min.x, 0.2 - 0.5 * 0.2) && near(uv.min.y, 0.3 - 0.5 * 0.3), "{uv:?}");
-        let under = norm_on_slide(srect, uv, p).expect("on the slide");
-        assert!(near(under.0, 0.2) && near(under.1, 0.3), "the point under the pointer moved to {under:?}");
-
-        // Again from the zoomed view: the same slide point stays under the pointer.
-        show.wheel_zoom(srect, p, 2.0);
-        let (_, _, scale) = show.zoom_view().expect("zoomed in");
-        assert!(near(scale, 2f32.powf(1.5)), "{scale}");
-        let under = norm_on_slide(srect, show.zoom_uv(), p).expect("on the slide");
-        assert!(near(under.0, 0.2) && near(under.1, 0.3), "{under:?}");
-
-        show.wheel_zoom(srect, p, 40.0);
-        let (_, _, scale) = show.zoom_view().expect("zoomed in");
-        assert!(near(scale, 4.0), "capped at 4×, got {scale}");
-        assert!(near(show.zoom_uv().width(), 0.25));
-
-        show.wheel_zoom(srect, p, -7.0);
-        assert!(show.zoom_view().is_some(), "one notch short of the whole slide is still zoomed");
-        show.wheel_zoom(srect, p, -1.0);
-        assert!(show.zoom_view().is_none(), "back to the whole slide leaves the zoom");
-        assert_eq!(show.zoom_uv(), unit_uv());
-        show.wheel_zoom(srect, p, -3.0);
-        assert!(show.zoom_view().is_none(), "zooming out of the whole slide does nothing");
-
-        // Off the slide (the letterbox) the wheel does not zoom.
-        show.wheel_zoom(srect, pos2(10.0, 10.0), 4.0);
-        assert!(show.zoom_view().is_none());
-        // An armed click-zoom gives way to the wheel.
-        show.zoom_arm = true;
-        show.wheel_zoom(srect, p, 4.0);
-        assert!(!show.zoom_arm && show.zoom_view().is_some());
-    }
-
-    #[test]
-    fn wheel_zoom_reads_only_the_wheel_with_ctrl_or_cmd() {
-        let wheel = |unit, y: f32, modifiers| egui::Event::MouseWheel {
-            unit,
-            delta: vec2(0.0, y),
-            phase: egui::TouchPhase::Move,
-            source: egui::MouseWheelSource::Wheel,
-            modifiers,
-        };
-        use egui::MouseWheelUnit::{Line, Point};
-        assert_eq!(wheel_zoom_lines(&[wheel(Line, 1.0, egui::Modifiers::CTRL)], 40.0), Some(1.0));
-        assert_eq!(wheel_zoom_lines(&[wheel(Line, -2.0, egui::Modifiers::COMMAND)], 40.0), Some(-2.0));
-        assert_eq!(wheel_zoom_lines(&[wheel(Point, 20.0, egui::Modifiers::CTRL), wheel(Point, 20.0, egui::Modifiers::CTRL)], 40.0), Some(1.0));
-        assert_eq!(wheel_zoom_lines(&[wheel(Line, 1.0, egui::Modifiers::NONE)], 40.0), None, "a plain wheel turns the page");
-        assert_eq!(wheel_zoom_lines(&[wheel(Line, 1.0, egui::Modifiers::SHIFT)], 40.0), None);
-        assert_eq!(wheel_zoom_lines(&[egui::Event::Zoom(2.0)], 40.0), None, "a pinch is not a show gesture");
-        assert_eq!(wheel_zoom_lines(&[wheel(Line, f32::NAN, egui::Modifiers::CTRL)], 40.0), Some(0.0));
-    }
-
-    /// A running show on the first of three slides, with presenter view off.
-    fn show_of_three() -> egui_kittest::Harness<'static, SlideApp> {
-        let mut session = deckcraft_engine::Session::with_new();
-        session.execute("slide.new", &json!({})).unwrap();
-        session.execute("slide.new", &json!({})).unwrap();
-        let mut app = SlideApp::new(session, crate::Services::default());
-        app.ui.presenter_view = false;
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).with_step_dt(1.0 / 60.0).build_ui_state(
-            |ui, app: &mut SlideApp| {
-                app.logic(ui.ctx());
-                app.ui(ui);
-            },
-            app,
-        );
-        harness.run_steps(3);
-        harness.state_mut().start_show(0, false);
-        harness.run_steps(2);
-        harness
-    }
-
-    fn show_wheel(harness: &mut egui_kittest::Harness<'static, SlideApp>, at: Pos2, y: f32, modifiers: egui::Modifiers) {
-        harness.input_mut().events.push(egui::Event::PointerMoved(at));
-        harness.input_mut().events.push(egui::Event::MouseWheel {
-            unit: egui::MouseWheelUnit::Line,
-            delta: vec2(0.0, y),
-            phase: egui::TouchPhase::Move,
-            source: egui::MouseWheelSource::Wheel,
-            modifiers,
-        });
-        harness.run_steps(40);
-    }
-
-    /// #1286: in the show, Ctrl+wheel (Cmd+wheel on a Mac) zooms the slide and does not turn the
-    /// page; the plain wheel still turns it.
-    #[test]
-    fn ctrl_wheel_zooms_the_show_and_the_plain_wheel_turns_the_page() {
-        for held in [egui::Modifiers::CTRL, egui::Modifiers::COMMAND] {
-            let mut h = show_of_three();
-            let centre = pos2(500.0, 350.0);
-            show_wheel(&mut h, centre, 4.0, held);
-            let show = h.state().show.as_ref().expect("still showing");
-            assert_eq!(show.state.slide, 0, "{held:?}: the zoom wheel does not turn the page");
-            let (_, _, scale) = show.zoom_view().expect("zoomed in");
-            assert!(near(scale, 2.0), "{held:?}: {scale}");
-
-            show_wheel(&mut h, centre, -4.0, held);
-            let show = h.state().show.as_ref().expect("still showing");
-            assert_eq!(show.state.slide, 0, "{held:?}: zooming out does not go back a page either");
-            assert!(show.zoom_view().is_none(), "{held:?}: back to the whole slide");
-
-            show_wheel(&mut h, centre, -3.0, egui::Modifiers::NONE);
-            assert_eq!(h.state().show.as_ref().expect("still showing").state.slide, 1, "the plain wheel turns the page");
-        }
-    }
-
-    #[test]
-    fn escape_only_closes_the_grid_of_its_own_window() {
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({})).unwrap();
-        let doc = s.active().unwrap().doc.clone();
-        let mut show = Show::new(&doc, 0, false, true);
-        show.presenter_grid = true;
-        assert!(!show.back_out(false), "audience Esc leaves the show, the Presenter View grid stays");
-        assert!(show.presenter_grid);
-        assert!(show.back_out(true));
-        assert!(!show.presenter_grid);
-        show.grid = true;
-        assert!(!show.back_out(true), "Presenter View Esc does not close the audience grid");
-        assert!(show.grid);
-        assert!(show.back_out(false));
-        assert!(!show.grid);
-    }
-
-    #[test]
-    fn escape_leaves_the_grid_then_the_zoom_and_blank_toggles() {
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({})).unwrap();
-        let doc = s.active().unwrap().doc.clone();
-        let mut show = Show::new(&doc, 0, false, true);
-        show.grid = true;
-        show.zoom = Some(Zoom::at(0.2, 0.3));
-        assert!(show.back_out(false));
-        assert!(!show.grid);
-        assert!(show.zoom.is_some(), "closing the grid leaves the zoom");
-        assert!(show.back_out(false));
-        assert!(show.zoom.is_none());
-        assert!(!show.back_out(false));
-        show.zoom_key();
-        assert!(show.zoom_arm);
-        show.zoom_key();
-        assert!(!show.zoom_arm);
-        toggle_blank(&mut show, Color32::BLACK);
-        assert_eq!(show.blank_name(), Some("black"));
-        toggle_blank(&mut show, Color32::WHITE);
-        assert_eq!(show.blank_name(), Some("white"));
-        toggle_blank(&mut show, Color32::WHITE);
-        assert_eq!(show.blank_name(), None);
-        show.zoom = Some(Zoom::at(0.4, 0.6));
-        assert!(show.apply(ShowAction::Slide(1), &doc, 1.0));
-        assert!(show.zoom.is_none(), "a new slide is shown whole");
-    }
-
-    /// #1128: the presenter drew the notes as plain text, so bullets, numbers and bold were lost
-    /// although the notes pane shows them; the notes stay selectable.
