Source/WebCore/platform/KeyboardScrollingAnimator.h

/*
 * Copyright (C) 2021 Apple Inc. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
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 */

#pragma once

#include "KeyboardScroll.h" // FIXME: This is a layering violation.
#include "RectEdges.h"
#include "ScrollAnimator.h"

namespace WebCore {

class PlatformKeyboardEvent;

class KeyboardScrollingAnimator {
    WTF_MAKE_NONCOPYABLE(KeyboardScrollingAnimator);
    WTF_MAKE_FAST_ALLOCATED;
public:
    KeyboardScrollingAnimator(ScrollAnimator&, ScrollingEffectsController&);

    bool beginKeyboardScrollGesture(const PlatformKeyboardEvent&);
    void handleKeyUpEvent();
    void updateKeyboardScrollPosition(MonotonicTime);

private:
    void stopKeyboardScrollAnimation();
    RectEdges<bool> scrollableDirectionsFromPosition(FloatPoint) const;
    std::optional<KeyboardScroll> keyboardScrollForKeyboardEvent(const PlatformKeyboardEvent&) const;
    float scrollDistance(ScrollDirection, ScrollGranularity) const;

    ScrollAnimator& m_scrollAnimator;
    ScrollingEffectsController& m_scrollController;
    std::optional<WebCore::KeyboardScroll> m_currentKeyboardScroll;
    bool m_scrollTriggeringKeyIsPressed { false };
    FloatSize m_velocity;
    MonotonicTime m_timeAtLastFrame;
    FloatPoint m_idealPositionForMinimumTravel;
    FloatPoint m_idealPosition;
};

} // namespace WebCore