Add warning message when PlatformView's origin is not 0

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

@@ -454,7 +454,25 @@ - (BOOL)flt_hasFirstResponderInViewHierarchySubtree {
 void FlutterPlatformViewsController::CompositeWithParams(int view_id,
                                                          const EmbeddedViewParams& params) {
   CGRect frame = CGRectMake(0, 0, params.sizePoints().width(), params.sizePoints().height());
-  UIView* touchInterceptor = touch_interceptors_[view_id].get();
+  FlutterTouchInterceptingView* touchInterceptor = touch_interceptors_[view_id].get();
+#if FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DEBUG
+  FML_DCHECK(CGPointEqualToPoint([touchInterceptor embeddedView].frame.origin, CGPointZero));
+  if (non_zero_origin_views_.find(view_id) == non_zero_origin_views_.end() &&
+      !CGPointEqualToPoint([touchInterceptor embeddedView].frame.origin, CGPointZero)) {
+    non_zero_origin_views_.insert(view_id);
+    NSLog(
+        @"A Embedded PlatformView's origin is not CGPointZero.\n"
+         "  View id: %@\n"
+         "  View info: \n %@ \n"
+         "A non-zero origin might cause undefined behavior.\n"
+         "See https://github.com/flutter/flutter/issues/109700 for more details.\n"
+         "If you are the author of the PlatformView, please update the implementation of the "
+         "PlatformView to have a (0, 0) origin.\n"
+         "If you have a valid case of using a non-zero origin, "
+         "please leave a comment at https://github.com/flutter/flutter/issues/109700 with details.",
+        @(view_id), [touchInterceptor embeddedView]);
+  }
+#endif
   touchInterceptor.layer.transform = CATransform3DIdentity;
   touchInterceptor.frame = frame;
   touchInterceptor.alpha = 1;

shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.h

@@ -307,6 +307,14 @@ class FlutterPlatformViewsController {
 
   // WeakPtrFactory must be the last member.
   std::unique_ptr<fml::WeakPtrFactory<FlutterPlatformViewsController>> weak_factory_;
+
+#if FLUTTER_RUNTIME_MODE == FLUTTER_RUNTIME_MODE_DEBUG
+  // A set to keep track of embedded views that does not have (0, 0) origin.
+  // An insertion triggers a warning message about non-zero origin logged on the debug console.
+  // See https://github.com/flutter/flutter/issues/109700 for details.
+  std::unordered_set<int64_t> non_zero_origin_views_;
+#endif
+
   FML_DISALLOW_COPY_AND_ASSIGN(FlutterPlatformViewsController);
 };
 

testing/scenario_app/ios/Scenarios/Scenarios/TextPlatformView.m

@@ -65,6 +65,7 @@ @interface TextPlatformView () <TestGestureRecognizerDelegate>
 @end
 
 @implementation TextPlatformView {
+  UIView* _containerView;
   UITextView* _textView;
   FlutterMethodChannel* _channel;
   BOOL _viewCreated;
@@ -75,18 +76,26 @@ - (instancetype)initWithFrame:(CGRect)frame
                     arguments:(id _Nullable)args
               binaryMessenger:(NSObject<FlutterBinaryMessenger>*)messenger {
   if ([super init]) {
-    _textView = [[UITextView alloc] initWithFrame:CGRectMake(50.0, 50.0, 250.0, 100.0)];
-    _textView.textColor = UIColor.blueColor;
+    _containerView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 250, 100)];
+    _containerView.backgroundColor = UIColor.lightGrayColor;
+    _containerView.clipsToBounds = YES;
+    _containerView.accessibilityIdentifier = @"platform_view";
+
+    _textView = [[UITextView alloc] initWithFrame:CGRectMake(50.0, 50.0, 250, 100)];
     _textView.backgroundColor = UIColor.lightGrayColor;
+    _textView.textColor = UIColor.blueColor;
     [_textView setFont:[UIFont systemFontOfSize:52]];
     _textView.text = args;
-    _textView.accessibilityIdentifier = @"platform_view";
+    _textView.autoresizingMask =
+        (UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight);
+    [_containerView addSubview:_textView];
 