-    #[test]
-    fn presenter_notes_keep_bullets_numbers_and_bold() {
-        use deckcraft_model::text::{Bullet, ParaProps, Paragraph, Run, RunProps, TextBody};
-        let point = |text: &str, bullet: Bullet| Paragraph {
-            level: 1,
-            props: ParaProps { bullet: Some(bullet), ..Default::default() },
-            runs: vec![Run::new(text)],
-            ..Default::default()
-        };
-        let num = || Bullet::AutoNum { scheme: "arabicPeriod".into(), start_at: 1 };
-        let notes = TextBody {
-            paragraphs: vec![
-                Paragraph { runs: vec![Run::with("Opening", RunProps { bold: Some(true), ..Default::default() })], ..Default::default() },
-                point("Welcome", Bullet::Char { char: "•".into() }),
-                point("Agenda", num()),
-                point("Demo", num()),
-            ],
-            ..Default::default()
-        };
-        let ctx = egui::Context::default();
-        theme::install_fonts(&ctx);
-        let mut sense = None;
-        let mut out = ctx.run_ui(Default::default(), |ui| sense = Some(presenter_notes(ui, &notes, 24.0).sense));
-        out.textures_delta.clear();
-        assert!(sense.unwrap().senses_drag(), "the notes can be selected, as the plain label could");
-        let mut texts = vec![];
-        let mut stack: Vec<egui::Shape> = out.shapes.into_iter().map(|c| c.shape).collect();
-        while let Some(shape) = stack.pop() {
-            match shape {
-                egui::Shape::Vec(v) => stack.extend(v),
-                egui::Shape::Text(t) => texts.push(t.galley),
-                _ => {}
-            }
-        }
-        let painted: Vec<&str> = texts.iter().map(|g| g.job.text.as_str()).collect();
-        for marker in ["•", "1.", "2."] {
-            assert!(painted.contains(&marker), "{marker} is drawn: {painted:?}");
-        }
-        let notes_galley = texts.iter().find(|g| g.job.text.contains("Agenda")).expect("the notes are drawn");
-        let font_of = |s: &str| {
-            let b = notes_galley.job.text.find(s).unwrap();
-            notes_galley.job.sections.iter().find(|x| (x.byte_range.start.0..x.byte_range.end.0).contains(&b)).unwrap().format.font_id.clone()
-        };
-        assert_eq!(font_of("Opening"), theme::bold(24.0), "bold runs stay bold at the pane's size");
-        assert_eq!(font_of("Agenda"), theme::font(24.0));
-    }
-
-    /// Hidden logic keeps playing from wall time even though `run_logic` leaves egui's input
-    /// time at the last visible frame. A visible pass re-anchors instead of shifting a pause.
-    #[test]
-    fn hidden_logic_advances_the_show_and_visible_frames_reanchor() {
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({})).unwrap();
-        let doc = s.active().unwrap().doc.clone();
-        let mut show = Show::new(&doc, 0, false, true);
-        show.started = true;
-        show.step_start = 10.0;
-        show.slide_start = 10.0;
-        show.step_end = 10.0;
-        show.show_start = 10.0;
-        show.last_move = 10.0;
-        show.timer = PresenterTimer::start(10.0);
-        let t0 = web_time::Instant::now();
-        show.observe_visible_frame(10.0, t0);
-        assert_eq!(show.hidden_logic_time(10.0, t0), 10.0, "the first hidden tick starts at the last visible time");
-        let hidden = show.hidden_logic_time(10.0, t0 + std::time::Duration::from_secs(2));
-        assert!((hidden - 12.0).abs() < 1e-9, "hidden logic advances the show time: {hidden}");
-        assert!((show.presenter_elapsed(hidden) - 2.0).abs() < 1e-9, "presenter time keeps running");
-        assert!((show.clock_snapshot().step_start - 10.0).abs() < 1e-9, "the clock origin is not shifted");
-        let later = show.hidden_logic_time(10.0, t0 + std::time::Duration::from_secs(5));
-        assert!((later - 15.0).abs() < 1e-9, "repeated hidden ticks do not stack a pause: {later}");
-        show.observe_visible_frame(20.0, t0 + std::time::Duration::from_secs(10));
-        assert_eq!(show.hidden_logic_time(20.0, t0 + std::time::Duration::from_secs(10)), 20.0, "a visible frame re-anchors");
-    }
-
-    #[test]
-    fn presenter_timer_pauses_resets_and_notes_size_clamps() {
-        let mut t = PresenterTimer::start(10.0);
-        assert!((t.elapsed(12.5) - 2.5).abs() < 1e-9);
-        t.toggle(15.0);
-        assert!(t.paused());
-        assert!((t.elapsed(100.0) - 5.0).abs() < 1e-9);
-        t.reset(100.0);
-        assert!(t.paused());
-        assert_eq!(t.elapsed(200.0), 0.0);
-        t.toggle(200.0);
-        assert!(!t.paused());
-        assert!((t.elapsed(203.0) - 3.0).abs() < 1e-9);
-        t.reset(203.0);
-        assert!(!t.paused());
-        assert!((t.elapsed(204.0) - 1.0).abs() < 1e-9);
-        let bad = PresenterTimer::start(f64::NAN);
-        assert_eq!(bad.elapsed(f64::INFINITY), 0.0);
-        assert_eq!(format_elapsed(3661.4), "01:01:01");
-        assert_eq!(format_elapsed(-1.0), "00:00:00");
-        assert_eq!(format_elapsed(f64::NAN), "00:00:00");
-        let clock = wall_clock();
-        assert!(clock == "--:--" || (clock.len() == 5 && clock.as_bytes().get(2) == Some(&b':')));
-
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({})).unwrap();
-        let doc = s.active().unwrap().doc.clone();
-        let mut show = Show::new(&doc, 0, false, true);
-        assert_eq!(show.notes_px, NOTES_DEFAULT);
-        show.nudge_notes(NOTES_STEP);
-        assert_eq!(show.notes_px, 22.0);
-        show.nudge_notes(1000.0);
-        assert_eq!(show.notes_px, NOTES_MAX);
-        show.nudge_notes(-1000.0);
-        assert_eq!(show.notes_px, NOTES_MIN);
-        show.nudge_notes(f32::NAN);
-        assert_eq!(show.notes_px, NOTES_MIN);
-        let v = show.showing_value(1, 16.0 / 9.0, Rect::from_min_size(Pos2::ZERO, vec2(100.0, 100.0)), 0.0);
-        assert_eq!(v["presenterPaused"], json!(false));
-        assert_eq!(v["notesPx"], json!(NOTES_MIN));
-    }
-
-    #[test]
-    fn a_typed_slide_number_jumps_and_then_expires() {
-        let mut s = deckcraft_engine::Session::with_new();
-        s.execute("slide.new", &json!({})).unwrap();
-        let doc = s.active().unwrap().doc.clone();
-        let mut show = Show::new(&doc, 0, false, false);
-        show.push_slide_number('1', 10.0);
-        show.push_slide_number('2', 10.2);
-        assert_eq!(show.goto, "12");
-        assert_eq!(show.take_goto(), Some(11));
-        assert!(show.goto.is_empty());
-        show.push_slide_number('0', 1.0);
-        assert_eq!(show.take_goto(), None, "slide 0 is not a slide");
-        show.push_slide_number('4', 5.0);
-        show.expire_goto(7.0);
-        assert_eq!(show.goto, "4");
-        show.expire_goto(8.1);
-        assert!(show.goto.is_empty());
-        show.push_slide_number('9', 0.0);
-        assert!(show.clear_goto());
-        assert!(!show.clear_goto());
-        for _ in 0..6 {
-            show.push_slide_number('9', 1.0);
-        }
-        assert_eq!(show.goto.len(), GOTO_DIGITS);
-        show.push_slide_number('a', 1.0);
-        assert!(show.goto.chars().all(|c| c.is_ascii_digit()));
-    }
-
-    #[test]
-    fn browsed_by_an_individual_stays_in_a_window() {
-        assert!(!show_fills_screen(false, "browsed"));
-        assert!(!show_fills_screen(true, "speaker"));
-        assert!(show_fills_screen(false, "speaker"));
-        assert!(show_fills_screen(false, "kiosk"));
-    }
-
-    #[test]
-    fn the_next_preview_fits_its_column_whatever_the_slide_shape() {
-        let right = Rect::from_min_size(pos2(700.0, 100.0), vec2(400.0, 600.0));
-        let mut s = deckcraft_engine::Session::with_new();
-        for (w, h) in [(72, 4032), (4032, 72), (960, 540)] {
-            s.execute("design.slideSize", &json!({"w": w, "h": h})).unwrap();
-            let doc = s.active().unwrap().doc.clone();
-            let r = next_rect(right, &doc);
-            assert!(right.contains_rect(r), "{w}x{h}: {r:?}");
-            let aspect = r.height() / r.width();
-            assert!((aspect - h as f32 / w as f32).abs() / (h as f32 / w as f32) < 0.01, "{w}x{h}: {r:?}");
-        }
-        // 16:9 still takes the column's full width.
-        let doc = s.active().unwrap().doc.clone();
-        assert_eq!(next_rect(right, &doc).width(), 400.0);
-    }
-
-    #[test]
-    fn back_leaves_a_slide_whose_first_animation_is_with_previous() {
-        // #844: Back on such a slide undid its first step, and the next frame played that step
-        // again by itself, so Back never reached the slide before.
-        let mut session = deckcraft_engine::Session::with_new();
-        session.execute("slide.new", &json!({})).unwrap();
-        let id = session.active().unwrap().doc.slides[1].shapes[0].id;
-        session
-            .execute("animation.add", &json!({"effect": "fade", "class": "entrance", "ids": [id.0], "start": "withPrevious", "duration": 500}))
-            .unwrap();
-        let app = SlideApp::new(session, crate::Services::default());
-        let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).build_ui_state(
-            |ui, app: &mut SlideApp| {
-                app.logic(ui.ctx());
-                app.ui(ui);
-            },
-            app,
-        );
-        harness.run_steps(3);
-        harness.state_mut().start_show(0, false);
-        harness.run_steps(2);
-        harness.key_press(egui::Key::ArrowRight);
-        // The first step plays by itself and ends (0.5 s; a frame is 0.25 s).
