diff --git a/crates/ui-egui/src/canvas.rs b/crates/ui-egui/src/canvas.rs
index 5b68f657..54e32bd8 100644
--- a/crates/ui-egui/src/canvas.rs
+++ b/crates/ui-egui/src/canvas.rs
@@ -2779,7 +2779,9 @@ pub fn canvas_view(app: &mut PhotocraftApp, ui: &mut egui::Ui, idx: usize, rect:
                 // zooms nor slides the image towards the pointer.
                 let nz = crate::zoom_levels::clamp(view.zoom * f, view.doc_size);
                 if nz != view.zoom {
-                    zoom_about(&mut view, &xf, p, nz, false, ppp);
+                    // Over the pasteboard the anchor is the image's nearest point (#3720).
+                    let at = wheel_anchor(&xf, p, view.doc_size);
+                    zoom_about(&mut view, &xf, at, nz, false, ppp);
                 }
             }
             (Some(crate::wheel_nav::Wheel::Pan(scroll)), _) => {
@@ -3557,6 +3559,20 @@ pub fn canvas_view(app: &mut PhotocraftApp, ui: &mut egui::Ui, idx: usize, rect:
 /// Zoom to `new_zoom` about the pointer `p`. By default the document point under it stays under
 /// it; with Preferences › Tools › Zoom Clicked Point to Center (`center_on_point`) it moves to the
 /// centre of the view instead (#204).
+/// Where a wheel or pinch zoom anchors for a pointer at `p`: the pointer itself over the image,
+/// otherwise the nearest point of the image (#3720). Anchoring on a pointer out on the gray
+/// pasteboard slid the image away from it, out of the window after a few notches; Photoshop keeps
+/// the image in view. Clamped in document space, so a rotated or flipped view behaves the same.
+fn wheel_anchor(xf: &ViewXform, p: Pos2, doc_size: [u32; 2]) -> Pos2 {
+    let [w, h] = doc_size;
+    let d = xf.to_doc(p);
+    if w == 0 || h == 0 || !(d[0].is_finite() && d[1].is_finite()) {
+        return p;
+    }
+    let c = [d[0].clamp(0.0, f64::from(w)), d[1].clamp(0.0, f64::from(h))];
+    if c == d { p } else { xf.to_screen(c[0] as f32, c[1] as f32) }
+}
+
 fn zoom_about(view: &mut View, xf: &ViewXform, p: Pos2, new_zoom: f32, center_on_point: bool, ppp: f32) {
     let before = xf.to_doc(p);
     view.zoom = new_zoom;
@@ -6687,6 +6703,23 @@ mod tests {
         }
     }
 
+    #[test]
+    fn wheel_anchor_is_the_pointer_over_the_image_and_the_nearest_image_point_off_it() {
+        let rect = Rect::from_min_size(Pos2::ZERO, vec2(800.0, 600.0));
+        for (rotation, flip) in [(0.0, false), (30.0, false), (90.0, true)] {
+            let xf = ViewXform { rect, zoom: 0.5, center: [400.0, 300.0], flip, rotation, aspect: 1.0 };
+            let inside = xf.to_screen(100.0, 200.0);
+            assert_eq!(wheel_anchor(&xf, inside, [800, 600]), inside);
+            for (p, want) in [((-300.0, -200.0), [0.0, 0.0]), ((1200.0, 300.0), [800.0, 300.0]), ((400.0, 900.0), [400.0, 600.0])] {
+                let a = xf.to_doc(wheel_anchor(&xf, xf.to_screen(p.0, p.1), [800, 600]));
+                assert!((a[0] - want[0]).abs() < 0.01 && (a[1] - want[1]).abs() < 0.01, "rot {rotation}: {p:?} -> {a:?}");
+            }
+        }
+        let p = pos2(5.0, 5.0);
+        let xf = ViewXform { rect, zoom: 1.0, center: [400.0, 300.0], flip: false, rotation: 0.0, aspect: 1.0 };
+        assert_eq!(wheel_anchor(&xf, p, [0, 0]), p, "no document: the pointer");
+    }
+
     #[test]
     fn zoom_about_centres_the_clicked_point_with_the_preference() {
         let rect = Rect::from_min_size(Pos2::ZERO, vec2(800.0, 600.0));
diff --git a/crates/ui-egui/src/input_tests.rs b/crates/ui-egui/src/input_tests.rs
index d78dbedb..bb87d477 100644
--- a/crates/ui-egui/src/input_tests.rs
+++ b/crates/ui-egui/src/input_tests.rs
@@ -707,3 +707,62 @@ fn escape_with_targa_options_open_does_not_deselect() {
     h.run_steps(2);
     assert!(h.state().session.active().unwrap().doc.selection.is_some(), "Esc belongs to Targa Options");
 }
+
+/// How much of the 400 × 300 document is on screen: the visible document span on each axis,
+/// clipped to the image (0 when the image has left the view on that axis).
