fix: exaggerate pointer exit listener on mouseout to account for hita…

…reas too close to the artboard border

[Bug reported](https://2dimensions.slack.com/archives/CLLCU09T6/p1699924347919509) where hitareas for a listener ~2px away from the Artboard border were not getting their `pointer exit` listener invoked. There seems to be a small rounding issue when taking into account the [2px hitRadius](https://github.com/rive-app/rive-cpp/blob/master/src/animation/state_machine_instance.cpp#L336) we use downstream that doesn't invoke the pointer exit accordingly.

Flutter web doesn't have this issue because it taps out early before doing this hitRadius detection by doing a check first on the shape's bounds (which [doesn't exist](https://github.com/rive-app/rive-cpp/blob/master/src/animation/state_machine_instance.cpp#L346) in C++).

Adding a large buffer to the coordinates when the user "mouseout"'s the canvas to ensure we report the user has effectively `pointer exit`'d. We can't just add/subtract 2 here because if for example, Rive is setup with `fit: cover`, it expands the rive graphic potentially past the canvas bounds. Open to other suggestions here

Diffs=
f0ca1b0ef fix: exaggerate pointer exit listener on mouseout to account for hitareas too close to the artboard border (#6319)

Co-authored-by: Zachary Plata <plata.zach@gmail.com>

.rive_head

@@ -1 +1 @@
-53972cc17b532e83ffee7cae7d3420e95f822e8f
+f0ca1b0ef3052ecb92f5bf6ca8411e85d4368e86

js/src/utils/registerTouchInteractions.ts

@@ -112,10 +112,30 @@ export const registerTouchInteractions = ({
     forwardMatrix.delete();
 
     switch (event.type) {
+      /**
+       * There's a 2px buffer for a hitRadius when translating the pointer coordinates
+       * down to the state machine. In cases where the hitbox is about that much away
+       * from the Artboard border, we don't have exact precision on determining pointer
+       * exit. We're therefore adding to the translated coordinates on mouseout of a canvas
+       * to ensure that we report the mouse has truly exited the hitarea.
+       * https://github.com/rive-app/rive-cpp/blob/master/src/animation/state_machine_instance.cpp#L336
+       * 
+       * We add/subtract 10000 to account for when the graphic goes beyond the canvas bound
+       * due to for example, a fit: 'cover'. Not perfect, but helps reliably (for now) ensure
+       * we report going out of bounds when the mouse is out of the canvas
+       */
+      case "mouseout":
+        for (const stateMachine of stateMachines) {
+          stateMachine.pointerMove(
+            transformedX < 0 ? transformedX - 10000 : transformedX + 10000,
+            transformedY < 0 ? transformedY - 10000 : transformedY + 10000
+          );
+        }
+        break;
+
       // Pointer moving/hovering on the canvas
       case "touchmove":
       case "mouseover":
-      case "mouseout":
       case "mousemove": {
         for (const stateMachine of stateMachines) {
           stateMachine.pointerMove(transformedX, transformedY);

js/test/registerTouchInteractions.test.ts

@@ -105,3 +105,16 @@ test("touchend event can invoke pointerUp", (): void => {
   expect(mockStateMachines[0].pointerMove).not.toBeCalledWith();
   expect(mockStateMachines[0].pointerUp).toBeCalledWith(100, 100);
 });
+
+test("mouseout event can invoke pointerMove with out of bounds coordinates", (): void => {
+  canvas.dispatchEvent(
+    new MouseEvent("mouseout", {
+      clientX: -1,
+      clientY: 1,
+    })
+  );
+
+  expect(mockStateMachines[0].pointerDown).not.toBeCalled();
+  expect(mockStateMachines[0].pointerMove).toBeCalledWith(-10001, 10001);
+  expect(mockStateMachines[0].pointerUp).not.toBeCalled();
+});