feat: flutter hit test self on rive render object

This PR adds hit testing to Flutter by overriding `hitTestSelf` on the Rive RenderObject.

Currently, the hit area is the entire bounding box of the canvas. This means that when a Rive animation is rendered above any other Flutter content (for example, a Stack) all hits are absorbed by Rive and do not pass through.

With this change, Rive will only absorb hits if the pointer comes in contact with a hittable Rive element.

With this change, `handleEvent` will only be called if `hitTestSelf` returns true. There is some duplicate work here as `_processEvent` already performs similar hit test logic, which we can look at optimizing. But `hitTest` needed to be separate method call, as `hitTestSelf` is called before `handleEvent` and `handleEvent` sends additional information (whether it's a pointer down/up etc.).

Diffs=
95beaa4f5 feat: add flutter hit test self on rive render object (#6341)
bd71143bc chore: fix broken docs link (#6360)

Co-authored-by: Gordon <[email protected]>

.rive_head

@@ -1 +1 @@
-423366fb78e2370b998c9015b4bda621d0047ace
+95beaa4f50086409b35317a34cf9c2b341e468c5

example/macos/Podfile.lock

@@ -39,9 +39,9 @@ SPEC CHECKSUMS:
   FlutterMacOS: 8f6f14fa908a6fb3fba0cd85dbd81ec4b251fb24
   just_audio: 9b67ca7b97c61cfc9784ea23cd8cc55eb226d489
   path_provider_foundation: 29f094ae23ebbca9d3d0cec13889cd9060c0e943
-  rive_common: acedcab7802c0ece4b0d838b71d7deb637e1309a
+  rive_common: 0f0aadf670f0c6a7872dfe3e6186f112a5319108
   url_launcher_macos: d2691c7dd33ed713bf3544850a623080ec693d95
 
 PODFILE CHECKSUM: 353c8bcc5d5b0994e508d035b5431cfe18c1dea7
 
-COCOAPODS: 1.12.1
+COCOAPODS: 1.11.3

lib/src/rive.dart

@@ -8,6 +8,23 @@ import 'package:rive/src/rive_render_box.dart';
 import 'package:rive/src/runtime_artboard.dart';
 import 'package:rive_common/math.dart';
 
+/// How to behave during hit tests on Rive Listeners (hit targets).
+enum RiveHitTestBehavior {
+  /// The bounds of the Rive animation will consume all hits, even if there is
+  /// no animation listener (hit area) at the target point. Content
+  /// behind the animation will not receive hits.
+  opaque,
+
+  /// Rive will only consume hits where there is a listener (hit area) at the
+  /// target point. Content behind the animation will only receive hits if
+  /// no animation listener was hit.
+  translucent,
+
+  /// All hits will pass through the animation, regardless of whether a
+  /// a Rive listener was hit. Rive listeners will still receive hits.
+  transparent,
+}
+
 class Rive extends LeafRenderObjectWidget {
   /// Artboard used for drawing
   final Artboard artboard;
@@ -58,6 +75,16 @@ class Rive extends LeafRenderObjectWidget {
   /// cursor to the next region behind it in hit-test order.
   final MouseCursor cursor;
 
+  /// {@template Rive.behavior}
+  /// How to behave during hit testing to consider targets behind this
+  /// animation.
+  ///
+  /// Defaults to [RiveHitTestBehavior.opaque].
+  ///
+  /// See [RiveHitTestBehavior] for the allowed values and their meanings.
+  /// {@endtemplate}
+  final RiveHitTestBehavior behavior;
+
   /// {@template Rive.clipRect}
   /// Clip the artboard to this rect.
   ///
@@ -73,6 +100,7 @@ class Rive extends LeafRenderObjectWidget {
     this.antialiasing = true,
     this.enablePointerEvents = false,
     this.cursor = MouseCursor.defer,
+    this.behavior = RiveHitTestBehavior.opaque,
     BoxFit? fit,
     Alignment? alignment,
     this.clipRect,
@@ -92,7 +120,8 @@ class Rive extends LeafRenderObjectWidget {
       ..clipRect = clipRect
       ..tickerModeEnabled = tickerModeValue
       ..enableHitTests = enablePointerEvents
-      ..cursor = cursor;
+      ..cursor = cursor
+      ..behavior = behavior;
   }
 
