Flutter Engine
flutter::PlatformView Class Reference

Platform views are created by the shell on the platform task runner. Unless explicitly specified, all platform view methods are called on the platform task runner as well. Platform views are usually sub-classed on a per platform basis and the bulk of the window system integration happens using that subclass. Since most platform window toolkits are usually only safe to access on a single "main" thread, any interaction that requires access to the underlying platform's window toolkit is routed through the platform view associated with that shell. This involves operations like settings up and tearing down the render surface, platform messages, interacting with accessibility features on the platform, input events, etc. More...

#include <platform_view.h>

Inheritance diagram for flutter::PlatformView:
flutter::PlatformViewAndroid flutter::PlatformViewEmbedder flutter::PlatformViewIOS flutter::TesterPlatformView flutter::testing::ShellTestPlatformView flutter_runner::PlatformView flutter::testing::ShellTestPlatformViewGL flutter::testing::ShellTestPlatformViewMetal flutter::testing::ShellTestPlatformViewVulkan flutter_runner::FlatlandPlatformView flutter_runner::GfxPlatformView

Classes

class  Delegate
 Used to forward events from the platform view to interested subsystems. This forwarding is done by the shell which sets itself up as the delegate of the platform view. More...
 

Public Member Functions

 PlatformView (Delegate &delegate, TaskRunners task_runners)
 Creates a platform view with the specified delegate and task runner. The base class by itself does not do much but is suitable for use in test environments where full platform integration may not be necessary. The platform view may only be created, accessed and destroyed on the platform task runner. More...
 
virtual ~PlatformView ()
 Destroys the platform view. The platform view is owned by the shell and will be destroyed by the same on the platform tasks runner. More...
 
virtual std::unique_ptr< VsyncWaiterCreateVSyncWaiter ()
 Invoked by the shell to obtain a platform specific vsync waiter. It is optional for platforms to override this method and provide a custom vsync waiter because a timer based fall-back waiter is used by default. However, it is highly recommended that platform provide their own Vsync waiter as the timer based fall-back will not render frames aligned with vsync boundaries. More...
 
void DispatchPlatformMessage (std::unique_ptr< PlatformMessage > message)
 Used by embedders to dispatch a platform message to a running root isolate hosted by the engine. If an isolate is not running, the message is dropped. If there is no one on the other side listening on the channel, the message is dropped. When a platform message is dropped, any response handles associated with that message will be dropped as well. All users of platform messages must assume that message may not be delivered and/or their response handles may not be invoked. Platform messages are not buffered. More...
 
virtual void HandlePlatformMessage (std::unique_ptr< PlatformMessage > message)
 Overridden by embedders to perform actions in response to platform messages sent from the framework to the embedder. Default implementation of this method simply returns an empty response. More...
 
void DispatchSemanticsAction (int32_t id, SemanticsAction action, fml::MallocMapping args)
 Used by embedders to dispatch an accessibility action to a running isolate hosted by the engine. More...
 
virtual void SetSemanticsEnabled (bool enabled)
 Used by embedder to notify the running isolate hosted by the engine on the UI thread that the accessibility tree needs to be generated. More...
 
virtual void SetAccessibilityFeatures (int32_t flags)
 Used by the embedder to specify the features to enable in the accessibility tree generated by the isolate. This information is forwarded to the root isolate hosted by the engine on the UI thread. More...
 
virtual void UpdateSemantics (SemanticsNodeUpdates updates, CustomAccessibilityActionUpdates actions)
 Used by the framework to tell the embedder to apply the specified semantics node updates. The default implementation of this method does nothing. More...
 
void SetViewportMetrics (const ViewportMetrics &metrics)
 Used by embedders to specify the updated viewport metrics. In response to this call, on the raster thread, the rasterizer may need to be reconfigured to the updated viewport dimensions. On the UI thread, the framework may need to start generating a new frame for the updated viewport metrics as well. More...
 
void NotifyCreated ()
 Used by embedders to notify the shell that a platform view has been created. This notification is used to create a rendering surface and pick the client rendering API to use to render into this surface. No frames will be scheduled or rendered before this call. The surface must remain valid till the corresponding call to NotifyDestroyed. More...
 
virtual void NotifyDestroyed ()
 Used by embedders to notify the shell that the platform view has been destroyed. This notification used to collect the rendering surface and all associated resources. Frame scheduling is also suspended. More...
 
virtual sk_sp< GrDirectContext > CreateResourceContext () const
 Used by the shell to obtain a Skia GPU context that is capable of operating on the IO thread. The context must be in the same share-group as the Skia GPU context used on the render thread. This context will always be used on the IO thread. Because it is in the same share-group as the separate render thread context, any GPU resources uploaded in this context will be visible to the render thread context (synchronization of GPU resources is managed by Skia). More...
 
virtual void ReleaseResourceContext () const
 Used by the shell to notify the embedder that the resource context previously obtained via a call to CreateResourceContext() is being collected. The embedder is free to collect an platform specific resources associated with this context. More...
 
virtual PointerDataDispatcherMaker GetDispatcherMaker ()
 Returns a platform-specific PointerDataDispatcherMaker so the Engine can construct the PointerDataPacketDispatcher based on platforms. More...
 
