Revert "PlatformView partial blur"

flow/embedded_views.cc

@@ -100,10 +100,8 @@ void MutatorsStack::PushOpacity(const int& alpha) {
 };
 
 void MutatorsStack::PushBackdropFilter(
-    const std::shared_ptr<const DlImageFilter>& filter,
-    const SkRect& filter_rect) {
-  std::shared_ptr<Mutator> element =
-      std::make_shared<Mutator>(filter, filter_rect);
+    const std::shared_ptr<const DlImageFilter>& filter) {
+  std::shared_ptr<Mutator> element = std::make_shared<Mutator>(filter);
   vector_.push_back(element);
 };
 

flow/embedded_views.h

@@ -32,33 +32,6 @@ enum MutatorType {
   kBackdropFilter
 };
 
-// Represents an image filter mutation.
-//
-// Should be used for image_filter_layer and backdrop_filter_layer.
-// TODO(cyanglaz): Refactor this into a ImageFilterMutator class.
-// https://github.com/flutter/flutter/issues/108470
-class ImageFilterMutation {
- public:
-  ImageFilterMutation(std::shared_ptr<const DlImageFilter> filter,
-                      const SkRect& filter_rect)
-      : filter_(filter), filter_rect_(filter_rect) {}
-
-  const DlImageFilter& GetFilter() const { return *filter_; }
-  const SkRect& GetFilterRect() const { return filter_rect_; }
-
-  bool operator==(const ImageFilterMutation& other) const {
-    return *filter_ == *other.filter_ && filter_rect_ == other.filter_rect_;
-  }
-
-  bool operator!=(const ImageFilterMutation& other) const {
-    return !operator==(other);
-  }
-
- private:
-  std::shared_ptr<const DlImageFilter> filter_;
-  const SkRect filter_rect_;
-};
-
 // Stores mutation information like clipping or kTransform.
 //
 // The `type` indicates the type of the mutation: kClipRect, kTransform and etc.
@@ -86,7 +59,7 @@ class Mutator {
         alpha_ = other.alpha_;
         break;
       case kBackdropFilter:
-        filter_mutation_ = other.filter_mutation_;
+        filter_ = other.filter_;
         break;
       default:
         break;
@@ -100,20 +73,15 @@ class Mutator {
   explicit Mutator(const SkMatrix& matrix)
       : type_(kTransform), matrix_(matrix) {}
   explicit Mutator(const int& alpha) : type_(kOpacity), alpha_(alpha) {}
-  explicit Mutator(std::shared_ptr<const DlImageFilter> filter,
-                   const SkRect& filter_rect)
-      : type_(kBackdropFilter),
-        filter_mutation_(
-            std::make_shared<ImageFilterMutation>(filter, filter_rect)) {}
+  explicit Mutator(std::shared_ptr<const DlImageFilter> filter)
+      : type_(kBackdropFilter), filter_(filter) {}
 
   const MutatorType& GetType() const { return type_; }
   const SkRect& GetRect() const { return rect_; }
   const SkRRect& GetRRect() const { return rrect_; }
   const SkPath& GetPath() const { return *path_; }
   const SkMatrix& GetMatrix() const { return matrix_; }
-  const ImageFilterMutation& GetFilterMutation() const {
-    return *filter_mutation_;
-  }
+  const DlImageFilter& GetFilter() const { return *filter_; }
   const int& GetAlpha() const { return alpha_; }
   float GetAlphaFloat() const { return (alpha_ / 255.0); }
 
@@ -133,7 +101,7 @@ class Mutator {
       case kOpacity:
         return alpha_ == other.alpha_;
       case kBackdropFilter:
-        return *filter_mutation_ == *other.filter_mutation_;
+        return *filter_ == *other.filter_;
     }
 
     return false;
@@ -164,7 +132,8 @@ class Mutator {
     int alpha_;
   };
 
-  std::shared_ptr<ImageFilterMutation> filter_mutation_;
+  std::shared_ptr<const DlImageFilter> filter_;
+
 };  // Mutator
 
 // A stack of mutators that can be applied to an embedded platform view.
@@ -185,8 +154,7 @@ class MutatorsStack {
   void PushClipPath(const SkPath& path);
   void PushTransform(const SkMatrix& matrix);
   void PushOpacity(const int& alpha);
-  void PushBackdropFilter(const std::shared_ptr<const DlImageFilter>& filter,
-                          const SkRect& filter_rect);
+  void PushBackdropFilter(const std::shared_ptr<const DlImageFilter>& filter);
 
