IOS Platform view transform/clipping

flow/embedded_views.cc

@@ -6,7 +6,46 @@
 
 namespace flutter {
 
+ExternalViewEmbedder::ExternalViewEmbedder()
+    : transformStack(std::make_shared<EmbeddedViewMutatorStack>()){};
+
 bool ExternalViewEmbedder::SubmitFrame(GrContext* context) {
   return false;
 };
+
+void EmbeddedViewMutatorStack::pushClipRect(const SkRect& rect) {
+  EmbeddedViewMutator element = EmbeddedViewMutator();
+  element.setType(clip_rect);
+  element.setRect(rect);
+  vector_.push_back(element);
+};
+
+void EmbeddedViewMutatorStack::pushClipRRect(const SkRRect& rrect) {
+  EmbeddedViewMutator element = EmbeddedViewMutator();
+  element.setType(clip_rrect);
+  element.setRRect(rrect);
+  vector_.push_back(element);
+};
+
+void EmbeddedViewMutatorStack::pushTransform(const SkMatrix& matrix) {
+  EmbeddedViewMutator element = EmbeddedViewMutator();
+  element.setType(transform);
+  element.setMatrix(matrix);
+  vector_.push_back(element);
+};
+
+void EmbeddedViewMutatorStack::pop() {
+  vector_.pop_back();
+}
+
+std::vector<EmbeddedViewMutator>::reverse_iterator
+EmbeddedViewMutatorStack::rbegin() {
+  return vector_.rbegin();
+}
+
+std::vector<EmbeddedViewMutator>::reverse_iterator
+EmbeddedViewMutatorStack::rend() {
+  return vector_.rend();
+}
+
 }  // namespace flutter

flow/embedded_views.h

@@ -9,18 +9,27 @@
 
 #include "flutter/fml/memory/ref_counted.h"
 #include "third_party/skia/include/core/SkCanvas.h"
+#include "third_party/skia/include/core/SkPath.h"
 #include "third_party/skia/include/core/SkPoint.h"
+#include "third_party/skia/include/core/SkRRect.h"
+#include "third_party/skia/include/core/SkRect.h"
 #include "third_party/skia/include/core/SkSize.h"
 
 namespace flutter {
 
+class EmbeddedViewMutatorStack;
+class EmbeddedViewMutator;
+
 class EmbeddedViewParams {
  public:
   SkPoint offsetPixels;
   SkSize sizePoints;
+  std::shared_ptr<EmbeddedViewMutatorStack> transformStack;
 
   bool operator==(const EmbeddedViewParams& other) const {
-    return offsetPixels == other.offsetPixels && sizePoints == other.sizePoints;
+    return offsetPixels == other.offsetPixels &&
+           sizePoints == other.sizePoints &&
+           transformStack == other.transformStack;
   }
 };
 
@@ -29,7 +38,7 @@ class EmbeddedViewParams {
 // FlutterPlatformViewsController which is owned by FlutterViewController.
 class ExternalViewEmbedder {
  public:
-  ExternalViewEmbedder() = default;
+  ExternalViewEmbedder();
 
   virtual void BeginFrame(SkISize frame_size) = 0;
 
@@ -46,7 +55,86 @@ class ExternalViewEmbedder {
   virtual ~ExternalViewEmbedder() = default;
 