fml::WeakPtr< PlatformViewGetWeakPtr () const
 Returns a weak pointer to the platform view. Since the platform view may only be created, accessed and destroyed on the platform thread, any access to the platform view from a non-platform task runner needs a weak pointer to the platform view along with a reference to the platform task runner. A task must be posted to the platform task runner with the weak pointer captured in the same. The platform view method may only be called in the posted task once the weak pointer validity has been checked. This method is used by callers to obtain that weak pointer. More...
 
virtual void OnPreEngineRestart () const
 Gives embedders a chance to react to a "cold restart" of the running isolate. The default implementation of this method does nothing. More...
 
void SetNextFrameCallback (const fml::closure &closure)
 Sets a callback that gets executed when the rasterizer renders the next frame. Due to the asynchronous nature of rendering in Flutter, embedders usually add a placeholder over the contents in which Flutter is going to render when Flutter is first initialized. This callback may be used as a signal to remove that placeholder. The callback is executed on the render task runner and not the platform task runner. It is the embedder's responsibility to re-thread as necessary. More...
 
void DispatchPointerDataPacket (std::unique_ptr< PointerDataPacket > packet)
 Dispatches pointer events from the embedder to the framework. Each pointer data packet may contain multiple pointer input events. Each call to this method wakes up the UI thread. More...
 
void DispatchKeyDataPacket (std::unique_ptr< KeyDataPacket > packet, Delegate::KeyDataResponse callback)
 Dispatches key events from the embedder to the framework. Each key data packet contains one physical event and multiple logical key events. Each call to this method wakes up the UI thread. More...
 
void RegisterTexture (std::shared_ptr< flutter::Texture > texture)
 Used by the embedder to specify a texture that it wants the rasterizer to composite within the Flutter layer tree. All textures must have a unique identifier. When the rasterizer encounters an external texture within its hierarchy, it gives the embedder a chance to update that texture on the raster thread before it composites the same on-screen. More...
 
void UnregisterTexture (int64_t texture_id)
 Used by the embedder to notify the rasterizer that it will no longer attempt to composite the specified texture within the layer tree. This allows the rasterizer to collect associated resources. More...
 
void MarkTextureFrameAvailable (int64_t texture_id)
 Used by the embedder to notify the rasterizer that the context of the previously registered texture have been updated. Typically, Flutter will only render a frame if there is an updated layer tree. However, in cases where the layer tree is static but one of the externally composited textures has been updated by the embedder, the embedder needs to notify the rasterizer to render a new frame. In such cases, the existing layer tree may be reused with the frame re-composited with all updated external textures. Unlike the calls to register and unregister the texture, this call must be made each time a new texture frame is available. More...
 
virtual std::unique_ptr< std::vector< std::string > > ComputePlatformResolvedLocales (const std::vector< std::string > &supported_locale_data)
 Directly invokes platform-specific APIs to compute the locale the platform would have natively resolved to. More...
 
virtual std::shared_ptr< ExternalViewEmbedderCreateExternalViewEmbedder ()
 
virtual void RequestDartDeferredLibrary (intptr_t loading_unit_id)
 Invoked when the dart VM requests that a deferred library be loaded. Notifies the engine that the deferred library identified by the specified loading unit id should be downloaded and loaded into the Dart VM via LoadDartDeferredLibrary More...
 
virtual void LoadDartDeferredLibrary (intptr_t loading_unit_id, std::unique_ptr< const fml::Mapping > snapshot_data, std::unique_ptr< const fml::Mapping > snapshot_instructions)
 Loads the Dart shared library into the Dart VM. When the Dart library is loaded successfully, the Dart future returned by the originating loadLibrary() call completes. More...
 
virtual void LoadDartDeferredLibraryError (intptr_t loading_unit_id, const std::string error_message, bool transient)
 Indicates to the dart VM that the request to load a deferred library with the specified loading unit id has failed. More...
 
virtual void UpdateAssetResolverByType (std::unique_ptr< AssetResolver > updated_asset_resolver, AssetResolver::AssetResolverType type)
 Replaces the asset resolver handled by the engine's AssetManager of the specified type with updated_asset_resolver. The matching AssetResolver is removed and replaced with updated_asset_resolvers. More...
 
virtual std::unique_ptr< SnapshotSurfaceProducerCreateSnapshotSurfaceProducer ()
 Creates an object that produces surfaces suitable for raster snapshotting. The rasterizer will request this surface if no on screen surface is currently available when an application requests a snapshot, e.g. if Scene.toImage or Picture.toImage are called while the application is in the background. More...
 
virtual std::shared_ptr< PlatformMessageHandlerGetPlatformMessageHandler () const
 Specifies a delegate that will receive PlatformMessages from Flutter to the host platform. More...
 

Protected Member Functions

virtual std::unique_ptr< SurfaceCreateRenderingSurface ()
 

Protected Attributes

PlatformView::Delegatedelegate_
 
const TaskRunners task_runners_
 
PointerDataPacketConverter pointer_data_packet_converter_
 
SkISize size_
 
fml::WeakPtrFactory< PlatformViewweak_factory_
 

Detailed Description

Platform views are created by the shell on the platform task runner. Unless explicitly specified, all platform view methods are called on the platform task runner as well. Platform views are usually sub-classed on a per platform basis and the bulk of the window system integration happens using that subclass. Since most platform window toolkits are usually only safe to access on a single "main" thread, any interaction that requires access to the underlying platform's window toolkit is routed through the platform view associated with that shell. This involves operations like settings up and tearing down the render surface, platform messages, interacting with accessibility features on the platform, input events, etc.

