Composites Flutter UI and overlay layers alongside embedded UIViews. More...

#include <platform_views_controller.h>

Public Member Functions
	PlatformViewsController ()

	~PlatformViewsController ()=default

fml::WeakPtr< flutter::PlatformViewsController >	GetWeakPtr ()
	Retrieve a weak pointer to this controller. More...

void	SetTaskRunner (const fml::RefPtr< fml::TaskRunner > &platform_task_runner)
	Set the platform task runner used to post rendering tasks. More...

void	SetFlutterView (UIView *flutter_view) __attribute__((cf_audited_transfer))
	Set the flutter view. More...

void	SetFlutterViewController (UIViewController< FlutterViewResponder > *flutter_view_controller) __attribute__((cf_audited_transfer))
	Set the flutter view controller. More...

UIViewController< FlutterViewResponder > *	GetFlutterViewController () __attribute__((cf_audited_transfer))
	Retrieve the view controller. More...

void	RegisterViewFactory (NSObject< FlutterPlatformViewFactory > factory, NSString factoryId, FlutterPlatformViewGestureRecognizersBlockingPolicy gestureRecognizerBlockingPolicy) __attribute__((cf_audited_transfer))
	set the factory used to construct embedded UI Views. More...

void	BeginFrame (SkISize frame_size)
	Mark the beginning of a frame and record the size of the onscreen. More...

void	CancelFrame ()
	Cancel the current frame, indicating that no platform views are composited. More...

void	PrerollCompositeEmbeddedView (int64_t view_id, std::unique_ptr< flutter::EmbeddedViewParams > params)
	Record a platform view in the layer tree to be rendered, along with the positioning and mutator parameters. More...

FlutterTouchInterceptingView *	GetFlutterTouchInterceptingViewByID (int64_t view_id)
	Returns the`FlutterTouchInterceptingView` with the provided view_id. More...

PostPrerollResult	PostPrerollAction (const fml::RefPtr< fml::RasterThreadMerger > &raster_thread_merger, bool impeller_enabled)
	Determine if thread merging is required after prerolling platform views. More...

void	EndFrame (bool should_resubmit_frame, const fml::RefPtr< fml::RasterThreadMerger > &raster_thread_merger, bool impeller_enabled)
	Mark the end of a compositor frame. More...

DlCanvas *	CompositeEmbeddedView (int64_t view_id)
	Returns the Canvas for the overlay slice for the given platform view. More...

void	Reset ()
	Discards all platform views instances and auxiliary resources. More...

bool	SubmitFrame (GrDirectContext *gr_context, const std::shared_ptr< IOSContext > &ios_context, std::unique_ptr< SurfaceFrame > frame)
	Encode rendering for the Flutter overlay views and queue up perform platform view mutations. More...

void	OnMethodCall (FlutterMethodCall *call, FlutterResult result) __attribute__((cf_audited_transfer))
	Handler for platform view message channels. More...

long	FindFirstResponderPlatformViewId ()
	Returns the platform view id if the platform view (or any of its descendant view) is the first responder. More...

void	PushFilterToVisitedPlatformViews (const std::shared_ptr< const DlImageFilter > &filter, const SkRect &filter_rect)
	Pushes backdrop filter mutation to the mutator stack of each visited platform view. More...

void	PushVisitedPlatformView (int64_t view_id)
	Pushes the view id of a visted platform view to the list of visied platform views. More...

size_t	EmbeddedViewCount () const

size_t	LayerPoolSize () const

UIView *	GetPlatformViewByID (int64_t view_id)

void	CompositeWithParams (int64_t view_id, const EmbeddedViewParams &params)

const EmbeddedViewParams &	GetCompositionParams (int64_t view_id) const

Detailed Description

Composites Flutter UI and overlay layers alongside embedded UIViews.

Definition at line 31 of file platform_views_controller.h.