-        harness.run_steps(8);
-        let st = &harness.state().show.as_ref().unwrap().state;
-        assert_eq!((st.slide, st.step, st.playing), (1, 1, false), "on slide 2, fully built");
-        for _ in 0..5 {
-            harness.key_press(egui::Key::ArrowLeft);
-            harness.run_steps(2);
-        }
-        let st = &harness.state().show.as_ref().unwrap().state;
-        assert_eq!(st.slide, 0, "five Backs leave slide 2 (step {}, playing {})", st.step, st.playing);
-    }
-
-    /// Click-target state follows show instance, reading/presenter modes, grid, and other layout
-    /// changes instead of retaining a stale target.
-    #[test]
-    fn input_state_tracks_the_modes_that_move_show_click_targets() {
-        let session = deckcraft_engine::Session::with_new();
-        let doc = &session.active().unwrap().doc;
-        let mut show = Show::new(doc, 0, false, false);
-        let base = show.input_state();
-        assert_eq!(show.input_state(), base);
-
-        show.instance += 1;
-        assert_ne!(show.input_state(), base, "a new show instance is a new input target");
-        show.instance = base.instance;
-
-        show.reading = true;
-        assert_ne!(show.input_state(), base, "the reading layout moves the slide");
-        show.reading = false;
-
-        show.presenter = true;
-        assert_ne!(show.input_state(), base, "presenter view changes the available area");
-        show.presenter = false;
-
-        show.grid = true;
-        assert_ne!(show.input_state(), base, "See All Slides replaces the slide with thumbnails");
-        show.grid = false;
-
-        show.pen = true;
-        assert_ne!(show.input_state(), base, "the pen changes what a drag means");
-        show.pen = false;
-
-        show.laser = true;
-        assert_ne!(show.input_state(), base, "the laser changes what a drag means");
-        show.laser = false;
-
-        show.zoom_arm = true;
-        assert_ne!(show.input_state(), base, "armed zoom changes what a click means");
-        show.zoom_arm = false;
-
-        show.zoom = Some(Zoom::at(0.25, 0.75));
-        assert_ne!(show.input_state(), base, "a zoomed slide has a different click mapping");
-        show.zoom = None;
-
-        show.blank = Some(Color32::BLACK);
-        assert_ne!(show.input_state(), base, "a blank screen has no slide click targets");
-    }
-}
+mod tests;
diff --git a/crates/ui-egui/src/show/tests.rs b/crates/ui-egui/src/show/tests.rs
new file mode 100644
index 00000000..8c515363
--- /dev/null
+++ b/crates/ui-egui/src/show/tests.rs
@@ -0,0 +1,995 @@
+#![allow(clippy::unwrap_used, clippy::expect_used)]
+
+use super::*;
+
+/// #1005: shapes stacked above a playing video must be drawn over its frame; the video, what
+/// is below it and other videos stay out of that overlay.
+#[test]
+fn shapes_above_a_playing_video_are_the_overlay() {
+    let mut session = deckcraft_engine::Session::with_new();
+    for _ in 0..3 {
+        session.execute("shape.insert", &json!({"preset": "rect", "rect": [0.0, 0.0, 100.0, 100.0]})).unwrap();
+    }
+    let mut doc = (*session.active().unwrap().doc).clone();
+    // Keep only the three inserted rects (a new slide may start with placeholders).
+    let slide = std::sync::Arc::make_mut(&mut doc.slides[0]);
+    let keep = slide.shapes.len() - 3;
+    slide.shapes.drain(..keep);
+    let ids: Vec<ShapeId> = slide.shapes.iter().map(|s| s.id).collect();
+    slide.shapes[1].kind = deckcraft_model::ShapeKind::Media(deckcraft_model::MediaClip { video: true, ..Default::default() });
+    // Video in the middle: the shape above it is drawn over it.
+    assert_eq!(below_playing_video(&doc, 0, &[ids[1]]), vec![ids[0], ids[1]]);
+    // Video on top: nothing above it, the frame is painted last as before.
+    std::sync::Arc::make_mut(&mut doc.slides[0]).shapes.swap(1, 2);
+    assert!(below_playing_video(&doc, 0, &[ids[1]]).is_empty());
+    // No video playing.
+    assert!(below_playing_video(&doc, 0, &[]).is_empty());
+}
+
+/// #968: over a shape a click acts on (a clip with its play trigger, a link) the pointing hand
+/// never gave way to the idle hide, so a still pointer stayed on the playing video.
+#[test]
+fn a_still_cursor_hides_over_a_clickable_shape() {
+    let mut session = deckcraft_engine::Session::with_new();
+    let size = session.active().unwrap().doc.slide_size;
+    let r = session.execute("shape.insert", &json!({"preset": "rect", "rect": [0.0, 0.0, size.width, size.height]})).unwrap();
+    session.execute("insert.hyperlink", &json!({"url": "https://example.org", "ids": [r["id"]]})).unwrap();
+    let app = SlideApp::new(session, crate::Services::default());
+    let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).with_step_dt(0.25).build_ui_state(
+        |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        app,
+    );
+    harness.run_steps(3);
+    harness.state_mut().start_show(0, false);
+    harness.run_steps(2);
+    harness.hover_at(pos2(500.0, 350.0));
+    harness.run_steps(2);
+    assert_eq!(harness.output().platform_output.cursor_icon, egui::CursorIcon::PointingHand);
+    harness.run_steps(12);
+    assert_eq!(harness.output().platform_output.cursor_icon, egui::CursorIcon::None, "still for 3 s: hidden");
+}
+
+/// #1130: the Presenter View's All slides button opens the grid in that window, not on the audience screen.
+#[test]
+fn presenter_all_slides_does_not_cover_the_audience_screen() {
+    use egui_kittest::kittest::Queryable;
+
+    let mut session = deckcraft_engine::Session::with_new();
+    session.execute("slide.new", &json!({})).unwrap();
+    let doc = session.active().unwrap().doc.clone();
+    let show = Show::new(&doc, 0, false, true);
+    let mut harness = egui_kittest::Harness::builder().with_size(vec2(1100.0, 700.0)).build_ui_state(
+        |ui, (doc, show, keep): &mut (std::sync::Arc<Presentation>, Show, bool)| {
+            let now = ui.input(|i| i.time);
+            presenter_window(ui.ctx(), show, doc, now, keep);
+        },
+        (doc, show, true),
+    );
+    harness.run_steps(2);
+    harness.get_by_label("All slides").click();
+    harness.run_steps(2);
+    assert!(harness.state().1.presenter_grid, "the grid opens in the Presenter View");
+    assert!(!harness.state().1.grid, "the audience screen keeps showing the slide");
+    harness.key_press(egui::Key::Escape);
+    harness.run_steps(2);
+    assert!(!harness.state().1.presenter_grid, "Esc closes the Presenter View grid");
+    assert!(harness.state().2, "and does not end the show");
+    harness.key_press(egui::Key::G);
+    harness.run_steps(2);
+    assert!(harness.state().1.presenter_grid, "G in Presenter View opens its own grid");
+    assert!(!harness.state().1.grid, "G in Presenter View leaves the audience screen alone");
+    harness.key_press(egui::Key::G);
+    harness.run_steps(2);
+    assert!(!harness.state().1.presenter_grid, "G again closes it");
+}
+
+/// A silent mono 8 kHz WAV, so the clip has a real duration to seek in.
+fn silent_wav(secs: u32) -> Vec<u8> {
+    let rate = 8_000u32;
+    let data = vec![0u8; (rate * secs * 2) as usize];
+    let mut b = Vec::new();
+    b.extend_from_slice(b"RIFF");
+    b.extend_from_slice(&(36 + data.len() as u32).to_le_bytes());
+    b.extend_from_slice(b"WAVEfmt ");
+    b.extend_from_slice(&16u32.to_le_bytes());
+    b.extend_from_slice(&1u16.to_le_bytes());
+    b.extend_from_slice(&1u16.to_le_bytes());
+    b.extend_from_slice(&rate.to_le_bytes());
+    b.extend_from_slice(&(rate * 2).to_le_bytes());
+    b.extend_from_slice(&2u16.to_le_bytes());
+    b.extend_from_slice(&16u16.to_le_bytes());
+    b.extend_from_slice(b"data");
+    b.extend_from_slice(&(data.len() as u32).to_le_bytes());
+    b.extend_from_slice(&data);
+    b
+}
+
+/// A running show on a slide with one 10 s clip. Returns the harness, the clip, a point on the
+/// bar's seek track, and what `pointer_on_media_bar` said on the last frame.
