io/router: add tests for Enter/Leave pointer events

Signed-off-by: Chris Waldon <christopher.waldon.dev@gmail.com>

io/router/pointer_test.go

@@ -130,3 +130,172 @@ func countPointerEvents(typ pointer.Type, events []event.Event) int {
 	}
 	return c
 }
+
+func TestPointerEnterLeave(t *testing.T) {
+	handler1 := new(int)
+	handler2 := new(int)
+	var ops op.Ops
+
+	// Handler 1 area: (0, 0) - (100, 100)
+	pointer.Rect(image.Rectangle{
+		Max: image.Point{
+			X: 100,
+			Y: 100,
+		},
+	}).Add(&ops)
+	pointer.InputOp{Key: handler1}.Add(&ops)
+	// Handler 2 area: (50, 50) - (100, 100) (areas intersect).
+	pointer.Rect(image.Rectangle{
+		Min: image.Point{
+			X: 50,
+			Y: 50,
+		},
+		Max: image.Point{
+			X: 200,
+			Y: 200,
+		},
+	}).Add(&ops)
+	pointer.InputOp{Key: handler2}.Add(&ops)
+
+	var r Router
+	r.Frame(&ops)
+	// Hit both handlers.
+	r.Add(
+		pointer.Event{
+			Type: pointer.Move,
+			Position: f32.Point{
+				X: 50,
+				Y: 50,
+			},
+		},
+	)
+	// First event for a handler is always a Cancel.
+	assertEventSequence(t, r.Events(handler1), pointer.Cancel, pointer.Enter, pointer.Move)
+	assertEventSequence(t, r.Events(handler2), pointer.Cancel, pointer.Enter, pointer.Move)
+
+	// Leave the second area by moving into the first.
+	r.Add(
+		pointer.Event{
+			Type: pointer.Move,
+			Position: f32.Point{
+				X: 45,
+				Y: 45,
+			},
+		},
+	)
+	assertEventSequence(t, r.Events(handler1), pointer.Move)
+	assertEventSequence(t, r.Events(handler2), pointer.Leave)
+
+	// Move, but stay within the same hit area.
+	r.Add(
+		pointer.Event{
+			Type: pointer.Move,
+			Position: f32.Point{
+				X: 40,
+				Y: 40,
+			},
+		},
+	)
+	assertEventSequence(t, r.Events(handler1), pointer.Move)
+	assertEventSequence(t, r.Events(handler2))
+
+	// Move outside of both inputs.
+	r.Add(
+		pointer.Event{
+			Type: pointer.Move,
+			Position: f32.Point{
+				X: 300,
+				Y: 300,
+			},
+		},
+	)
+	assertEventSequence(t, r.Events(handler1), pointer.Leave)
+	assertEventSequence(t, r.Events(handler2))
+
+	// Check that a Press event generates Enter Events.
+	r.Add(
+		pointer.Event{
+			Type: pointer.Press,
+			Position: f32.Point{
+				X: 125,
+				Y: 125,
+			},
+		},
+	)
+	assertEventSequence(t, r.Events(handler1))
+	assertEventSequence(t, r.Events(handler2), pointer.Enter, pointer.Press)
+
+	// Check that a Release event generates Enter/Leave Events.
+	r.Add(
+		pointer.Event{
+			Type: pointer.Release,
+			Position: f32.Point{
+				// Move out of the second hit area and into the first.
+				X: 25,
+				Y: 25,
+			},
+		},
+	)
+	assertEventSequence(t, r.Events(handler1), pointer.Enter, pointer.Release)
+	assertEventSequence(t, r.Events(handler2), pointer.Leave)
+}
+
+// assertEventSequence ensures that the provided actualEvents match the expected event types
+// in the provided order
+func assertEventSequence(t *testing.T, actualEvents []event.Event, expected ...pointer.Type) {
+	for i, event := range actualEvents {
+		pointerEvent, ok := event.(pointer.Event)
+		if !ok {
+			t.Errorf("actualEvents[%d] is not a pointer event, type %T", i, event)
+			continue
+		}
+		if len(expected) <= i {
+			t.Errorf("actualEvents is longer than expected, has len %d, expected len %d", len(actualEvents), len(expected))
+			continue
+		}
+		if pointerEvent.Type != expected[i] {
+			t.Errorf("actualEvents[%d] has type %s, expected %s", i, pointerEvent.Type.String(), expected[i].String())
+			continue
+		}
+	}
+}
+
+func BenchmarkRouterAdd(b *testing.B) {
+	// Set this to the number of overlapping handlers that you want to
+	// evaluate performance for. Typical values for the example applications
+	// are 1-3, though checking highers values helps evaluate performance for
+	// more complex applications.
+	const handlerCount = 3
+	handlers := make([]event.Key, handlerCount)
+	for i := 0; i < handlerCount; i++ {
+		h := new(int)
+		*h = i
+		handlers[i] = h
+	}
+	var ops op.Ops
+
+	for i := range handlers {
+		pointer.Rect(image.Rectangle{
+			Max: image.Point{
+				X: 100,
+				Y: 100,
+			},
+		}).Add(&ops)
+		pointer.InputOp{Key: handlers[i]}.Add(&ops)
+	}
+	var r Router
+	r.Frame(&ops)
+	b.ReportAllocs()
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		r.Add(
+			pointer.Event{
+				Type: pointer.Move,
+				Position: f32.Point{
+					X: 50,
+					Y: 50,
+				},
+			},
+		)
+	}
+}