Definition at line 47 of file platform_view.h.

Constructor & Destructor Documentation

◆ PlatformView()

flutter::PlatformView::PlatformView ( Delegate delegate,
TaskRunners  task_runners 
)
explicit

Creates a platform view with the specified delegate and task runner. The base class by itself does not do much but is suitable for use in test environments where full platform integration may not be necessary. The platform view may only be created, accessed and destroyed on the platform task runner.

Parameters
delegateThe delegate. This is typically the shell.
[in]task_runnersThe task runners used by this platform view.

Definition at line 16 of file platform_view.cc.

Referenced by flutter::PlatformViewEmbedder::PlatformViewEmbedder().

17  : delegate_(delegate),
18  task_runners_(std::move(task_runners)),
19  size_(SkISize::Make(0, 0)),
20  weak_factory_(this) {}
fml::WeakPtrFactory< PlatformView > weak_factory_
const TaskRunners task_runners_
PlatformView::Delegate & delegate_

◆ ~PlatformView()

flutter::PlatformView::~PlatformView ( )
virtualdefault

Destroys the platform view. The platform view is owned by the shell and will be destroyed by the same on the platform tasks runner.

Reimplemented in flutter_runner::PlatformView.

Member Function Documentation

◆ ComputePlatformResolvedLocales()

std::unique_ptr< std::vector< std::string > > flutter::PlatformView::ComputePlatformResolvedLocales ( const std::vector< std::string > &  supported_locale_data)
virtual

Directly invokes platform-specific APIs to compute the locale the platform would have natively resolved to.

Parameters
[in]supported_locale_dataThe vector of strings that represents the locales supported by the app. Each locale consists of three strings: languageCode, countryCode, and scriptCode in that order.
Returns
A vector of 3 strings languageCode, countryCode, and scriptCode that represents the locale selected by the platform. Empty strings mean the value was unassigned. Empty vector represents a null locale.

Definition at line 158 of file platform_view.cc.

159  {
160  std::unique_ptr<std::vector<std::string>> out =
161  std::make_unique<std::vector<std::string>>();
162  return out;
163 }

◆ CreateExternalViewEmbedder()

std::shared_ptr< ExternalViewEmbedder > flutter::PlatformView::CreateExternalViewEmbedder ( )
virtual

Reimplemented in flutter::TesterPlatformView, and flutter_runner::PlatformView.

Definition at line 143 of file platform_view.cc.

References FML_DLOG.

143  {
144  FML_DLOG(WARNING)
145  << "This platform doesn't support embedding external views.";
146  return nullptr;
147 }
#define FML_DLOG(severity)
Definition: logging.h:85

◆ CreateRenderingSurface()

std::unique_ptr< Surface > flutter::PlatformView::CreateRenderingSurface ( )
protectedvirtual

Reimplemented in flutter_runner::PlatformView, and flutter::TesterPlatformView.

Definition at line 134 of file platform_view.cc.

References FML_DCHECK.

134  {
135  // We have a default implementation because tests create a platform view but
136  // never a rendering surface.
137  FML_DCHECK(false) << "This platform does not provide a rendering surface but "
138  "it was notified of surface rendering surface creation.";
139  return nullptr;
140 }
#define FML_DCHECK(condition)
Definition: logging.h:86

◆ CreateResourceContext()

sk_sp< GrDirectContext > flutter::PlatformView::CreateResourceContext ( ) const
virtual

Used by the shell to obtain a Skia GPU context that is capable of operating on the IO thread. The context must be in the same share-group as the Skia GPU context used on the render thread. This context will always be used on the IO thread. Because it is in the same share-group as the separate render thread context, any GPU resources uploaded in this context will be visible to the render thread context (synchronization of GPU resources is managed by Skia).

If such context cannot be created on the IO thread, callers may return nullptr. This will mean that all texture uploads will be queued onto the render thread which will cause performance issues. When this context is nullptr, an error is logged to the console. It is highly recommended that all platforms provide a resource context.

Attention
Unlike all other methods on the platform view, this will be called on IO task runner.
Returns
The Skia GPU context that is in the same share-group as the main render thread GPU context. May be nullptr in case such a context cannot be created.

Definition at line 93 of file platform_view.cc.

References FML_DLOG.

93  {
94  FML_DLOG(WARNING) << "This platform does not set up the resource "
95  "context on the IO thread for async texture uploads.";
96  return nullptr;
97 }
#define FML_DLOG(severity)
Definition: logging.h:85

◆ CreateSnapshotSurfaceProducer()

std::unique_ptr< SnapshotSurfaceProducer > flutter::PlatformView::CreateSnapshotSurfaceProducer ( )
virtual

Creates an object that produces surfaces suitable for raster snapshotting. The rasterizer will request this surface if no on screen surface is currently available when an application requests a snapshot, e.g. if Scene.toImage or Picture.toImage are called while the application is in the background.

Not all backends support this kind of surface usage, and the default implementation returns nullptr. Platforms should override this if they can support GPU operations in the background and support GPU resource context usage.

