diff --git a/crates/ui-egui/src/tools/crop_mode.rs b/crates/ui-egui/src/tools/crop_mode.rs
index cc946b30b9..14eb64c8d3 100644
--- a/crates/ui-egui/src/tools/crop_mode.rs
+++ b/crates/ui-egui/src/tools/crop_mode.rs
@@ -3,7 +3,8 @@
 //! - **Default mode** (Photoshop's default, Use Classic Mode off): the crop box stays upright on
 //!   screen and the image turns behind it. A drag outside the box turns the image about the box's
 //!   centre (⇧ in 15° steps; the readout beside the pointer is the image's turn, clockwise
-//!   positive), a drag inside moves the image under the box (the box stays put; with View › Snap
+//!   positive) and keeps the frame inside the turned image ([`keep_inside`]; not with ⌘ held), a
+//!   drag inside moves the image under the box (the box stays put; with View › Snap
 //!   on, the upright frame's edges and centre snap as a Classic Mode frame's do, #8580), the arrow
 //!   keys nudge the image, and the handles resize the box on screen as usual. With **Auto Center
 //!   Preview** on (the default), a box being resized keeps its centre where it is on screen (also
@@ -114,6 +115,74 @@ pub fn image_turn(frame_angle: f64) -> f64 {
     if a == 0.0 { 0.0 } else { a }
 }
 
+/// How far (document px) a turned frame's corner may lie past the canvas and still count as on
+/// it: rounding, not a visible gap.
+const FIT_TOLERANCE: f64 = 1e-6;
+
+/// Frame `rect` turned `deg` degrees about its centre, kept inside a `cw`×`ch` canvas (#10869):
+/// `rect` itself when it fits; else moved the shortest way in; else shrunk about its centre,
+/// keeping its proportions, to the largest size that fits anywhere, then moved in. `None` when a
+/// size or the angle isn't finite, or a size isn't positive.
+pub fn kept_inside(rect: [f64; 4], deg: f64, cw: f64, ch: f64) -> Option<[f64; 4]> {
+    let (w, h) = (rect[2] - rect[0], rect[3] - rect[1]);
+    if ![w, h, cw, ch, deg].iter().all(|v| v.is_finite()) || w <= 0.0 || h <= 0.0 || cw <= 0.0 || ch <= 0.0 {
+        return None;
+    }
+    let (s, c) = deg.to_radians().sin_cos();
+    let (s, c) = (s.abs(), c.abs());
+    // Half the turned frame's bounds: its corners are on the canvas when these are.
+    let (ex, ey) = ((w * c + h * s) / 2.0, (w * s + h * c) / 2.0);
+    let m = crate::crop_ui::center(rect);
+    // A frame that fits stays bit for bit, also one whose corners a rounding error puts a hair
+    // past the edges (a frame fitted by an earlier turn touches them).
+    let fits = |v: f64, e: f64, len: f64| v - e >= -FIT_TOLERANCE && v + e <= len + FIT_TOLERANCE;
+    if fits(m[0], ex, cw) && fits(m[1], ey, ch) {
+        return Some(rect);
+    }
+    // The scale that makes the bounds fit the canvas; a rounding error short of 1 (180°) fits.
+    let k = (cw / (2.0 * ex)).min(ch / (2.0 * ey));
+    let k = if k >= 1.0 - 1e-9 { 1.0 } else { k };
+    // Each axis on its own: the nearest centre that keeps the bounds on the canvas.
+    let along = |v: f64, e: f64, len: f64| if 2.0 * e >= len { len / 2.0 } else { v.clamp(e, len - e) };
+    let n = [along(m[0], ex * k, cw), along(m[1], ey * k, ch)];
+    let r = if k == 1.0 {
+        // Kept size: moved by exactly the offset.