   // Removes the `Mutator` on the top of the stack
   // and destroys it.
@@ -284,9 +252,8 @@ class EmbeddedViewParams {
   const SkRect& finalBoundingRect() const { return final_bounding_rect_; }
 
   // Pushes the stored DlImageFilter object to the mutators stack.
-  void PushImageFilter(std::shared_ptr<const DlImageFilter> filter,
-                       const SkRect& filter_rect) {
-    mutators_stack_.PushBackdropFilter(filter, filter_rect);
+  void PushImageFilter(std::shared_ptr<const DlImageFilter> filter) {
+    mutators_stack_.PushBackdropFilter(filter);
   }
 
   // Whether the embedder should construct DisplayList objects to hold the
@@ -490,8 +457,7 @@ class ExternalViewEmbedder {
   // See also: |PushVisitedPlatformView| for pushing platform view ids to the
   // visited platform views list.
   virtual void PushFilterToVisitedPlatformViews(
-      std::shared_ptr<const DlImageFilter> filter,
-      const SkRect& filter_rect) {}
+      std::shared_ptr<const DlImageFilter> filter) {}
 
  private:
   bool used_this_frame_ = false;

flow/layers/backdrop_filter_layer.cc

@@ -43,8 +43,7 @@ void BackdropFilterLayer::Preroll(PrerollContext* context) {
   Layer::AutoPrerollSaveLayerState save =
       Layer::AutoPrerollSaveLayerState::Create(context, true, bool(filter_));
   if (context->view_embedder != nullptr) {
-    context->view_embedder->PushFilterToVisitedPlatformViews(
-        filter_, context->cull_rect);
+    context->view_embedder->PushFilterToVisitedPlatformViews(filter_);
   }
   SkRect child_paint_bounds = SkRect::MakeEmpty();
   PrerollChildren(context, &child_paint_bounds);

flow/mutators_stack_unittests.cc

@@ -94,19 +94,14 @@ TEST(MutatorsStack, PushBackdropFilter) {
   const int num_of_mutators = 10;
   for (int i = 0; i < num_of_mutators; i++) {
     auto filter = std::make_shared<DlBlurImageFilter>(i, 5, DlTileMode::kClamp);
-    stack.PushBackdropFilter(filter, SkRect::MakeXYWH(i, i, i, i));
+    stack.PushBackdropFilter(filter);
   }
 
   auto iter = stack.Begin();
   int i = 0;
   while (iter != stack.End()) {
     ASSERT_EQ(iter->get()->GetType(), MutatorType::kBackdropFilter);
-    ASSERT_EQ(iter->get()->GetFilterMutation().GetFilter().asBlur()->sigma_x(),
-              i);
-    ASSERT_EQ(iter->get()->GetFilterMutation().GetFilterRect().x(), i);
-    ASSERT_EQ(iter->get()->GetFilterMutation().GetFilterRect().x(), i);
-    ASSERT_EQ(iter->get()->GetFilterMutation().GetFilterRect().width(), i);
-    ASSERT_EQ(iter->get()->GetFilterMutation().GetFilterRect().height(), i);
+    ASSERT_EQ(iter->get()->GetFilter().asBlur()->sigma_x(), i);
     ++iter;
     ++i;
   }
@@ -169,7 +164,7 @@ TEST(MutatorsStack, Equality) {
   int alpha = 240;
   stack.PushOpacity(alpha);
   auto filter = std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
-  stack.PushBackdropFilter(filter, SkRect::MakeEmpty());
+  stack.PushBackdropFilter(filter);
 
   MutatorsStack stack_other;
   SkMatrix matrix_other = SkMatrix::Scale(1, 1);
@@ -184,7 +179,7 @@ TEST(MutatorsStack, Equality) {
   stack_other.PushOpacity(other_alpha);
   auto other_filter =
       std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
-  stack_other.PushBackdropFilter(other_filter, SkRect::MakeEmpty());
+  stack_other.PushBackdropFilter(other_filter);
 
   ASSERT_TRUE(stack == stack_other);
 }
@@ -216,9 +211,9 @@ TEST(Mutator, Initialization) {
   ASSERT_TRUE(mutator5.GetType() == MutatorType::kOpacity);
 
   auto filter = std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
-  Mutator mutator6 = Mutator(filter, SkRect::MakeEmpty());
+  Mutator mutator6 = Mutator(filter);
   ASSERT_TRUE(mutator6.GetType() == MutatorType::kBackdropFilter);
-  ASSERT_TRUE(mutator6.GetFilterMutation().GetFilter() == *filter);
+  ASSERT_TRUE(mutator6.GetFilter() == *filter);
 }
 