Constructor & Destructor Documentation

◆ PlatformViewsController()

flutter::PlatformViewsController::PlatformViewsController ( )

Definition at line 113 of file platform_views_controller.mm.

     : layer_pool_(std::make_unique<OverlayLayerPool>()),
       weak_factory_(std::make_unique<fml::WeakPtrFactory<PlatformViewsController>>(this)) {
   mask_view_pool_.reset(
       [[FlutterClippingMaskViewPool alloc] initWithCapacity:kFlutterClippingMaskViewPoolCapacity]);
 };

◆ ~PlatformViewsController()

flutter::PlatformViewsController::~PlatformViewsController ( )

default

Member Function Documentation

◆ BeginFrame()

void flutter::PlatformViewsController::BeginFrame ( SkISize frame_size )

Mark the beginning of a frame and record the size of the onscreen.

Definition at line 282 of file platform_views_controller.mm.

                                                            {
   ResetFrameState();
   frame_size_ = frame_size;
 }

◆ CancelFrame()

void flutter::PlatformViewsController::CancelFrame ( )

Cancel the current frame, indicating that no platform views are composited.

Additionally, reverts the composition order to its original state at the beginning of the frame.

Definition at line 287 of file platform_views_controller.mm.

                                           {
   ResetFrameState();
 }

Referenced by PostPrerollAction().

◆ CompositeEmbeddedView()

DlCanvas * flutter::PlatformViewsController::CompositeEmbeddedView ( int64_t view_id )

Returns the Canvas for the overlay slice for the given platform view.

Called from the raster thread.

Definition at line 579 of file platform_views_controller.mm.

                                                                         {
   return slices_[view_id]->canvas();
 }

◆ CompositeWithParams()

void flutter::PlatformViewsController::CompositeWithParams	(	int64_t	view_id,
		const EmbeddedViewParams &	params
	)

Definition at line 540 of file platform_views_controller.mm.

                                                                                     {
   CGRect frame = CGRectMake(0, 0, params.sizePoints().width(), params.sizePoints().height());
   FlutterTouchInterceptingView* touchInterceptor = platform_views_[view_id].touch_interceptor.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;
  
   const MutatorsStack& mutatorStack = params.mutatorsStack();
   UIView* clippingView = platform_views_[view_id].root_view.get();
   // The frame of the clipping view should be the final bounding rect.
   // Because the translate matrix in the Mutator Stack also includes the offset,
   // when we apply the transforms matrix in |ApplyMutators|, we need
   // to remember to do a reverse translate.
   const SkRect& rect = params.finalBoundingRect();
   CGFloat screenScale = [UIScreen mainScreen].scale;
   clippingView.frame = CGRectMake(rect.x() / screenScale, rect.y() / screenScale,
                                   rect.width() / screenScale, rect.height() / screenScale);
   ApplyMutators(mutatorStack, touchInterceptor, rect);
 }

◆ EmbeddedViewCount()

size_t flutter::PlatformViewsController::EmbeddedViewCount ( ) const

Definition at line 369 of file platform_views_controller.mm.

                                                         {
   return composition_order_.size();
 }

◆ EndFrame()

void flutter::PlatformViewsController::EndFrame	(	bool	should_resubmit_frame,
		const fml::RefPtr< fml::RasterThreadMerger > &	raster_thread_merger,
		bool	impeller_enabled
	)

Mark the end of a compositor frame.

May determine changes are required to the thread merging state. Called from the raster thread.

Definition at line 326 of file platform_views_controller.mm.

                            {
 #if FML_OS_IOS_SIMULATOR
   bool run_check = true;
 #else
   bool run_check = !impeller_enabled;
 #endif  // FML_OS_IOS_SIMULATOR
   if (run_check && should_resubmit_frame) {
     raster_thread_merger->MergeWithLease(kDefaultMergedLeaseDuration);
   }
 }

◆ FindFirstResponderPlatformViewId()

long flutter::PlatformViewsController::FindFirstResponderPlatformViewId ( )

Returns the platform view id if the platform view (or any of its descendant view) is the first responder.

