1/*
2 * Copyright (C) 2015 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
14 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
15 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
17 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
18 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
19 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
20 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
21 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
22 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
23 * THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "FloatSize.h"
29#include <wtf/Deque.h>
30
31namespace WebCore {
32
33class WheelEventDeltaFilter {
34public:
35 WheelEventDeltaFilter();
36 virtual ~WheelEventDeltaFilter();
37
38 WEBCORE_EXPORT static std::unique_ptr<WheelEventDeltaFilter> create();
39 WEBCORE_EXPORT virtual void updateFromDelta(const FloatSize&) = 0;
40 WEBCORE_EXPORT virtual void beginFilteringDeltas() = 0;
41 WEBCORE_EXPORT virtual void endFilteringDeltas() = 0;
42 WEBCORE_EXPORT FloatSize filteredVelocity() const;
43 WEBCORE_EXPORT bool isFilteringDeltas() const;
44 WEBCORE_EXPORT FloatSize filteredDelta() const;
45
46protected:
47 FloatSize m_currentFilteredDelta;
48 FloatSize m_currentFilteredVelocity;
49 bool m_isFilteringDeltas { false };
50};
51
52enum class DominantScrollGestureDirection {
53 None,
54 Vertical,
55 Horizontal
56};
57
58class BasicWheelEventDeltaFilter final : public WheelEventDeltaFilter {
59 WTF_MAKE_FAST_ALLOCATED;
60public:
61 BasicWheelEventDeltaFilter();
62 void updateFromDelta(const FloatSize&) override;
63 void beginFilteringDeltas() override;
64 void endFilteringDeltas() override;
65
66private:
67 DominantScrollGestureDirection dominantScrollGestureDirection() const;
68
69 Deque<FloatSize> m_recentWheelEventDeltas;
70};
71
72} // namespace WebCore
73