 TEST(Mutator, CopyConstructor) {
@@ -249,7 +244,7 @@ TEST(Mutator, CopyConstructor) {
   ASSERT_TRUE(mutator5 == copy5);
 
   auto filter = std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
-  Mutator mutator6 = Mutator(filter, SkRect::MakeEmpty());
+  Mutator mutator6 = Mutator(filter);
   Mutator copy6 = Mutator(mutator6);
   ASSERT_TRUE(mutator6 == copy6);
 }
@@ -281,10 +276,9 @@ TEST(Mutator, Equality) {
   Mutator other_mutator5 = Mutator(alpha);
   ASSERT_TRUE(mutator5 == other_mutator5);
 
-  auto filter1 = std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
-  auto filter2 = std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
-  Mutator mutator6 = Mutator(filter1, SkRect::MakeEmpty());
-  Mutator other_mutator6 = Mutator(filter2, SkRect::MakeEmpty());
+  auto filter = std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
+  Mutator mutator6 = Mutator(filter);
+  Mutator other_mutator6 = Mutator(filter);
   ASSERT_TRUE(mutator6 == other_mutator6);
 }
 
@@ -305,8 +299,8 @@ TEST(Mutator, UnEquality) {
   auto filter = std::make_shared<DlBlurImageFilter>(5, 5, DlTileMode::kClamp);
   auto filter2 =
       std::make_shared<DlBlurImageFilter>(10, 10, DlTileMode::kClamp);
-  Mutator mutator3 = Mutator(filter, SkRect::MakeEmpty());
-  Mutator other_mutator3 = Mutator(filter2, SkRect::MakeEmpty());
+  Mutator mutator3 = Mutator(filter);
+  Mutator other_mutator3 = Mutator(filter2);
   ASSERT_TRUE(mutator3 != other_mutator3);
 }
 

shell/common/shell_test_external_view_embedder.cc

@@ -89,11 +89,10 @@ void ShellTestExternalViewEmbedder::PushVisitedPlatformView(int64_t view_id) {
 
 // |ExternalViewEmbedder|
 void ShellTestExternalViewEmbedder::PushFilterToVisitedPlatformViews(
-    std::shared_ptr<const DlImageFilter> filter,
-    const SkRect& filter_rect) {
+    std::shared_ptr<const DlImageFilter> filter) {
   for (int64_t id : visited_platform_views_) {
     EmbeddedViewParams params = current_composition_params_[id];
-    params.PushImageFilter(filter, filter_rect);
+    params.PushImageFilter(filter);
     current_composition_params_[id] = params;
     mutators_stacks_[id] = params.mutatorsStack();
   }

shell/common/shell_test_external_view_embedder.h

@@ -76,8 +76,7 @@ class ShellTestExternalViewEmbedder final : public ExternalViewEmbedder {
 
   // |ExternalViewEmbedder|
   void PushFilterToVisitedPlatformViews(
-      std::shared_ptr<const DlImageFilter> filter,
-      const SkRect& filter_rect) override;
+      std::shared_ptr<const DlImageFilter> filter) override;
 
   // |ExternalViewEmbedder|
   void SubmitFrame(GrDirectContext* context,

shell/common/shell_unittests.cc

@@ -845,7 +845,7 @@ TEST_F(ShellTest, PushBackdropFilterToVisitedPlatformViews) {
   auto filter = DlBlurImageFilter(5, 5, DlTileMode::kClamp);
   auto mutator = *external_view_embedder->GetStack(50).Begin();
   ASSERT_EQ(mutator->GetType(), MutatorType::kBackdropFilter);
-  ASSERT_EQ(mutator->GetFilterMutation().GetFilter(), filter);
+  ASSERT_EQ(mutator->GetFilter(), filter);
 
   DestroyShell(std::move(shell));
 }

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

@@ -321,11 +321,10 @@ - (BOOL)flt_hasFirstResponderInViewHierarchySubtree {
 }
 
 void FlutterPlatformViewsController::PushFilterToVisitedPlatformViews(
-    std::shared_ptr<const DlImageFilter> filter,
-    const SkRect& filter_rect) {
+    std::shared_ptr<const DlImageFilter> filter) {
   for (int64_t id : visited_platform_views_) {
     EmbeddedViewParams params = current_composition_params_[id];
-    params.PushImageFilter(filter, filter_rect);
+    params.PushImageFilter(filter);
     current_composition_params_[id] = params;
   }
 }
@@ -426,7 +425,7 @@ - (BOOL)flt_hasFirstResponderInViewHierarchySubtree {
                                CGRectGetWidth(flutter_view.bounds),
                                CGRectGetHeight(flutter_view.bounds))] autorelease];
 