Returns -1 if no such platform view is found.

Definition at line 389 of file platform_views_controller.mm.

                                                                {
   for (auto const& [id, platform_view_data] : platform_views_) {
     UIView* root_view = (UIView*)platform_view_data.root_view.get();
     if (root_view.flt_hasFirstResponderInViewHierarchySubtree) {
       return id;
     }
   }
   return -1;
 }

◆ GetCompositionParams()

const EmbeddedViewParams& flutter::PlatformViewsController::GetCompositionParams ( int64_t view_id ) const

inline

Definition at line 151 of file platform_views_controller.h.

                                                                         {
     return current_composition_params_.find(view_id)->second;
   }

◆ GetFlutterTouchInterceptingViewByID()

FlutterTouchInterceptingView * flutter::PlatformViewsController::GetFlutterTouchInterceptingViewByID ( int64_t view_id )

Returns theFlutterTouchInterceptingView with the provided view_id.

Returns nil if there is no platform view with the provided id. Called from the platform thread.

Definition at line 381 of file platform_views_controller.mm.

                      {
   if (platform_views_.empty()) {
     return nil;
   }
   return platform_views_[view_id].touch_interceptor.get();
 }

Referenced by GetPlatformViewByID().

◆ GetFlutterViewController()

UIViewController< FlutterViewResponder > * flutter::PlatformViewsController::GetFlutterViewController ( )

Retrieve the view controller.

Definition at line 138 of file platform_views_controller.mm.

                                                                                           {
   return flutter_view_controller_.get();
 }

◆ GetPlatformViewByID()

UIView * flutter::PlatformViewsController::GetPlatformViewByID ( int64_t view_id )

Definition at line 377 of file platform_views_controller.mm.

                                                                     {
   return [GetFlutterTouchInterceptingViewByID(view_id) embeddedView];
 }

References GetFlutterTouchInterceptingViewByID().

◆ GetWeakPtr()

fml::WeakPtr< flutter::PlatformViewsController > flutter::PlatformViewsController::GetWeakPtr ( )

Retrieve a weak pointer to this controller.

Definition at line 125 of file platform_views_controller.mm.

                                                                                {
   return weak_factory_->GetWeakPtr();
 }

◆ LayerPoolSize()

size_t flutter::PlatformViewsController::LayerPoolSize ( ) const

Definition at line 373 of file platform_views_controller.mm.

                                                     {
   return layer_pool_->size();
 }

◆ OnMethodCall()

void flutter::PlatformViewsController::OnMethodCall	(	FlutterMethodCall *	call,
		FlutterResult	result
	)

Handler for platform view message channels.

Definition at line 142 of file platform_views_controller.mm.

                                                                                         {
   if ([[call method] isEqualToString:@"create"]) {
     OnCreate(call, result);
   } else if ([[call method] isEqualToString:@"dispose"]) {
     OnDispose(call, result);
   } else if ([[call method] isEqualToString:@"acceptGesture"]) {
     OnAcceptGesture(call, result);
   } else if ([[call method] isEqualToString:@"rejectGesture"]) {
     OnRejectGesture(call, result);
   } else {
     result(FlutterMethodNotImplemented);
   }
 }

References FlutterMethodNotImplemented.

◆ PostPrerollAction()

PostPrerollResult flutter::PlatformViewsController::PostPrerollAction	(	const fml::RefPtr< fml::RasterThreadMerger > &	raster_thread_merger,
		bool	impeller_enabled
	)

Determine if thread merging is required after prerolling platform views.

Called from the raster thread.

Definition at line 291 of file platform_views_controller.mm.

