chromium/components/input/touchpad_pinch_event_queue.h

// Copyright 2018 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef COMPONENTS_INPUT_TOUCHPAD_PINCH_EVENT_QUEUE_H_
#define COMPONENTS_INPUT_TOUCHPAD_PINCH_EVENT_QUEUE_H_

#include <memory>
#include <optional>

#include "base/containers/circular_deque.h"
#include "base/memory/raw_ptr.h"
#include "components/input/event_with_latency_info.h"
#include "base/component_export.h"
#include "third_party/blink/public/common/input/web_input_event.h"
#include "third_party/blink/public/mojom/input/input_event_result.mojom-shared.h"

namespace input {

class QueuedTouchpadPinchEvent;

// Interface with which TouchpadPinchEventQueue can forward synthetic mouse
// wheel events and notify of pinch events.
class COMPONENT_EXPORT(INPUT) TouchpadPinchEventQueueClient { … };

// A queue for sending synthetic mouse wheel events for touchpad pinches.
// In order for a page to prevent touchpad pinch zooming, we send synthetic
// wheel events which may be cancelled. Once we've determined whether a page
// has prevented the pinch, the TouchpadPinchEventQueueClient may proceed with
// handling the pinch.
// See README.md for further details.
class COMPONENT_EXPORT(INPUT) TouchpadPinchEventQueue { … };

}  // namespace input

#endif  // COMPONENTS_INPUT_TOUCHPAD_PINCH_EVENT_QUEUE_H_