+        let d = [n[0] - m[0], n[1] - m[1]];
+        [rect[0] + d[0], rect[1] + d[1], rect[2] + d[0], rect[3] + d[1]]
+    } else {
+        let (hw, hh) = (w * k / 2.0, h * k / 2.0);
+        [n[0] - hw, n[1] - hh, n[0] + hw, n[1] + hh]
+    };
+    r.iter().all(|v| v.is_finite()).then_some(r)
+}
+
+/// A default-mode turn keeps the frame inside the turned image, as in Photoshop (#10869): the
+/// frame the drag started from, `rect` (turned `from` degrees then), keeps its size and place
+/// when it fits the image at the frame's angle now, else [`kept_inside`] moves it in or shrinks
+/// it. Each step starts from the press frame, so turning back gives the frame back. The view
+/// moves with the frame's centre, so the box stays put on screen. With ⌘ (Ctrl) `held` the frame
+/// stays as it was at the press and ↵ fills the uncovered corners.
+///
+/// Not measured in Photoshop, so they keep the frame as before: Fill set to Content-Aware Fill,
+/// and a frame that already reached past the canvas at the press.
+pub fn keep_inside(app: &mut PhotocraftApp, rect: [f64; 4], from: f64, held: bool) {
+    let Some(now) = finite_frame(app) else { return };
+    let Some((cw, ch)) = app.session.active().map(|st| (f64::from(st.doc.size.width), f64::from(st.doc.size.height))) else { return };
+    let inside_at_press = kept_inside(rect, from, cw, ch) == Some(rect);
+    let want = if held || app.ui.tool_options.crop_content_aware || !inside_at_press {
+        rect
+    } else {
+        kept_inside(rect, crate::crop_ui::angle(app), cw, ch).unwrap_or(rect)
+    };
+    if want == now {
+        return;
+    }
+    // Moves the frame's centre and the view together (the box stays put), then sets the size.
+    let (a, b) = (crate::crop_ui::center(now), crate::crop_ui::center(want));
+    shift_image(app, [a[0] - b[0], a[1] - b[1]]);
+    app.ui.crop_rect = Some(want);
+}
+
 /// A live-centred resize ([`live_resize`]): the frame `rect` and handle (`hx`, `hy`) at the press,
 /// grabbed at document point `start`; the pointer now at `q` (in the press view); the frame's turn
 /// `deg`, the aspect `ratio` to hold and ⌥ (resize about the centre).
diff --git a/crates/ui-egui/src/tools/crop_ui.rs b/crates/ui-egui/src/tools/crop_ui.rs
index c276762bc5..4bd756dcd8 100644
--- a/crates/ui-egui/src/tools/crop_ui.rs
+++ b/crates/ui-egui/src/tools/crop_ui.rs
@@ -98,8 +98,9 @@ pub enum CropDrag {
     MoveImage { start: [f64; 2], rect: [f64; 4], view: Option<crate::crop_mode::PressView> },
     /// Default mode, outside the box: the image turns about the frame's `center` (which stays put
     /// on screen). `grab` is the pointer's direction from it at the press (radians, in the press
-    /// `view`), `from` the frame's angle then (degrees).
-    TurnImage { center: [f64; 2], grab: f64, from: f64, view: Option<crate::crop_mode::PressView> },
+    /// `view`), `from` the frame's angle then (degrees) and `rect` the frame then, which the turn
+    /// keeps inside the turned image (`crop_mode::keep_inside`).
+    TurnImage { center: [f64; 2], grab: f64, from: f64, rect: [f64; 4], view: Option<crate::crop_mode::PressView> },
 }
 
 /// What the pointer is over, relative to a crop frame.
@@ -950,7 +951,7 @@ fn outside_drag(app: &PhotocraftApp, p: [f64; 2], rect: [f64; 4], deg: f64) -> C
     let c = center(rect);
     let grab = (p[1] - c[1]).atan2(p[0] - c[0]);
     if crate::crop_mode::moves_image(app) {
-        CropDrag::TurnImage { center: c, grab, from: deg, view: crate::crop_mode::press_view(app) }
+        CropDrag::TurnImage { center: c, grab, from: deg, rect, view: crate::crop_mode::press_view(app) }
     } else {
         // Outside the frame a drag turns it, as in Photoshop (#1792).