-  NSMutableArray* blurFilters = [[[NSMutableArray alloc] init] autorelease];
+  NSMutableArray* blurRadii = [[[NSMutableArray alloc] init] autorelease];
 
   auto iter = mutators_stack.Begin();
   while (iter != mutators_stack.End()) {
@@ -449,35 +448,13 @@ - (BOOL)flt_hasFirstResponderInViewHierarchySubtree {
         embedded_view.alpha = (*iter)->GetAlphaFloat() * embedded_view.alpha;
         break;
       case kBackdropFilter: {
-        // Only support DlBlurImageFilter for BackdropFilter.
-        if (!(*iter)->GetFilterMutation().GetFilter().asBlur() || !canApplyBlurBackdrop) {
-          break;
-        }
-        CGRect filterRect =
-            flutter::GetCGRectFromSkRect((*iter)->GetFilterMutation().GetFilterRect());
-        // `filterRect` reprents the rect that should be filtered inside the `flutter_view_`.
-        // The `PlatformViewFilter` needs the frame inside the `clipView` that needs to be
-        // filtered.
-        if (CGRectIsNull(CGRectIntersection(filterRect, clipView.frame))) {
-          break;
-        }
-        CGRect intersection = CGRectIntersection(filterRect, clipView.frame);
-        CGRect frameInClipView = [flutter_view_.get() convertRect:intersection toView:clipView];
-        // sigma_x is arbitrarily chosen as the radius value because Quartz sets
-        // sigma_x and sigma_y equal to each other. DlBlurImageFilter's Tile Mode
-        // is not supported in Quartz's gaussianBlur CAFilter, so it is not used
-        // to blur the PlatformView.
-        CGFloat blurRadius = (*iter)->GetFilterMutation().GetFilter().asBlur()->sigma_x();
-        UIVisualEffectView* visualEffectView = [[[UIVisualEffectView alloc]
-            initWithEffect:[UIBlurEffect effectWithStyle:UIBlurEffectStyleLight]] autorelease];
-        PlatformViewFilter* filter =
-            [[[PlatformViewFilter alloc] initWithFrame:frameInClipView
-                                            blurRadius:blurRadius
-                                      visualEffectView:visualEffectView] autorelease];
-        if (!filter) {
-          canApplyBlurBackdrop = NO;
-        } else {
-          [blurFilters addObject:filter];
+        // We only support DlBlurImageFilter for BackdropFilter.
+        if ((*iter)->GetFilter().asBlur() && canApplyBlurBackdrop) {
+          // sigma_x is arbitrarily chosen as the radius value because Quartz sets
+          // sigma_x and sigma_y equal to each other. DlBlurImageFilter's Tile Mode
+          // is not supported in Quartz's gaussianBlur CAFilter, so it is not used
+          // to blur the PlatformView.
+          [blurRadii addObject:@((*iter)->GetFilter().asBlur()->sigma_x())];
         }
         break;
       }
@@ -486,16 +463,15 @@ - (BOOL)flt_hasFirstResponderInViewHierarchySubtree {
   }
 
   if (canApplyBlurBackdrop) {
-    [clipView applyBlurBackdropFilters:blurFilters];
+    canApplyBlurBackdrop = [clipView applyBlurBackdropFilters:blurRadii];
   }
 
   // Reverse the offset of the clipView.
   // The clipView's frame includes the final translate of the final transform matrix.
-  // Thus, this translate needs to be reversed so the platform view can layout at the correct
-  // offset.
+  // So we need to revese this translate so the platform view can layout at the correct offset.
   //
-  // Note that the transforms are not applied to the clipping paths because clipping paths happen on
-  // the mask view, whose origin is always (0,0) to the flutter_view.
+  // Note that we don't apply this transform matrix the clippings because clippings happen on the
+  // mask view, whose origin is always (0,0) to the flutter_view.
   CATransform3D reverseTranslate =
       CATransform3DMakeTranslation(-clipView.frame.origin.x, -clipView.frame.origin.y, 0);
   embedded_view.layer.transform = CATransform3DConcat(finalTransform, reverseTranslate);