+fn show_with_clip() -> (egui_kittest::Harness<'static, SlideApp>, ShapeId, Pos2, std::rc::Rc<std::cell::Cell<bool>>) {
+    let size = vec2(1000.0, 700.0);
+    let mut session = deckcraft_engine::Session::with_new();
+    let id = ShapeId(4000);
+    session
+        .edit(|doc, _| {
+            let media = doc.add_media("clip.wav", "audio/wav", silent_wav(10)).unwrap();
+            let (w, h) = (doc.slide_size.width, doc.slide_size.height);
+            let clip = deckcraft_model::MediaClip { media, video: true, volume: 1.0, duration_ms: 10_000, ..Default::default() };
+            let xfrm = deckcraft_geom::Xfrm::new(w * 0.2, h * 0.2, w * 0.6, h * 0.6);
+            let slide = std::sync::Arc::make_mut(&mut doc.slides[0]);
+            slide.shapes.push(deckcraft_model::Shape { id, xfrm: Some(xfrm), kind: deckcraft_model::ShapeKind::Media(clip), ..Default::default() });
+            Ok(())
+        })
+        .unwrap();
+    let on_bar = std::rc::Rc::new(std::cell::Cell::new(false));
+    let seen = on_bar.clone();
+    let slide = std::rc::Rc::new(std::cell::Cell::new(Rect::NOTHING));
+    let slide_seen = slide.clone();
+    // Presenter view opens an embedded window over the whole screen here, which takes the clicks.
+    let mut app = SlideApp::new(session, crate::Services::default());
+    app.ui.presenter_view = false;
+    let mut harness = egui_kittest::Harness::builder().with_size(size).with_step_dt(0.25).build_ui_state(
+        move |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            if let (Some(show), Some(d)) = (app.show.as_ref(), app.session.active()) {
+                let now = ui.input(|i| i.time);
+                seen.set(pointer_on_media_bar(ui.ctx(), ui, &d.doc, show, now));
+                slide_seen.set(shown_slide_rect(ui, show, &d.doc));
+            }
+            app.ui(ui);
+        },
+        app,
+    );
+    harness.run_steps(3);
+    harness.state_mut().start_show(0, false);
+    harness.run_steps(2);
+    let doc = harness.state().session.active().unwrap().doc.clone();
+    let bar = slide_media_bars(slide.get(), &doc, 0)[0].3;
+    let track = pos2(bar.min.x + bar.width() * 0.8, bar.center().y);
+    (harness, id, track, on_bar)
+}
+
+/// Press and release the primary button at `p`.
+fn click_at(harness: &mut egui_kittest::Harness<'static, SlideApp>, p: Pos2) {
+    for pressed in [true, false] {
+        harness.event(egui::Event::PointerButton { pos: p, button: egui::PointerButton::Primary, pressed, modifiers: egui::Modifiers::NONE });
+        harness.step();
+    }
+}
+
+/// #967: hovering a clip shows its bar and a click on the bar seeks. After 3 s without moving
+/// the bar is gone, and a click where it was acts on the clip itself (play), not on the bar.
+#[test]
+fn media_controls_hide_when_pointer_is_idle() {
+    // Awake: the bar is there and a click on its timeline seeks, leaving the clip paused.
+    let (mut harness, id, track, on_bar) = show_with_clip();
+    harness.hover_at(track);
+    harness.run_steps(2);
+    assert!(harness.state().show.as_ref().unwrap().pointer_awake(harness.ctx.input(|i| i.time)));
+    assert!(on_bar.get(), "the bar is under a pointer that just moved");
+    click_at(&mut harness, track);
+    harness.run_steps(2);
+    let status = harness.state().media.status(id).expect("the click on the bar cued the clip");
+    assert!(!harness.state().media.is_playing(id), "a bar click seeks, it does not play");
+    assert!(status.position > 1.0, "seeked along the timeline, at {}", status.position);
+
+    // Idle: same spot, no movement for 3 s.
+    let (mut harness, id, track, on_bar) = show_with_clip();
+    harness.hover_at(track);
+    harness.run_steps(2);
+    assert!(on_bar.get());
+    harness.run_steps(12);
+    assert!(!harness.state().show.as_ref().unwrap().pointer_awake(harness.ctx.input(|i| i.time)));
+    assert!(!on_bar.get(), "the bar is hidden once the pointer is idle");
+    click_at(&mut harness, track);
+    harness.run_steps(2);
+    assert!(harness.state().media.is_playing(id), "the click reached the clip");
+    let at = harness.state().media.status(id).map_or(0.0, |s| s.position);
+    assert!(at < 5.0, "the click did not seek along the timeline, position {at}");
+}
+
+/// Two 1×1 frames (black, then white), 100 ms each.
+fn two_frame_gif() -> Vec<u8> {
+    let mut b = b"GIF89a\x01\x00\x01\x00\x80\x00\x00\x00\x00\x00\xff\xff\xff".to_vec();
+    for pixel in [b"\x44\x01", b"\x4c\x01"] {
+        b.extend_from_slice(b"\x21\xf9\x04\x00\x0a\x00\x00\x00");
+        b.extend_from_slice(b"\x2c\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x02");
+        b.extend_from_slice(pixel);
+        b.push(0);
+    }
+    b.push(0x3b);
+    b
+}
+
+/// A running show on the first of two slides; slide 1 holds a large animated GIF. Returns the
+/// harness, the GIF, and its play/pause button's centre.
+fn show_with_gif() -> (egui_kittest::Harness<'static, SlideApp>, ShapeId, Pos2) {
+    let mut session = deckcraft_engine::Session::with_new();
+    // The GIF is on slide 1, the slide the editor has selected, with a slide after it.
+    session.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    session.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    session.execute("slide.go", &json!({"index": 1})).unwrap();
+    let id = ShapeId(4100);
+    session
+        .edit(|doc, _| {
+            let media = doc.add_media("a.gif", "image/gif", two_frame_gif()).unwrap();
+            let (w, h) = (doc.slide_size.width, doc.slide_size.height);
+            let slide = std::sync::Arc::make_mut(&mut doc.slides[1]);
+            slide.shapes.push(deckcraft_model::Shape {
+                id,
+                xfrm: Some(deckcraft_geom::Xfrm::new(w * 0.2, h * 0.2, w * 0.6, h * 0.6)),
+                kind: deckcraft_model::ShapeKind::Picture { fill: deckcraft_model::style::PictureFill { media, ..Default::default() } },
+                ..Default::default()
+            });
+            Ok(())
+        })
+        .unwrap();
+    let slide = std::rc::Rc::new(std::cell::Cell::new(Rect::NOTHING));
+    let slide_seen = slide.clone();
+    let mut app = SlideApp::new(session, crate::Services::default());
+    app.ui.presenter_view = false;
+    let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).with_step_dt(0.25).build_ui_state(
+        move |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            if let (Some(show), Some(d)) = (app.show.as_ref(), app.session.active()) {
+                slide_seen.set(shown_slide_rect(ui, show, &d.doc));
+            }
+            app.ui(ui);
+        },
+        app,
+    );
+    harness.run_steps(3);
+    harness.state_mut().start_show(1, false);
+    harness.run_steps(2);
+    let doc = harness.state().session.active().unwrap().doc.clone();
+    let srect = slide.get();
+    let k = srect.width() / doc.slide_size.width.max(1.0) as f32;
+    let rect = doc.slides[1].shapes.last().unwrap().xfrm.unwrap();
+    let button = crate::media::gif_button_rect(on_screen(srect, k, &rect)).center();
+    (harness, id, button)
+}
+
+/// The GIF's play/pause button is drawn only while the pointer is awake, so a click on its
+/// spot after 2.5 s without movement advances the show instead of pausing the GIF.
+#[test]
+fn gif_button_click_needs_an_awake_pointer() {
+    let (mut harness, id, button) = show_with_gif();
+    harness.hover_at(button);
+    harness.run_steps(2);
+    click_at(&mut harness, button);
+    harness.run_steps(2);
+    assert!(harness.state().session.gif_paused.contains(&id), "an awake pointer's click pauses the GIF");
+    assert_eq!(harness.state().show.as_ref().unwrap().state.slide, 1);
+
+    let (mut harness, id, button) = show_with_gif();
+    harness.hover_at(button);
+    harness.run_steps(2);
+    harness.run_steps(12);
+    assert!(!harness.state().show.as_ref().unwrap().pointer_awake(harness.ctx.input(|i| i.time)));
+    click_at(&mut harness, button);
+    harness.run_steps(2);
+    assert!(!harness.state().session.gif_paused.contains(&id), "the hidden button is not clickable");
+    assert_eq!(harness.state().show.as_ref().unwrap().state.slide, 2, "the click advanced the show");
+}
+
+/// Send real egui key events to the presenter UI, without the audience window's handler.