   @override
@@ -109,14 +138,16 @@ class Rive extends LeafRenderObjectWidget {
       ..clipRect = clipRect
       ..tickerModeEnabled = tickerModeValue
       ..enableHitTests = enablePointerEvents
-      ..cursor = cursor;
+      ..cursor = cursor
+      ..behavior = behavior;
   }
 }
 
 class RiveRenderObject extends RiveRenderBox implements MouseTrackerAnnotation {
   RuntimeArtboard _artboard;
   RiveRenderObject(
     this._artboard, {
+    this.behavior = RiveHitTestBehavior.opaque,
     MouseCursor cursor = MouseCursor.defer,
     bool validForMouseTracker = true,
   })  : _cursor = cursor,
@@ -153,6 +184,50 @@ class RiveRenderObject extends RiveRenderBox implements MouseTrackerAnnotation {
     }
   }
 
+  @override
+  bool hitTest(BoxHitTestResult result, {required Offset position}) {
+    // super.hitTest(result, position: position)
+    bool hitTarget = false;
+    if (size.contains(position)) {
+      hitTarget = hitTestSelf(position);
+      if (hitTarget) {
+        // if hit add to results
+        result.add(BoxHitTestEntry(this, position));
+      }
+    }
+
+    // Let the hit continue to targets behind the animation.
+    if (behavior == RiveHitTestBehavior.transparent) {
+      return false;
+    }
+
+    // Opaque will always return true, translucent will return true if we
+    // hit a Rive listener target.
+    return hitTarget;
+  }
+
+  @override
+  bool hitTestSelf(Offset screenOffset) {
+    switch (behavior) {
+      case RiveHitTestBehavior.opaque:
+        return true; // Always hit
+      case RiveHitTestBehavior.translucent:
+      case RiveHitTestBehavior.transparent:
+        {
+          // test to see if any Rive animation listeners were hit
+          final artboardPosition = _toArtboard(screenOffset);
+          final stateMachineControllers = _artboard.animationControllers
+              .whereType<StateMachineController>();
+          for (final stateMachineController in stateMachineControllers) {
+            if (stateMachineController.hitTest(artboardPosition)) {
+              return true;
+            }
+          }
+        }
+    }
+    return false;
+  }
+
   @override
   void handleEvent(PointerEvent event, HitTestEntry entry) {
     assert(debugHandleEvent(event, entry));
@@ -225,6 +300,9 @@ class RiveRenderObject extends RiveRenderBox implements MouseTrackerAnnotation {
   bool get validForMouseTracker => _validForMouseTracker;
   bool _validForMouseTracker;
 
+  /// {@macro Rive.behavior}
+  RiveHitTestBehavior behavior;
+
   @override
   void attach(PipelineOwner owner) {
     super.attach(owner);

lib/src/rive_core/animation/nested_state_machine.dart

@@ -16,6 +16,8 @@ abstract class NestedStateMachineInstance {
 
   void apply(covariant MountedArtboard artboard, double elapsedSeconds);
 
+  bool hitTest(Vec2D position);
+
   void pointerMove(Vec2D position);
 
   void pointerDown(Vec2D position, PointerDownEvent event);
@@ -74,6 +76,9 @@ class NestedStateMachine extends NestedStateMachineBase {
     _stateMachineInstance?.setInputValue(inputId, value);
   }
 
+  bool hitTest(Vec2D position) =>
+      _stateMachineInstance?.hitTest(position) ?? false;
+
   void pointerMove(Vec2D position) =>
       _stateMachineInstance?.pointerMove(position);
 

lib/src/rive_core/state_machine_controller.dart

@@ -604,6 +604,70 @@ class StateMachineController extends RiveAnimationController<CoreContext>
     return hitSomething;
   }
 
