iOS PlatformView clip path (flutter#9478)

darrenaustin · Jul 2, 2019 · a9ee687 · a9ee687
1 parent c19b53c
commit a9ee687
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Showing 7 changed files with 107 additions and 14 deletions.
diff --git a/flow/embedded_views.cc b/flow/embedded_views.cc
@@ -20,6 +20,11 @@ void MutatorsStack::pushClipRRect(const SkRRect& rrect) {
   vector_.push_back(element);
 };
 
+void MutatorsStack::pushClipPath(const SkPath& path) {
+  std::shared_ptr<Mutator> element = std::make_shared<Mutator>(path);
+  vector_.push_back(element);
+};
+
 void MutatorsStack::pushTransform(const SkMatrix& matrix) {
   std::shared_ptr<Mutator> element = std::make_shared<Mutator>(matrix);
   vector_.push_back(element);

diff --git a/flow/embedded_views.h b/flow/embedded_views.h
@@ -120,7 +120,6 @@ class MutatorsStack {
   void pushClipRect(const SkRect& rect);
   void pushClipRRect(const SkRRect& rrect);
   void pushClipPath(const SkPath& path);
-
   void pushTransform(const SkMatrix& matrix);
 
   // Removes the `Mutator` on the top of the stack

diff --git a/flow/layers/clip_path_layer.cc b/flow/layers/clip_path_layer.cc
@@ -60,13 +60,16 @@ void ClipPathLayer::Paint(PaintContext& context) const {
   SkAutoCanvasRestore save(context.internal_nodes_canvas, true);
   context.internal_nodes_canvas->clipPath(clip_path_,
                                           clip_behavior_ != Clip::hardEdge);
+  context.mutators_stack.pushClipPath(clip_path_);
+
   if (clip_behavior_ == Clip::antiAliasWithSaveLayer) {
     context.internal_nodes_canvas->saveLayer(paint_bounds(), nullptr);
   }
   PaintChildren(context);
   if (clip_behavior_ == Clip::antiAliasWithSaveLayer) {
     context.internal_nodes_canvas->restore();
   }
+  context.mutators_stack.pop();
 }
 
 }  // namespace flutter
diff --git a/flow/mutators_stack_unittests.cc b/flow/mutators_stack_unittests.cc
@@ -41,6 +41,15 @@ TEST(MutatorsStack, PushClipRRect) {
   ASSERT_TRUE(iter->get()->rrect() == rrect);
 }
 
+TEST(MutatorsStack, PushClipPath) {
+  flutter::MutatorsStack stack;
+  SkPath path;
+  stack.pushClipPath(path);
+  auto iter = stack.bottom();
+  ASSERT_TRUE(iter->get()->type() == flutter::MutatorType::clip_path);
+  ASSERT_TRUE(iter->get()->path() == path);
+}
+
 TEST(MutatorsStack, PushTransform) {
   MutatorsStack stack;
   SkMatrix matrix;
@@ -102,6 +111,8 @@ TEST(MutatorsStack, Equality) {
   stack.pushClipRect(rect);
   SkRRect rrect = SkRRect::MakeEmpty();
   stack.pushClipRRect(rrect);
+  SkPath path;
+  stack.pushClipPath(path);
 
   MutatorsStack stackOther;
   SkMatrix matrixOther = SkMatrix::MakeScale(1, 1);
@@ -110,6 +121,8 @@ TEST(MutatorsStack, Equality) {
   stackOther.pushClipRect(rectOther);
   SkRRect rrectOther = SkRRect::MakeEmpty();
   stackOther.pushClipRRect(rrectOther);
+  SkPath otherPath;
+  stackOther.pushClipPath(otherPath);
 
   ASSERT_TRUE(stack == stackOther);
 }
@@ -177,6 +190,10 @@ TEST(Mutator, Equality) {
   Mutator otherMutator3 = Mutator(rrect);
   ASSERT_TRUE(mutator3 == otherMutator3);
 