     TestTapGestureRecognizer* gestureRecognizer =
         [[TestTapGestureRecognizer alloc] initWithTarget:self action:@selector(platformViewTapped)];
 
     [_textView addGestureRecognizer:gestureRecognizer];
     gestureRecognizer.testTapGestureRecognizerDelegate = self;
+
     _textView.accessibilityLabel = @"";
 
     _viewCreated = NO;
@@ -100,7 +109,7 @@ - (UIView*)view {
     abort();
   }
   _viewCreated = YES;
-  return _textView;
+  return _containerView;
 }
 
 - (void)platformViewTapped {

testing/scenario_app/ios/Scenarios/ScenariosUITests/PlatformViewGestureRecognizerTests.m

@@ -28,24 +28,25 @@ - (void)testRejectPolicyUtilTouchesEnded {
         XCUIElement* element = evaluatedObject;
         return [element.identifier hasPrefix:@"platform_view"];
       }];
-  XCUIElement* platformView = [app.textViews elementMatchingPredicate:predicateToFindPlatformView];
-  if (![platformView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
+  XCUIElement* textView =
+      [app.otherElements elementMatchingPredicate:predicateToFindPlatformView].textViews.firstMatch;
+  if (![textView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
     NSLog(@"%@", app.debugDescription);
-    XCTFail(@"Failed due to not able to find any platformView with %@ seconds",
+    XCTFail(@"Failed due to not able to find any textView with %@ seconds",
             @(kSecondsToWaitForPlatformView));
   }
 
-  XCTAssertNotNil(platformView);
-  XCTAssertEqualObjects(platformView.label, @"");
+  XCTAssertNotNil(textView);
+  XCTAssertEqualObjects(textView.label, @"");
 
   NSPredicate* predicate =
       [NSPredicate predicateWithFormat:@"label == %@", @"-gestureTouchesBegan-gestureTouchesEnded"];
   XCTNSPredicateExpectation* exception =
-      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:platformView];
+      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:textView];
 
-  [platformView tap];
+  [textView tap];
   [self waitForExpectations:@[ exception ] timeout:kSecondsToWaitForPlatformView];
-  XCTAssertEqualObjects(platformView.label, @"-gestureTouchesBegan-gestureTouchesEnded");
+  XCTAssertEqualObjects(textView.label, @"-gestureTouchesBegan-gestureTouchesEnded");
 }
 
 - (void)testRejectPolicyEager {
@@ -59,15 +60,16 @@ - (void)testRejectPolicyEager {
         XCUIElement* element = evaluatedObject;
         return [element.identifier hasPrefix:@"platform_view"];
       }];
-  XCUIElement* platformView = [app.textViews elementMatchingPredicate:predicateToFindPlatformView];
-  if (![platformView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
+  XCUIElement* textView =
+      [app.otherElements elementMatchingPredicate:predicateToFindPlatformView].textViews.firstMatch;
+  if (![textView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
     NSLog(@"%@", app.debugDescription);
-    XCTFail(@"Failed due to not able to find any platformView with %@ seconds",
+    XCTFail(@"Failed due to not able to find any textView with %@ seconds",
             @(kSecondsToWaitForPlatformView));
   }
 
-  XCTAssertNotNil(platformView);
-  XCTAssertEqualObjects(platformView.label, @"");
+  XCTAssertNotNil(textView);
+  XCTAssertEqualObjects(textView.label, @"");
 
   NSPredicate* predicate =
       [NSPredicate predicateWithBlock:^BOOL(id _Nullable evaluatedObject,
@@ -76,11 +78,11 @@ - (void)testRejectPolicyEager {
         return [view.label containsString:@"-gestureTouchesBegan"];
       }];
   XCTNSPredicateExpectation* exception =
-      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:platformView];
+      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:textView];
 