         CropDrag::Rotate { center: c, grab, from: deg }
@@ -1018,13 +1019,14 @@ fn update(app: &mut PhotocraftApp, p: [f64; 2], mods: Modifiers) {
 fn follow_view_drag(app: &mut PhotocraftApp, p: [f64; 2], mods: Modifiers) -> bool {
     match app.crop.drag {
         Some(CropDrag::Rotate { center, grab, from }) => app.ui.crop_angle = turned_angle(center, grab, from, p, mods.shift),
-        Some(CropDrag::TurnImage { center, grab, from, view }) => {
+        Some(CropDrag::TurnImage { center, grab, from, rect, view }) => {
             // The image turns with the pointer's sweep on screen, so the frame turns against it.
             let at = crate::crop_mode::to_press(app, view, p);
             let turned = from - ((at[1] - center[1]).atan2(at[0] - center[0]) - grab).to_degrees();
             if turned.is_finite() {
                 app.ui.crop_angle = normalized_angle(if mods.shift { (turned / 15.0).round() * 15.0 } else { turned });
                 crate::crop_mode::sync_frame(app);
+                crate::crop_mode::keep_inside(app, rect, from, mods.command);
             }
         }
         Some(CropDrag::MoveImage { start, rect, view }) => {
diff --git a/crates/ui-egui/tests/it/crop_turn_keeps_frame_inside.rs b/crates/ui-egui/tests/it/crop_turn_keeps_frame_inside.rs
new file mode 100644
index 0000000000..74e7fbbef9
--- /dev/null
+++ b/crates/ui-egui/tests/it/crop_turn_keeps_frame_inside.rs
@@ -0,0 +1,308 @@
+//! Crop tool, default mode: turning the image keeps the frame inside the turned image (#10869).
+//!
+//! Measured in the reference application on an 800 × 500 document, turning by a drag outside the
+//! frame with Auto Center Preview off: the frame keeps its size where it fits the turned image,
+//! else moves the shortest way into it, else shrinks about its centre keeping its proportions.
+//! With Ctrl (⌘) held the frame isn't adjusted and the uncovered corners get the Fill.
+//! PhotoCraft never adjusted the frame, so ↵ filled the corners with the background colour.
+//!
+//! Driven as an agent does, through `ui.pointer` (document px as the view showed them at the
+//! press).
+
+use photocraft_ui_egui::PhotocraftApp;
+use photocraft_ui_egui::canvas::ViewXform;
+use photocraft_ui_egui::control::{ControlRequest, Outcome, handle};
+use photocraft_ui_egui::crop_mode::kept_inside;
+use photocraft_ui_egui::crop_ui::{angle, center, corners};
+use serde_json::{Value, json};
+
+/// The document's size.
+const W: f64 = 800.0;
+const H: f64 = 500.0;
+/// The whole canvas, the default frame.
+const CANVAS: [f64; 4] = [0.0, 0.0, W, H];
+
+/// An 800 × 500 white document with a #1050e0 background colour, the Crop tool in the default
+/// mode with Auto Center Preview off, and `frame` as the pending crop frame: the default frame
+/// when it is the whole canvas, else drawn from its bottom-right corner to its top-left one (a
+/// press on the default frame's corner handle would resize it).
