Interaction · Pointer: handles inside the box, drags from the press

Resizable's grip sits inside the box's lower right corner and its edge
handles lie inside the edges, their lines on the edge; the edges use
layout::resize_edge, a resize_handle whose line shows only while
hovered, since the box draws its own border. A drag now measures from
the handle's press, kept in keyed state, so the edge follows the
pointer from the first move. Tests drag the right edge downward and
the bottom edge sideways, turn the dial without Shift, and draw a band
with Shift over a selection.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/interaction/tests.rs

@@ -109,16 +109,43 @@ fn a_box_resizes_from_its_grip_and_its_edge_within_its_limits(cx: &mut TestAppCo
     let stepped = host.read_with(cx, |bench, _| bench.size);
     assert_eq!(stepped, size(px(208.0), px(128.0)));
     drag(
-        at(228.0, 60.0),
-        &[at(240.0, 60.0), at(260.0, 60.0), at(400.0, 60.0)],
+        at(225.0, 60.0),
+        &[at(240.0, 80.0), at(260.0, 100.0), at(400.0, 120.0)],
         Modifiers::none(),
         cx,
     );
-    let dragged = host.read_with(cx, |bench, _| bench.size);
+    let widened = host.read_with(cx, |bench, _| bench.size);
     assert_eq!(
-        dragged,
+        widened,
         size(px(300.0), px(128.0)),
-        "the edge stops at the widest"
+        "the right edge only widens, and stops at the widest"
+    );
+    drag(
+        at(100.0, 145.0),
+        &[at(150.0, 160.0), at(180.0, 180.0), at(200.0, 200.0)],
+        Modifiers::none(),
+        cx,
+    );
+    let deepened = host.read_with(cx, |bench, _| bench.size);
+    assert_eq!(
+        deepened,
+        size(px(300.0), px(183.0)),
+        "the bottom edge only deepens, by the pointer's way from the press"
+    );
+}
+
+/// The grip and the edges' handles lie inside the box, the grip in its lower right corner.
+#[gpui::test]
+fn the_grip_lies_inside_the_box(cx: &mut TestAppContext) {
+    let (_, cx) = bench(resizable, cx);
+    let (grip, frame) = (
+        cx.debug_bounds("resizable-grip").expect("the grip"),
+        cx.debug_bounds("resizable-box").expect("the box"),
+    );
+    assert_eq!(
+        (grip.right(), grip.bottom()),
+        (frame.right(), frame.bottom()),
+        "the grip ends at the box's corner: {grip:?} in {frame:?}"
     );
 }
 
@@ -158,6 +185,23 @@ fn a_dial_turns_toward_its_dragged_knob(cx: &mut TestAppContext) {
     assert_eq!(host.read_with(cx, |bench, _| bench.angle), 90.0);
 }
 
+/// Without Shift the same drag turns the dial to the pointer's own angle.
+#[gpui::test]
+fn a_free_drag_turns_to_the_pointer(cx: &mut TestAppContext) {
+    let (host, cx) = bench(rotatable, cx);
+    drag(
+        at(70.0, 26.0),
+        &[at(90.0, 40.0), at(110.0, 55.0), at(130.0, 66.0)],
+        Modifiers::none(),
+        cx,
+    );
+    let angle = host.read_with(cx, |bench, _| bench.angle);
+    assert!(
+        (angle - 86.19).abs() < 0.05,
+        "turned to 86 degrees: {angle}"
+    );
+}
+
 fn area(bench: &Bench, owner: Entity<Bench>) -> AnyElement {
     ["a", "b", "c"]
         .into_iter()
@@ -222,6 +266,24 @@ fn presses_and_keys_pick_tiles(cx: &mut TestAppContext) {
     assert!(picked(&host, cx).is_empty());
 }
 
+/// With "a" selected, a band over "c" with Shift adds it.
+#[gpui::test]
+fn a_band_with_shift_adds_to_the_selection(cx: &mut TestAppContext) {
+    let (host, cx) = bench(area, cx);
+    host.update(cx, |bench, cx| {
+        bench.selected = vec!["a".into()];
+        cx.notify();
+    });
+    settle(cx);
+    drag(
+        at(200.0, 100.0),
+        &[at(190.0, 90.0), at(170.0, 70.0), at(160.0, 60.0)],
+        Modifiers::shift(),
+        cx,
+    );
+    assert_eq!(picked(&host, cx), ["a", "c"]);
+}
+
 /// The box is one stop: the arrows walk the cursor and Space adds or drops the tile it is on.
 #[gpui::test]
 fn the_keyboard_walks_and_picks_tiles(cx: &mut TestAppContext) {