Definition at line 183 of file platform_view.cc.

183  {
184  return nullptr;
185 }

◆ CreateVSyncWaiter()

std::unique_ptr< VsyncWaiter > flutter::PlatformView::CreateVSyncWaiter ( )
virtual

Invoked by the shell to obtain a platform specific vsync waiter. It is optional for platforms to override this method and provide a custom vsync waiter because a timer based fall-back waiter is used by default. However, it is highly recommended that platform provide their own Vsync waiter as the timer based fall-back will not render frames aligned with vsync boundaries.

Attention
If a timer based fall-back is used, a warning is logged to the console. In case this method is overridden in a subclass, it must return a valid vsync waiter. Returning null will lead to internal errors. If a valid vsync waiter cannot be returned, subclasses should just call the based class method instead.
Returns
A vsync waiter. If is an internal error to return a null waiter.

Reimplemented in flutter_runner::PlatformView.

Definition at line 24 of file platform_view.cc.

References FML_DLOG, and task_runners_.

Referenced by flutter::PlatformViewEmbedder::HandlePlatformMessage().

24  {
25  FML_DLOG(WARNING)
26  << "This platform does not provide a Vsync waiter implementation. A "
27  "simple timer based fallback is being used.";
28  return std::make_unique<VsyncWaiterFallback>(task_runners_);
29 }
const TaskRunners task_runners_
#define FML_DLOG(severity)
Definition: logging.h:85

◆ DispatchKeyDataPacket()

void flutter::PlatformView::DispatchKeyDataPacket ( std::unique_ptr< KeyDataPacket packet,
Delegate::KeyDataResponse  callback 
)

Dispatches key events from the embedder to the framework. Each key data packet contains one physical event and multiple logical key events. Each call to this method wakes up the UI thread.

Parameters
[in]packetThe key data packet to dispatch to the framework.

Definition at line 42 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewDispatchKeyDataPacket().

43  {
45  std::move(callback));
46 }
FlKeyEvent FlKeyResponderAsyncCallback callback
PlatformView::Delegate & delegate_
virtual void OnPlatformViewDispatchKeyDataPacket(std::unique_ptr< KeyDataPacket > packet, std::function< void(bool)> callback)=0
Notifies the delegate that the platform view has encountered a key event. This key event and the call...

◆ DispatchPlatformMessage()

void flutter::PlatformView::DispatchPlatformMessage ( std::unique_ptr< PlatformMessage message)

Used by embedders to dispatch a platform message to a running root isolate hosted by the engine. If an isolate is not running, the message is dropped. If there is no one on the other side listening on the channel, the message is dropped. When a platform message is dropped, any response handles associated with that message will be dropped as well. All users of platform messages must assume that message may not be delivered and/or their response handles may not be invoked. Platform messages are not buffered.

For embedders that wish to respond to platform message directed from the framework to the embedder, the HandlePlatformMessage method may be overridden.

See also
HandlePlatformMessage()
Parameters
[in]messageThe platform message to deliver to the root isolate.

Definition at line 31 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewDispatchPlatformMessage().

Referenced by flutter_runner::PlatformView::DidUpdateState(), flutter::PlatformViewAndroid::DispatchEmptyPlatformMessage(), flutter::PlatformViewAndroid::DispatchPlatformMessage(), flutter_runner::PlatformView::OnAction(), flutter_runner::FlatlandPlatformView::OnChildViewStatus(), and flutter_runner::PlatformView::OnKeyEvent().

32  {
34 }
virtual void OnPlatformViewDispatchPlatformMessage(std::unique_ptr< PlatformMessage > message)=0
Notifies the delegate that the platform has dispatched a platform message from the embedder to the Fl...
PlatformView::Delegate & delegate_

◆ DispatchPointerDataPacket()

void flutter::PlatformView::DispatchPointerDataPacket ( std::unique_ptr< PointerDataPacket packet)

Dispatches pointer events from the embedder to the framework. Each pointer data packet may contain multiple pointer input events. Each call to this method wakes up the UI thread.

Parameters
[in]packetThe pointer data packet to dispatch to the framework.

Definition at line 36 of file platform_view.cc.

References flutter::PointerDataPacketConverter::Convert(), delegate_, flutter::PlatformView::Delegate::OnPlatformViewDispatchPointerDataPacket(), and pointer_data_packet_converter_.

Referenced by flutter_runner::PlatformView::OnHandlePointerEvent().

37  {
39  pointer_data_packet_converter_.Convert(std::move(packet)));
40 }
std::unique_ptr< PointerDataPacket > Convert(std::unique_ptr< PointerDataPacket > packet)
Converts pointer data packet into a form that framework understands. The raw pointer data packet from...
PlatformView::Delegate & delegate_
PointerDataPacketConverter pointer_data_packet_converter_
virtual void OnPlatformViewDispatchPointerDataPacket(std::unique_ptr< PointerDataPacket > packet)=0
Notifies the delegate that the platform view has encountered a pointer event. This pointer event need...

◆ DispatchSemanticsAction()

void flutter::PlatformView::DispatchSemanticsAction ( int32_t  id,
SemanticsAction  action,
fml::MallocMapping  args 
)

Used by embedders to dispatch an accessibility action to a running isolate hosted by the engine.