+#[test]
+fn presenter_navigation_uses_its_own_keyboard_events() {
+    use egui_kittest::kittest::Queryable;
+
+    let mut session = deckcraft_engine::Session::with_new();
+    session.execute("slide.new", &json!({})).unwrap();
+    session.execute("slide.new", &json!({})).unwrap();
+    let doc = session.active().unwrap().doc.clone();
+    let show = Show::new(&doc, 0, false, true);
+    let mut harness = egui_kittest::Harness::builder().with_size(vec2(1100.0, 700.0)).build_ui_state(
+        |ui, (doc, show, keep): &mut (std::sync::Arc<Presentation>, Show, bool)| {
+            let now = ui.input(|i| i.time);
+            presenter_window(ui.ctx(), show, doc, now, keep);
+        },
+        (doc, show, true),
+    );
+    harness.run_steps(2);
+    for (key, slide) in [
+        (egui::Key::ArrowRight, 1),
+        (egui::Key::ArrowLeft, 0),
+        (egui::Key::Space, 1),
+        (egui::Key::PageDown, 2),
+        (egui::Key::PageUp, 1),
+        (egui::Key::Home, 0),
+        (egui::Key::End, 2),
+    ] {
+        harness.key_press(key);
+        harness.run_steps(2);
+        assert_eq!(harness.state().1.state.slide, slide, "presenter key {key:?}");
+    }
+    harness.key_press(egui::Key::ArrowRight);
+    harness.run_steps(2);
+    assert!(harness.state().1.ended);
+    harness.key_press(egui::Key::ArrowLeft);
+    harness.run_steps(2);
+    assert!(!harness.state().1.ended);
+    assert_eq!(harness.state().1.state.slide, 2, "back from the end screen restores the last slide");
+    harness.key_press(egui::Key::ArrowRight);
+    harness.run_steps(2);
+    assert!(harness.state().1.ended);
+    harness.get_by_label("◀ Previous").click();
+    harness.run_steps(2);
+    assert!(!harness.state().1.ended, "the presenter Previous button also leaves the end screen");
+    harness.key_press(egui::Key::Home);
+    harness.run_steps(2);
+    harness.get_by_label("Next ▶").click();
+    harness.run_steps(2);
+    assert_eq!(harness.state().1.state.slide, 1);
+    harness.key_press(egui::Key::Space);
+    harness.run_steps(2);
+    assert_eq!(harness.state().1.state.slide, 2);
+    assert!(!harness.state().1.ended, "Space must not also activate the focused Next button");
+    harness.key_press(egui::Key::Escape);
+    harness.run_steps(2);
+    assert!(!harness.state().2, "Escape from Presenter View ends the show");
+}
+
+#[test]
+fn slideshow_navigation_advances_once_with_presenter_view() {
+    use egui_kittest::kittest::Queryable;
+
+    let mut session = deckcraft_engine::Session::with_new();
+    session.execute("slide.new", &json!({})).unwrap();
+    session.execute("slide.new", &json!({})).unwrap();
+    let mut app = SlideApp::new(session, crate::Services::default());
+    app.ui.presenter_view = true;
+    let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).build_ui_state(
+        |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        app,
+    );
+    harness.run_steps(3);
+    harness.state_mut().start_show(0, false);
+    harness.run_steps(2);
+    harness.key_press(egui::Key::ArrowRight);
+    harness.run_steps(2);
+    assert_eq!(harness.state().show.as_ref().unwrap().state.slide, 1, "one key advances one slide");
+    harness.key_press(egui::Key::End);
+    harness.run_steps(2);
+    harness.key_press(egui::Key::ArrowRight);
+    harness.run_steps(2);
+    assert!(harness.state().show.as_ref().unwrap().ended);
+    assert!(harness.query_by_label("End Show").is_some(), "the presenter remains available at the end screen");
+    harness.key_press(egui::Key::Escape);
+    harness.run_steps(2);
+    assert!(harness.state().show.is_none());
+}
+
+#[test]
+fn the_prefetched_frame_is_the_frame_shown_on_entry() {
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({"title": "Second"})).unwrap();
+    let doc = s.active().unwrap().doc.clone();
+    let size = (96, 54);
+    let p = start_prefetch(&doc, 1, size).expect("prefetch starts");
+    assert_eq!(p.key, Key { slide: 1, step: 0, size, doc: std::sync::Arc::as_ptr(&doc) as usize, hidden: vec![], gif: 0, plays: vec![] });
+    let got = p.rx.recv().expect("the frame arrives");
+    let want = render_frame(&doc, 1, ShowState::timeline(&doc, 1), 0, 0.0, size, vec![], &[], 0, &[], &[], None);
+    assert_eq!(got.size, want.size);
+    assert_eq!(got.pixels, want.pixels);
+}
+
+/// A glowing full-slide picture in a layout made every animation frame re-render (and re-blur)
+/// the backdrop: 2–3 frames a second. Frames now draw the slide's shapes over the kept
+/// backdrop, and must look the same as a whole-slide render.
+#[test]
+fn an_animation_frame_over_the_kept_backdrop_matches_a_full_render() {
+    let mut s = deckcraft_engine::Session::with_new();
+    let r = s.execute("shape.insert", &json!({"preset": "star5", "rect": [100.0, 100.0, 300.0, 200.0]})).unwrap();
+    s.execute("animation.set", &json!({"effect": "fade", "ids": [r["id"]]})).unwrap();
+    let mut doc = (*s.active().unwrap().doc).clone();
+    // A glowing master graphic under the animated star.
+    let mut deco = doc.slides[0].shapes.last().unwrap().clone();
+    deco.id = ShapeId(9000);
+    deco.xfrm = deco.xfrm.map(|x| deckcraft_geom::Xfrm { x: x.x - 60.0, y: x.y + 40.0, ..x });
+    deco.effects = Some(deckcraft_model::Effects {
+        glow: Some(deckcraft_model::style::Glow {
+            color: deckcraft_model::style::ColorRef::rgb(deckcraft_color::Rgba::rgb(0, 120, 255)),
+            radius: 12.0,
+        }),
+        ..Default::default()
+    });
+    std::sync::Arc::make_mut(&mut doc.masters[0]).shapes.push(deco);
+    let doc = std::sync::Arc::new(doc);
+    let size = (480, 270);
+    let key = BackKey { slide: 0, size, doc: std::sync::Arc::as_ptr(&doc) as usize };
+    let mut show = Show::new(&doc, 0, false, false);
+    show.prefetch_backdrop(&doc, key);
+    let back = show.backdrop(&doc, key);
+    let tl = ShowState::timeline(&doc, 0);
+    assert!(!tl.is_empty());
+    // Half-way through the fade, the star half see-through over the glow.
+    let fast = render_frame(&doc, 0, tl.clone(), 0, 0.25, size, vec![], &[], 0, &[], &[], Some(&back));
+    let full = render_frame(&doc, 0, tl, 0, 0.25, size, vec![], &[], 0, &[], &[], None);
+    assert_eq!(fast.size, full.size);
+    let worst =
+        fast.pixels.iter().zip(&full.pixels).map(|(a, b)| a.to_array().iter().zip(b.to_array()).map(|(x, y)| x.abs_diff(y)).max().unwrap_or(0)).max();
+    assert!(worst.is_some_and(|d| d <= 2), "frames differ by up to {worst:?}");
+    // The backdrop is kept, not rendered again.
+    assert!(std::sync::Arc::ptr_eq(&back, &show.backdrop(&doc, key)));
+    // Another document under the same key (an edit whose copy reused the old address) gets
+    // its own backdrop.
+    let edited = std::sync::Arc::new((*doc).clone());
+    assert!(!std::sync::Arc::ptr_eq(&back, &show.backdrop(&edited, key)));
+}
+
+#[test]
+fn a_transition_keeps_the_old_slide_in_its_own_texture() {
+    // #33: the old slide's handle was cloned, so the new slide was rendered into the same
+    // texture and every transition blended the new slide with itself.
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({})).unwrap();
+    s.execute("transition.set", &json!({"kind": "fade", "index": 1})).unwrap();
+    let doc = s.active().unwrap().doc.clone();
+    let ctx = egui::Context::default();
+    let red = crate::textures::upload(&ctx, "show", egui::ColorImage::filled([1, 1], Color32::RED));
+    let mut show = Show::new(&doc, 0, false, false);
+    show.tex = Some((Key { slide: 0, step: 0, size: (1, 1), doc: 0, hidden: vec![], gif: 0, plays: vec![] }, red.clone()));
+    assert!(show.apply(ShowAction::Slide(1), &doc, 0.0));
+    let tr = show.trans.as_ref().expect("the fade plays");
+    assert_eq!(tr.old.as_ref().map(TextureHandle::id), Some(red.id()));
+    assert_eq!(tr.from, Some(0));
+    assert!(show.tex.is_none(), "the new slide gets a texture of its own instead of overwriting the old one");
+}
+
+#[test]
+fn media_in_the_click_sequence_plays_with_its_step() {
+    // #116: media set to play in the click sequence never started; only a click on it did.
+    let s = deckcraft_engine::Session::with_new();
+    let mut doc = s.active().unwrap().doc.clone();
+    let id = doc.slides[0].shapes[0].id;
+    let play = |delay_ms| deckcraft_model::Animation {
+        shape: id,
+        class: deckcraft_model::AnimClass::Media,
+        effect: "play".into(),
+        duration_ms: 5000,
+        delay_ms,
+        ..Default::default()
+    };
+    std::sync::Arc::make_mut(&mut std::sync::Arc::make_mut(&mut doc).slides[0]).animations = vec![play(0), play(2000)];
+    let mut show = Show::new(&doc, 0, false, false);
+    assert!(show.apply(ShowAction::Slide(0), &doc, 0.0));
+    // Next: the first step plays and sets off its Play once.
+    let a = show.state.next(&doc);
+    assert_eq!(a, ShowAction::PlayStep(0));
+    assert!(show.apply(a, &doc, 1.0));
+    show.cue_media(&doc, 0, 0.0);
+    show.cue_media(&doc, 0, 0.5);
+    assert_eq!(std::mem::take(&mut show.media_cues), [(id, "play".to_string())]);
+    // The step doesn't wait for the video: the step clock ends it at once.
