Tests: the UI arrow-pan test at the new step; the step at other zooms and on both axes (#2106 review)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Model-Effort: Opus 5.5 drove; Opus 5.5 briefed; Sonnet 5.5 wrote at low

crates/engine/src/cmd/view.rs

@@ -688,4 +688,33 @@ mod start_on_home_tests {
         let v = &s.ds().unwrap().view;
         assert_eq!((v.cx, v.cy), (364.0, -120.0), "Shift pans 320 px");
     }
+
+    #[test]
+    fn the_arrow_pan_is_the_same_screen_distance_at_any_zoom_on_both_axes() {
+        // (zoom, dx, dy, big, expected centre change in document px)
+        let cases = [
+            (2.0, 1.0, 0.0, false, 32.0, 0.0),
+            (0.5, 1.0, 0.0, false, 128.0, 0.0),
+            (2.0, 0.0, 1.0, true, 0.0, 160.0),
+            (0.5, 0.0, 1.0, true, 0.0, 640.0),
+            (1.0, -1.0, 0.0, false, -64.0, 0.0),
+            (1.0, 1.0, 0.0, true, 320.0, 0.0),
+            (1.0, -1.0, 0.0, true, -320.0, 0.0),
+            (1.0, 0.0, -1.0, false, 0.0, -64.0),
+            (1.0, 0.0, 1.0, false, 0.0, 64.0),
+            (1.0, 0.0, -1.0, true, 0.0, -320.0),
+        ];
+        for (zoom, dx, dy, big, ex, ey) in cases {
+            let mut s = crate::Session::new();
+            s.execute("view.set", &json!({"zoom": zoom, "cx": 300, "cy": 200})).unwrap();
+            s.execute("view.pan", &json!({"dx": dx, "dy": dy, "big": big})).unwrap();
+            let v = &s.ds().unwrap().view;
+            let got = (v.cx - 300.0, v.cy - 200.0);
+            assert!(
+                (got.0 - ex).abs() < 1e-6 && (got.1 - ey).abs() < 1e-6,
+                "zoom {zoom} dx {dx} dy {dy} big {big}: moved {got:?}, expected {:?}",
+                (ex, ey)
+            );
+        }
+    }
 }

crates/ui-egui/src/inspect_fields_tests.rs

@@ -62,12 +62,12 @@ fn control_key_arrows_pan_with_nothing_selected() {
         (v.cx, v.cy)
     };
     call(&mut u, "ui.key", json!({"key": "ArrowRight"})).unwrap();
-    assert_eq!(view(&u), (10.0, 0.0), "20 screen pixels at 200%");
+    assert_eq!(view(&u), (32.0, 0.0), "64 screen pixels at 200% are 32 document pixels");
     call(&mut u, "ui.key", json!({"key": "ArrowUp", "shift": true})).unwrap();
-    assert_eq!(view(&u), (10.0, -100.0), "Shift: ten times as far");
+    assert_eq!(view(&u), (32.0, -160.0), "Shift: 320 screen pixels, 160 document pixels");
     u.app.run("select.set", json!({"ids": [r]}));
     call(&mut u, "ui.key", json!({"key": "ArrowRight"})).unwrap();
-    assert_eq!(view(&u), (10.0, -100.0), "with a selection the view stays");
+    assert_eq!(view(&u), (32.0, -160.0), "with a selection the view stays");
     let id = figcraft_engine::params::id_of(&r).unwrap();
     assert_eq!(u.app.session.doc().unwrap().world_bounds(id).unwrap().x0, 1.0, "the selection moved instead");
     // With a shape tool chosen and nothing selected the arrows move the placement crosshair

crates/ui-egui/src/shortcut_keys_tests.rs

@@ -44,13 +44,13 @@ fn arrows_pan_the_view_when_nothing_is_selected() {
     u.app.run("select.set", json!({"ids": []}));
     u.app.run("view.set", json!({"zoom": 2.0, "cx": 0, "cy": 0}));
     press(&mut u, Key::ArrowRight, Modifiers::NONE);
-    assert_eq!(view(&u), (10.0, 0.0, 2.0), "20 screen pixels at 200%");
+    assert_eq!(view(&u), (32.0, 0.0, 2.0), "64 screen pixels at 200% are 32 document pixels");
     press(&mut u, Key::ArrowUp, Modifiers::SHIFT);
-    assert_eq!(view(&u), (10.0, -100.0, 2.0), "Shift: ten times as far");
+    assert_eq!(view(&u), (32.0, -160.0, 2.0), "Shift: 320 screen pixels, 160 document pixels");
     // With a selection the arrows nudge it and the view stays.
     u.app.run("select.set", json!({"ids": [r]}));
     press(&mut u, Key::ArrowRight, Modifiers::NONE);
-    assert_eq!(view(&u), (10.0, -100.0, 2.0));
+    assert_eq!(view(&u), (32.0, -160.0, 2.0));
     assert_eq!(u.app.session.doc().unwrap().world_bounds(r).unwrap().x0, 1.0);
 }