Use a single mask view to clip platform view

shell/platform/darwin/ios/framework/Source/FlutterPlatformViewsTest.mm

@@ -14,6 +14,7 @@
 FLUTTER_ASSERT_NOT_ARC
 @class FlutterPlatformViewsTestMockPlatformView;
 static FlutterPlatformViewsTestMockPlatformView* gMockPlatformView = nil;
+const float kFloatCompareEpsilon = 0.001;
 
 @interface FlutterPlatformViewsTestMockPlatformView : UIView
 @end
@@ -143,4 +144,128 @@ - (void)testCanCreatePlatformViewWithoutFlutterView {
   flutterPlatformViewsController->Reset();
 }
 
+- (void)testChildClippingViewHitTests {
+  ChildClippingView *childCilppingView = [[[ChildClippingView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)] autorelease];
+  UIView *childView = [[[UIView alloc] initWithFrame:CGRectMake(100, 100, 100, 100)] autorelease];
+  [childCilppingView addSubview:childView];
+
+  XCTAssertFalse([childCilppingView pointInside:CGPointMake(50, 50) withEvent:nil]);
+  XCTAssertTrue([childCilppingView pointInside:CGPointMake(150, 150) withEvent:nil]);
+}
+
+- (void)testCompositePlatformView {
+  flutter::FlutterPlatformViewsTestMockPlatformViewDelegate mock_delegate;
+  auto thread_task_runner = CreateNewThread("FlutterPlatformViewsTest");
+  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
+                               /*platform=*/thread_task_runner,
+                               /*raster=*/thread_task_runner,
+                               /*ui=*/thread_task_runner,
+                               /*io=*/thread_task_runner);
+  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
+      /*delegate=*/mock_delegate,
+      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
+      /*task_runners=*/runners);
+
+  auto flutterPlatformViewsController = std::make_unique<flutter::FlutterPlatformViewsController>();
+
+  FlutterPlatformViewsTestMockFlutterPlatformFactory* factory =
+      [[FlutterPlatformViewsTestMockFlutterPlatformFactory new] autorelease];
+  flutterPlatformViewsController->RegisterViewFactory(
+      factory, @"MockFlutterPlatformView",
+      FlutterPlatformViewGestureRecognizersBlockingPolicyEager);
+  FlutterResult result = ^(id result) {
+  };
+  flutterPlatformViewsController->OnMethodCall(
+      [FlutterMethodCall
+          methodCallWithMethodName:@"create"
+                         arguments:@{@"id" : @2, @"viewType" : @"MockFlutterPlatformView"}],
+      result);
+
+  XCTAssertNotNil(gMockPlatformView);
+
+  UIView *mockFlutterView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)] autorelease];
+  flutterPlatformViewsController->SetFlutterView(mockFlutterView);
+  // Create embedded view params
+  flutter::MutatorsStack stack;
+  // Layer tree always pushes a screen scale factor to the stack
+  SkMatrix screenScaleMatrix = SkMatrix::MakeScale([UIScreen mainScreen].scale, [UIScreen mainScreen].scale);
+  stack.PushTransform(screenScaleMatrix);
+  // Push a translate matrix
+  SkMatrix translateMatrix = SkMatrix::MakeTrans(100, 100);
+  stack.PushTransform(translateMatrix);
+  SkMatrix finalMatrix;
+  finalMatrix.setConcat(screenScaleMatrix, translateMatrix);
+
+  auto embeddedViewParams = std::make_unique<flutter::EmbeddedViewParams>(finalMatrix, SkSize::Make(300, 300), stack);
+
+  flutterPlatformViewsController->PrerollCompositeEmbeddedView(2, std::move(embeddedViewParams));
+  flutterPlatformViewsController->CompositeEmbeddedView(2);
+  CGRect platformViewRectInFlutterView = [gMockPlatformView convertRect:gMockPlatformView.bounds
+                                                    toView:mockFlutterView];
+  XCTAssertTrue(CGRectEqualToRect(platformViewRectInFlutterView, CGRectMake(100, 100, 300, 300)));