+    assert_eq!(show.timeline(&doc).step_duration(0), 0.0);
+    let a = show.state.step_done(&doc);
+    assert!(show.apply(a, &doc, 1.0));
+    assert!(show.media_cues.is_empty(), "set off once");
+    // Next again, before the second Play's delay: cutting the step short still sets it off.
+    let a = show.state.next(&doc);
+    assert_eq!(a, ShowAction::PlayStep(1));
+    assert!(show.apply(a, &doc, 2.0));
+    show.cue_media(&doc, 1, 0.5);
+    assert!(show.media_cues.is_empty());
+    let a = show.state.step_done(&doc);
+    assert!(show.apply(a, &doc, 2.6));
+    assert_eq!(std::mem::take(&mut show.media_cues), [(id, "play".to_string())]);
+    // Going back doesn't set anything off.
+    let a = show.state.prev(&doc);
+    assert!(show.apply(a, &doc, 3.0));
+    show.cue_media(&doc, 1, 9.0);
+    assert!(show.media_cues.is_empty());
+}
+
+#[test]
+fn the_laser_and_the_pen_are_not_on_together() {
+    let doc = deckcraft_model::Presentation::default();
+    let mut show = Show::new(&doc, 0, false, false);
+    show.set_laser(true);
+    assert!(show.laser && !show.pen);
+    show.set_pen(true);
+    assert!(show.pen && !show.laser);
+    show.set_laser(true);
+    show.arrow();
+    assert!(!show.laser && !show.pen);
+    show.set_laser(false);
+    assert!(!show.laser);
+}
+
+fn deck_with_first_animation(start: deckcraft_model::anim::AnimStart) -> Presentation {
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({})).unwrap();
+    let mut doc = Presentation::clone(&s.active().unwrap().doc);
+    let slide = std::sync::Arc::make_mut(&mut doc.slides[1]);
+    let shape = slide.shapes[0].id;
+    slide.animations = vec![deckcraft_model::anim::Animation { shape, start, duration_ms: 3000, ..Default::default() }];
+    doc
+}
+
+#[test]
+fn a_first_animation_after_or_with_previous_plays_when_the_slide_appears() {
+    // #631: it was started twice and the second start finished it, so the slide appeared
+    // fully built.
+    use deckcraft_model::anim::AnimStart;
+    for start in [AnimStart::AfterPrevious, AnimStart::WithPrevious] {
+        let doc = deck_with_first_animation(start);
+        // Starting the show on the slide.
+        let mut show = Show::new(&doc, 1, false, false);
+        show.after_enter(&doc, 5.0);
+        assert_eq!((show.state.step, show.state.playing), (0, true), "{start:?} from the start");
+        assert_eq!(show.step_start, 5.0);
+        // Arriving from the slide before.
+        let mut show = Show::new(&doc, 0, false, false);
+        let a = show.state.next(&doc);
+        assert!(matches!(a, ShowAction::Slide(1)));
+        assert!(show.apply(a, &doc, 7.0));
+        assert_eq!((show.state.step, show.state.playing), (0, true), "{start:?} on arrival");
+    }
+    // On Click still waits for the click.
+    let doc = deck_with_first_animation(AnimStart::OnClick);
+    let mut show = Show::new(&doc, 1, false, false);
+    show.after_enter(&doc, 5.0);
+    assert_eq!((show.state.step, show.state.playing), (0, false));
+    assert!(matches!(show.state.next(&doc), ShowAction::PlayStep(0)));
+}
+
+#[test]
+fn zoom_stays_on_the_slide_and_the_grid_hits_a_thumbnail() {
+    let uv = zoom_uv(0.5, 0.5, 2.0);
+    assert!((uv.min.x - 0.25).abs() < 1e-4 && (uv.min.y - 0.25).abs() < 1e-4);
+    assert!((uv.width() - 0.5).abs() < 1e-4);
+    let corner = zoom_uv(0.0, 0.0, 2.0);
+    assert_eq!(corner.min, pos2(0.0, 0.0));
+    assert!(corner.max.x <= 1.0 && corner.max.y <= 1.0);
+    let full = Rect::from_min_size(Pos2::ZERO, vec2(1728.0, 1084.0));
+    let cells = see_all_cells(full, 7, 16.0 / 9.0);
+    assert_eq!(cells.len(), 7);
+    for (i, a) in cells.iter().enumerate() {
+        assert!(full.contains_rect(*a), "cell {i} leaves the window");
+        for b in cells.iter().skip(i + 1) {
+            let overlap = a.intersect(*b);
+            assert!(overlap.width() < 1.0 || overlap.height() < 1.0, "thumbnails overlap {a:?} {b:?}");
+        }
+    }
+    let hit = see_all_hit(full, 7, 16.0 / 9.0, cells[3].center());
+    assert_eq!(hit, Some(3));
+    assert_eq!(see_all_hit(full, 7, 16.0 / 9.0, pos2(2.0, 2.0)), None);
+    let srect = Rect::from_min_size(pos2(10.0, 20.0), vec2(200.0, 100.0));
+    assert_eq!(norm_on_slide(srect, unit_uv(), pos2(110.0, 70.0)), Some((0.5, 0.5)));
+    let zoomed = zoom_uv(0.5, 0.5, 2.0);
+    let back = norm_on_slide(srect, zoomed, pos2(110.0, 70.0)).expect("on the slide");
+    assert!((back.0 - 0.5).abs() < 1e-3 && (back.1 - 0.5).abs() < 1e-3);
+}
+
+fn near(a: f32, b: f32) -> bool {
+    (a - b).abs() < 1e-3
+}
+
+/// #1286: Ctrl+wheel zooms around the pointer, four notches per doubling, up to 4× (the most
+/// PowerPoint's magnifier goes); zooming back to the whole slide leaves the zoom.
+#[test]
+fn wheel_zoom_keeps_the_point_under_the_pointer_and_stops_at_4x() {
+    let doc = deckcraft_model::Presentation::default();
+    let mut show = Show::new(&doc, 0, false, false);
+    // A 16:9 slide, not at the origin, and a pointer off its centre.
+    let srect = Rect::from_min_size(pos2(40.0, 30.0), vec2(320.0, 180.0));
+    let p = pos2(40.0 + 320.0 * 0.2, 30.0 + 180.0 * 0.3);
+    show.wheel_zoom(srect, p, 4.0);
+    let (_, _, scale) = show.zoom_view().expect("zoomed in");
+    assert!(near(scale, 2.0), "four notches double, got {scale}");
+    // The window keeps the slide's shape: half the width and half the height of the slide.
+    let uv = show.zoom_uv();
+    assert!(near(uv.width(), 0.5) && near(uv.height(), 0.5), "{uv:?}");
+    assert!(near(uv.min.x, 0.2 - 0.5 * 0.2) && near(uv.min.y, 0.3 - 0.5 * 0.3), "{uv:?}");
+    let under = norm_on_slide(srect, uv, p).expect("on the slide");
+    assert!(near(under.0, 0.2) && near(under.1, 0.3), "the point under the pointer moved to {under:?}");
+
+    // Again from the zoomed view: the same slide point stays under the pointer.
+    show.wheel_zoom(srect, p, 2.0);
+    let (_, _, scale) = show.zoom_view().expect("zoomed in");
+    assert!(near(scale, 2f32.powf(1.5)), "{scale}");
+    let under = norm_on_slide(srect, show.zoom_uv(), p).expect("on the slide");
+    assert!(near(under.0, 0.2) && near(under.1, 0.3), "{under:?}");
+
+    show.wheel_zoom(srect, p, 40.0);
+    let (_, _, scale) = show.zoom_view().expect("zoomed in");
+    assert!(near(scale, 4.0), "capped at 4×, got {scale}");
+    assert!(near(show.zoom_uv().width(), 0.25));
+
+    show.wheel_zoom(srect, p, -7.0);
+    assert!(show.zoom_view().is_some(), "one notch short of the whole slide is still zoomed");
+    show.wheel_zoom(srect, p, -1.0);
+    assert!(show.zoom_view().is_none(), "back to the whole slide leaves the zoom");
+    assert_eq!(show.zoom_uv(), unit_uv());
+    show.wheel_zoom(srect, p, -3.0);
+    assert!(show.zoom_view().is_none(), "zooming out of the whole slide does nothing");
+
+    // Off the slide (the letterbox) the wheel does not zoom.
+    show.wheel_zoom(srect, pos2(10.0, 10.0), 4.0);
+    assert!(show.zoom_view().is_none());
+    // An armed click-zoom gives way to the wheel.