                            {
   // TODO(jonahwilliams): remove this once Software backend is removed for iOS Sim.
 #ifdef FML_OS_IOS_SIMULATOR
   const bool merge_threads = true;
 #else
   const bool merge_threads = !impeller_enabled;
 #endif  // FML_OS_IOS_SIMULATOR
  
   if (merge_threads) {
     if (composition_order_.empty()) {
       return PostPrerollResult::kSuccess;
     }
     if (!raster_thread_merger->IsMerged()) {
       // The raster thread merger may be disabled if the rasterizer is being
       // created or teared down.
       //
       // In such cases, the current frame is dropped, and a new frame is attempted
       // with the same layer tree.
       //
       // Eventually, the frame is submitted once this method returns `kSuccess`.
       // At that point, the raster tasks are handled on the platform thread.
       CancelFrame();
       return PostPrerollResult::kSkipAndRetryFrame;
     }
     // If the post preroll action is successful, we will display platform views in the current
     // frame. In order to sync the rendering of the platform views (quartz) with skia's rendering,
     // We need to begin an explicit CATransaction. This transaction needs to be submitted
     // after the current frame is submitted.
     raster_thread_merger->ExtendLeaseTo(kDefaultMergedLeaseDuration);
   }
   return PostPrerollResult::kSuccess;
 }

References CancelFrame().

◆ PrerollCompositeEmbeddedView()

void flutter::PlatformViewsController::PrerollCompositeEmbeddedView	(	int64_t	view_id,
		std::unique_ptr< flutter::EmbeddedViewParams >	params
	)

Record a platform view in the layer tree to be rendered, along with the positioning and mutator parameters.

Called from the raster thread.

Definition at line 350 of file platform_views_controller.mm.

                                               {
   SkRect view_bounds = SkRect::Make(frame_size_);
   std::unique_ptr<EmbedderViewSlice> view;
   view = std::make_unique<DisplayListEmbedderViewSlice>(view_bounds);
   slices_.insert_or_assign(view_id, std::move(view));
  
   composition_order_.push_back(view_id);
  
   if (current_composition_params_.count(view_id) == 1 &&
       current_composition_params_[view_id] == *params.get()) {
     // Do nothing if the params didn't change.
     return;
   }
   current_composition_params_[view_id] = EmbeddedViewParams(*params.get());
   views_to_recomposite_.insert(view_id);
 }

◆ PushFilterToVisitedPlatformViews()

void flutter::PlatformViewsController::PushFilterToVisitedPlatformViews	(	const std::shared_ptr< const DlImageFilter > &	filter,
		const SkRect &	filter_rect
	)

Pushes backdrop filter mutation to the mutator stack of each visited platform view.

Definition at line 340 of file platform_views_controller.mm.

                                {
   for (int64_t id : visited_platform_views_) {
     EmbeddedViewParams params = current_composition_params_[id];
     params.PushImageFilter(filter, filter_rect);
     current_composition_params_[id] = params;
   }
 }

◆ PushVisitedPlatformView()

void flutter::PlatformViewsController::PushVisitedPlatformView ( int64_t view_id )

inline

Pushes the view id of a visted platform view to the list of visied platform views.

Definition at line 131 of file platform_views_controller.h.

131 { visited_platform_views_.push_back(view_id); }

◆ RegisterViewFactory()

void flutter::PlatformViewsController::RegisterViewFactory	(	NSObject< FlutterPlatformViewFactory > *	factory,
		NSString *	factoryId,
		FlutterPlatformViewGestureRecognizersBlockingPolicy	gestureRecognizerBlockingPolicy
	)

set the factory used to construct embedded UI Views.

Definition at line 272 of file platform_views_controller.mm.

                                                                                          {
   std::string idString([factoryId UTF8String]);
   FML_CHECK(factories_.count(idString) == 0);
   factories_[idString] = fml::scoped_nsobject<NSObject<FlutterPlatformViewFactory>>(factory);
   gesture_recognizers_blocking_policies_[idString] = gestureRecognizerBlockingPolicy;
 }

◆ Reset()

void flutter::PlatformViewsController::Reset ( )

Discards all platform views instances and auxiliary resources.