+  SkPath path;
+  flutter::Mutator mutator4 = flutter::Mutator(path);
+  flutter::Mutator otherMutator4 = flutter::Mutator(path);
+  ASSERT_TRUE(mutator4 == otherMutator4);
   ASSERT_FALSE(mutator2 == mutator);
 }
 

diff --git a/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm b/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews.mm
@@ -261,7 +261,6 @@
     }
     ++iter;
   }
-
   // Reverse scale based on screen scale.
   //
   // The UIKit frame is set based on the logical resolution instead of physical.
@@ -363,7 +362,6 @@
     UIView* platform_view_root = root_views_[view_id].get();
     UIView* overlay = overlays_[view_id]->overlay_view;
     FML_CHECK(platform_view_root.superview == overlay.superview);
-
     if (platform_view_root.superview == flutter_view) {
       [flutter_view bringSubviewToFront:platform_view_root];
       [flutter_view bringSubviewToFront:overlay];

diff --git a/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.h b/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.h
@@ -42,7 +42,6 @@
 @end
 
 namespace flutter {
-
 // Converts a SkMatrix to CATransform3D.
 // Certain fields are ignored in CATransform3D since SkMatrix is 3x3 and CATransform3D is 4x4.
 CATransform3D GetCATransform3DFromSkMatrix(const SkMatrix& matrix);
@@ -85,8 +84,8 @@ class FlutterPlatformViewsController {
   // Returns the `FlutterPlatformView` object associated with the view_id.
   //
   // If the `FlutterPlatformViewsController` does not contain any `FlutterPlatformView` object or
-  // a `FlutterPlatformView` object asscociated with the view_id cannot be found, the method returns
-  // nil.
+  // a `FlutterPlatformView` object asscociated with the view_id cannot be found, the method
+  // returns nil.
   NSObject<FlutterPlatformView>* GetPlatformViewByID(int view_id);
 
   std::vector<SkCanvas*> GetCurrentCanvases();
@@ -109,8 +108,8 @@ class FlutterPlatformViewsController {
   std::map<std::string, fml::scoped_nsobject<NSObject<FlutterPlatformViewFactory>>> factories_;
   std::map<int64_t, fml::scoped_nsobject<NSObject<FlutterPlatformView>>> views_;
   std::map<int64_t, fml::scoped_nsobject<FlutterTouchInterceptingView>> touch_interceptors_;
-  // Mapping a platform view ID to the top most parent view (root_view) who is a direct child to the
-  // `flutter_view_`.
+  // Mapping a platform view ID to the top most parent view (root_view) who is a direct child to
+  // the `flutter_view_`.
   //
   // The platform view with the view ID is a child of the root view; If the platform view is not
   // clipped, and no clipping view is added, the root view will be the intercepting view.
@@ -152,6 +151,7 @@ class FlutterPlatformViewsController {
   void EnsureGLOverlayInitialized(int64_t overlay_id,
                                   std::shared_ptr<IOSGLContext> gl_context,
                                   GrContext* gr_context);
+
   // Traverse the `mutators_stack` and return the number of clip operations.
   int CountClips(const MutatorsStack& mutators_stack);
 
@@ -172,10 +172,10 @@ class FlutterPlatformViewsController {
   // Applies the mutators in the mutators_stack to the UIView chain that was constructed by
   // `ReconstructClipViewsChain`
   //
-  // Clips are applied to the super view with a CALayer mask. Transforms are applied to the current
-  // view that's at the head of the chain. For example the following mutators stack [T_1, C_2, T_3,
-  // T_4, C_5, T_6] where T denotes a transform and C denotes a clip, will result in the following
-  // UIView tree:
+  // Clips are applied to the super view with a CALayer mask. Transforms are applied to the
+  // current view that's at the head of the chain. For example the following mutators stack [T_1,
+  // C_2, T_3, T_4, C_5, T_6] where T denotes a transform and C denotes a clip, will result in the
+  // following UIView tree:
   //
   // C_2 -> C_5 -> PLATFORM_VIEW
   // (PLATFORM_VIEW is a subview of C_5 which is a subview of C_2)
@@ -184,7 +184,6 @@ class FlutterPlatformViewsController {
   //
   // After each clip operation, we update the head to the super view of the current head.
   void ApplyMutators(const MutatorsStack& mutators_stack, UIView* embedded_view);
-
   void CompositeWithParams(int view_id, const flutter::EmbeddedViewParams& params);
 