-  [platformView tap];
+  [textView tap];
   [self waitForExpectations:@[ exception ] timeout:kSecondsToWaitForPlatformView];
-  XCTAssertTrue([platformView.label containsString:@"-gestureTouchesBegan"]);
+  XCTAssertTrue([textView.label containsString:@"-gestureTouchesBegan"]);
 }
 
 - (void)testAccept {
@@ -94,26 +96,27 @@ - (void)testAccept {
         XCUIElement* element = evaluatedObject;
         return [element.identifier hasPrefix:@"platform_view"];
       }];
-  XCUIElement* platformView = [app.textViews elementMatchingPredicate:predicateToFindPlatformView];
-  if (![platformView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
+  XCUIElement* textView =
+      [app.otherElements elementMatchingPredicate:predicateToFindPlatformView].textViews.firstMatch;
+  if (![textView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
     NSLog(@"%@", app.debugDescription);
-    XCTFail(@"Failed due to not able to find any platformView with %@ seconds",
+    XCTFail(@"Failed due to not able to find any textView with %@ seconds",
             @(kSecondsToWaitForPlatformView));
   }
 
-  XCTAssertNotNil(platformView);
-  XCTAssertEqualObjects(platformView.label, @"");
+  XCTAssertNotNil(textView);
+  XCTAssertEqualObjects(textView.label, @"");
 
   NSPredicate* predicate = [NSPredicate
       predicateWithFormat:@"label == %@",
                           @"-gestureTouchesBegan-gestureTouchesEnded-platformViewTapped"];
   XCTNSPredicateExpectation* exception =
-      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:platformView];
+      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:textView];
 
-  [platformView tap];
+  [textView tap];
 
   [self waitForExpectations:@[ exception ] timeout:kSecondsToWaitForPlatformView];
-  XCTAssertEqualObjects(platformView.label,
+  XCTAssertEqualObjects(textView.label,
                         @"-gestureTouchesBegan-gestureTouchesEnded-platformViewTapped");
 }
 
@@ -128,30 +131,31 @@ - (void)testGestureWithMaskViewBlockingPlatformView {
         XCUIElement* element = evaluatedObject;
         return [element.identifier hasPrefix:@"platform_view"];
       }];
-  XCUIElement* platformView = [app.textViews elementMatchingPredicate:predicateToFindPlatformView];
-  if (![platformView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
+  XCUIElement* textView =
+      [app.otherElements elementMatchingPredicate:predicateToFindPlatformView].textViews.firstMatch;
+  if (![textView waitForExistenceWithTimeout:kSecondsToWaitForPlatformView]) {
     NSLog(@"%@", app.debugDescription);
     XCTFail(@"Failed due to not able to find any platformView with %@ seconds",
             @(kSecondsToWaitForPlatformView));
   }
 
-  XCTAssertNotNil(platformView);
-  XCTAssertEqualObjects(platformView.label, @"");
+  XCTAssertNotNil(textView);
+  XCTAssertEqualObjects(textView.label, @"");
 
   NSPredicate* predicate = [NSPredicate
       predicateWithFormat:@"label == %@",
                           @"-gestureTouchesBegan-gestureTouchesEnded-platformViewTapped"];
   XCTNSPredicateExpectation* exception =
-      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:platformView];
+      [[XCTNSPredicateExpectation alloc] initWithPredicate:predicate object:textView];
 
   XCUICoordinate* coordinate =
       [self getNormalizedCoordinate:app
-                              point:CGVectorMake(platformView.frame.origin.x + 10,
-                                                 platformView.frame.origin.y + 10)];
+                              point:CGVectorMake(textView.frame.origin.x + 10,
+                                                 textView.frame.origin.y + 10)];
   [coordinate tap];
 
   [self waitForExpectations:@[ exception ] timeout:kSecondsToWaitForPlatformView];
-  XCTAssertEqualObjects(platformView.label,
+  XCTAssertEqualObjects(textView.label,
                         @"-gestureTouchesBegan-gestureTouchesEnded-platformViewTapped");
 }