Called from the raster thread.

Definition at line 583 of file platform_views_controller.mm.

                                     {
   // Reset will only be called from the raster thread or a merged raster/platform thread.
   // platform_views_ must only be modified on the platform thread, and any operations that
   // read or modify platform views should occur there.
   fml::TaskRunner::RunNowOrPostTask(
       platform_task_runner_, [&, composition_order = composition_order_]() {
         for (int64_t view_id : composition_order_) {
           [platform_views_[view_id].root_view.get() removeFromSuperview];
         }
         platform_views_.clear();
       });
  
   composition_order_.clear();
   slices_.clear();
   current_composition_params_.clear();
   views_to_recomposite_.clear();
   layer_pool_->RecycleLayers();
   visited_platform_views_.clear();
 }

◆ SetFlutterView()

void flutter::PlatformViewsController::SetFlutterView ( UIView * flutter_view )

Set the flutter view.

Definition at line 129 of file platform_views_controller.mm.

                                                                  {
   flutter_view_.reset(flutter_view);
 }

◆ SetFlutterViewController()

void flutter::PlatformViewsController::SetFlutterViewController ( UIViewController< FlutterViewResponder > * flutter_view_controller )

Set the flutter view controller.

Definition at line 133 of file platform_views_controller.mm.

                                                                      {
   flutter_view_controller_.reset(flutter_view_controller);
 }

◆ SetTaskRunner()

void flutter::PlatformViewsController::SetTaskRunner ( const fml::RefPtr< fml::TaskRunner > & platform_task_runner )

Set the platform task runner used to post rendering tasks.

Definition at line 120 of file platform_views_controller.mm.

                                                           {
   platform_task_runner_ = platform_task_runner;
 }

◆ SubmitFrame()

bool flutter::PlatformViewsController::SubmitFrame	(	GrDirectContext *	gr_context,
		const std::shared_ptr< IOSContext > &	ios_context,
		std::unique_ptr< SurfaceFrame >	frame
	)

Encode rendering for the Flutter overlay views and queue up perform platform view mutations.

Called from the raster thread.

Definition at line 603 of file platform_views_controller.mm.

                                                                                         {
   TRACE_EVENT0("flutter", "PlatformViewsController::SubmitFrame");
  
   // No platform views to render; we're done.
   if (flutter_view_ == nullptr || (composition_order_.empty() && !had_platform_views_)) {
     had_platform_views_ = false;
     return background_frame->Submit();
   }
   had_platform_views_ = !composition_order_.empty();
  
   bool did_encode = true;
   LayersMap platform_view_layers;
   std::vector<std::unique_ptr<SurfaceFrame>> surface_frames;
   surface_frames.reserve(composition_order_.size());
   std::unordered_map<int64_t, SkRect> view_rects;
  
   for (int64_t view_id : composition_order_) {
     view_rects[view_id] = current_composition_params_[view_id].finalBoundingRect();
   }
  
   std::unordered_map<int64_t, SkRect> overlay_layers =
       SliceViews(background_frame->Canvas(), composition_order_, slices_, view_rects);
  
   size_t required_overlay_layers = 0;
   for (int64_t view_id : composition_order_) {
     std::unordered_map<int64_t, SkRect>::const_iterator overlay = overlay_layers.find(view_id);
     if (overlay == overlay_layers.end()) {
       continue;
     }
     required_overlay_layers++;
   }
  