   FML_DISALLOW_COPY_AND_ASSIGN(FlutterPlatformViewsController);

diff --git a/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.mm b/shell/platform/darwin/ios/framework/Source/FlutterPlatformViews_Internal.mm
@@ -6,6 +6,8 @@
 
 #include "flutter/shell/platform/darwin/ios/ios_surface.h"
 
+static int kMaxPointsInVerb = 4;
+
 namespace flutter {
 
 FlutterPlatformViewLayer::FlutterPlatformViewLayer(fml::scoped_nsobject<UIView> overlay_view,
@@ -129,6 +131,76 @@ - (void)clipRRect:(const SkRRect&)clipSkRRect {
   CGPathRelease(pathRef);
 }
 
+- (void)clipPath:(const SkPath&)path {
+  CGMutablePathRef pathRef = CGPathCreateMutable();
+  if (!path.isValid()) {
+    return;
+  }
+  if (path.isEmpty()) {
+    CAShapeLayer* clip = [[CAShapeLayer alloc] init];
+    clip.path = pathRef;
+    self.layer.mask = clip;
+    CGPathRelease(pathRef);
+    return;
+  }
+
+  // Loop through all verbs and translate them into CGPath
+  SkPath::Iter iter(path, true);
+  SkPoint pts[kMaxPointsInVerb];
+  SkPath::Verb verb = iter.next(pts);
+  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) {
+      FML_DCHECK(last_pt_from_last_verb == pts[0]);
+    }
+    switch (verb) {
+      case SkPath::kMove_Verb: {
+        CGPathMoveToPoint(pathRef, nil, pts[0].x(), pts[0].y());
+        last_pt_from_last_verb = pts[0];
+        break;
+      }
+      case SkPath::kLine_Verb: {
+        CGPathAddLineToPoint(pathRef, nil, pts[1].x(), pts[1].y());
+        last_pt_from_last_verb = pts[1];
+        break;
+      }
+      case SkPath::kQuad_Verb: {
+        CGPathAddQuadCurveToPoint(pathRef, nil, pts[1].x(), pts[1].y(), pts[2].x(), pts[2].y());
+        last_pt_from_last_verb = pts[2];
+        break;
+      }
+      case SkPath::kConic_Verb: {
+        // Conic is not available in quartz, we use quad to approximate.
+        // TODO(cyanglaz): Better approximate the conic path.
+        // https://github.com/flutter/flutter/issues/35062
+        CGPathAddQuadCurveToPoint(pathRef, nil, pts[1].x(), pts[1].y(), pts[2].x(), pts[2].y());
+        last_pt_from_last_verb = pts[2];
+        break;
+      }
+      case SkPath::kCubic_Verb: {
+        CGPathAddCurveToPoint(pathRef, nil, pts[1].x(), pts[1].y(), pts[2].x(), pts[2].y(),
+                              pts[3].x(), pts[3].y());
+        last_pt_from_last_verb = pts[3];
+        break;
+      }
+      case SkPath::kClose_Verb: {
+        CGPathCloseSubpath(pathRef);
+        break;
+      }
+      case SkPath::kDone_Verb: {
+        break;
+      }
+    }
+    verb = iter.next(pts);
+  }
+
+  CAShapeLayer* clip = [[CAShapeLayer alloc] init];
+  clip.path = pathRef;
+  self.layer.mask = clip;
+  CGPathRelease(pathRef);
+}
+
 - (void)setClip:(flutter::MutatorType)type
            rect:(const SkRect&)rect
           rrect:(const SkRRect&)rrect
@@ -143,7 +215,7 @@ - (void)setClip:(flutter::MutatorType)type
       [self clipRRect:rrect];
       break;
     case flutter::clip_path:
-      // TODO(cyanglaz): Add clip path
+      [self clipPath:path];
       break;
     default:
       break;