Parameters
[in]idThe identifier of the accessibility node on which to perform the action.
[in]actionThe action
[in]argsThe arguments

Definition at line 48 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewDispatchSemanticsAction().

Referenced by flutter::AccessibilityBridge::DispatchSemanticsAction(), and flutter::PlatformViewAndroid::DispatchSemanticsAction().

50  {
52 }
PlatformView::Delegate & delegate_
SemanticsAction action
virtual void OnPlatformViewDispatchSemanticsAction(int32_t id, SemanticsAction action, fml::MallocMapping args)=0
Notifies the delegate that the platform view has encountered an accessibility related action on the s...

◆ GetDispatcherMaker()

PointerDataDispatcherMaker flutter::PlatformView::GetDispatcherMaker ( )
virtual

Returns a platform-specific PointerDataDispatcherMaker so the Engine can construct the PointerDataPacketDispatcher based on platforms.

Reimplemented in flutter::PlatformViewIOS.

Definition at line 101 of file platform_view.cc.

101  {
102  return [](DefaultPointerDataDispatcher::Delegate& delegate) {
103  return std::make_unique<DefaultPointerDataDispatcher>(delegate);
104  };
105 }

◆ GetPlatformMessageHandler()

std::shared_ptr< PlatformMessageHandler > flutter::PlatformView::GetPlatformMessageHandler ( ) const
virtual

Specifies a delegate that will receive PlatformMessages from Flutter to the host platform.

If this returns null that means PlatformMessages should be sent to the PlatformView. That is to protect legacy behavior, any embedder that wants to support executing Platform Channel handlers on background threads should be returing a thread-safe PlatformMessageHandler instead.

Reimplemented in flutter::PlatformViewAndroid.

Definition at line 188 of file platform_view.cc.

188  {
189  return nullptr;
190 }

◆ GetWeakPtr()

fml::WeakPtr< PlatformView > flutter::PlatformView::GetWeakPtr ( ) const

Returns a weak pointer to the platform view. Since the platform view may only be created, accessed and destroyed on the platform thread, any access to the platform view from a non-platform task runner needs a weak pointer to the platform view along with a reference to the platform task runner. A task must be posted to the platform task runner with the weak pointer captured in the same. The platform view method may only be called in the posted task once the weak pointer validity has been checked. This method is used by callers to obtain that weak pointer.

Returns
The weak pointer to the platform view.

Definition at line 107 of file platform_view.cc.

References weak_factory_.

Referenced by flutter::PlatformViewAndroid::UpdateAssetResolverByType().

107  {
108  return weak_factory_.GetWeakPtr();
109 }
fml::WeakPtrFactory< PlatformView > weak_factory_

◆ HandlePlatformMessage()

void flutter::PlatformView::HandlePlatformMessage ( std::unique_ptr< PlatformMessage message)
virtual

Overridden by embedders to perform actions in response to platform messages sent from the framework to the embedder. Default implementation of this method simply returns an empty response.

Embedders that wish to send platform messages to the framework may use the DispatchPlatformMessage method. This method is for messages that go the other way.

See also
DispatchPlatformMessage()
Parameters
[in]messageThe message

Reimplemented in flutter::PlatformViewEmbedder.

Definition at line 114 of file platform_view.cc.

Referenced by flutter_runner::PlatformView::HandlePlatformMessage().

115  {
116  if (auto response = message->response())
117  response->CompleteEmpty();
118 }

◆ LoadDartDeferredLibrary()

void flutter::PlatformView::LoadDartDeferredLibrary ( intptr_t  loading_unit_id,
std::unique_ptr< const fml::Mapping snapshot_data,
std::unique_ptr< const fml::Mapping snapshot_instructions 
)
virtual

Loads the Dart shared library into the Dart VM. When the Dart library is loaded successfully, the Dart future returned by the originating loadLibrary() call completes.

The Dart compiler may generate separate shared libraries files called 'loading units' when libraries are imported as deferred. Each of these shared libraries are identified by a unique loading unit id. Callers should open and resolve a SymbolMapping from the shared library. The Mappings should be moved into this method, as ownership will be assumed by the dart isolate after successful loading and released after shutdown of the dart isolate. If loading fails, the mappings will naturally go out of scope.

This method is paired with a RequestDartDeferredLibrary invocation that provides the embedder with the loading unit id of the deferred library to load.

Parameters
[in]loading_unit_idThe unique id of the deferred library's loading unit, as passed in by RequestDartDeferredLibrary.
[in]snapshot_dataDart snapshot data of the loading unit's shared library.
[in]snapshot_dataDart snapshot instructions of the loading unit's shared library.

Reimplemented in flutter::PlatformViewAndroid.

Definition at line 167 of file platform_view.cc.

170  {}

◆ LoadDartDeferredLibraryError()

void flutter::PlatformView::LoadDartDeferredLibraryError ( intptr_t  loading_unit_id,
const std::string  error_message,
bool  transient 
)
virtual

Indicates to the dart VM that the request to load a deferred library with the specified loading unit id has failed.

The dart future returned by the initiating loadLibrary() call will complete with an error.