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

@@ -45,54 +45,18 @@
 
 @end
 
-// An object represents a blur filter.
-//
-// This object produces a `backdropFilterView`.
-// To blur a View, add `backdropFilterView` as a subView of the View.
-@interface PlatformViewFilter : NSObject
-
-// Determines the rect of the blur effect in the coordinate system of `backdropFilterView`'s
-// parentView.
-@property(assign, nonatomic, readonly) CGRect frame;
-
-// Determines the blur intensity.
-//
-// It is set as the value of `inputRadius` of the `gaussianFilter` that is internally used.
-@property(assign, nonatomic, readonly) CGFloat blurRadius;
-
-// This is the view to use to blur the PlatformView.
-//
-// It is a modified version of UIKit's `UIVisualEffectView`.
-// The inputRadius can be customized and it doesn't add any color saturation to the blurred view.
-@property(nonatomic, retain, readonly) UIVisualEffectView* backdropFilterView;
-
-// For testing only.
-+ (void)resetPreparation;
-
-- (instancetype)init NS_UNAVAILABLE;
-
-// Initialize the filter object.
-//
-// The `frame` determines the rect of the blur effect in the coordinate system of
-// `backdropFilterView`'s parentView. The `blurRadius` determines the blur intensity. It is set as
-// the value of `inputRadius` of the `gaussianFilter` that is internally used. The
-// `UIVisualEffectView` is the view that is used to add the blur effects. It is modified to become
-// `backdropFilterView`, which better supports the need of Flutter.
-//
-// Note: if the implementation of UIVisualEffectView changes in a way that affects the
-// implementation in `PlatformViewFilter`, this method will return nil.
-- (instancetype)initWithFrame:(CGRect)frame
-                   blurRadius:(CGFloat)blurRadius
-             visualEffectView:(UIVisualEffectView*)visualEffectView NS_DESIGNATED_INITIALIZER;
-
-@end
-
-// The parent view handles clipping to its subViews.
+// The parent view handles clipping to its subviews.
 @interface ChildClippingView : UIView
 
-// Applies blur backdrop filters to the ChildClippingView with blur values from
-// filters.
-- (void)applyBlurBackdropFilters:(NSMutableArray<PlatformViewFilter*>*)filters;
+// Applies blur backdrop filters to the ChildClippingView with blur radius values from
+// blurRadii. Returns NO if Apple's API has changed and blurred backdrop filters cannot
+// be applied, otherwise returns YES.
+- (BOOL)applyBlurBackdropFilters:(NSArray*)blurRadii;
+
+// The UIView used to extract the gaussianBlur filter. This must be a UIVisualEffectView
+// initalized with UIBlurEffect to extract the correct filter. Made a public property
+// for custom unit tests.
+@property(nonatomic, retain) UIView* blurEffectView;
 
 @end
 
@@ -105,9 +69,6 @@ CATransform3D GetCATransform3DFromSkMatrix(const SkMatrix& matrix);
 // The position of the `layer` should be unchanged after resetting the anchor.
 void ResetAnchor(CALayer* layer);
 
-CGRect GetCGRectFromSkRect(const SkRect& clipSkRect);
-BOOL BlurRadiusEqualToBlurRadius(CGFloat radius1, CGFloat radius2);
-
 class IOSContextGL;
 class IOSSurface;
 
@@ -236,8 +197,7 @@ class FlutterPlatformViewsController {
   long FindFirstResponderPlatformViewId();
 
   // Pushes backdrop filter mutation to the mutator stack of each visited platform view.
-  void PushFilterToVisitedPlatformViews(std::shared_ptr<const DlImageFilter> filter,
-                                        const SkRect& filter_rect);
+  void PushFilterToVisitedPlatformViews(std::shared_ptr<const DlImageFilter> filter);
 
   // Pushes the view id of a visted platform view to the list of visied platform views.
   void PushVisitedPlatformView(int64_t view_id) { visited_platform_views_.push_back(view_id); }

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

@@ -55,165 +55,124 @@ void ResetAnchor(CALayer* layer) {
   layer.position = CGPointZero;
 }
 
-CGRect GetCGRectFromSkRect(const SkRect& clipSkRect) {
-  return CGRectMake(clipSkRect.fLeft, clipSkRect.fTop, clipSkRect.fRight - clipSkRect.fLeft,
-                    clipSkRect.fBottom - clipSkRect.fTop);
-}
+}  // namespace flutter
 
