OLD | NEW |
(Empty) | |
| 1 // Copyright 2015 The Chromium Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style license that can be |
| 3 // found in the LICENSE file. |
| 4 |
| 5 #ifndef CONTENT_BROWSER_RENDERER_HOST_INPUT_WHEEL_EVENT_QUEUE_H_ |
| 6 #define CONTENT_BROWSER_RENDERER_HOST_INPUT_WHEEL_EVENT_QUEUE_H_ |
| 7 |
| 8 #include <deque> |
| 9 |
| 10 #include "base/basictypes.h" |
| 11 #include "base/timer/timer.h" |
| 12 #include "content/browser/renderer_host/event_with_latency_info.h" |
| 13 #include "content/common/content_export.h" |
| 14 #include "content/common/input/input_event_ack_state.h" |
| 15 #include "third_party/WebKit/public/web/WebInputEvent.h" |
| 16 |
| 17 namespace content { |
| 18 |
| 19 // Interface with which the WheelEventQueue can forward wheel events, and |
| 20 // dispatch wheel event responses. |
| 21 class CONTENT_EXPORT WheelEventQueueClient { |
| 22 public: |
| 23 virtual ~WheelEventQueueClient() {} |
| 24 |
| 25 virtual void SendWheelEventImmediately( |
| 26 const MouseWheelEventWithLatencyInfo& event) = 0; |
| 27 |
| 28 virtual void OnWheelEventAck(const MouseWheelEventWithLatencyInfo& event, |
| 29 InputEventAckState ack_result) = 0; |
| 30 |
| 31 virtual void SetNeedsFlush() = 0; |
| 32 }; |
| 33 |
| 34 class CONTENT_EXPORT WheelEventQueue { |
| 35 public: |
| 36 // |client| must outlive the WheelEventQueue. |
| 37 WheelEventQueue(WheelEventQueueClient* client, bool buffer_until_flush); |
| 38 ~WheelEventQueue(); |
| 39 |
| 40 // Adds a wheel event to the queue, forwarding if appropriate. |
| 41 void QueueEvent(const MouseWheelEventWithLatencyInfo& wheel_event); |
| 42 |
| 43 // Indicates that the caller has received an acknowledgement from the renderer |
| 44 // with state |ack_result| and event |type|. May send wheel events if the |
| 45 // queue is not empty. |
| 46 void ProcessWheelAck(InputEventAckState ack_result, |
| 47 const ui::LatencyInfo& latency); |
| 48 |
| 49 // Called in response to a flush request made through the client. |
| 50 void Flush(); |
| 51 |
| 52 bool empty() const { |
| 53 return !mouse_wheel_pending_ && coalesced_wheel_events_.empty(); |
| 54 } |
| 55 |
| 56 private: |
| 57 void SendEvent(const MouseWheelEventWithLatencyInfo& wheel_event); |
| 58 |
| 59 WheelEventQueueClient* const client_; |
| 60 |
| 61 // Whether to buffer wheel events until a call to |FlushInput()|. |
| 62 const bool buffer_until_flush_; |
| 63 |
| 64 // True if a wheel event was sent and we are waiting for a corresponding ack. |
| 65 bool mouse_wheel_pending_; |
| 66 MouseWheelEventWithLatencyInfo current_wheel_event_; |
| 67 |
| 68 // Whether we're inside a call to |Flush()|. |
| 69 bool flushing_; |
| 70 |
| 71 // The next mouse wheel events to send. Mouse wheel events received while one |
| 72 // is pending are coalesced (by accumulating deltas) if they match the |
| 73 // previous event in modifiers. On the Mac, in particular, mouse wheel events |
| 74 // are received at a high rate; not waiting for the ack results in jankiness, |
| 75 // and using the same mechanism as for mouse moves (just dropping old events |
| 76 // when multiple ones/ would be queued) results in very slow scrolling. |
| 77 std::deque<MouseWheelEventWithLatencyInfo> coalesced_wheel_events_; |
| 78 |
| 79 DISALLOW_COPY_AND_ASSIGN(WheelEventQueue); |
| 80 }; |
| 81 |
| 82 } // namespace content |
| 83 |
| 84 #endif // CONTENT_BROWSER_RENDERER_HOST_INPUT_WHEEL_EVENT_QUEUE_H_ |
OLD | NEW |