Flutter Engine
flutter::PointerDataDispatcher Class Referenceabstract

#include <pointer_data_dispatcher.h>

Inheritance diagram for flutter::PointerDataDispatcher:
flutter::DefaultPointerDataDispatcher flutter::SmoothPointerDataDispatcher


class  Delegate
 The interface for Engine to implement. More...

Public Member Functions

virtual void DispatchPacket (std::unique_ptr< PointerDataPacket > packet, uint64_t trace_flow_id)=0
 Signal that PlatformView has a packet to be dispatched. More...
virtual ~PointerDataDispatcher ()
 Default destructor. More...

Detailed Description

The Engine pointer data dispatcher that forwards the packet received from PlatformView::DispatchPointerDataPacket on the platform thread, to Window::DispatchPointerDataPacket on the UI thread.

This class is used to filter the packets so the Flutter framework on the UI thread will receive packets with some desired properties. See SmoothPointerDataDispatcher for an example which filters irregularly delivered packets, and dispatches them in sync with the VSYNC signal.

This object will be owned by the engine because it relies on the engine's Animator (which owns VsyncWaiter) and RuntimeController to do the filtering. This object is currently designed to be only called from the UI thread (no thread safety is guaranteed).

The PlatformView decides which subclass of PointerDataDispatcher is constructed by sending a PointerDataDispatcherMaker to the engine's constructor in Shell::CreateShellOnPlatformThread. This is needed because: (1) Different platforms (e.g., Android, iOS) have different dispatchers so the decision has to be made per PlatformView. (2) The PlatformView can only be accessed from the PlatformThread while this class (as owned by engine) can only be accessed in the UI thread. Hence PlatformView creates a PointerDataDispatchMaker on the platform thread, and sends it to the UI thread for the final construction of the PointerDataDispatcher.

Definition at line 40 of file pointer_data_dispatcher.h.

Constructor & Destructor Documentation

◆ ~PointerDataDispatcher()

flutter::PointerDataDispatcher::~PointerDataDispatcher ( )

Default destructor.

Member Function Documentation

◆ DispatchPacket()

virtual void flutter::PointerDataDispatcher::DispatchPacket ( std::unique_ptr< PointerDataPacket packet,
uint64_t  trace_flow_id 
pure virtual

Signal that PlatformView has a packet to be dispatched.

[in]packetThe PointerDataPacket to be dispatched.
[in]trace_flow_idThe id for Animator::EnqueueTraceFlowId.

Implemented in flutter::SmoothPointerDataDispatcher, and flutter::DefaultPointerDataDispatcher.

Referenced by flutter::DefaultPointerDataDispatcher::DefaultPointerDataDispatcher().

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