-BOOL BlurRadiusEqualToBlurRadius(CGFloat radius1, CGFloat radius2) {
-  const CGFloat epsilon = 0.01;
-  return radius1 - radius2 < epsilon;
+@implementation ChildClippingView {
+  // A gaussianFilter from UIVisualEffectView that can be copied for new backdrop filters.
+  NSObject* _gaussianFilter;
 }
 
-}  // namespace flutter
+// Lazy initializes blurEffectView as the expected UIVisualEffectView. The backdropFilter blur
+// requires this UIVisualEffectView initialization. The lazy initalization is only used to allow
+// custom unit tests.
+- (UIView*)blurEffectView {
+  if (!_blurEffectView) {
+    // blurEffectView is only needed to extract its gaussianBlur filter. It is released after
+    // searching its subviews and extracting the filter.
+    _blurEffectView = [[[UIVisualEffectView alloc]
+        initWithEffect:[UIBlurEffect effectWithStyle:UIBlurEffectStyleLight]] retain];
+  }
+  return _blurEffectView;
+}
 
-@implementation PlatformViewFilter
-
-static NSObject* _gaussianBlurFilter = nil;
-// The index of "_UIVisualEffectBackdropView" in UIVisualEffectView's subViews.
-static NSInteger _indexOfBackdropView = -1;
-// The index of "_UIVisualEffectSubview" in UIVisualEffectView's subViews.
-static NSInteger _indexOfVisualEffectSubview = -1;
-static BOOL _preparedOnce = NO;
-
-- (instancetype)initWithFrame:(CGRect)frame
-                   blurRadius:(CGFloat)blurRadius
-             visualEffectView:(UIVisualEffectView*)visualEffectView {
-  if (self = [super init]) {
-    _frame = frame;
-    _blurRadius = blurRadius;
-    [PlatformViewFilter prepareOnce:visualEffectView];
-    if (![PlatformViewFilter isUIVisualEffectViewImplementationValid]) {
-      FML_DLOG(ERROR) << "Apple's API for UIVisualEffectView changed. Update the implementation to "
-                         "access the gaussianBlur CAFilter.";
-      [self release];
-      return nil;
+// The ChildClippingView's frame is the bounding rect of the platform view. we only want touches to
+// be hit tested and consumed by this view if they are inside the embedded platform view which could
+// be smaller the embedded platform view is rotated.
+- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent*)event {
+  for (UIView* view in self.subviews) {
+    if ([view pointInside:[self convertPoint:point toView:view] withEvent:event]) {
+      return YES;
     }
-    NSObject* gaussianBlurFilter = [[_gaussianBlurFilter copy] autorelease];
-    FML_DCHECK(gaussianBlurFilter);
-    UIView* backdropView = visualEffectView.subviews[_indexOfBackdropView];
-    [gaussianBlurFilter setValue:@(_blurRadius) forKey:@"inputRadius"];
-    backdropView.layer.filters = @[ gaussianBlurFilter ];
-
-    UIView* visualEffectSubview = visualEffectView.subviews[_indexOfVisualEffectSubview];
-    visualEffectSubview.layer.backgroundColor = UIColor.clearColor.CGColor;
-
-    _backdropFilterView = [visualEffectView retain];
-    _backdropFilterView.frame = _frame;
   }
-  return self;
+  return NO;
 }
 
-+ (void)resetPreparation {
-  _preparedOnce = NO;
-  [_gaussianBlurFilter release];
-  _gaussianBlurFilter = nil;
-  _indexOfBackdropView = -1;
-  _indexOfVisualEffectSubview = -1;
-}
+// Creates and initializes a UIVisualEffectView with a UIBlurEffect. Extracts and returns its
+// gaussianFilter. Returns nil if Apple's API has changed and the filter cannot be extracted.
+- (NSObject*)extractGaussianFilter {
+  NSObject* gaussianFilter = nil;
 