+fn visible_image(h: &Harness<'static, PhotocraftApp>) -> [f32; 2] {
+    let r = h.state().last_canvas_rect;
+    let (a, b) = (doc_at(h, r.min), doc_at(h, r.max));
+    [(b[0].min(400.0) - a[0].max(0.0)).max(0.0), (b[1].min(300.0) - a[1].max(0.0)).max(0.0)]
+}
+
+#[test]
+fn wheel_zoom_over_the_pasteboard_keeps_the_image_in_view() {
+    // #3720: zooming in with the pointer on the gray pasteboard anchored on the pointer, so a few
+    // notches pushed the image out of the window. The anchor is now the nearest point of the image.
+    for (zoom_with_wheel, m) in [(true, Modifiers::NONE), (false, Modifiers::ALT)] {
+        let mut h = harness();
+        h.state_mut().session.edit_prefs(|p| p.general.zoom_with_scroll_wheel = zoom_with_wheel);
+        let r = h.state().last_canvas_rect;
+        let p = pos2(r.left() + 20.0, r.top() + 20.0);
+        let d = doc_at(&h, p);
+        assert!(d[0] < 0.0 && d[1] < 0.0, "the pointer starts on the pasteboard: {d:?}");
+        h.hover_at(p);
+        h.run_steps(2);
+        let z0 = zoom(&h);
+        for _ in 0..20 {
+            wheel(&h, 1.0, m);
+            h.run_steps(3);
+        }
+        h.run_steps(20);
+        assert!(zoom(&h) > z0 * 5.0, "the notches zoomed in: {z0} -> {}", zoom(&h));
+        let v = visible_image(&h);
+        assert!(v[0] > 0.0 && v[1] > 0.0, "zoom_with_wheel {zoom_with_wheel}: the image left the view {v:?}");
+        // The image's corner nearest the pointer is the anchor: it stays where it was on screen.
+        let c = doc_at(&h, pos2(r.left() + 20.0, r.top() + 20.0));
+        assert!(c[0] < 0.0 && c[1] < 0.0, "still pasteboard under the pointer, the corner held: {c:?}");
+        // A pinch from there behaves the same.
+        h.event(egui::Event::Zoom(4.0));
+        h.run_steps(3);
+        let v = visible_image(&h);
+        assert!(v[0] > 0.0 && v[1] > 0.0, "pinch: the image left the view {v:?}");
+    }
+}
+
+#[test]
+fn wheel_zoom_over_the_image_still_anchors_on_the_pointer() {
+    let mut h = harness();
+    let r = h.state().last_canvas_rect;
+    let p = pos2(r.center().x - 150.0, r.center().y - 100.0);
+    h.hover_at(p);
+    h.run_steps(2);
+    let d0 = doc_at(&h, p);
+    assert!(d0[0] > 0.0 && d0[1] > 0.0);
+    for _ in 0..5 {
+        wheel(&h, 1.0, Modifiers::ALT);
+        h.run_steps(3);
+    }
+    h.run_steps(20);
+    let d1 = doc_at(&h, p);
+    assert!((d1[0] - d0[0]).abs() < 0.1 && (d1[1] - d0[1]).abs() < 0.1, "{d0:?} -> {d1:?}");
+}