   FML_DISALLOW_COPY_AND_ASSIGN(ExternalViewEmbedder);
-};
+
+  std::shared_ptr<EmbeddedViewMutatorStack> transformStack;
+
+};  // ExternalViewEmbedder
+
+class EmbeddedViewMutatorStack {
+ public:
+  void pushClipRect(const SkRect& rect);
+  void pushClipRRect(const SkRRect& rrect);
+  void pushClipPath(const SkPath& path);
+
+  void pushTransform(const SkMatrix& matrix);
+
+  // Removes the `EmbeddedViewMutator` on the top of the stack
+  // and destroys it.
+  void pop();
+
+  // Returns the iterator points to the bottom of the stack.
+  // When we composite a embedded view, this is the first mutator we should
+  // apply to the view. And we should iterate through all the mutators until we
+  // reach `rend()` and apply all the mutations to the view along the way.
+  std::vector<EmbeddedViewMutator>::reverse_iterator rbegin();
+  // Returns the iterator points to the top of the stack.
+  // When we composite a embedded view, this is the last mutator we apply to the
+  // view.
+  std::vector<EmbeddedViewMutator>::reverse_iterator rend();
+
+  bool operator==(const EmbeddedViewMutatorStack& other) const {
+    return vector_ == other.vector_;
+  }
+
+ private:
+  std::vector<EmbeddedViewMutator> vector_;
+};  // EmbeddedViewMutatorStack
+
+enum EmbeddedViewMutationType { clip_rect, clip_rrect, clip_path, transform };
+
+class EmbeddedViewMutator {
+ public:
+  void setType(const EmbeddedViewMutationType type) { type_ = type; }
+  void setRect(const SkRect& rect) { rect_ = rect; }
+  void setRRect(const SkRRect& rrect) { rrect_ = rrect; }
+  void setMatrix(const SkMatrix& matrix) { matrix_ = matrix; }
+
+  EmbeddedViewMutationType type() { return type_; }
+  SkRect rect() { return rect_; }
+  SkRRect rrect() { return rrect_; }
+  SkPath path() { return path_; }
+  SkMatrix matrix() { return matrix_; }
+
+  bool operator==(const EmbeddedViewMutator& other) const {
+    if (type_ != other.type_) {
+      return false;
+    }
+    if (type_ == clip_rect && rect_ == other.rect_) {
+      return true;
+    }
+    if (type_ == clip_rect && rrect_ == other.rrect_) {
+      return true;
+    }
+    if (type_ == clip_path && path_ == other.path_) {
+      return true;
+    }
+    if (type_ == transform && matrix_ == other.matrix_) {
+      return true;
+    }
+    return false;
+  }
+
+  bool isClipType() {
+    return type_ == clip_rect || type_ == clip_rrect || type_ == clip_path;
+  }
+
+ private:
+  EmbeddedViewMutationType type_;
+  SkRect rect_;
+  SkRRect rrect_;
+  SkPath path_;
+  SkMatrix matrix_;
+};  // EmbeddedViewMutator
 
 }  // namespace flutter
 

flow/layers/clip_rect_layer.cc

@@ -50,13 +50,19 @@ void ClipRectLayer::Paint(PaintContext& context) const {
   SkAutoCanvasRestore save(context.internal_nodes_canvas, true);
   context.internal_nodes_canvas->clipRect(clip_rect_,
                                           clip_behavior_ != Clip::hardEdge);
+  if (context.view_embedder != nullptr) {
+    context.view_embedder->transformStack->pushClipRect(clip_rect_);
+  }
   if (clip_behavior_ == Clip::antiAliasWithSaveLayer) {
     context.internal_nodes_canvas->saveLayer(clip_rect_, nullptr);
   }
   PaintChildren(context);
   if (clip_behavior_ == Clip::antiAliasWithSaveLayer) {
     context.internal_nodes_canvas->restore();
   }
+  if (context.view_embedder != nullptr) {
+    context.view_embedder->transformStack->pop();
+  }
 }
 
 }  // namespace flutter

flow/layers/clip_rrect_layer.cc

@@ -58,13 +58,19 @@ void ClipRRectLayer::Paint(PaintContext& context) const {
   SkAutoCanvasRestore save(context.internal_nodes_canvas, true);
   context.internal_nodes_canvas->clipRRect(clip_rrect_,
                                            clip_behavior_ != Clip::hardEdge);
+  if (context.view_embedder != nullptr) {
+    context.view_embedder->transformStack->pushClipRRect(clip_rrect_);
+  }
   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();
   }
+  if (context.view_embedder != nullptr) {
+    context.view_embedder->transformStack->pop();
+  }
 }
 
 }  // namespace flutter

flow/layers/platform_view_layer.cc

@@ -34,6 +34,7 @@ void PlatformViewLayer::Paint(PaintContext& context) const {
   params.offsetPixels =
       SkPoint::Make(transform.getTranslateX(), transform.getTranslateY());
   params.sizePoints = size_;
+  params.transformStack = context.view_embedder->transformStack;
 
   SkCanvas* canvas =
       context.view_embedder->CompositeEmbeddedView(view_id_, params);

flow/layers/transform_layer.cc

@@ -66,7 +66,13 @@ void TransformLayer::Paint(PaintContext& context) const {
 
   SkAutoCanvasRestore save(context.internal_nodes_canvas, true);
   context.internal_nodes_canvas->concat(transform_);
+  if (context.view_embedder != nullptr) {
+    context.view_embedder->transformStack->pushTransform(transform_);
+  }
   PaintChildren(context);
+  if (context.view_embedder != nullptr) {
+    context.view_embedder->transformStack->pop();
+  }
 }
 
 }  // namespace flutter