1/*
2 * Copyright (C) 2015-2016 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#include "config.h"
27#include "WheelEventDeltaFilter.h"
28
29#include "FloatSize.h"
30#include "Logging.h"
31#include <wtf/text/TextStream.h>
32
33#if PLATFORM(MAC)
34#include "WheelEventDeltaFilterMac.h"
35#endif
36
37namespace WebCore {
38
39WheelEventDeltaFilter::WheelEventDeltaFilter() = default;
40
41WheelEventDeltaFilter::~WheelEventDeltaFilter() = default;
42
43std::unique_ptr<WheelEventDeltaFilter> WheelEventDeltaFilter::create()
44{
45#if PLATFORM(MAC)
46 return std::make_unique<WheelEventDeltaFilterMac>();
47#else
48 return std::make_unique<BasicWheelEventDeltaFilter>();
49#endif
50}
51
52bool WheelEventDeltaFilter::isFilteringDeltas() const
53{
54 return m_isFilteringDeltas;
55}
56
57FloatSize WheelEventDeltaFilter::filteredDelta() const
58{
59 return m_currentFilteredDelta;
60}
61
62FloatSize WheelEventDeltaFilter::filteredVelocity() const
63{
64 return m_currentFilteredVelocity;
65}
66
67BasicWheelEventDeltaFilter::BasicWheelEventDeltaFilter()
68 : WheelEventDeltaFilter()
69{
70}
71
72const size_t basicWheelEventDeltaFilterWindowSize = 3;
73
74void BasicWheelEventDeltaFilter::updateFromDelta(const FloatSize& delta)
75{
76 m_currentFilteredDelta = delta;
77 if (!m_isFilteringDeltas)
78 return;
79
80 m_recentWheelEventDeltas.append(delta);
81 if (m_recentWheelEventDeltas.size() > basicWheelEventDeltaFilterWindowSize)
82 m_recentWheelEventDeltas.removeFirst();
83
84 DominantScrollGestureDirection scrollDirection = dominantScrollGestureDirection();
85 if (scrollDirection == DominantScrollGestureDirection::Vertical)
86 m_currentFilteredDelta.setWidth(0);
87 else if (scrollDirection == DominantScrollGestureDirection::Horizontal)
88 m_currentFilteredDelta.setHeight(0);
89}
90
91void BasicWheelEventDeltaFilter::beginFilteringDeltas()
92{
93 m_recentWheelEventDeltas.clear();
94 m_isFilteringDeltas = true;
95}
96
97void BasicWheelEventDeltaFilter::endFilteringDeltas()
98{
99 m_currentFilteredDelta = FloatSize(0, 0);
100 m_isFilteringDeltas = false;
101}
102
103static inline bool deltaIsPredominantlyVertical(const FloatSize& delta)
104{
105 return fabs(delta.height()) > fabs(delta.width());
106}
107
108DominantScrollGestureDirection BasicWheelEventDeltaFilter::dominantScrollGestureDirection() const
109{
110 bool allVertical = m_recentWheelEventDeltas.size();
111 bool allHorizontal = m_recentWheelEventDeltas.size();
112
113 for (const auto& delta : m_recentWheelEventDeltas) {
114 bool isVertical = deltaIsPredominantlyVertical(delta);
115 allVertical &= isVertical;
116 allHorizontal &= !isVertical;
117 }
118
119 if (allVertical)
120 return DominantScrollGestureDirection::Vertical;
121
122 if (allHorizontal)
123 return DominantScrollGestureDirection::Horizontal;
124
125 return DominantScrollGestureDirection::None;
126}
127
128};
129