+fn app(frame: [f64; 4]) -> (PhotocraftApp, egui::Context) {
+    let mut app = PhotocraftApp::new(photocraft_engine::Session::new(), Default::default());
+    let ctx = egui::Context::default();
+    app.run("file.new", json!({"width": W, "height": H, "background": "white"})).expect("new");
+    app.run("tools.setColors", json!({"background": "#1050e0"})).expect("colors");
+    app.sync_views();
+    app.ui.extras.snap = false;
+    app.ui.view.show.smart_guides = false;
+    app.ui.tool_options.crop_shield.auto_center_preview = false;
+    control(&mut app, &ctx, "ui.set", json!({"tool": "crop", "zoom": 1.0, "center": [W / 2.0, H / 2.0]}));
+    photocraft_ui_egui::crop_ui::ensure_frame(&mut app);
+    assert!(!app.ui.tool_options.crop_shield.classic_mode, "Photoshop's default mode");
+    if frame != CANVAS {
+        let events = json!([
+            {"kind": "down", "x": frame[2], "y": frame[3]},
+            {"kind": "move", "x": frame[0], "y": frame[1]},
+            {"kind": "up", "x": frame[0], "y": frame[1]},
+        ]);
+        control(&mut app, &ctx, "ui.pointer", json!({"events": events}));
+    }
+    assert_eq!(app.ui.crop_rect, Some(frame));
+    (app, ctx)
+}
+
+/// Runs one control-channel request, which must succeed.
+fn control(app: &mut PhotocraftApp, ctx: &egui::Context, method: &str, params: Value) {
+    let (req, _rx) = ControlRequest::new(method, params.clone());
+    assert!(matches!(handle(app, ctx, &req), Outcome::Done(_)), "{method} {params}");
+}
+
+/// The point 500 px right of the frame's centre turned `deg` degrees clockwise about it: a press
+/// there is outside every frame below, and moving to it from the unturned point turns the image
+/// `deg` degrees clockwise.
+fn around(frame: [f64; 4], deg: f64) -> [f64; 2] {
+    let c = center(frame);
+    let (s, k) = deg.to_radians().sin_cos();
+    [c[0] + 500.0 * k, c[1] + 500.0 * s]
+}
+
+/// A turn of the image: a press outside `frame`, then for each `(deg, modifiers)` step a move to
+/// `deg` with those modifiers held (one `ui.pointer` call each, so a key can be pressed during
+/// the drag); `each` runs after every step. Releases at the last step's point with its modifiers.
+fn turn(app: &mut PhotocraftApp, ctx: &egui::Context, frame: [f64; 4], steps: &[(f64, Value)], mut each: impl FnMut(&PhotocraftApp, f64)) {
+    let p = around(frame, 0.0);
+    control(app, ctx, "ui.pointer", json!({"events": [{"kind": "down", "x": p[0], "y": p[1]}]}));
+    for (deg, mods) in steps {
+        let p = around(frame, *deg);
+        control(app, ctx, "ui.pointer", json!({"modifiers": mods, "events": [{"kind": "move", "x": p[0], "y": p[1]}]}));
+        each(app, *deg);
+    }
+    let (deg, mods) = steps.last().expect("a step");
+    let p = around(frame, *deg);
+    control(app, ctx, "ui.pointer", json!({"modifiers": mods, "events": [{"kind": "up", "x": p[0], "y": p[1]}]}));
+}
+
+/// No modifier held.
+fn plain() -> Value {
+    json!({})
+}
+
+/// The pending frame.
+fn frame(app: &PhotocraftApp) -> [f64; 4] {
+    app.ui.crop_rect.expect("a frame")
+}
+
+/// The pending frame's corners, turned with it, all lie on the canvas.
+fn inside(app: &PhotocraftApp) -> bool {
+    corners(frame(app), angle(app)).iter().all(|c| (-1e-6..=W + 1e-6).contains(&c[0]) && (-1e-6..=H + 1e-6).contains(&c[1]))
+}
+
+/// Where the frame's centre shows on screen.
+fn on_screen(app: &PhotocraftApp) -> egui::Pos2 {
+    let c = center(frame(app));
+    ViewXform::active(app).expect("a view").to_screen(c[0] as f32, c[1] as f32)
+}
+
+/// ↵: commits the crop and returns the document's new size.
+fn committed(app: &mut PhotocraftApp) -> (u32, u32) {
+    photocraft_ui_egui::canvas::commit_crop(app);
+    let size = app.session.active().expect("document").doc.size;
+    (size.width, size.height)
+}
+
+/// The flattened document's four corner pixels and its middle one.