-+ (void)prepareOnce:(UIVisualEffectView*)visualEffectView {
-  if (_preparedOnce) {
-    return;
-  }
-  for (NSUInteger i = 0; i < visualEffectView.subviews.count; i++) {
-    UIView* view = visualEffectView.subviews[i];
+  for (UIView* view in self.blurEffectView.subviews) {
     if ([view isKindOfClass:NSClassFromString(@"_UIVisualEffectBackdropView")]) {
-      _indexOfBackdropView = i;
-      for (NSObject* filter in view.layer.filters) {
-        if ([[filter valueForKey:@"name"] isEqual:@"gaussianBlur"] &&
-            [[filter valueForKey:@"inputRadius"] isKindOfClass:[NSNumber class]]) {
-          _gaussianBlurFilter = [filter retain];
+      for (CIFilter* filter in view.layer.filters) {
+        if ([[filter valueForKey:@"name"] isEqual:@"gaussianBlur"]) {
+          if ([[filter valueForKey:@"inputRadius"] isKindOfClass:[NSNumber class]]) {
+            gaussianFilter = filter;
+          }
+          // No need to look at other CIFilters. If the API structure has not changed, the
+          // gaussianBlur filter was succesfully saved. Otherwise, still exit the loop because the
+          // filter cannot be extracted.
           break;
         }
       }
-    } else if ([view isKindOfClass:NSClassFromString(@"_UIVisualEffectSubview")]) {
-      _indexOfVisualEffectSubview = i;
+      // No need to look at other UIViews. If the API structure has not changed, the gaussianBlur
+      // filter was succesfully saved. Otherwise, still exit the loop because the filter cannot
+      // be extracted.
+      break;
     }
   }
-  _preparedOnce = YES;
-}
 
-+ (BOOL)isUIVisualEffectViewImplementationValid {
-  return _indexOfBackdropView > -1 && _indexOfVisualEffectSubview > -1 && _gaussianBlurFilter;
+  return gaussianFilter;
 }
 
-- (void)dealloc {
-  [_backdropFilterView release];
-  _backdropFilterView = nil;
-
-  [super dealloc];
-}
-
-@end
+- (BOOL)applyBlurBackdropFilters:(NSArray*)blurRadii {
+  // The outer if-statement checks for the first time this method is called and _gaussianFilter is
+  // not initialized. The inner if-statement checks if extracting the gaussianBlur was successful.
+  // If it was not successful, this method will not be called again. Thus the if-statements check
+  // for different conditions.
+  if (!_gaussianFilter) {
+    _gaussianFilter = [self extractGaussianFilter];
 
-@interface ChildClippingView ()
-
-@property(retain, nonatomic) NSMutableArray<PlatformViewFilter*>* filters;
-
-@end
-
-@implementation ChildClippingView
-
-// The ChildClippingView's frame is the bounding rect of the platform view. we only want touches to
-// be hit tested and consumed by this view if they are inside the embedded platform view which could
-// be smaller the embedded platform view is rotated.
-- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent*)event {
-  for (UIView* view in self.subviews) {
-    if ([view pointInside:[self convertPoint:point toView:view] withEvent:event]) {
-      return YES;
+    if (!_gaussianFilter) {
+      FML_DLOG(ERROR) << "Apple's API for UIVisualEffectView changed. Update the implementation to "
+                         "access the gaussianBlur CAFilter.";
+      return NO;
     }
   }
-  return NO;
-}
 
-- (void)applyBlurBackdropFilters:(NSMutableArray<PlatformViewFilter*>*)filters {
-  BOOL needUpdateFilterViews = NO;
-  if (self.filters.count != filters.count) {
-    needUpdateFilterViews = YES;
+  BOOL newRadiusValues = NO;
+
+  if ([blurRadii count] != [self.layer.filters count]) {
+    newRadiusValues = YES;
   } else {
-    for (NSUInteger i = 0; i < filters.count; i++) {
-      if (!CGRectEqualToRect(self.filters[i].frame, filters[i].frame) ||
-          !flutter::BlurRadiusEqualToBlurRadius(self.filters[i].blurRadius,
-                                                filters[i].blurRadius)) {
-        needUpdateFilterViews = YES;
+    for (NSUInteger i = 0; i < [blurRadii count]; i++) {
+      if ([self.layer.filters[i] valueForKey:@"inputRadius"] != blurRadii[i]) {
+        newRadiusValues = YES;
+        break;
       }
     }
   }
-  if (needUpdateFilterViews) {
-    // Clear the old filter views.
-    for (PlatformViewFilter* filter in self.filters) {
-      [[filter backdropFilterView] removeFromSuperview];
-    }
-    // Update to the new filters.
-    self.filters = [filters retain];
-    // Add new filter views.
-    for (PlatformViewFilter* filter in self.filters) {
-      UIView* backdropFilterView = [filter backdropFilterView];
-      [self addSubview:backdropFilterView];
+
+  if (newRadiusValues) {
+    NSMutableArray* newGaussianFilters = [[[NSMutableArray alloc] init] autorelease];
+
+    for (NSUInteger i = 0; i < [blurRadii count]; i++) {
+      NSObject* newGaussianFilter = [[_gaussianFilter copy] autorelease];
+      [newGaussianFilter setValue:blurRadii[i] forKey:@"inputRadius"];
+      [newGaussianFilters addObject:newGaussianFilter];
     }
+
+    self.layer.filters = newGaussianFilters;
   }
+
+  return YES;
 }
 