Parameters
[in]loading_unit_idThe unique id of the deferred library's loading unit, as passed in by RequestDartDeferredLibrary.
[in]error_messageThe error message that will appear in the dart Future.
[in]transientA transient error is a failure due to temporary conditions such as no network. Transient errors allow the dart VM to re-request the same deferred library and and loading_unit_id again. Non-transient errors are permanent and attempts to re-request the library will instantly complete with an error.

Reimplemented in flutter::PlatformViewAndroid.

Definition at line 172 of file platform_view.cc.

174  {}

◆ MarkTextureFrameAvailable()

void flutter::PlatformView::MarkTextureFrameAvailable ( int64_t  texture_id)

Used by the embedder to notify the rasterizer that the context of the previously registered texture have been updated. Typically, Flutter will only render a frame if there is an updated layer tree. However, in cases where the layer tree is static but one of the externally composited textures has been updated by the embedder, the embedder needs to notify the rasterizer to render a new frame. In such cases, the existing layer tree may be reused with the frame re-composited with all updated external textures. Unlike the calls to register and unregister the texture, this call must be made each time a new texture frame is available.

See also
RegisterTexture, UnregisterTexture
Parameters
[in]texture_idThe identifier of the texture that has been updated.

Definition at line 130 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewMarkTextureFrameAvailable().

130  {
132 }
virtual void OnPlatformViewMarkTextureFrameAvailable(int64_t texture_id)=0
Notifies the delegate that the embedder has updated the contents of the texture with the specified id...
int64_t texture_id
PlatformView::Delegate & delegate_

◆ NotifyCreated()

void flutter::PlatformView::NotifyCreated ( )

Used by embedders to notify the shell that a platform view has been created. This notification is used to create a rendering surface and pick the client rendering API to use to render into this surface. No frames will be scheduled or rendered before this call. The surface must remain valid till the corresponding call to NotifyDestroyed.

Definition at line 66 of file platform_view.cc.

References delegate_, FML_LOG, flutter::TaskRunners::GetRasterTaskRunner(), flutter::PlatformView::Delegate::OnPlatformViewCreated(), platform_view, fml::TaskRunner::RunNowOrPostTask(), fml::ManualResetWaitableEvent::Signal(), task_runners_, and fml::ManualResetWaitableEvent::Wait().

Referenced by flutter::PlatformViewAndroid::NotifyCreated(), and flutter_runner::testing::TEST_F().

66  {
67  std::unique_ptr<Surface> surface;
68  // Threading: We want to use the platform view on the non-platform thread.
69  // Using the weak pointer is illegal. But, we are going to introduce a latch
70  // so that the platform view is not collected till the surface is obtained.
71  auto* platform_view = this;
74  task_runners_.GetRasterTaskRunner(), [platform_view, &surface, &latch]() {
75  surface = platform_view->CreateRenderingSurface();
76  if (surface && !surface->IsValid()) {
77  surface.reset();
78  }
79  latch.Signal();
80  });
81  latch.Wait();
82  if (!surface) {
83  FML_LOG(ERROR) << "Failed to create platform view rendering surface";
84  return;
85  }
86  delegate_.OnPlatformViewCreated(std::move(surface));
87 }
std::unique_ptr< flutter::PlatformViewIOS > platform_view
const TaskRunners task_runners_
static void RunNowOrPostTask(fml::RefPtr< fml::TaskRunner > runner, const fml::closure &task)
Definition: task_runner.cc:55
#define FML_LOG(severity)
Definition: logging.h:65
fml::RefPtr< fml::TaskRunner > GetRasterTaskRunner() const
Definition: task_runners.cc:42
PlatformView::Delegate & delegate_
virtual void OnPlatformViewCreated(std::unique_ptr< Surface > surface)=0
Notifies the delegate that the platform view was created with the given render surface. This surface is platform (iOS, Android) and client-rendering API (OpenGL, Software, Metal, Vulkan) specific. This is usually a sign to the rasterizer to set up and begin rendering to that surface.

◆ NotifyDestroyed()

void flutter::PlatformView::NotifyDestroyed ( )
virtual

Used by embedders to notify the shell that the platform view has been destroyed. This notification used to collect the rendering surface and all associated resources. Frame scheduling is also suspended.

Attention
Subclasses may choose to override this method to perform platform specific functions. However, they must call the base class method at some point in their implementation.

Reimplemented in flutter::PlatformViewAndroid.

Definition at line 89 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewDestroyed().

Referenced by flutter::PlatformViewAndroid::NotifyDestroyed(), and flutter::PlatformViewIOS::SetOwnerViewController().

89  {
91 }
PlatformView::Delegate & delegate_
virtual void OnPlatformViewDestroyed()=0
Notifies the delegate that the platform view was destroyed. This is usually a sign to the rasterizer ...

◆ OnPreEngineRestart()

void flutter::PlatformView::OnPreEngineRestart ( ) const
virtual

Gives embedders a chance to react to a "cold restart" of the running isolate. The default implementation of this method does nothing.

While a "hot restart" patches a running isolate, a "cold restart" restarts the root isolate in a running shell.

Definition at line 120 of file platform_view.cc.

120 {}

◆ RegisterTexture()

void flutter::PlatformView::RegisterTexture ( std::shared_ptr< flutter::Texture texture)

Used by the embedder to specify a texture that it wants the rasterizer to composite within the Flutter layer tree. All textures must have a unique identifier. When the rasterizer encounters an external texture within its hierarchy, it gives the embedder a chance to update that texture on the raster thread before it composites the same on-screen.