+fn corners_and_middle(app: &PhotocraftApp) -> [[f32; 4]; 5] {
+    let doc = &app.session.active().expect("document").doc;
+    let flat = photocraft_compose::flatten(doc);
+    let (w, h) = (doc.size.width as usize, doc.size.height as usize);
+    let px = |x: usize, y: usize| flat.px[y * w + x];
+    [px(0, 0), px(w - 1, 0), px(w - 1, h - 1), px(0, h - 1), px(w / 2, h / 2)]
+}
+
+/// The background colour #1050e0 rather than the white image: its red is 16/255. A corner that
+/// the turned image covers only in part still has far more red than that.
+fn background(p: [f32; 4]) -> bool {
+    p[0] < 0.5 && (p[2] - 224.0 / 255.0).abs() < 0.02
+}
+
+/// White: the image.
+fn white(p: [f32; 4]) -> bool {
+    p[..3].iter().all(|&v| v > 0.98)
+}
+
+/// The frame's angle is `want` degrees, up to the `f32` rounding of the view the pointer is read
+/// through.
+fn near_angle(deg: f64, want: f64) -> bool {
+    (deg - want).abs() < 1e-4
+}
+
+/// The size of the largest frame of the canvas's proportions that fits inside the canvas turned
+/// `deg` degrees.
+fn fitted_size(deg: f64) -> (f64, f64) {
+    let (s, c) = deg.to_radians().sin_cos();
+    let (s, c) = (s.abs(), c.abs());
+    let k = (W / (W * c + H * s)).min(H / (W * s + H * c));
+    (W * k, H * k)
+}
+
+/// The issue's first two rows: the whole-canvas frame shrinks about its centre, keeping its
+/// proportions, to the largest size that fits (687 × 429 measured at 6.3°, 580 × 362 at the 15°
+/// that ⇧ snaps to), live while dragging, with the box put on screen. ↵ crops to it and no corner
+/// shows the background colour.
+#[test]
+fn turning_the_whole_canvas_frame_shrinks_it_inside_the_turned_image() {
+    for (deg, shift, measured) in [(6.3, false, (687.0, 429.0)), (13.0, true, (580.0, 362.0))] {
+        let what = format!("turned {deg}°, shift {shift}");
+        let (mut app, ctx) = app(CANVAS);
+        let screen = on_screen(&app);
+        // ⇧ pressed after the press, as measured: the turn snaps to 15°.
+        let steps = [(deg / 2.0, plain()), (deg, json!({"shift": shift}))];
+        turn(&mut app, &ctx, CANVAS, &steps, |app, step| {
+            assert!(inside(app), "{what}: at {step}° the frame {:?} turned {} leaves the image", frame(app), angle(app));
+            assert!(on_screen(app).distance(screen) < 0.01, "{what}: at {step}° the box moved on screen to {:?}", on_screen(app));
+        });
+        let turned = if shift { 15.0 } else { deg };
+        assert!(near_angle(angle(&app), -turned), "{what}: the frame's angle is {}", angle(&app));
+        let (w, h) = fitted_size(angle(&app));
+        let f = frame(&app);
+        let (fw, fh) = (f[2] - f[0], f[3] - f[1]);
+        assert!((fw - w).abs() < 1e-6 && (fh - h).abs() < 1e-6, "{what}: {fw} × {fh}, want {w} × {h}");
+        assert!((fw - measured.0).abs() <= 3.0 && (fh - measured.1).abs() <= 3.0, "{what}: {fw} × {fh} is far from the reference's {measured:?}");
+        let c = center(f);
+        assert!((c[0] - W / 2.0).abs() < 1e-6 && (c[1] - H / 2.0).abs() < 1e-6, "{what}: centred, not at {c:?}");
+        let (cw, ch) = committed(&mut app);
+        assert!((f64::from(cw) - w).abs() <= 1.0 && (f64::from(ch) - h).abs() <= 1.0, "{what}: committed {cw} × {ch}");
+        for p in corners_and_middle(&app) {
+            assert!(!background(p), "{what}: a corner shows the background colour: {p:?}");
+        }
+        assert!(white(corners_and_middle(&app)[4]), "{what}: the middle is the image");
+    }
+}
+
+/// The issue's Ctrl row: with Ctrl (⌘) held the frame keeps the whole canvas and ↵ fills the
+/// corners the turn uncovered. Pressed part way through the turn, Ctrl gives the press frame back
+/// at once.