+    show.zoom_arm = true;
+    show.wheel_zoom(srect, p, 4.0);
+    assert!(!show.zoom_arm && show.zoom_view().is_some());
+}
+
+#[test]
+fn wheel_zoom_reads_only_the_wheel_with_ctrl_or_cmd() {
+    let wheel = |unit, y: f32, modifiers| egui::Event::MouseWheel {
+        unit,
+        delta: vec2(0.0, y),
+        phase: egui::TouchPhase::Move,
+        source: egui::MouseWheelSource::Wheel,
+        modifiers,
+    };
+    use egui::MouseWheelUnit::{Line, Point};
+    assert_eq!(wheel_zoom_lines(&[wheel(Line, 1.0, egui::Modifiers::CTRL)], 40.0), Some(1.0));
+    assert_eq!(wheel_zoom_lines(&[wheel(Line, -2.0, egui::Modifiers::COMMAND)], 40.0), Some(-2.0));
+    assert_eq!(wheel_zoom_lines(&[wheel(Point, 20.0, egui::Modifiers::CTRL), wheel(Point, 20.0, egui::Modifiers::CTRL)], 40.0), Some(1.0));
+    assert_eq!(wheel_zoom_lines(&[wheel(Line, 1.0, egui::Modifiers::NONE)], 40.0), None, "a plain wheel turns the page");
+    assert_eq!(wheel_zoom_lines(&[wheel(Line, 1.0, egui::Modifiers::SHIFT)], 40.0), None);
+    assert_eq!(wheel_zoom_lines(&[egui::Event::Zoom(2.0)], 40.0), None, "a pinch is not a show gesture");
+    assert_eq!(wheel_zoom_lines(&[wheel(Line, f32::NAN, egui::Modifiers::CTRL)], 40.0), Some(0.0));
+}
+
+/// A running show on the first of three slides, with presenter view off.
+fn show_of_three() -> egui_kittest::Harness<'static, SlideApp> {
+    let mut session = deckcraft_engine::Session::with_new();
+    session.execute("slide.new", &json!({})).unwrap();
+    session.execute("slide.new", &json!({})).unwrap();
+    let mut app = SlideApp::new(session, crate::Services::default());
+    app.ui.presenter_view = false;
+    let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).with_step_dt(1.0 / 60.0).build_ui_state(
+        |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        app,
+    );
+    harness.run_steps(3);
+    harness.state_mut().start_show(0, false);
+    harness.run_steps(2);
+    harness
+}
+
+fn show_wheel(harness: &mut egui_kittest::Harness<'static, SlideApp>, at: Pos2, y: f32, modifiers: egui::Modifiers) {
+    harness.input_mut().events.push(egui::Event::PointerMoved(at));
+    harness.input_mut().events.push(egui::Event::MouseWheel {
+        unit: egui::MouseWheelUnit::Line,
+        delta: vec2(0.0, y),
+        phase: egui::TouchPhase::Move,
+        source: egui::MouseWheelSource::Wheel,
+        modifiers,
+    });
+    harness.run_steps(40);
+}
+
+/// #1286: in the show, Ctrl+wheel (Cmd+wheel on a Mac) zooms the slide and does not turn the
+/// page; the plain wheel still turns it.
+#[test]
+fn ctrl_wheel_zooms_the_show_and_the_plain_wheel_turns_the_page() {
+    for held in [egui::Modifiers::CTRL, egui::Modifiers::COMMAND] {
+        let mut h = show_of_three();
+        let centre = pos2(500.0, 350.0);
+        show_wheel(&mut h, centre, 4.0, held);
+        let show = h.state().show.as_ref().expect("still showing");
+        assert_eq!(show.state.slide, 0, "{held:?}: the zoom wheel does not turn the page");
+        let (_, _, scale) = show.zoom_view().expect("zoomed in");
+        assert!(near(scale, 2.0), "{held:?}: {scale}");
+
+        show_wheel(&mut h, centre, -4.0, held);
+        let show = h.state().show.as_ref().expect("still showing");
+        assert_eq!(show.state.slide, 0, "{held:?}: zooming out does not go back a page either");
+        assert!(show.zoom_view().is_none(), "{held:?}: back to the whole slide");
+
+        show_wheel(&mut h, centre, -3.0, egui::Modifiers::NONE);
+        assert_eq!(h.state().show.as_ref().expect("still showing").state.slide, 1, "the plain wheel turns the page");
+    }
+}
+
+#[test]
+fn escape_only_closes_the_grid_of_its_own_window() {
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({})).unwrap();
+    let doc = s.active().unwrap().doc.clone();
+    let mut show = Show::new(&doc, 0, false, true);
+    show.presenter_grid = true;
+    assert!(!show.back_out(false), "audience Esc leaves the show, the Presenter View grid stays");
+    assert!(show.presenter_grid);
+    assert!(show.back_out(true));
+    assert!(!show.presenter_grid);
+    show.grid = true;
+    assert!(!show.back_out(true), "Presenter View Esc does not close the audience grid");
+    assert!(show.grid);
+    assert!(show.back_out(false));
+    assert!(!show.grid);
+}
+
+#[test]
+fn escape_leaves_the_grid_then_the_zoom_and_blank_toggles() {
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({})).unwrap();
+    let doc = s.active().unwrap().doc.clone();
+    let mut show = Show::new(&doc, 0, false, true);
+    show.grid = true;
+    show.zoom = Some(Zoom::at(0.2, 0.3));
+    assert!(show.back_out(false));
+    assert!(!show.grid);
+    assert!(show.zoom.is_some(), "closing the grid leaves the zoom");
+    assert!(show.back_out(false));
+    assert!(show.zoom.is_none());
+    assert!(!show.back_out(false));
+    show.zoom_key();
+    assert!(show.zoom_arm);
+    show.zoom_key();
+    assert!(!show.zoom_arm);
+    toggle_blank(&mut show, Color32::BLACK);
+    assert_eq!(show.blank_name(), Some("black"));
+    toggle_blank(&mut show, Color32::WHITE);
+    assert_eq!(show.blank_name(), Some("white"));
+    toggle_blank(&mut show, Color32::WHITE);
+    assert_eq!(show.blank_name(), None);
+    show.zoom = Some(Zoom::at(0.4, 0.6));
+    assert!(show.apply(ShowAction::Slide(1), &doc, 1.0));
+    assert!(show.zoom.is_none(), "a new slide is shown whole");
+}
+
+/// #1128: the presenter drew the notes as plain text, so bullets, numbers and bold were lost
+/// although the notes pane shows them; the notes stay selectable.
+#[test]
+fn presenter_notes_keep_bullets_numbers_and_bold() {
+    use deckcraft_model::text::{Bullet, ParaProps, Paragraph, Run, RunProps, TextBody};
+    let point = |text: &str, bullet: Bullet| Paragraph {
+        level: 1,
+        props: ParaProps { bullet: Some(bullet), ..Default::default() },
+        runs: vec![Run::new(text)],
+        ..Default::default()
+    };
+    let num = || Bullet::AutoNum { scheme: "arabicPeriod".into(), start_at: 1 };
+    let notes = TextBody {
+        paragraphs: vec![
+            Paragraph { runs: vec![Run::with("Opening", RunProps { bold: Some(true), ..Default::default() })], ..Default::default() },
+            point("Welcome", Bullet::Char { char: "•".into() }),
+            point("Agenda", num()),
+            point("Demo", num()),
+        ],
+        ..Default::default()
+    };
+    let ctx = egui::Context::default();
+    theme::install_fonts(&ctx);
+    let mut sense = None;
+    let mut out = ctx.run_ui(Default::default(), |ui| sense = Some(presenter_notes(ui, &notes, 24.0).sense));
+    out.textures_delta.clear();
+    assert!(sense.unwrap().senses_drag(), "the notes can be selected, as the plain label could");
+    let mut texts = vec![];
+    let mut stack: Vec<egui::Shape> = out.shapes.into_iter().map(|c| c.shape).collect();
+    while let Some(shape) = stack.pop() {
+        match shape {
+            egui::Shape::Vec(v) => stack.extend(v),
+            egui::Shape::Text(t) => texts.push(t.galley),
+            _ => {}
+        }
+    }
+    let painted: Vec<&str> = texts.iter().map(|g| g.job.text.as_str()).collect();
+    for marker in ["•", "1.", "2."] {
+        assert!(painted.contains(&marker), "{marker} is drawn: {painted:?}");
+    }
+    let notes_galley = texts.iter().find(|g| g.job.text.contains("Agenda")).expect("the notes are drawn");
+    let font_of = |s: &str| {
+        let b = notes_galley.job.text.find(s).unwrap();
+        notes_galley.job.sections.iter().find(|x| (x.byte_range.start.0..x.byte_range.end.0).contains(&b)).unwrap().format.font_id.clone()
+    };
+    assert_eq!(font_of("Opening"), theme::bold(24.0), "bold runs stay bold at the pane's size");
+    assert_eq!(font_of("Agenda"), theme::font(24.0));
+}
+
+/// Hidden logic keeps playing from wall time even though `run_logic` leaves egui's input
+/// time at the last visible frame. A visible pass re-anchors instead of shifting a pause.
