Source/WebCore/rendering/ScrollAlignment.h

/*
 * Copyright (C) 2003, 2009, 2016 Apple Inc.  All rights reserved.
 *
 * Portions are Copyright (C) 1998 Netscape Communications Corporation.
 *
 * Other contributors:
 *   Robert O'Callahan <roc+@cs.cmu.edu>
 *   David Baron <dbaron@fas.harvard.edu>
 *   Christian Biesinger <cbiesinger@web.de>
 *   Randall Jesup <rjesup@wgate.com>
 *   Roland Mainz <roland.mainz@informatik.med.uni-giessen.de>
 *   Josh Soref <timeless@mac.com>
 *   Boris Zbarsky <bzbarsky@mit.edu>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Alternatively, the contents of this file may be used under the terms
 * of either the Mozilla Public License Version 1.1, found at
 * http://www.mozilla.org/MPL/ (the "MPL") or the GNU General Public
 * License Version 2.0, found at http://www.fsf.org/copyleft/gpl.html
 * (the "GPL"), in which case the provisions of the MPL or the GPL are
 * applicable instead of those above.  If you wish to allow use of your
 * version of this file only under the terms of one of those two
 * licenses (the MPL or the GPL) and not to allow others to use your
 * version of this file under the LGPL, indicate your decision by
 * deletingthe provisions above and replace them with the notice and
 * other provisions required by the MPL or the GPL, as the case may be.
 * If you do not delete the provisions above, a recipient may use your
 * version of this file under any of the LGPL, the MPL or the GPL.
 */

#pragma once

namespace WTF {
class TextStream;
}

namespace WebCore {

struct ScrollAlignment {

    enum class Behavior {
        NoScroll,
        AlignCenter,
        AlignTop,
        AlignBottom,
        AlignLeft,
        AlignRight,
        AlignToClosestEdge
    };

    Behavior getVisibleBehavior() const { return m_rectVisible; }
    Behavior getPartialBehavior() const { return m_rectPartial; }
    Behavior getHiddenBehavior() const { return m_rectHidden; }
    void disableLegacyHorizontalVisibilityThreshold() { m_enableLegacyHorizontalVisibilityThreshold = false; }
    bool legacyHorizontalVisibilityThresholdEnabled() const { return m_enableLegacyHorizontalVisibilityThreshold; }

    static const ScrollAlignment alignCenterIfNotVisible;
    static const ScrollAlignment alignToEdgeIfNotVisible;
    WEBCORE_EXPORT static const ScrollAlignment alignCenterIfNeeded;
    WEBCORE_EXPORT static const ScrollAlignment alignToEdgeIfNeeded;
    WEBCORE_EXPORT static const ScrollAlignment alignCenterAlways;
    static const ScrollAlignment alignTopAlways;
    static const ScrollAlignment alignRightAlways;
    static const ScrollAlignment alignLeftAlways;
    static const ScrollAlignment alignBottomAlways;

    Behavior m_rectVisible;
    Behavior m_rectHidden;
    Behavior m_rectPartial;
    bool m_enableLegacyHorizontalVisibilityThreshold { true };
};
    
WEBCORE_EXPORT WTF::TextStream& operator<<(WTF::TextStream&, ScrollAlignment::Behavior);
WEBCORE_EXPORT WTF::TextStream& operator<<(WTF::TextStream&, const ScrollAlignment&);

}; // namespace WebCore