   // If there are not sufficient overlay layers, we must construct them on the platform
   // thread, at least until we've refactored iOS surface creation to use IOSurfaces
   // instead of CALayers.
   CreateMissingOverlays(gr_context, ios_context, required_overlay_layers);
  
   int64_t overlay_id = 0;
   for (int64_t view_id : composition_order_) {
     std::unordered_map<int64_t, SkRect>::const_iterator overlay = overlay_layers.find(view_id);
     if (overlay == overlay_layers.end()) {
       continue;
     }
     std::shared_ptr<OverlayLayer> layer = GetExistingLayer();
     if (!layer) {
       continue;
     }
  
     std::unique_ptr<SurfaceFrame> frame = layer->surface->AcquireFrame(frame_size_);
     // If frame is null, AcquireFrame already printed out an error message.
     if (!frame) {
       continue;
     }
     DlCanvas* overlay_canvas = frame->Canvas();
     int restore_count = overlay_canvas->GetSaveCount();
     overlay_canvas->Save();
     overlay_canvas->ClipRect(overlay->second);
     overlay_canvas->Clear(DlColor::kTransparent());
     slices_[view_id]->render_into(overlay_canvas);
     overlay_canvas->RestoreToCount(restore_count);
  
     // This flutter view is never the last in a frame, since we always submit the
     // underlay view last.
     frame->set_submit_info({.frame_boundary = false, .present_with_transaction = true});
     layer->did_submit_last_frame = frame->Encode();
  
     did_encode &= layer->did_submit_last_frame;
     platform_view_layers[view_id] = LayerData{
         .rect = overlay->second,   //
         .view_id = view_id,        //
         .overlay_id = overlay_id,  //
         .layer = layer             //
     };
     surface_frames.push_back(std::move(frame));
     overlay_id++;
   }
  
   auto previous_submit_info = background_frame->submit_info();
   background_frame->set_submit_info({
       .frame_damage = previous_submit_info.frame_damage,
       .buffer_damage = previous_submit_info.buffer_damage,
       .present_with_transaction = true,
   });
   background_frame->Encode();
   surface_frames.push_back(std::move(background_frame));
  
   // Mark all layers as available, so they can be used in the next frame.
   std::vector<std::shared_ptr<OverlayLayer>> unused_layers = layer_pool_->RemoveUnusedLayers();
   layer_pool_->RecycleLayers();
  
   auto task = [&,                                                         //
                platform_view_layers = std::move(platform_view_layers),    //
                current_composition_params = current_composition_params_,  //
                views_to_recomposite = views_to_recomposite_,              //
                composition_order = composition_order_,                    //
                unused_layers = std::move(unused_layers),                  //
                surface_frames = std::move(surface_frames)                 //
   ]() mutable {
     PerformSubmit(platform_view_layers,        //
                   current_composition_params,  //
                   views_to_recomposite,        //
                   composition_order,           //
                   unused_layers,               //
                   surface_frames               //
     );
   };
  
   fml::TaskRunner::RunNowOrPostTask(platform_task_runner_, fml::MakeCopyable(std::move(task)));
  
   return did_encode;
 }

The documentation for this class was generated from the following files:

shell/platform/darwin/ios/framework/Source/platform_views_controller.h
shell/platform/darwin/ios/framework/Source/platform_views_controller.mm

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ PlatformViewsController()

◆ ~PlatformViewsController()

Member Function Documentation

◆ BeginFrame()

◆ CancelFrame()

◆ CompositeEmbeddedView()

◆ CompositeWithParams()

◆ EmbeddedViewCount()

◆ EndFrame()

◆ FindFirstResponderPlatformViewId()

◆ GetCompositionParams()

◆ GetFlutterTouchInterceptingViewByID()

◆ GetFlutterViewController()

◆ GetPlatformViewByID()

◆ GetWeakPtr()

◆ LayerPoolSize()

◆ OnMethodCall()

◆ PostPrerollAction()

◆ PrerollCompositeEmbeddedView()

◆ PushFilterToVisitedPlatformViews()

◆ PushVisitedPlatformView()

◆ RegisterViewFactory()

◆ Reset()

◆ SetFlutterView()

◆ SetFlutterViewController()

◆ SetTaskRunner()

◆ SubmitFrame()