+  /// Hit testing. If any listeners were hit, returns true.
+  bool hitTest(
+    Vec2D position, {
+    PointerEvent? pointerEvent,
+    ListenerType? hitEvent,
+  }) {
+    var artboard = this.artboard;
+    if (artboard == null) {
+      return false;
+    }
+    if (artboard.frameOrigin) {
+      // ignore: parameter_assignments
+      position = position -
+          Vec2D.fromValues(
+            artboard.width * artboard.originX,
+            artboard.height * artboard.originY,
+          );
+    }
+    const hitRadius = 2;
+    var hitArea = IAABB(
+      (position.x - hitRadius).round(),
+      (position.y - hitRadius).round(),
+      (position.x + hitRadius).round(),
+      (position.y + hitRadius).round(),
+    );
+
+    for (final hitShape in hitShapes) {
+      var shape = hitShape.shape;
+      var bounds = shape.worldBounds;
+
+      // Quick reject
+      bool isOver = false;
+      if (bounds.contains(position)) {
+        // Make hit tester.
+        var hitTester = TransformingHitTester(hitArea);
+        shape.fillHitTester(hitTester);
+
+        isOver = hitTester.test();
+        if (isOver) {
+          return true; // exit early
+        }
+      }
+    }
+
+    for (final nestedArtboard in hitNestedArtboards) {
+      if (nestedArtboard.isCollapsed) {
+        continue;
+      }
+      var nestedPosition = nestedArtboard.worldToLocal(position);
+      if (nestedPosition == null) {
+        // Mounted artboard isn't ready or has a 0 scale transform.
+        continue;
+      }
+      for (final nestedStateMachine
+          in nestedArtboard.animations.whereType<NestedStateMachine>()) {
+        if (nestedStateMachine.hitTest(nestedPosition)) {
+          return true; // exit early
+        }
+      }
+    }
+
+    return false; // no hit targets found
+  }
+
   void pointerMove(Vec2D position) => _processEvent(
         position,
         hitEvent: ListenerType.move,

lib/src/runtime_nested_artboard.dart

@@ -119,6 +119,9 @@ class RuntimeNestedStateMachineInstance extends NestedStateMachineInstance {
   ValueListenable<bool> get isActiveChanged =>
       stateMachineController.isActiveChanged;
 
+  @override
+  bool hitTest(Vec2D position) => stateMachineController.hitTest(position);
+
   @override
   void pointerDown(Vec2D position, PointerDownEvent event) =>
       stateMachineController.pointerDown(position, event);

lib/src/widgets/rive_animation.dart

@@ -63,6 +63,9 @@ class RiveAnimation extends StatefulWidget {
   /// Headers for network requests
   final Map<String, String>? headers;
 
+  /// {@macro Rive.behavior}
+  final RiveHitTestBehavior behavior;
+
   /// Creates a new [RiveAnimation] from an asset bundle.
   ///
   /// *Example:*
@@ -82,6 +85,7 @@ class RiveAnimation extends StatefulWidget {
     this.clipRect,
     this.controllers = const [],
     this.onInit,
+    this.behavior = RiveHitTestBehavior.opaque,
     Key? key,
   })  : name = asset,
         file = null,
@@ -109,6 +113,7 @@ class RiveAnimation extends StatefulWidget {
     this.controllers = const [],
     this.onInit,
     this.headers,
+    this.behavior = RiveHitTestBehavior.opaque,
     Key? key,
   })  : name = url,
         file = null,
@@ -134,6 +139,7 @@ class RiveAnimation extends StatefulWidget {
     this.clipRect,
     this.controllers = const [],
     this.onInit,
+    this.behavior = RiveHitTestBehavior.opaque,
     Key? key,
   })  : name = path,
         file = null,
@@ -163,6 +169,7 @@ class RiveAnimation extends StatefulWidget {
     this.controllers = const [],
     this.onInit,
     Key? key,
+    this.behavior = RiveHitTestBehavior.opaque,
   })  : name = null,
         headers = null,
         src = _Source.direct,
@@ -327,6 +334,7 @@ class RiveAnimationState extends State<RiveAnimation> {
           useArtboardSize: widget.useArtboardSize,
           clipRect: widget.clipRect,
           enablePointerEvents: _shouldAddHitTesting,
+          behavior: widget.behavior,
         )
       : widget.placeHolder ?? const SizedBox();
 }