+#[test]
+fn with_command_held_the_turn_keeps_the_frame() {
+    for late in [false, true] {
+        let (mut app, ctx) = app(CANVAS);
+        let first = if late { plain() } else { json!({"command": true}) };
+        turn(&mut app, &ctx, CANVAS, &[(3.0, first), (6.0, json!({"command": true}))], |app, step| {
+            if late && step == 3.0 {
+                assert!(frame(app) != CANVAS && inside(app), "Ctrl not held yet: the frame fits, {:?}", frame(app));
+            } else {
+                assert_eq!(frame(app), CANVAS, "late {late}: at {step}°");
+            }
+        });
+        assert!(near_angle(angle(&app), -6.0), "late {late}: {}", angle(&app));
+        assert_eq!(committed(&mut app), (800, 500), "late {late}");
+        let [corner @ .., middle] = corners_and_middle(&app);
+        for p in corner {
+            assert!(background(p), "late {late}: an uncovered corner is {p:?}");
+        }
+        assert!(white(middle), "late {late}: the middle is the image");
+    }
+}
+
+/// The issue's fourth row: a 300 × 201 frame at (100, 99) still lies inside the image turned
+/// 11.3° about its centre, so it stays exactly as it was.
+#[test]
+fn a_frame_that_fits_the_turned_image_keeps_its_size_and_place() {
+    let start = [100.0, 99.0, 400.0, 300.0];
+    let (mut app, ctx) = app(start);
+    turn(&mut app, &ctx, start, &[(5.0, plain()), (11.3, plain())], |app, step| {
+        assert_eq!(frame(app), start, "at {step}°");
+    });
+    assert!(near_angle(angle(&app), -11.3), "{}", angle(&app));
+    assert_eq!(committed(&mut app), (300, 201));
+    for p in corners_and_middle(&app) {
+        assert!(white(p), "{p:?}");
+    }
+}
+
+/// The issue's last row: a 300 × 200 frame in the top-left corner, turned 11.1°, keeps its size
+/// and moves the shortest way into the turned image: its turned corners end up touching the
+/// canvas's left and top edges, not further in. The box stays put on screen while the image
+/// slides under it.
+#[test]
+fn a_frame_in_the_corner_moves_in_without_shrinking() {
+    let start = [0.0, 0.0, 300.0, 200.0];
+    let (mut app, ctx) = app(start);
+    let screen = on_screen(&app);
+    turn(&mut app, &ctx, start, &[(5.0, plain()), (11.1, plain())], |app, step| {
+        assert!(inside(app), "at {step}° the frame {:?} leaves the image", frame(app));
+        assert!(on_screen(app).distance(screen) < 0.01, "at {step}° the box moved on screen to {:?}", on_screen(app));
+    });
+    let f = frame(&app);
+    assert!(((f[2] - f[0]) - 300.0).abs() < 1e-9 && ((f[3] - f[1]) - 200.0).abs() < 1e-9, "the size is kept: {f:?}");
+    let turned = corners(f, angle(&app));
+    let left = turned.iter().map(|c| c[0]).fold(f64::INFINITY, f64::min);
+    let top = turned.iter().map(|c| c[1]).fold(f64::INFINITY, f64::min);
+    assert!(left.abs() < 1e-9 && top.abs() < 1e-9, "moved the shortest way: the turned frame's left {left}, top {top}");
+    assert_eq!(committed(&mut app), (300, 200));
+    for p in corners_and_middle(&app) {
+        assert!(!background(p), "a corner shows the background colour: {p:?}");
+    }
+}
+
+/// Every step of the turn starts from the frame at the press, so turning back within the same
+/// drag gives the whole frame back instead of keeping the smallest size it passed through.