Attention
This method must only be called once per texture. When the texture is updated, calling MarkTextureFrameAvailable with the specified texture identifier is sufficient to make Flutter re-render the frame with the updated texture composited in-line.
See also
UnregisterTexture, MarkTextureFrameAvailable
Parameters
[in]textureThe texture that is being updated by the embedder but composited by Flutter in its own hierarchy.

Definition at line 122 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewRegisterTexture().

Referenced by flutter::PlatformViewIOS::RegisterExternalTexture(), and flutter::PlatformViewAndroid::RegisterExternalTexture().

122  {
124 }
G_BEGIN_DECLS FlTexture * texture
virtual void OnPlatformViewRegisterTexture(std::shared_ptr< Texture > texture)=0
Notifies the delegate that the embedder has specified a texture that it want the rasterizer to compos...
PlatformView::Delegate & delegate_

◆ ReleaseResourceContext()

void flutter::PlatformView::ReleaseResourceContext ( ) const
virtual

Used by the shell to notify the embedder that the resource context previously obtained via a call to CreateResourceContext() is being collected. The embedder is free to collect an platform specific resources associated with this context.

Attention
Unlike all other methods on the platform view, this will be called on IO task runner.

Definition at line 99 of file platform_view.cc.

99 {}

◆ RequestDartDeferredLibrary()

void flutter::PlatformView::RequestDartDeferredLibrary ( intptr_t  loading_unit_id)
virtual

Invoked when the dart VM requests that a deferred library be loaded. Notifies the engine that the deferred library identified by the specified loading unit id should be downloaded and loaded into the Dart VM via LoadDartDeferredLibrary

Upon encountering errors or otherwise failing to load a loading unit with the specified id, the failure should be directly reported to dart by calling LoadDartDeferredLibraryFailure to ensure the waiting dart future completes with an error.

Parameters
[in]loading_unit_idThe unique id of the deferred library's loading unit. This id is to be passed back into LoadDartDeferredLibrary in order to identify which deferred library to load.

Definition at line 165 of file platform_view.cc.

165 {}

◆ SetAccessibilityFeatures()

void flutter::PlatformView::SetAccessibilityFeatures ( int32_t  flags)
virtual

Used by the embedder to specify the features to enable in the accessibility tree generated by the isolate. This information is forwarded to the root isolate hosted by the engine on the UI thread.

The engine does not care about the accessibility feature flags as all it does is forward this information from the embedder to the framework. However, curious readers may refer to AccessibilityFeatures in window.dart for currently supported accessibility feature flags.

Attention
Subclasses may choose to override this method to perform platform specific functions. However, they must call the base class method at some point in their implementation.
Parameters
[in]flagsThe features to enable in the accessibility tree.

Definition at line 58 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewSetAccessibilityFeatures().

Referenced by flutter_runner::PlatformView::SetSemanticsEnabled(), and flutter::PlatformViewIOS::SetSemanticsEnabled().

58  {
60 }
PlatformView::Delegate & delegate_
virtual void OnPlatformViewSetAccessibilityFeatures(int32_t flags)=0
Notifies the delegate that the embedder has expressed an opinion about the features to enable in the ...
DEF_SWITCHES_START snapshot asset Path to the directory containing the four files specified by VmSnapshotInstructions and IsolateSnapshotInstructions vm snapshot The VM instructions snapshot that will be memory mapped as read and executable SnapshotAssetPath must be present isolate snapshot The isolate instructions snapshot that will be memory mapped as read and executable SnapshotAssetPath must be present icu symbol Prefix for the symbols representing ICU data linked into the Flutter library dart flags
Definition: switches.h:66

◆ SetNextFrameCallback()

void flutter::PlatformView::SetNextFrameCallback ( const fml::closure closure)

Sets a callback that gets executed when the rasterizer renders the next frame. Due to the asynchronous nature of rendering in Flutter, embedders usually add a placeholder over the contents in which Flutter is going to render when Flutter is first initialized. This callback may be used as a signal to remove that placeholder. The callback is executed on the render task runner and not the platform task runner. It is the embedder's responsibility to re-thread as necessary.

Attention
The callback is executed on the render task runner and not the platform task runner. Embedders must re-thread as necessary.
Parameters
[in]closureThe callback to execute on the render thread when the next frame gets rendered.

Definition at line 149 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewSetNextFrameCallback().

Referenced by FlutterViewController::pushRoute:, and flutter::PlatformViewAndroid::UpdateAssetResolverByType().

149  {
150  if (!closure) {
151  return;
152  }
153 
155 }
std::function< void()> closure
Definition: closure.h:14
PlatformView::Delegate & delegate_
virtual void OnPlatformViewSetNextFrameCallback(const fml::closure &closure)=0
Notifies the delegate that the specified callback needs to be invoked after the rasterizer is done re...

◆ SetSemanticsEnabled()

void flutter::PlatformView::SetSemanticsEnabled ( bool  enabled)
virtual

Used by embedder to notify the running isolate hosted by the engine on the UI thread that the accessibility tree needs to be generated.

Attention
Subclasses may choose to override this method to perform platform specific functions. However, they must call the base class method at some point in their implementation.
Parameters
[in]enabledWhether the accessibility tree needs to be generated.