+#[test]
+fn hidden_logic_advances_the_show_and_visible_frames_reanchor() {
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({})).unwrap();
+    let doc = s.active().unwrap().doc.clone();
+    let mut show = Show::new(&doc, 0, false, true);
+    show.started = true;
+    show.step_start = 10.0;
+    show.slide_start = 10.0;
+    show.step_end = 10.0;
+    show.show_start = 10.0;
+    show.last_move = 10.0;
+    show.timer = PresenterTimer::start(10.0);
+    let t0 = web_time::Instant::now();
+    show.observe_visible_frame(10.0, t0);
+    assert_eq!(show.hidden_logic_time(10.0, t0), 10.0, "the first hidden tick starts at the last visible time");
+    let hidden = show.hidden_logic_time(10.0, t0 + std::time::Duration::from_secs(2));
+    assert!((hidden - 12.0).abs() < 1e-9, "hidden logic advances the show time: {hidden}");
+    assert!((show.presenter_elapsed(hidden) - 2.0).abs() < 1e-9, "presenter time keeps running");
+    assert!((show.clock_snapshot().step_start - 10.0).abs() < 1e-9, "the clock origin is not shifted");
+    let later = show.hidden_logic_time(10.0, t0 + std::time::Duration::from_secs(5));
+    assert!((later - 15.0).abs() < 1e-9, "repeated hidden ticks do not stack a pause: {later}");
+    show.observe_visible_frame(20.0, t0 + std::time::Duration::from_secs(10));
+    assert_eq!(show.hidden_logic_time(20.0, t0 + std::time::Duration::from_secs(10)), 20.0, "a visible frame re-anchors");
+}
+
+#[test]
+fn presenter_timer_pauses_resets_and_notes_size_clamps() {
+    let mut t = PresenterTimer::start(10.0);
+    assert!((t.elapsed(12.5) - 2.5).abs() < 1e-9);
+    t.toggle(15.0);
+    assert!(t.paused());
+    assert!((t.elapsed(100.0) - 5.0).abs() < 1e-9);
+    t.reset(100.0);
+    assert!(t.paused());
+    assert_eq!(t.elapsed(200.0), 0.0);
+    t.toggle(200.0);
+    assert!(!t.paused());
+    assert!((t.elapsed(203.0) - 3.0).abs() < 1e-9);
+    t.reset(203.0);
+    assert!(!t.paused());
+    assert!((t.elapsed(204.0) - 1.0).abs() < 1e-9);
+    let bad = PresenterTimer::start(f64::NAN);
+    assert_eq!(bad.elapsed(f64::INFINITY), 0.0);
+    assert_eq!(format_elapsed(3661.4), "01:01:01");
+    assert_eq!(format_elapsed(-1.0), "00:00:00");
+    assert_eq!(format_elapsed(f64::NAN), "00:00:00");
+    let clock = wall_clock();
+    assert!(clock == "--:--" || (clock.len() == 5 && clock.as_bytes().get(2) == Some(&b':')));
+
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({})).unwrap();
+    let doc = s.active().unwrap().doc.clone();
+    let mut show = Show::new(&doc, 0, false, true);
+    assert_eq!(show.notes_px, NOTES_DEFAULT);
+    show.nudge_notes(NOTES_STEP);
+    assert_eq!(show.notes_px, 22.0);
+    show.nudge_notes(1000.0);
+    assert_eq!(show.notes_px, NOTES_MAX);
+    show.nudge_notes(-1000.0);
+    assert_eq!(show.notes_px, NOTES_MIN);
+    show.nudge_notes(f32::NAN);
+    assert_eq!(show.notes_px, NOTES_MIN);
+    let v = show.showing_value(1, 16.0 / 9.0, Rect::from_min_size(Pos2::ZERO, vec2(100.0, 100.0)), 0.0);
+    assert_eq!(v["presenterPaused"], json!(false));
+    assert_eq!(v["notesPx"], json!(NOTES_MIN));
+}
+
+#[test]
+fn a_typed_slide_number_jumps_and_then_expires() {
+    let mut s = deckcraft_engine::Session::with_new();
+    s.execute("slide.new", &json!({})).unwrap();
+    let doc = s.active().unwrap().doc.clone();
+    let mut show = Show::new(&doc, 0, false, false);
+    show.push_slide_number('1', 10.0);
+    show.push_slide_number('2', 10.2);
+    assert_eq!(show.goto, "12");
+    assert_eq!(show.take_goto(), Some(11));
+    assert!(show.goto.is_empty());
+    show.push_slide_number('0', 1.0);
+    assert_eq!(show.take_goto(), None, "slide 0 is not a slide");
+    show.push_slide_number('4', 5.0);
+    show.expire_goto(7.0);
+    assert_eq!(show.goto, "4");
+    show.expire_goto(8.1);
+    assert!(show.goto.is_empty());
+    show.push_slide_number('9', 0.0);
+    assert!(show.clear_goto());
+    assert!(!show.clear_goto());
+    for _ in 0..6 {
+        show.push_slide_number('9', 1.0);
+    }
+    assert_eq!(show.goto.len(), GOTO_DIGITS);
+    show.push_slide_number('a', 1.0);
+    assert!(show.goto.chars().all(|c| c.is_ascii_digit()));
+}
+
+#[test]
+fn browsed_by_an_individual_stays_in_a_window() {
+    assert!(!show_fills_screen(false, "browsed"));
+    assert!(!show_fills_screen(true, "speaker"));
+    assert!(show_fills_screen(false, "speaker"));
+    assert!(show_fills_screen(false, "kiosk"));
+}
+
+#[test]
+fn the_next_preview_fits_its_column_whatever_the_slide_shape() {
+    let right = Rect::from_min_size(pos2(700.0, 100.0), vec2(400.0, 600.0));
+    let mut s = deckcraft_engine::Session::with_new();
+    for (w, h) in [(72, 4032), (4032, 72), (960, 540)] {
+        s.execute("design.slideSize", &json!({"w": w, "h": h})).unwrap();
+        let doc = s.active().unwrap().doc.clone();
+        let r = next_rect(right, &doc);
+        assert!(right.contains_rect(r), "{w}x{h}: {r:?}");
+        let aspect = r.height() / r.width();
+        assert!((aspect - h as f32 / w as f32).abs() / (h as f32 / w as f32) < 0.01, "{w}x{h}: {r:?}");
+    }
+    // 16:9 still takes the column's full width.
+    let doc = s.active().unwrap().doc.clone();
+    assert_eq!(next_rect(right, &doc).width(), 400.0);
+}
+
+#[test]
+fn back_leaves_a_slide_whose_first_animation_is_with_previous() {
+    // #844: Back on such a slide undid its first step, and the next frame played that step
+    // again by itself, so Back never reached the slide before.
+    let mut session = deckcraft_engine::Session::with_new();
+    session.execute("slide.new", &json!({})).unwrap();
+    let id = session.active().unwrap().doc.slides[1].shapes[0].id;
+    session
+        .execute("animation.add", &json!({"effect": "fade", "class": "entrance", "ids": [id.0], "start": "withPrevious", "duration": 500}))
+        .unwrap();
+    let app = SlideApp::new(session, crate::Services::default());
+    let mut harness = egui_kittest::Harness::builder().with_size(vec2(1000.0, 700.0)).build_ui_state(
+        |ui, app: &mut SlideApp| {
+            app.logic(ui.ctx());
+            app.ui(ui);
+        },
+        app,
+    );
+    harness.run_steps(3);
+    harness.state_mut().start_show(0, false);
+    harness.run_steps(2);
+    harness.key_press(egui::Key::ArrowRight);
+    // The first step plays by itself and ends (0.5 s; a frame is 0.25 s).
+    harness.run_steps(8);
+    let st = &harness.state().show.as_ref().unwrap().state;
+    assert_eq!((st.slide, st.step, st.playing), (1, 1, false), "on slide 2, fully built");
+    for _ in 0..5 {
+        harness.key_press(egui::Key::ArrowLeft);
+        harness.run_steps(2);
+    }
+    let st = &harness.state().show.as_ref().unwrap().state;
+    assert_eq!(st.slide, 0, "five Backs leave slide 2 (step {}, playing {})", st.step, st.playing);
+}
+
+/// Click-target state follows show instance, reading/presenter modes, grid, and other layout
+/// changes instead of retaining a stale target.
+#[test]
+fn input_state_tracks_the_modes_that_move_show_click_targets() {
+    let session = deckcraft_engine::Session::with_new();
+    let doc = &session.active().unwrap().doc;
+    let mut show = Show::new(doc, 0, false, false);
+    let base = show.input_state();
+    assert_eq!(show.input_state(), base);
+
+    show.instance += 1;
+    assert_ne!(show.input_state(), base, "a new show instance is a new input target");
+    show.instance = base.instance;
+
+    show.reading = true;
+    assert_ne!(show.input_state(), base, "the reading layout moves the slide");
+    show.reading = false;
+
+    show.presenter = true;
+    assert_ne!(show.input_state(), base, "presenter view changes the available area");
+    show.presenter = false;
+
+    show.grid = true;
+    assert_ne!(show.input_state(), base, "See All Slides replaces the slide with thumbnails");
+    show.grid = false;
+
+    show.pen = true;
+    assert_ne!(show.input_state(), base, "the pen changes what a drag means");
+    show.pen = false;
+
+    show.laser = true;
+    assert_ne!(show.input_state(), base, "the laser changes what a drag means");
+    show.laser = false;
+
+    show.zoom_arm = true;
+    assert_ne!(show.input_state(), base, "armed zoom changes what a click means");
+    show.zoom_arm = false;
+
+    show.zoom = Some(Zoom::at(0.25, 0.75));
+    assert_ne!(show.input_state(), base, "a zoomed slide has a different click mapping");
+    show.zoom = None;
+
+    show.blank = Some(Color32::BLACK);
+    assert_ne!(show.input_state(), base, "a blank screen has no slide click targets");
+}