+#[test]
+fn turning_back_gives_the_frame_back() {
+    let (mut app, ctx) = app(CANVAS);
+    turn(&mut app, &ctx, CANVAS, &[(10.0, plain()), (0.0, plain())], |_, _| {});
+    assert_eq!((frame(&app), angle(&app)), (CANVAS, 0.0));
+}
+
+/// A second turn starts from the frame the first one fitted, whose turned corners touch the
+/// canvas's edges: turned further it shrinks again, turned back upright it stays as it is.
+#[test]
+fn a_second_turn_starts_from_the_fitted_frame() {
+    for second in [10.0, -6.3] {
+        let (mut app, ctx) = app(CANVAS);
+        turn(&mut app, &ctx, CANVAS, &[(6.3, plain())], |_, _| {});
+        let first = frame(&app);
+        turn(&mut app, &ctx, first, &[(second, plain())], |_, _| {});
+        let f = frame(&app);
+        let what = format!("then {second}°: {f:?} turned {}", angle(&app));
+        assert!(near_angle(angle(&app), -(6.3 + second)), "{what}");
+        assert!(inside(&app), "{what}");
+        if second > 0.0 {
+            let want = fitted_size(angle(&app));
+            assert!(((f[2] - f[0]) - want.0).abs() < 1e-6 && ((f[3] - f[1]) - want.1).abs() < 1e-6, "{what}: want {want:?}");
+        } else {
+            assert_eq!(f, first, "{what}");
+        }
+    }
+}
+
+/// A frame `kept_inside` fitted is left exactly as it is at the same angle, at every tenth of a
+/// degree up to 90°. The fitted frame's turned corners touch the canvas's edges, and at many
+/// angles rounding puts them a hair past: without the fit's tolerance such a frame would count as
+/// reaching past the canvas, and a second turn would no longer keep it inside.
+#[test]
+fn a_fitted_frame_fits_at_its_own_angle() {
+    let off_centre = [0.0, 0.0, 300.0, 200.0];
+    for i in 1..900 {
+        let deg = f64::from(i) / 10.0;
+        for start in [CANVAS, off_centre] {
+            let f = kept_inside(start, deg, W, H).expect("a frame");
+            assert_eq!(kept_inside(f, deg, W, H), Some(f), "{start:?} at {deg}°");
+        }
+    }
+}
+
+/// Not measured, so they keep today's behaviour: with Fill set to Content-Aware Fill, with a
+/// frame already reaching past the canvas at the press, and in Classic Mode (where the frame
+/// turns over the image) the frame keeps its size and place.
+#[test]
+fn content_aware_fill_a_frame_past_the_canvas_and_classic_mode_keep_the_frame() {
+    let past = [-50.0, 100.0, 300.0, 300.0];
+    for (what, start) in [("content-aware", CANVAS), ("past the canvas", past), ("classic", CANVAS)] {
+        let (mut app, ctx) = app(start);
+        app.ui.tool_options.crop_content_aware = what == "content-aware";
+        app.ui.tool_options.crop_shield.classic_mode = what == "classic";
+        turn(&mut app, &ctx, start, &[(6.3, plain())], |_, _| {});
+        assert!(angle(&app).abs() > 6.0, "{what}: turned, {}", angle(&app));
+        assert_eq!(frame(&app), start, "{what}");
+    }
+}
diff --git a/crates/ui-egui/tests/it/main.rs b/crates/ui-egui/tests/it/main.rs
index 319928686c..94ef9ddee0 100644
--- a/crates/ui-egui/tests/it/main.rs
+++ b/crates/ui-egui/tests/it/main.rs
@@ -17,6 +17,7 @@ mod crop_default_mode;
 mod crop_overlay_icons;
 mod crop_popup_keys;
 mod crop_shift_corner;
+mod crop_turn_keeps_frame_inside;
 mod custom_print_paper;
 mod display_shadows;
 mod drag_preview_canvas;