 - (void)dealloc {
-  [_filters release];
-  _filters = nil;
+  [_blurEffectView release];
+  _blurEffectView = nil;
 
+  [_gaussianFilter release];
+  _gaussianFilter = nil;
   [super dealloc];
 }
 
-- (NSMutableArray*)filters {
-  if (!_filters) {
-    _filters = [[[NSMutableArray alloc] init] retain];
-  }
-  return _filters;
-}
-
 @end
 
 @interface FlutterClippingMaskView ()
 
 - (fml::CFRef<CGPathRef>)getTransformedPath:(CGPathRef)path matrix:(CATransform3D)matrix;
+- (CGRect)getCGRectFromSkRect:(const SkRect&)clipSkRect;
 
 @end
 
@@ -253,7 +212,7 @@ - (void)drawRect:(CGRect)rect {
 }
 
 - (void)clipRect:(const SkRect&)clipSkRect matrix:(const CATransform3D&)matrix {
-  CGRect clipRect = flutter::GetCGRectFromSkRect(clipSkRect);
+  CGRect clipRect = [self getCGRectFromSkRect:clipSkRect];
   CGPathRef path = CGPathCreateWithRect(clipRect, nil);
   paths_.push_back([self getTransformedPath:path matrix:matrix]);
 }
@@ -270,7 +229,7 @@ - (void)clipRRect:(const SkRRect&)clipSkRRect matrix:(const CATransform3D&)matri
     }
     case SkRRect::kOval_Type:
     case SkRRect::kSimple_Type: {
-      CGRect clipRect = flutter::GetCGRectFromSkRect(clipSkRRect.rect());
+      CGRect clipRect = [self getCGRectFromSkRect:clipSkRRect.rect()];
       pathRef = CGPathCreateWithRoundedRect(clipRect, clipSkRRect.getSimpleRadii().x(),
                                             clipSkRRect.getSimpleRadii().y(), nil);
       break;
@@ -337,7 +296,7 @@ - (void)clipPath:(const SkPath&)path matrix:(const CATransform3D&)matrix {
   SkPath::Iter iter(path, true);
   SkPoint pts[kMaxPointsInVerb];
   SkPath::Verb verb = iter.next(pts);
-  SkPoint last_pt_from_last_verb = SkPoint::Make(0, 0);
+  SkPoint last_pt_from_last_verb;
   while (verb != SkPath::kDone_Verb) {
     if (verb == SkPath::kLine_Verb || verb == SkPath::kQuad_Verb || verb == SkPath::kConic_Verb ||
         verb == SkPath::kCubic_Verb) {
@@ -394,4 +353,9 @@ - (void)clipPath:(const SkPath&)path matrix:(const CATransform3D&)matrix {
   return fml::CFRef<CGPathRef>(transformedPath);
 }
 
+- (CGRect)getCGRectFromSkRect:(const SkRect&)clipSkRect {
+  return CGRectMake(clipSkRect.fLeft, clipSkRect.fTop, clipSkRect.fRight - clipSkRect.fLeft,
+                    clipSkRect.fBottom - clipSkRect.fTop);
+}
+
 @end

shell/platform/darwin/ios/ios_external_view_embedder.h

@@ -69,8 +69,7 @@ class IOSExternalViewEmbedder : public ExternalViewEmbedder {
 
   // |ExternalViewEmbedder|
   void PushFilterToVisitedPlatformViews(
-      std::shared_ptr<const DlImageFilter> filter,
-      const SkRect& filter_rect) override;
+      std::shared_ptr<const DlImageFilter> filter) override;
 
   // |ExternalViewEmbedder|
   void PushVisitedPlatformView(int64_t view_id) override;

shell/platform/darwin/ios/ios_external_view_embedder.mm

@@ -100,9 +100,8 @@
 
 // |ExternalViewEmbedder|
 void IOSExternalViewEmbedder::PushFilterToVisitedPlatformViews(
-    std::shared_ptr<const DlImageFilter> filter,
-    const SkRect& filter_rect) {
-  platform_views_controller_->PushFilterToVisitedPlatformViews(filter, filter_rect);
+    std::shared_ptr<const DlImageFilter> filter) {
+  platform_views_controller_->PushFilterToVisitedPlatformViews(filter);
 }
 
 // |ExternalViewEmbedder|