Reimplemented in flutter::PlatformViewIOS, and flutter_runner::PlatformView.

Definition at line 54 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewSetSemanticsEnabled().

Referenced by flutter::PlatformViewIOS::PlatformViewIOS(), flutter_runner::PlatformView::SetSemanticsEnabled(), and flutter::PlatformViewIOS::SetSemanticsEnabled().

54  {
56 }
virtual void OnPlatformViewSetSemanticsEnabled(bool enabled)=0
Notifies the delegate that the embedder has expressed an opinion about whether the accessibility tree...
PlatformView::Delegate & delegate_

◆ SetViewportMetrics()

void flutter::PlatformView::SetViewportMetrics ( const ViewportMetrics metrics)

Used by embedders to specify the updated viewport metrics. In response to this call, on the raster thread, the rasterizer may need to be reconfigured to the updated viewport dimensions. On the UI thread, the framework may need to start generating a new frame for the updated viewport metrics as well.

Parameters
[in]metricsThe updated viewport metrics.

Definition at line 62 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewSetViewportMetrics().

Referenced by flutter_runner::FlatlandPlatformView::OnGetLayout().

62  {
64 }
PlatformView::Delegate & delegate_
virtual void OnPlatformViewSetViewportMetrics(const ViewportMetrics &metrics)=0
Notifies the delegate the viewport metrics of the platform view have been updated. The rasterizer will need to be reconfigured to render the frame in the updated viewport metrics.

◆ UnregisterTexture()

void flutter::PlatformView::UnregisterTexture ( int64_t  texture_id)

Used by the embedder to notify the rasterizer that it will no longer attempt to composite the specified texture within the layer tree. This allows the rasterizer to collect associated resources.

Attention
This call must only be called once per texture identifier.
See also
RegisterTexture, MarkTextureFrameAvailable
Parameters
[in]texture_idThe identifier of the texture to unregister. If the texture has not been previously registered, this call does nothing.

Definition at line 126 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::OnPlatformViewUnregisterTexture().

126  {
128 }
int64_t texture_id
PlatformView::Delegate & delegate_
virtual void OnPlatformViewUnregisterTexture(int64_t texture_id)=0
Notifies the delegate that the embedder will no longer attempt to composite the specified texture wit...

◆ UpdateAssetResolverByType()

void flutter::PlatformView::UpdateAssetResolverByType ( std::unique_ptr< AssetResolver updated_asset_resolver,
AssetResolver::AssetResolverType  type 
)
virtual

Replaces the asset resolver handled by the engine's AssetManager of the specified type with updated_asset_resolver. The matching AssetResolver is removed and replaced with updated_asset_resolvers.

AssetResolvers should be updated when the existing resolver becomes obsolete and a newer one becomes available that provides updated access to the same type of assets as the existing one. This update process is meant to be performed at runtime.

If a null resolver is provided, nothing will be done. If no matching resolver is found, the provided resolver will be added to the end of the AssetManager resolvers queue. The replacement only occurs with the first matching resolver. Any additional matching resolvers are untouched.

Parameters
[in]updated_asset_resolverThe asset resolver to replace the resolver of matching type with.
[in]typeThe type of AssetResolver to update. Only resolvers of the specified type will be replaced by the updated resolver.

Reimplemented in flutter::PlatformViewAndroid.

Definition at line 176 of file platform_view.cc.

References delegate_, and flutter::PlatformView::Delegate::UpdateAssetResolverByType().

178  {
179  delegate_.UpdateAssetResolverByType(std::move(updated_asset_resolver), type);
180 }
KeyCallType type
PlatformView::Delegate & delegate_
virtual void UpdateAssetResolverByType(std::unique_ptr< AssetResolver > updated_asset_resolver, AssetResolver::AssetResolverType type)=0
Replaces the asset resolver handled by the engine&#39;s AssetManager of the specified type with updated_a...

◆ UpdateSemantics()

void flutter::PlatformView::UpdateSemantics ( SemanticsNodeUpdates  updates,
CustomAccessibilityActionUpdates  actions 
)
virtual

Used by the framework to tell the embedder to apply the specified semantics node updates. The default implementation of this method does nothing.

See also
SemanticsNode, SemticsNodeUpdates, CustomAccessibilityActionUpdates
Parameters
[in]updatesA map with the stable semantics node identifier as key and the node properties as the value.
[in]actionsA map with the stable semantics node identifier as key and the custom node action as the value.

Reimplemented in flutter_runner::PlatformView, and flutter::PlatformViewEmbedder.

Definition at line 111 of file platform_view.cc.

112  {}

Member Data Documentation

◆ delegate_

◆ pointer_data_packet_converter_

PointerDataPacketConverter flutter::PlatformView::pointer_data_packet_converter_
protected

Definition at line 829 of file platform_view.h.

Referenced by DispatchPointerDataPacket().

◆ size_

SkISize flutter::PlatformView::size_
protected

Definition at line 830 of file platform_view.h.

◆ task_runners_

◆ weak_factory_

fml::WeakPtrFactory<PlatformView> flutter::PlatformView::weak_factory_
protected

Definition at line 831 of file platform_view.h.

Referenced by GetWeakPtr().


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