1/*
2 * Copyright (C) 2014 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
28#include "WheelEventDeltaTracker.h"
29
30#include "PlatformWheelEvent.h"
31
32namespace WebCore {
33
34WheelEventDeltaTracker::WheelEventDeltaTracker()
35    : m_isTrackingDeltas(false)
36{
37}
38
39WheelEventDeltaTracker::~WheelEventDeltaTracker()
40{
41}
42
43void WheelEventDeltaTracker::beginTrackingDeltas()
44{
45    m_recentWheelEventDeltas.clear();
46    m_isTrackingDeltas = true;
47}
48
49void WheelEventDeltaTracker::endTrackingDeltas()
50{
51    m_isTrackingDeltas = false;
52}
53
54void WheelEventDeltaTracker::recordWheelEventDelta(const PlatformWheelEvent& event)
55{
56    m_recentWheelEventDeltas.append(FloatSize(event.deltaX(), event.deltaY()));
57    if (m_recentWheelEventDeltas.size() > recentEventCount)
58        m_recentWheelEventDeltas.removeFirst();
59}
60
61static bool deltaIsPredominantlyVertical(const FloatSize& delta)
62{
63    return fabs(delta.height()) > fabs(delta.width());
64}
65
66DominantScrollGestureDirection WheelEventDeltaTracker::dominantScrollGestureDirection() const
67{
68    bool allVertical = m_recentWheelEventDeltas.size();
69    bool allHorizontal = m_recentWheelEventDeltas.size();
70
71    for (const auto& delta : m_recentWheelEventDeltas) {
72        bool isVertical = deltaIsPredominantlyVertical(delta);
73        allVertical &= isVertical;
74        allHorizontal &= !isVertical;
75    }
76
77    if (allVertical)
78        return DominantScrollGestureDirection::Vertical;
79
80    if (allHorizontal)
81        return DominantScrollGestureDirection::Horizontal;
82
83    return DominantScrollGestureDirection::None;
84}
85
86} // namespace WebCore
87