+  flutterPlatformViewsController->Reset();
+}
+
+- (void)testChildClippingViewShouldBeTheBoundingRectOfPlatformView {
+  flutter::FlutterPlatformViewsTestMockPlatformViewDelegate mock_delegate;
+  auto thread_task_runner = CreateNewThread("FlutterPlatformViewsTest");
+  flutter::TaskRunners runners(/*label=*/self.name.UTF8String,
+                               /*platform=*/thread_task_runner,
+                               /*raster=*/thread_task_runner,
+                               /*ui=*/thread_task_runner,
+                               /*io=*/thread_task_runner);
+  auto platform_view = std::make_unique<flutter::PlatformViewIOS>(
+      /*delegate=*/mock_delegate,
+      /*rendering_api=*/flutter::IOSRenderingAPI::kSoftware,
+      /*task_runners=*/runners);
+
+  auto flutterPlatformViewsController = std::make_unique<flutter::FlutterPlatformViewsController>();
+
+  FlutterPlatformViewsTestMockFlutterPlatformFactory* factory =
+      [[FlutterPlatformViewsTestMockFlutterPlatformFactory new] autorelease];
+  flutterPlatformViewsController->RegisterViewFactory(
+      factory, @"MockFlutterPlatformView",
+      FlutterPlatformViewGestureRecognizersBlockingPolicyEager);
+  FlutterResult result = ^(id result) {
+  };
+  flutterPlatformViewsController->OnMethodCall(
+      [FlutterMethodCall
+          methodCallWithMethodName:@"create"
+                         arguments:@{@"id" : @2, @"viewType" : @"MockFlutterPlatformView"}],
+      result);
+
+  XCTAssertNotNil(gMockPlatformView);
+
+  UIView *mockFlutterView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0, 500, 500)] autorelease];
+  flutterPlatformViewsController->SetFlutterView(mockFlutterView);
+  // Create embedded view params
+  flutter::MutatorsStack stack;
+  // Layer tree always pushes a screen scale factor to the stack
+  SkMatrix screenScaleMatrix = SkMatrix::MakeScale([UIScreen mainScreen].scale, [UIScreen mainScreen].scale);
+  stack.PushTransform(screenScaleMatrix);
+  // Push a rotate matrix
+  SkMatrix rotateMatrix;
+  rotateMatrix.setRotate(10);
+  stack.PushTransform(rotateMatrix);
+  SkMatrix finalMatrix;
+  finalMatrix.setConcat(screenScaleMatrix, rotateMatrix);
+
+  auto embeddedViewParams = std::make_unique<flutter::EmbeddedViewParams>(finalMatrix, SkSize::Make(300, 300), stack);
+
+  flutterPlatformViewsController->PrerollCompositeEmbeddedView(2, std::move(embeddedViewParams));
+  flutterPlatformViewsController->CompositeEmbeddedView(2);
+  CGRect platformViewRectInFlutterView = [gMockPlatformView convertRect:gMockPlatformView.bounds
+                                                    toView:mockFlutterView];
+  XCTAssertTrue([gMockPlatformView.superview.superview isKindOfClass: ChildClippingView.class]);
+  ChildClippingView *childClippingView = (ChildClippingView *)gMockPlatformView.superview.superview;
+  // The childclippingview's frame is set based on flow, but the platform view's frame is set based on quartz.
+  // Although they should be the same, but we should tolerate small floating point errors.
+  XCTAssertTrue(fabs(platformViewRectInFlutterView.origin.x - childClippingView.frame.origin.x) < kFloatCompareEpsilon);
+  XCTAssertTrue(fabs(platformViewRectInFlutterView.origin.y - childClippingView.frame.origin.y) < kFloatCompareEpsilon);
+  XCTAssertTrue(fabs(platformViewRectInFlutterView.size.width - childClippingView.frame.size.width) < kFloatCompareEpsilon);
+  XCTAssertTrue(fabs(platformViewRectInFlutterView.size.height - childClippingView.frame.size.height) < kFloatCompareEpsilon);
+
+  flutterPlatformViewsController->Reset();
+}
+
 @end